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Multiplanetary Species Should Have Logical Measurements For Time And Distance

T Ivers

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T Ivers

T Ivers

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On another forum that is not science based I began a conversation regarding the fact that soon humans would be multiplanetary and most of the measurements that are in current use are based on silly and illogical Earth derived units.  I think we need to replace the time and distance measurements.

I have a degree in a non science area, so after starting the conversation, I took it to OpenAI's ChatGPT o1 Pro to see what it thought.  I did some basic research and displayed my findings on another forum and received some pushback.  I'm hoping to find some open minds here, and while I accept that the results from ChatGPT may not be well thought out or correct, that I leave to you to decide, debate amongst yourselves, and come up with logical systems for time and distance.

The entire conversation has been pasted below first creating a solution for time and then distance:

 

Humans are about to become a multiplanetary species and they need a proper measurement system as they travel throughout the galaxy and conduct research. There are problems with most measurement systems because they are based on non scientific reasoning and logic.
ChatGPT said:

Are you looking for research on existing universal measurement systems (such as SI units) and their limitations for space travel, or are you interested in proposals for a new scientifically sound measurement system that could work across different planets? Also, should this system account for relativistic effects and varying gravitational fields?

You said:
I think that we need a new new scientifically sound measurement system. Some measurements in current use need to be modified.
ChatGPT said:

That makes sense! I'll research and propose a new scientifically sound measurement system for a multiplanetary human civilization. This system will address the limitations of current measurement units, ensuring consistency across different planetary environments and space travel. I'll explore modifications to existing units where necessary and suggest new ones based on scientific reasoning. I'll let you know when the findings are ready!

Research completed in 6m · 17 sources
You said:
Does the "hour" even work? The hour was based on constellations in the Earth's sky, which is illogical. We may need a completely new way of telling time.
ChatGPT said:

Great point! The traditional 'hour' is indeed based on Earth's rotational cycle and historical astronomical observations, which may not be relevant for interplanetary travel.

Would you like research specifically on:

  • A new universal timekeeping system based on fundamental physical constants?
  • Adjustments to the existing second-minute-hour structure to be more useful in space?
  • How relativistic effects and varying planetary day lengths should be accounted for?

Let me know your preference, and I'll tailor the research accordingly!

You said:
A new universal timekeeping system based on fundamental physical constants
ChatGPT said:

Great! I will research and propose a new universal timekeeping system based on fundamental physical constants. This system will not rely on Earth's rotation or arbitrary historical conventions but will be designed for use in space and across multiple planets. It will consider:

  • A new base unit of time derived from fundamental constants, such as atomic transitions or the speed of light.
  • A logical, scalable system for measuring time intervals, replacing hours, minutes, and seconds if necessary.
  • Adjustments for relativistic time dilation in space travel.
  • Practical applications for space missions, interplanetary communication, and scientific research.

I'll let you know when the proposal is ready!

Research completed in 5m · 12 sources

A Universal Measurement System for a Multiplanetary Civilization

Humanity’s expansion to multiple planets and space habitats demands a measurement system that remains consistent and accurate anywhere – from Earth’s surface to Mars, deep space, or beyond. Current units largely originated from Earth-specific phenomena (days, kilograms of water, human anatomy, etc.), which can lead to confusion or inconsistency off-world. Here we propose a scientifically sound, universal measurement system designed for a multiplanetary civilization. This system builds on the strengths of the International System of Units (SI) — especially its recent fundamental redefinitions — while introducing adjustments for new challenges like different gravity, relativistic travel, and unique space needs. We present the base units, modifications for planetary and relativistic contexts, and new specialized units, with explanations and comparisons to existing systems.

Limitations of Earth-Centric Units

Earth-bound origins: Many traditional units are tied to Earth or human reference points: e.g. the day was based on Earth’s rotation, the meter was originally one ten-millionth of a quadrant of Earth’s meridian, and the kilogram was defined by a physical lump of metal on Earth. While these worked locally, they become arbitrary or impractical on other planets. For instance, a “day” on Mars (one sol) is about 24 hours 39 minutes Earth time

, and a Martian year is nearly twice an Earth year, so using Earth days/years off-world is confusing. A unit defined by Earth’s gravity (like the kilogram-force) has no universal meaning on Mars or the Moon.

Confusion and errors: Mixing measurement systems or using Earth-centric units in space missions has already caused serious errors. A famous example is NASA’s Mars Climate Orbiter loss in 1999 – a $327 million probe was destroyed due to a unit mix-up (imperial vs metric) in thruster calculations

. One software module output thrust in pound-force seconds while another expected newton-seconds, off by a factor of 4.45 . This tragedy underscores the need for a single, consistent system for interplanetary engineering and communication.

Local gravity effects: On different planets, the same mass has different weight (force). A 10 kg object weighs ~98 N on Earth but only ~37 N on Mars (Mars gravity ~38% of Earth’s). If we casually say “10 kg” as a weight, do we mean on Earth or elsewhere? In microgravity, traditional “weighing” fails entirely. Astronauts in orbit are weightless, yet they still have mass – on the ISS they must use special spring devices to measure mass via inertia, since a scale would read zero

. Clearly, a better way to handle mass vs weight is needed for consistency.

Timekeeping differences: Time units based on Earth’s day or year don’t translate elsewhere. Each planet has its own rotation period (day length) and orbital period (year length). Using Earth time for all human colonies is impractical for local daily life (e.g. Mars settlers using 24h Earth days would be out of sync with sunrise). Even the second, our base time unit, was historically 1/86,400 of an Earth day. Moreover, relativistic effects in space (time dilation in high-speed travel or different gravity potentials) mean clocks won’t stay perfectly synchronized between planets and spacecraft over long durations. A universal system must decide how to keep “one time” or at least relate different times.

Communication and usability: Any new system must be easy to adopt and unambiguous. It should use decimal prefixes and standard notation for clarity (as SI does) and avoid regional variations. (For example, in SI one billion is always 10^9, avoiding the ambiguity where some countries historically used 10^12 for a “billion”

.) It should minimize conversions and be intuitive for engineers and scientists who already mostly use the metric system .

In summary, the current SI is almost universal due to recent fundamental redefinitions, but we must refine it for a multiplanetary context – removing any lingering Earth-dependence, addressing gravity and relativity issues, and adding units for new space-related quantities.

Guiding Principles for a Multiplanetary Measurement System

Any proposed measurement system for a spacefaring civilization should follow these core principles:

  • Fundamental Constant Basis: Define units using immutable laws of physics, not local references. Base units should be tied to fundamental constants (speed of light, atomic frequencies, etc.) so they are identical anywhere in the universe

    . This ensures length, time, mass, etc., don’t change from planet to planet or over time. (Modern SI already does this for most units, as discussed below.)

  • Universality and Reproducibility: Every unit definition should be realizable in any advanced laboratory, whether on Earth, Mars, or a spacecraft, using standard experiments. No need for comparisons to Earth-based artifacts or environments. For example, one should be able to reproduce the time unit with an atomic clock, or the mass unit with a Kibble balance, on Mars just as on Earth.

  • Planet-Independent Coherence: Avoid units that bake in Earth-specific values (like Earth’s rotation, Earth’s gravity, or Earth’s orbital period). Where local environmental factors matter (gravity, atmospheric pressure, etc.), the system should clarify the context or provide conversion factors, rather than changing the unit. This prevents divergence of “Martian meters” vs “Earth meters,” etc. – a meter or second is the same everywhere

    .

  • Consistency Across Gravity Fields: Distinguish between invariant quantities (mass, intrinsic time) and environment-dependent ones (weight, local time-of-day). The system should encourage measuring fundamental quantities (e.g. mass in kilograms) rather than location-dependent effects (weight in “kg-force”), or explicitly define standard gravity references if needed. This principle ensures measurement consistency, so a mass or length measured on the Moon or in space is directly comparable to one measured on Earth.

  • Relativistic Stability: Establish a common time standard (and reference frame) for the civilization to coordinate events, accounting for relativity. While each location can have its local “proper time” and calendar for civil use, there should be an agreed synchronization framework for comparing time intervals and scheduling between planets. For example, use a coordinate time tied to the solar system barycenter or another stable frame to serve as “universal time” that doesn’t drift due to gravitational time dilation

    .

  • Clarity & Simplicity: Use a single unified system for all scientific and engineering purposes to avoid conversion errors. Favor the metric SI-style approach of one unit per quantity (with prefixes for scale) over multiple competing units. This makes communication unambiguous (no confusion between miles vs kilometers, pounds-force vs newtons, etc.). It also eases education and collaboration across planets. As noted, metric/SI is already the de facto language of science globally

    , so building on it leverages familiar infrastructure.

  • Scalable and Human-Centric: While based on physics, units should be reasonably scaled to human-relevant sizes to remain practical. Pure “natural units” like Planck units are elegant (fully based on c, G, ħ, etc.) but lead to inconveniently tiny or huge numbers for everyday use

    . The new system should strike a balance: rooted in nature’s constants yet scaled for usability (much as the SI second and meter give human-friendly lengths and times). We can achieve this by choosing appropriate fractions or multiples of fundamental units.

  • New Measures for New Needs: Introduce derived units or new quantities that are especially useful in space travel and multiplanetary life. This includes standardized ways to quantify rocket propulsion efficiency, radiation doses in space, and perhaps large distances or speeds, so that engineers and health scientists across planets use the same language. These new units should integrate consistently with the rest of the system (e.g. be defined in terms of base units).

With these principles in mind, we can outline the proposed Base Units and the key improvements over the current SI and other systems.

Universal Base Units and Definitions

Our system adopts four primary base units – for length, time, mass, and temperature – all defined by fundamental constants. (We assume other SI base units like electric current, amount of substance, and luminous intensity would also be included for completeness, but the focus here is on the ones listed.) Notably, SI itself has recently defined all base units in terms of physical constants as of 2019, which is a huge step toward universality

. We will use those definitions as a foundation, with minor modifications for clarity or coherence in a multiplanetary context.

Length – “Unit of Length” (UL)

Definition: We define our length unit equivalently to the SI meter: the distance light travels in vacuum in 1/299,792,458 of a second

. This ties the unit to the constant speed of light c. In practice, this unit of length is effectively the meter (we may keep the name “meter” due to familiarity), since the SI meter already meets our criteria of fundamental constant basis and Earth-independence. It is realized by precision laser interferometry or timing light signals.

Rationale: The speed of light c is universally constant in vacuum, providing a perfect yardstick. By linking length to c and the second, anyone anywhere can reproduce the unit with an accurate clock and laser. This definition is location-independent (ignoring minor relativistic effects): a meter doesn’t change whether on Earth, Mars, or in interstellar space

. It also fits human scale well – about the length of a stride – which is convenient for everyday engineering.

Notes: We considered more exotic fundamental lengths (like the Planck length), but those are astronomically small (1.6×10^–35 m

), impractical for human use. The meter is already an excellent compromise: fundamental in definition yet of manageable size. In a multiplanetary system, we might continue to use SI prefixes with the meter for small or large scales (millimeters for machine parts, kilometers for geography, megameters or gigameters for planetary distances). For extremely large distances (interplanetary or interstellar), we can introduce auxiliary units like the light-second (~3×10^8 m) or light-year (~9.46×10^15 m) for convenience, defined in terms of this base length and time. For example, 1 light-second is exactly 299,792,458 m by definition, providing a handy measure for communication lag or spacecraft distances. These are not new base units, just useful derived units that remain consistent (and are in fact already used in astronomy).

Time – “Unit of Time” (UT)

Definition: We retain the SI second as the base unit of time: defined by the intrinsic frequency of the cesium-133 atom. Specifically, one second is the duration of 9,192,631,770 cycles of the radiation corresponding to the transition between two hyperfine levels of Cs-133 in its ground state at 0 K

. This atomic definition makes the second the same everywhere, based on quantum properties of matter.

Rationale: The second’s definition is anchored to a fundamental property of nature (atomic energy levels), not any planetary motion, so it’s universally reproducible. Any advanced lab on another planet can, in principle, build an atomic clock and realize the second to high precision. The second is short enough for precise timing yet, when scaled up, relates well to human time scales (minutes, hours). We considered whether a different base unit (like a “universal day” or a fraction of some pulsar period) would be better, but the current definition is both extremely precise and non-Earth-based. Thus, it serves our multiplanetary needs.

Time Scales: While the unit (second) is universal, keeping clocks synchronized across different gravity fields and velocities is non-trivial. In our system, we propose a Universal Coordinate Time (UCT) for the solar system or beyond – essentially a timeline that ignores local relativistic deviations. One approach is similar to what astronomers call Barycentric Coordinate Time (TCB), the time a clock would keep at the solar system’s center-of-mass, removed from major gravity wells

. This universal time would tick at a uniform rate (SI seconds) unaffected by planetary gravity. All local clocks (on Earth, Mars, spacecraft) can be related to UCT via known relativistic offsets and synchronization signals. For practical use, an agency could maintain time servers broadcasting UCT, and each colony can apply a correction for their locale (much as GPS systems correct for time dilation in satellite clocks). This ensures that a “second” is the same duration everywhere, even if a second on a fast-moving ship might accumulate phase difference relative to one on Earth over long periods. When high precision isn’t needed, we can use simplified standards like TAI (International Atomic Time) or even UTC (which is TAI adjusted with leap seconds for Earth’s rotation ) for day-to-day operations, with the understanding that these are all fundamentally based on the same second.

Local Day/Year Units: For civil timekeeping on each planet, people will still use local days, hours, or years for convenience (a Mars sol, a Jupiter day, etc.). Our system treats those not as fundamental units, but as derived cultural units (like we treat “weeks” or “months” today). Schedules and calendars would be local, but whenever precise interplanetary communication is needed, events would be referenced in standard seconds (or a common epoch timestamp) to avoid ambiguity. For example, a mission log might record an event as “Mission Elapsed Time = 1.23×10^7 s” rather than “142 days” (since “day” could be misinterpreted). Overall, the second remains the backbone, with perhaps the introduction of kiloseconds (10^3 s ~ 16.7 minutes) and megageconds (10^6 s ~ 11.6 days) as convenient larger time intervals instead of mixed hour/day units.

Mass – “Unit of Mass” (UM)

Definition: We define the mass unit equivalent to the SI kilogram, but we clarify it as a base unit (the name “kilogram” historically is awkward since “kilo” is a prefix). It is defined via Planck’s constant h in combination with the meter and second. In essence, Planck’s constant is fixed at 6.62607015×10^−34 J·s exactly, and with the definitions of the second and meter, this defines the kilogram

. A more intuitive way to state it: 1 UM (1 kg) is the mass that makes $h = 6.62607015×10^{-34}$ J·s. This ties mass to fundamental quantum physics.

Rationale: Until recently, a kilogram was literally the mass of a platinum-iridium cylinder stored in France – clearly not suitable off Earth. Now, with the 2019 redefinition, the kilogram is free of that artifact and is based on constants

. This means any lab with a Kibble balance (an electromechanical scale measuring against electrical quantum standards) can realize the mass unit by linking mechanical power to electrical power units tied to Planck’s constant . By adopting this, our multiplanetary system ensures everyone uses the same mass scale. We might rename the unit to something like “mass-unit (mu)” to avoid the prefix issue, but that’s cosmetic – the value remains that of the kilogram.

Mass vs Weight: It’s crucial in a planetary context to reinforce the distinction: our mass unit is invariant, whereas weight (a force) will vary by gravity. A 1 kg mass always equals 1 UM of matter regardless of location, even though its weight is ~9.81 N on Earth, ~3.7 N on Mars, 0 N in deep space, etc. To avoid confusion, the system prohibits using the mass unit to measure force. In everyday Earth life, people say “I weigh 70 kg,” but in a multiplanet society this is bad practice – 70 kg is your mass. For weight, one should use newtons or the proposed “grav” unit (see Gravity section below). This convention will be taught and expected, so that mass measurements are consistent across planets (just as astronauts use inertial measurements on ISS to get their mass

). Scales on Mars would be calibrated to output mass in kg (perhaps by internally dividing the measured force by local g), or alternate devices could measure mass via acceleration (similar to the ISS’s spring-based mass measurement devices ). All these ensure that 1 UM of mass on Mars is identical to 1 UM on Earth within measurement uncertainty.

Alternate mass units: Just as a note, in scientific contexts one might use other mass units like the atomic mass unit (1 amu = 1/12 the mass of a carbon-12 atom) for convenience at microscopic scales, or the solar mass for astrophysics. These are fine as derived units (with 1 amu = 1.6605×10^−27 kg, etc.), but the base remains the kilogram/UM. The atomic mass unit is already universal (not Earth-tied), so it can be used in chemistry or particle physics without issue. For daily human use, the kilogram’s scale is appropriate.

Temperature – “Unit of Thermodynamic Temperature” (UTemp)

Definition: We adopt the SI kelvin (K) as the temperature base unit, defined by fixing the Boltzmann constant k_B = 1.380649×10^−23 J/K exactly

. In other words, one kelvin is the change in temperature that results in an average thermal energy change of 1.380649×10^−23 joules per particle. This definition anchors temperature to energy (with J already derived from kg, m, s).

Rationale: The kelvin is inherently universal because it starts from absolute zero (the same zero point for all of physics) and is now defined via a fundamental constant rather than the freezing/boiling points of water (which were Earth-centric). By fixing Boltzmann’s constant, we ensure that temperature is measured in a way directly proportional to underlying energy, which any civilization would understand. 0 K is absolute zero everywhere; 273.15 K is water’s freezing point on Earth, but water might freeze at different apparent “degrees” under other atmospheres – that doesn’t change the unit, just the conditions. Any lab can realize the kelvin by thermodynamic experiments relating temperature, energy, and the Boltzmann constant.

Human context: We might keep the name “kelvin” since it’s standard (and it’s not named after an Earth phenomenon, but after Lord Kelvin). The size of 1 K is convenient for many purposes; it equals 1°C change, just offset in scale (0°C = 273.15 K). For multiplanetary living, everyday weather may still be reported in degrees Celsius for familiarity, but scientific work would use kelvins to avoid ambiguity (especially since “room temperature” on a spaceship or another planet might not align with Earth norms).

Thermal environment considerations: Different planets have different temperature ranges (e.g., Mars averages ~210 K, Venus ~737 K). The unit itself remains kelvin, but we might adopt descriptive prefixes (milliKelvin for fine measurements, etc.). No new base unit is needed here. It’s worth noting that because kelvin is tied to energy, scientists on any planet can calibrate a thermometer through electrical or gas-based standards referencing k_B. Thus, temperature measurement stays coherent across the civilization.

Other Base Units: Electric current, amount of substance, luminous intensity

Though not explicitly requested, for completeness: we would include the other SI base units with their 2019 definitions, since they too are fundamental and non-Earth-based now

:
  • Electric current (Ampere): Defined by fixing the elementary charge e = 1.602176634×10^−19 coulombs. So 1 Ampere is the current of 1/(1.602×10^−19) electrons per second. Universally reproducible via quantum electrical standards.
  • Amount of substance (Mole): Defined by Avogadro’s number N_A = 6.02214076×10^23 per mole. So 1 mole is that many specified particles (atoms, molecules). This is the same anywhere; it’s simply a count.
  • Luminous intensity (Candela): Defined via a standardized luminosity function and a fixed constant for optical power per unit solid angle per unit spectral response. The candela is somewhat human-centric (based on human eye sensitivity), but it’s already part of SI. A multiplanetary system might keep it for continuity in lighting and vision applications for humans. (If non-human species were involved, this might be reconsidered, but assuming all are human or at least have similar perception, it’s fine.)

Each of these units is already defined by physical constants (elementary charge, Avogadro constant, etc.), so they inherently satisfy our fundamental criterion

. They integrate seamlessly with length, time, mass, and temperature in a coherent system.

Summary: The base units of our proposed system coincide with the SI base units in magnitude and fundamental definitions, because SI’s 2019 revision achieved exactly the kind of universality we need. The key difference is one of emphasis and cultural shift: we recast them explicitly as a universal standard for a spacefaring civilization and ensure that usage conventions (like distinguishing mass vs weight, using coordinate time, etc.) are adapted to multiplanetary life. This avoids reinventing the wheel, leveraging the internationally agreed system that is already “the dominant language of science and commerce”

and extending it for new frontiers.

Next, we address how the system deals with varying gravity and relativistic effects, then propose a few new units specialized for space travel contexts.

Addressing Planetary Gravity Variations

Gravity differences between planets pose a practical measurement issue: how to compare force or weight experienced in different environments. Our system’s strategy is to separate mass and force and to use standardized units for each:

  • Mass (in kilograms) – an intrinsic property, same everywhere, as discussed. A 50 kg mass is 50 kg whether on Earth, Mars, or floating in space.

  • Force (in newtons) – the unit of force is defined as 1 N = 1 kg·m/s². This is universal, but the weight of an object depends on local acceleration due to gravity (g). For instance, on Earth’s surface g ≈ 9.81 m/s², so a 50 kg person exerts ~50×9.81 ≈ 490 N of force on the ground. On Mars, g ≈ 3.72 m/s², the same person exerts ~186 N. The newton (N) remains the unit for any force, including weight, thrust, etc., but to avoid confusion we encourage always specifying mass vs force explicitly. Saying “force = 186 N” or “mass = 50 kg” is clear; saying “weight = 50 kg” is discouraged unless context is clear.

  • Standard gravity unit: We introduce a derived unit called “gee” (g₀) to conveniently express gravitational acceleration or compare weight forces. 1 gee is defined as the standard Earth gravity 9.80665 m/s² (exactly, by convention)

    . This unit is already informally used (pilots say “pulling 3 g’s” to mean 3 times Earth gravity). In our system, it serves as a conversion convenience: e.g., Mars surface gravity is 0.38 g₀, Moon is 0.16 g₀. It helps engineers and residents intuitively understand gravity levels relative to Earth-standard. However, it’s not a fundamental unit, just a shorthand: all calculations would still use m/s². We ensure everyone knows 1 g₀ = 9.80665 m/s² exactly, wherever they are.

  • Local weight measures: If needed for practicality, each colony could use a “local kilogram-force” for everyday commerce (e.g., a “Mars-kilogram-force” meaning the force a 1 kg mass exerts on Mars). But this might cause confusion and is against the spirit of universality. It’s better to always sell goods by mass (kg) not weight, or if selling by weight (force) then use newtons. In engineering documentation, weight is always in newtons. For example, a blueprint might say a machine applies 1000 N of load, not “100 kg of load,” since 100 kgf would differ off Earth.

By following these rules, gravity variations are handled simply by physics rather than by redefining units per planet. This approach aligns with how astronauts and scientists already handle it: measure mass directly, compute weight via F = m·g for the given location

. It also prevents costly mistakes: the system that failed to convert pound-force to newtons on the Mars orbiter would have been forced to use newtons throughout , eliminating the ambiguity.

As an added benefit, using a single force unit (N) means rocket thrust, engine outputs, and vehicle weights are comparable directly, without needing separate “pounds of thrust” vs “newtons.” In a multiplanetary economy, a spaceship engine can be rated at, say, 1 MN (meganewton) of thrust, and everyone knows what that means and can design accordingly.

In summary, the unit system itself stays constant; we just carefully distinguish what is being measured. Gravity might change the numeric readings of certain instruments (scales), but not the units or standards. Through calibration and conventions, we ensure mass, force, and acceleration are measured consistently.

(Aside: For scientific completeness, gravity not only affects weight but, via general relativity, can slightly affect length and time measurements as well – e.g., a ruler or clock in a strong gravitational field runs a bit differently to a distant observer. However, these effects are extremely small in our solar system for everyday precision and are corrected within the context of a chosen reference frame for high-precision needs. Our definitions (meter via c, second via atomic clocks) already account for that by being local proper definitions. And by adopting a coordinate time like UCT/TCB for reference, we conceptually remove gravitational time dilation for synchronization purposes

.)

Timekeeping Across Planets and Relativistic Effects

To maintain consistency in time measurements and coordination, our system implements a two-tier approach to timekeeping:

  1. Local Timekeeping: Each planet or habitat can have its own local civil time for daily life, tied to its day-night cycle if applicable. For example, Mars might use a 24-hour 39-minute “Martian day (sol)” clock

    , divided into 24 Mars hours of 61 minutes each, etc., or simply count in sols. This is analogous to time zones on Earth – convenient locally but not for interplanetary reference. Local calendars (Mars years, etc.) can also be used culturally.

  2. Universal Synchronized Time (UST): A single time scale based on the SI second and not rotating with any planet, used for science, navigation, and communication between planets. UST could be aligned with TAI (atomic time) or a similar continuous count of seconds from an epoch (say, Julian Date 0 at 2000-01-01). It would not have leap seconds or any adjustments for any planet’s rotation

    , making it uniform. Effectively, this is the time kept by ideal clocks far from gravitational masses and moving slowly relative to the solar system’s barycenter (like the defined TCB frame ). All spacecraft and colonies synchronize to UST for mission events.

Using UST, if a rover on Mars sends a message at “UST 12:00:00” and Earth receives it at “UST 12:00:15”, both sides agree on the timeline (the 15 s was light travel delay). This avoids confusion that would arise if Mars was using its own seconds or started its clock differently. In practice, UST might be disseminated via signals (similar to how GPS provides precise timing worldwide). It serves as the backbone for scheduling interplanetary meetings, data logs, or navigation.

Relativistic adjustments: Because gravity and high speeds can cause clocks to diverge (time dilation), there will be slight offsets to correct. For instance, a clock on Mars’s surface (shallower gravity well than Earth) runs slightly faster relative to one on Earth’s geoid – on the order of microseconds difference per day. A ship traveling at 0.1c would experience noticeable time dilation relative to Earth’s frame. Our system handles this by making local clocks traceable to UST. When absolute precision matters, each clock’s rate can be calibrated: e.g., planetary time centers will apply relativistic corrections to sync with UST (much as the GPS master clock adjusts satellite clocks). So if an astronaut takes an atomic clock on a high-speed journey, mission control can predict how much it will lag or lead and adjust readings to the UST standard.

In summary: The unit of time (second) doesn’t change, but the reference frame is defined. By analog, think of how we use “Universal Time (UTC)” on Earth to coordinate across time zones. Here we use UST across planets to coordinate across gravitational and kinematic offsets. This ensures that one second of UST is the same everywhere by definition, and any local differences are known and corrected for. Scientists and engineers thus have a common clock to timestamp observations (critical for things like synchronizing observations from Mars and Earth, or navigating spacecraft with signals that need precise time).

This approach aligns with current space operations where multiple time standards are juggled – UTC for Earth-based scheduling, spacecraft onboard time for local events, one-way light time for signal travel, etc.

– but it simplifies it under a single consistent framework. It acknowledges relativity (through the concept of a coordinate time) rather than ignoring it, which will become more important as our speed and reach increase.

New Units and Measures for Space Travel

Beyond the traditional quantities, a multiplanetary civilization regularly deals with scenarios not common in Earth-bound life. We propose or highlight a few derived units and measures to address these:

1. Propulsion and Thrust Efficiency

Space travel depends on rocket engines, ion drives, solar sails, etc., which have their performance characterized by how effectively they produce thrust from fuel. In current aerospace engineering, a key metric is Specific Impulse (Isp) – essentially the impulse delivered per unit weight of propellant. Unfortunately, Isp is often stated in “seconds,” which actually means “seconds of exhaust gas ejection under Earth gravity” (since $I_{sp} = v_{exhaust}/g_0$ with $g_0=9.81 m/s²$) – an Earth-centric artifact. This can be confusing because higher Isp is better and it’s not a time in any practical sense but a ratio involving Earth’s gravity.

Proposed approach: We eliminate the Earth-gravity term and directly use exhaust velocity or impulse per unit mass as the measure:

  • Exhaust velocity (m/s): Instead of saying an engine has $I_{sp} = 450 s$, we’d say its exhaust velocity is ~$450 × 9.81 = 4415 m/s$. Using meters per second is straightforward, clear, and requires no reference to Earth gravity

    . It directly tells you how fast the propellant is thrown out the back, which is what matters by $Δv$ calculations.

  • Momentum or impulse units: We standardize impulse in Newton-seconds (N·s) (which is equivalent to kg·m/s). The Mars Climate Orbiter’s problem arose because one team used pound-force seconds and another expected N·s

    . In our system, only N·s is allowed for impulse. For rocket engines, we can define a specific impulse unit as N·s per kg of propellant (which simplifies to m/s, as above). So one could say “this engine yields 3000 m/s per kg of propellant.” This is unambiguous and universal.

  • Thrust-to-mass ratio: For engine acceleration, rather than quoting “thrust-to-weight,” which varies by planet, we quote thrust-to-mass (in N per kg). On Earth, N/kg is numerically equal to m/s², so essentially it’s the acceleration the engine can produce. A vehicle that can exert 30 N per kg of its mass will accelerate at 30 m/s² (~3 g₀ wherever it is). This again avoids needing “weight” which is location-specific.

By using these measures, all aspects of propulsion can be discussed without any Earth-specific constants sneaking in. It also eases communication: an international team can discuss a spacecraft and know everyone is using m/s, N, kg consistently, avoiding confusion like the orbiter mishap. Most modern aerospace does use SI, but we formalize it and push to remove any leftover non-SI habit (like Isp in seconds). We might even give Isp in meters/second a special name (for example, call it “effective exhaust velocity, $v_{ex}$”) to make clear what it is. But since it’s just a velocity, using m/s with the label “exhaust velocity” is likely sufficient.

2. Radiation Exposure and Dosage

Space travel exposes humans and electronics to cosmic radiation far beyond Earth’s surface levels. Monitoring and measuring this exposure is vital for health and mission success. Currently, radiation dose is measured in Grays (Gy) for physical absorbed dose (J/kg) and Sieverts (Sv) for equivalent/effective dose (J/kg weighted for biological effect). These units are already universal (derived from energy and mass) and do not depend on Earth-specific factors. We propose continuing to use the sievert for human radiation exposure, as it is well-established in aerospace medicine.

  • Sievert (Sv): One sievert equals one joule of absorbed energy per kilogram of tissue, adjusted for the type of radiation’s biological impact. Astronauts on a 6-month ISS mission receive on the order of 70 mSv

    , and a 3-year Mars mission might accumulate >1000 mSv (1 Sv) . Having a common unit allows comparison of these doses to terrestrial standards (e.g., average background on Earth ~3 mSv/year ). The sievert is useful for setting universal safety limits (NASA might say an astronaut’s career limit is, say, 1 Sv, regardless of whether it’s received in LEO, on the Moon, or en route to Mars).

  • Dose rate: We often use microSieverts per hour (µSv/h) or milliSieverts per day to measure radiation environment. This will continue. For example, the radiation on the Martian surface might be ~200 µSv/day; in deep space during a solar minimum it might be higher. Using SI time and dose units makes these figures directly comparable and sums them linearly for total dose.

  • No new base unit needed: There was an old non-SI unit, the rem (Roentgen equivalent man), but 1 rem = 0.01 Sv. Our system would strictly use sieverts to avoid any mix-ups. We also keep the gray for when we only care about physical absorbed dose (especially for electronics or shielding calculations), and becquerels (Bq) for radioactivity (decays per second, already SI). All these units (Sv, Gy, Bq) are independent of Earth conditions.

  • Radiation fluence: For engineering, sometimes one measures particle flux (e.g., number of high-energy protons per cm²). We encourage using SI units for that too (e.g., particles per m², or per m²·s for flux). Specialists can still use cm² if needed, but it’s easy to convert. The key is consistency when reporting and comparing.

In summary, the system already has a solid approach to radiation units; our task is mainly to ensure they are rigorously used and communicated. In a multiplanet civilization, one might regularly report “astronaut X received 25 mSv during the solar storm” and everyone understands the significance via the common scale.

3. Large Distance Units

Distances in space are enormous. While the meter (and km) remain the base, it’s handy to introduce a standardized set of larger units for interplanetary and interstellar scales:

  • Astronomical Unit (AU): Roughly the Earth-Sun distance, ~1.496×10^11 m. Historically Earth-centric, but it’s a useful yardstick within a solar system. We can keep the AU as a defined derived unit for convenience (the International Astronomical Union now defines 1 AU = 149,597,870,700 m exactly). On the scale of a multiplanet civilization (at least initially within one solar system), the AU is a natural unit to describe orbits (Mars is 1.52 AU from the Sun, etc.). It does tie to Earth’s orbit, but only as a historical length – it’s now fixed in meters, so it’s universal for anyone in that system.

  • Light-year (ly) or Light-second: For interstellar or communications context. A light-year is the distance light travels in one Julian year (365.25 days of 86,400 s each). Again, that year length is based on Earth’s orbit, but we can define 1 Julian year = 31,557,600 s exactly for the unit’s purpose. That yields 1 ly ≈ 9.46×10^15 m. This is useful if our civilization spans multiple star systems eventually. Light-second/minute/hour are extremely useful for signal delay and nearby distances: e.g., Moon is ~1.3 light-seconds from Earth, Mars can be 3 to 22 light-minutes away. We would standardize these terms to avoid any confusion (and they are directly derived from c and the second, so perfectly consistent).

  • Parsec (pc): 3.26 ly, based on the parallax from 1 AU baseline. This is an Earth-origin concept (using 1 AU), but astronomers might still use parsecs routinely. We could retain it for tradition in astronomy circles, but it’s less fundamental for our measurement system itself (and the AU is already defined). Since parsec = 206265 AU by geometry, it’s locked to Earth’s orbital size. A truly Earth-independent civilization might prefer light-years or petameters (10^15 m) to describe interstellar distances, but parsec is deeply ingrained in astrophysics. In any case, we’d clarify its definition in standard units if used.

In engineering documents for spacecraft, likely kilometers or megameters will suffice (1 Mm = 1000 km, so Mars’s radius ~3.39 Mm, Earth–Moon distance ~384 Mm). We encourage using scientific notation or SI prefixes for clarity over ambiguous terms like “million miles.” For example, use “150 million km” or “150×10^6 km” instead of “93 million miles,” since the latter requires conversion and might be misheard.

4. Velocity for Space Travel

While no new unit is needed (m/s is perfectly fine), it’s worth noting how velocities can span huge ranges:

  • Sub-orbital rockets: a few km/s.
  • Orbital velocity (Earth): ~7.9 km/s.
  • Escape velocity (Earth): ~11.2 km/s.
  • Earth to Mars transfer: on the order of 10–20 km/s delta-v budget.
  • Fraction of light: expressed as dimensionless (e.g., 0.001 c). We can continue to use c as a constant for fractions of light-speed. It might be convenient to say “the ship is cruising at 0.1 c” as a way to immediately convey relativistic speed. This is not a unit, but a normalized measure. We will ensure that when used, it’s clearly defined (with c = 299,792,458 m/s).

For everyday speeds (landing spacecraft, rovers driving, etc.), km/h or m/s would remain. Perhaps on Mars they’ll use m/s or km/h for vehicles just as on Earth, since those are intuitive. The key difference is to avoid non-metric units like miles per hour, which have no place in an interplanetary standard.

5. Other Potential Units

A few other specialized measures might be defined for convenience as our civilization advances:

  • Thrust-to-weight ratio (TWR): Instead of a dimensionless number relative to Earth weight, we define it relative to local weight or as acceleration directly. Likely, using m/s² covers this as discussed.

  • Pressure: Already in Pascals (N/m²). Atmospheric pressures on planets (Mars ~600 Pa, Earth ~101,300 Pa). We keep Pa as is. Possibly introduce the bar (1 bar = 100,000 Pa) as a convenient unit for atmospheres (Earth ~1 bar, Venus ~92 bar at surface). Bar is not SI, but widely used in planetary science. We might officially allow “1 planetary atmosphere (atm_E)” as 101,325 Pa for reference, but better to stick to Pa or bar.

  • Energy and Power: Joules and Watts remain as derived SI units (with all fundamental constants definitions behind them). No changes needed. Spaceship energies (like delta-v budgets in kinetic energy) and power sources (solar panels output in kW) would use these.

  • Computer units: Perhaps outside the realm of fundamental units, but in interplanetary communication, units like byte (for data) will be used. We’d follow existing standards (byte = 8 bits, metric prefixes for kB=1000 bytes as per SI standard, etc.) for data sizes and rates.

Overall, the new units for space are more about standardizing practices than creating fundamentally new physical units. We ensure that measures like rocket efficiency or radiation exposure are expressed in a single coherent way across all planets and vehicles. This prevents mistakes and allows everyone to immediately understand quantities regardless of origin.

Comparison with Existing Systems

International System of Units (SI): Our proposed system is largely an augmentation and enforcement of SI for multiplanetary use. SI already meets most criteria of universality since its 2019 revision: all base units are defined by fundamental constants (speed of light, Cs-133 frequency, Planck constant, Boltzmann constant, etc.), meaning anyone anywhere can realize them

. We have kept the SI base units (meter, second, kilogram, kelvin, etc.) and their definitions . Thus, in magnitude and concept, the units remain familiar to current scientists. The differences are in emphasis and some additional units:

  • We explicitly integrate coordinate time (UST) to handle relativity, whereas SI itself doesn’t dictate timekeeping practices (it only defines the second). This addition addresses synchronization across frames.

  • We forbid or discourage Earth-specific usages like kilogram-force, Isp in seconds, or using “day” without specifying which planet. SI also discouraged non-SI units, but our context gives fresh urgency to it.

  • We defined a “gee” unit for convenience in discussing gravity and accelerations (a derived unit not present in formal SI). This is a minor add-on and is clearly defined in SI terms, so it doesn’t break coherence.

  • Some have proposed including the gravitational constant G as a defining constant (like Planck units do)

    , but the current precision of G is poor and it’s not necessary for daily measurements. We chose not to alter base units to include G (which would essentially move toward Planck unit system) because it would make units impractically large or small for everyday use, and SI units already cover all needed ranges with the help of prefixes.

In essence, our system can be seen as SI adapted for space: no fundamental unit changes, just added clarity (mass vs weight), additional derived units, and guidelines for use. This continuity means implementation is easier – existing technology and literature can be carried over with minimal conversion. Scientists have called SI “humanity’s most successful cooperative venture”

, and we build on that success for the new era.

Imperial/US Customary System: The legacy imperial units (feet, pounds, degrees Fahrenheit, etc.) are deeply Earth-bound and would be highly unsuitable for a spacefaring future. They are based on arbitrary human references (an English king’s foot, brine freezing points, etc.), and in many cases they mix mass and force (the pound can mean force or mass depending on context – a nightmare on other planets!). Using them interplanetarily would introduce huge risk of error. The Mars Climate Orbiter loss was a direct result of clinging to imperial units (pound-force) in a modern space mission

. By adopting one universal metric system, we eliminate such incompatibilities. Imperial units also lack a consistent decimal prefix system, making them unwieldy for very large or small measurements (astronomers long ago abandoned miles for light-years or kilometers). Our proposed system firmly sticks to metric units, meaning a complete phase-out of imperial in technical work. (Local use of say “pounds” as a casual term on Earth could continue culturally, but all official documentation should convert it to the standardized units. On Mars, one imagines no one will bother with “pounds” at all.)

Other unit systems (CGS, Planck units, etc.): Scientists sometimes use different unit systems for specialized fields (CGS for some physics, atomic units for quantum chemistry, Planck units in theoretical physics). Our system doesn’t prevent using those as calculational conveniences, but for communication and official purposes, we’d expect conversions back to the standard. For example, Planck units set many constants to 1, which is elegant for equations

, but when publishing results that engineers on Mars might use, it’s better to say “the spacecraft is 1.2×10^11 m from Earth” than “4 AU” or “8.0×10^–6 light-year” depending on audience. Consistency is key. Within our framework, anyone using alternate units would need to clearly define them in terms of the base units (just as is done today in scientific papers).

Practically, implementing our system in a multiplanetary civilization would mean:

  • All space agencies, colonies, and companies agree to use these units for designs, data, and trade. (This is already largely true for SI; the challenge is to extend it to things like Martian construction using N and kg strictly, etc.)
  • Education on other planets would teach these units from the start, ensuring new generations think in these terms.
  • Instrumentation is calibrated in these units. For instance, a pressure gauge on Venus reads out in Pascals or bar, not in an Earth PSI; a rover odometer on Titan ticks in meters or kilometers, not miles.
  • Communication protocols (from telemetry to engineering drawings) explicitly state units when there’s any potential ambiguity, since two planets might assume different contexts (e.g., always specify “sol” vs “day (24h)” if needed, or use seconds to avoid confusion).
  • The use of universal time would likely require an authority (maybe an “International Space Timekeeping Bureau”) to maintain the standard and dissemination, analogous to how leap seconds and UTC are managed by Earth organizations today .

Conclusion

As humanity becomes multiplanetary, a robust and universal measurement system will be as critical as life support or navigation systems. The proposed system extends our current SI foundations into a truly planet-agnostic framework. By defining all base units on immutable physical constants, we ensure a meter, second, kilogram, and kelvin mean exactly the same on any world

. By addressing gravity differences through clear separation of mass and force units and providing a common time reference to handle relativity , we maintain synchronization and consistency across space and time. The introduction of helpful derived units (like a gravity unit “g₀”, light-based distance units, and direct thrust metrics) further tailors the system to the practical needs of space travel, reducing chances for misunderstanding or error.

Compared to Earth-centric or old-fashioned systems, this universal system offers logical coherence (each unit rooted in fundamental physics, not parochial definitions

), ease of scaling via prefixes (from nanoseconds to gigaseconds, micrometers to terameters), and unambiguous communication for engineers and scientists from different planets. It transcends cultural and historical baggage, creating a common “language of science” that is truly universal .

In implementing this system, we build upon the proven success of SI – described as “operating smoothly and consistently from the smallest objects to the far reaches of the universe”

– and we adapt it for the new arenas our species will explore. The result is a measurement framework that will facilitate cooperation, trade, research, and exploration across planetary boundaries, ensuring that a calculation done on Mars or a measurement taken on Europa is immediately understood on Earth and vice versa. This coherence in our units of measure will be a fundamental infrastructure of our multiplanetary civilization, just as important as spacecraft or habitats, because it underpins how we quantify and understand everything in our new world(s).

Sources:

Universal Timekeeping System for a Multiplanetary Civilization

Rationale for a Universal Time System

Moving Beyond Earth-Centric Time: Our current timekeeping (hours, days, years) is rooted in Earth’s rotation and orbit

. This is impractical on other planets – for example, a Martian day (“sol”) is ~24 hours 39 minutes 35 seconds Earth time . As humans expand to Mars and beyond, using Earth’s day or year as a universal reference becomes confusing and arbitrary. A new system should not rely on any single planet’s rotation or orbit, but instead on unchanging laws of physics that are the same everywhere.

Consistency and Precision: Earth’s rotation is irregular (it even slows down slightly), forcing us to add leap seconds at irregular intervals to keep atomic clocks aligned with solar time

. This complicates timekeeping and can disrupt systems that require uniform time intervals. A universal system based on fundamental constants would tick uniformly, eliminating leap seconds and other Earth-specific adjustments. This provides a steady “heartbeat” for time that all planets and spacecraft can agree on.

Foundations in Physics: Max Planck suggested using nature’s fundamental constants to define units of measurement, making them truly universal

. Following this principle, we can derive a time unit from constants like the speed of light or atomic transition frequencies. Such a unit would be scientifically rigorous and identical anywhere in the universe, laying a foundation for a consistent multiplanetary time standard.

Defining a Fundamental Unit of Time

Planck Time – Theoretical Limit: One option is the Planck time, ~5.39×10^−44 seconds

, which is derived from fundamental constants (G, ℏ, c all set to 1). It represents the smallest meaningful slice of time in physics. While conceptually important, the Planck time is far too tiny for practical use – on the order of 10^43 Planck times elapse every second . We mention it to show the system’s roots in fundamental physics, but we need a larger base unit for human timekeeping.

Atomic Transition as Base Unit: A more practical base is provided by atomic physics. Currently, the SI second is defined by a fundamental constant: it is the duration of 9,192,631,770 oscillations of the microwave signal from a cesium-133 atom’s hyperfine transition

. This definition does not depend on Earth’s rotation – it’s the same no matter where you are. We adopt this “atomic second” as our universal base unit (we can call it the Universal Second). It is already measured with extreme precision by atomic clocks (to ~1 part in 10^15) and is stable over time . By using an atomic property, our time unit is anchored to immutable laws of physics and is reproducible in any laboratory on any planet.

Role of the Speed of Light: In our system, the speed of light (c) is implicitly part of the definition – recall that in SI units, the meter is defined so that light travels exactly 299,792,458 m in one second

. Thus, distance and time are linked via c. If needed, we can conceptualize the Universal Second in terms of light travel: it’s the time light in vacuum travels about 299,792.458 km. Using c ensures that our time unit is consistent with space measurements and relativity. (We need not redefine this further – the existing link between second and meter via c is sufficient .)

Optional – Higher Frequency Standards: As technology advances, we might redefine the base unit using even more stable references (e.g. an optical atomic transition). Optical clocks (like strontium lattice clocks) are ~10,000 times more precise than cesium and can detect minute relativistic effects from just a 2 cm elevation change

. In principle, any chosen atomic or quantum transition could define the “tick” of our universal clock. The key is that it should be based on a fundamental, unchanging frequency of nature. For now, the cesium-defined second serves well, with the understanding that future improvements can swap in an even more precise constant-frequency source without altering the overall system.

Structure of Time Units (Beyond Seconds)

With the Universal Second (Us) as the base, we build a logical, scalable hierarchy of time intervals to replace hours, minutes, and days:

  • Universal Minute (Um) – We define 1 Um = 100 Universal Seconds. This is a convenient chunk (100 Us = 100 seconds ≈ 1.67 minutes in old time). Using 100 instead of 60 makes calculation and conversion simpler, since it’s a single base (decimal) system . For example, 250 Us = 2 Um + 50 Us, no complex 60-base math needed.
  • Universal Hour (Uh) – 1 Uh = 100 Universal Minutes = 10,000 Us. This is analogous to an “hour,” but instead of 3,600 seconds, it’s 10,000 seconds (~2.78 old-hours). There are 100 minutes in a U-hour, and each minute has 100 seconds, giving a neat 100×100 structure.
  • (Optional) Universal Day (UD) – We can introduce a day-like cycle for convenience: 1 UD = 10 Universal Hours = 100,000 Us. This “day” is an arbitrary 100k-second period (~27.78 Earth hours). We choose 10 hours simply to keep the system cleanly decimal. Importantly, this UD is not tied to any planet’s day – it’s a human-defined cycle for long durations. Its length could be adjusted if needed for human circadian comfort, but using a round 100,000 seconds makes the math simple.

Using this structure, time of day can be expressed in a uniform format. For example, one might say “5:25:30 U” to mean 5 Universal Hours, 25 Universal Minutes, 30 Universal Seconds (which would be 5×10,000 + 25×100 + 30 = 52,530 Us after the start of the day). Because everything is base-10, converting this to total seconds or fractions of a day is straightforward. The representation is unambiguous and easy to compute – e.g., 5:25:30 U is simply 5.2530 hours in decimal, or 0.52530 of a day, etc. (compare to the difficulty of interpreting “5:25:30” AM/PM in the old system)

.

For longer intervals, we leverage metric prefixes on the base second:

  • 1 kilosecond (ksec) = 1,000 Us (about 16.7 minutes)
  • 1 megasecond (Msec) = 1,000,000 Us (~11.57 days)
  • 1 gigasecond (Gsec) = 1,000,000,000 Us (~31.7 years)

In scientific and logistical use, it may be more convenient to quote durations or timestamps in pure seconds (or scientific notation with SI prefixes) for absolute clarity. For instance, a deep-space mission event might be scheduled at “T = 550 Megaseconds” from launch. Meanwhile, everyday civil schedules can use the hour:minute:second (all in base-10) format for familiarity. This dual notation is similar to how we use both 24-hour clock times and also count seconds in technical contexts today.

No Months or Years: Notably absent in this system are months or years – those are based on Earth’s orbit and would differ on other planets. In a universal system, calendar dating would likely be counted in larger uniform units (like megaseconds or gigaseconds) or by specifying the planet if referring to a local year. For example, instead of “2025 AD” (Earth calendar), one might use a continuous count of seconds from a chosen epoch (see below) for scientific records. Culturally, each colony might still commemorate local orbital periods (“Mars Year 10”, etc.), but those are local calendrical layers separate from the universal time count.

Accounting for Relativity and Reference Frames

Single Reference Frame: A major challenge in interplanetary timekeeping is that time flows differently in different reference frames (due to relativistic effects). Clocks moving at high speed or in different gravity wells will tick at different rates relative to each other

. Our universal system adopts a coordinate time centered on an agreed reference frame – for example, the Solar System barycenter (the center-of-mass point around which planets orbit). This is analogous to the astronomical time standard Barycentric Coordinate Time (TCB), which is the time kept by a clock at rest at the solar system barycenter, unaffected by any planet’s gravity . By anchoring the master clock to an inertial frame outside major gravity wells, the base time runs uniformly (no gravitational slowing) .

Relativistic Corrections: Spacecraft and planets will not be exactly in that frame, so we must correct for time dilation. This is already done today on a smaller scale: GPS satellite clocks, for instance, are adjusted to account for both special and general relativity so that they stay synchronized with Earth clocks

. (GPS satellites experience about 38 microseconds per day net time gain relative to Earth surface clocks due to weaker gravity and orbital speed , and engineers preload an offset to cancel this difference.) Similarly, in our system any clock that is moving fast or deep in a gravity well will apply known corrections to keep in step with the universal coordinate time.

Practically, this means a spaceship’s onboard “universal clock” would apply relativistic adjustments based on its navigation data, so that what it displays (coordinate time) remains in sync with the master timeline. Each colony or ship could maintain an accurate local version of universal time by referencing pulsed updates from navigation beacons and applying relativistic formulas. Modern physics gives us the tools to compute these effects with extreme precision, so although each observer has their own proper time, we can always relate it back to the shared coordinate time with appropriate equations

.

Signal Synchronization: Communicating the time across space involves delays (at light speed). Our system would handle this by timestamping every signal with the send time according to the sender’s universal clock. The receiver, knowing the distance (via known ephemerides or two-way ranging), can compute the transit delay and thereby calibrate the incoming time. For instance, if Mars receives a signal timestamped 100,000,000 Us from Earth, and knows the signal took 3 minutes (180 s) to arrive, it realizes the current universal time is 100,000,180 Us when received. While there is a limit to synchrony due to lightspeed lag, the key is that everyone shares the same timeline reference – they just might see events late. This is analogous to how we use UTC in communication today: we account for time zones or delays but have a single reference clock.

Local Planetary Time vs Universal Time: Colonies will still maintain local time cycles for practical life – e.g. a Mars base will note the local sunrise in Martian sols. Our universal system doesn’t abolish local “day timekeeping” any more than UTC abolished local time zones on Earth. Rather, it provides a parallel, standardized clock. Astronauts might say, “We’ll meet at 08:00 local time, which is 543,000 Us universal time.” The local 08:00 could correspond to morning on Mars, but the 543,000 Us (which is 5.43 U-days in our system) is the same moment for everyone reading the universal clock. This separation ensures that while humans can follow natural daylight cycles on each world, all interplanetary coordination still references a single, objective timeline.

Implementation and Practical Use

Epoch and Time Zero: First, we’d establish an epoch – a starting point “time zero” for the universal clock. It could be something like January 1, 2000 00:00:00 UTC, or any agreed reference point in history (perhaps the moment of first Moon landing, etc., to give it cultural significance). From that epoch, we count Universal Seconds forward continuously. This creates a timestamp that looks like a large increasing number. For example, “Universal Time = 1.0000×10^9 Us” (1 gigasecond) would correspond to about 31.7 years after the epoch. Software and clocks would need to handle these large values, but they already do (e.g., Unix time is a count of seconds since Jan 1970).

Network of Atomic Clocks: The backbone of the system is a network of ultra-precise atomic clocks distributed across the solar system. Earth already has International Atomic Time (TAI), which is a weighted average of some 400 atomic clocks worldwide ticking SI seconds

. We would extend this concept with atomic clocks on other planets and spacecraft. These clocks “vote” to steer toward a consensus time . Periodically, they communicate and adjust for offsets (with relativistic corrections applied) to maintain one unified time scale. The goal is to realize the ideal coordinate time (as if all clocks were at the barycenter).

Time Signal Broadcasting: Much like GPS satellites broadcast timing signals, dedicated beacon satellites at strategic points (Earth, Mars, Moon, etc.) could broadcast the current universal time. Receivers anywhere (on planets or ships) can pick up these signals and sync their local universal clock. Even if a ship is far from any beacon, onboard atomic clocks can free-run for long periods with only minor drift, and occasional updates from pulsar timing or optical links can re-sync them. In addition, natural beacons like pulsars could complement this network – ESA has demonstrated a “PulChron” pulsar clock system that uses millisecond pulsar radio bursts as a time reference independent of atomic clocks

. Pulsar signals, observed commonly by all, could serve as a galactic GPS of time. While less practical for day-to-day use, they offer redundancy and long-term stability (over decades) to anchor the time scale .

Everyday Devices and Apps: For everyday civilian use, clocks and watches would be programmed to display both local time and universal time. A person might glance at their watch and see “Local: 09:32:18 (Mars Sol 145), Universal: 2:47:50 U” – meaning it’s 9:32:18 AM on the 145th sol of the mission, and simultaneously 2 Universal Hours, 47 Universal Minutes, 50 Universal Seconds into the current U-day of the shared timeline. Initially, this dual display helps with transition; eventually people may become accustomed to scheduling by universal time for any interplanetary meetings (“let’s have a call at 6.00 Uh on Friday, universal time”). Software calendars and mission planners would all use the universal time as the underlying reference, converting to local zone time only for user convenience.

Integration with Navigation and Communication: Space mission control centers would plan events (engine burns, maneuvers, data transfers) in universal time to avoid confusion. For example, a rover on Mars might be programmed to wake up at a certain local Martian time each sol, but critical events like “transmit data to orbiter” would be set by universal timestamps to coordinate with an orbiter that also runs on universal time. This ensures cross-planet events align correctly without each team constantly converting time zones. In crewed deep-space travel, the ship’s systems would log all data with universal timestamps, making it easier to analyze after the mission or in comparison with Earth-based observations. Scientific experiments, especially those involving multiple observatories on different planets, would greatly benefit: a phenomenon observed from Mars at a given UT can be directly compared to one observed from Earth at the same UT, with no ambiguity about clock differences.

Advantages of the New System

  • Universal Validity: Because it’s based on immutable physical constants (atomic frequencies, speed of light), the time unit is the same everywhere. Any advanced civilization would be able to reproduce our second by basic experiments – it’s not tied to Earth’s peculiar rotation or orbit. This makes it a truly universal language of time.
  • Equal Footing for All Worlds: No planet’s day or year dominates the system. Earth, Mars, the Moon, or a space station all use the same units and scale, preventing Earth from being the de facto reference for all schedules. Culturally, this is important as we become a multi-planet species – timekeeping should not implicitly favor one world over another.
  • Continuous and Consistent: The timeline runs uniformly without jumps. Unlike UTC which inserts leap seconds to match Earth’s slowing rotation , this system would let atomic time run free. One universal second is always the same, and 1000 Us from now will always be exactly 1000 atomic seconds later. This consistency is crucial for scientific measurements, data logging, and computer systems that crave steady time intervals .
  • Relativistically Robust: By defining time in a specific inertial frame (e.g., solar-system barycenter) and applying relativistic corrections, we ensure that all observers can synchronize to the same proper time standard . This provides a common reference even when relativistic effects come into play, a necessity for future high-speed travel or navigation near strong gravity wells. The system acknowledges reality (time dilation) yet offers a solution to “speak the same time” across frames.
  • Scalable and Decimal-Friendly: The use of a decimal structure (100 sec = 1 min, 100 min = 1 hour, etc.) makes it straightforward to convert and calculate time intervals . It aligns with the rest of the metric system, reducing confusion. For example, 1 kilosecond = 10^3 seconds, 1 megasecond = 10^6 seconds, directly. This is far easier for global science and engineering projects, where calculations with 60 or 24 as factors can introduce errors.
  • Alignment with Scientific Time Scales: Scientists already use time systems independent of Earth rotation for precision work (e.g. TAI, Barycentric Dynamical Time). Adopting a universal constant-based time for everyday use means no more bridging between “civil” time and “scientific” time – they become one. It simplifies everything from programming spacecraft to comparing experimental results timestamped on different planets.
  • Future-Proofing: As we travel beyond the solar system, an Earth-based time becomes obsolete. A constant-based system scales to an interstellar civilization. Even millennia in the future, long after Earth’s specific day length is irrelevant, this timekeeping will remain valid. It could even be extended to or synced with timekeeping by other intelligent civilizations (since any civilization will recognize the constants we used). It sets the stage for interstellar or galactic time standards.

Conclusion

Our proposed universal timekeeping system starts with what’s fundamental in nature – the unchanging beats of the cesium atom or similar – and builds up a human-usable framework of seconds, minutes, hours, and days that owe nothing to Earth’s cycles. By incorporating a consistent decimal structure and accounting for relativistic effects, it ensures that every colony, spacecraft, and planet can share a common clock. This will greatly streamline interplanetary communication, navigation, and science, much as standard time zones and UTC facilitated global interaction on Earth.

Implementing this system will require coordination between international space agencies and perhaps a governing time authority that maintains the standard (analogous to the Bureau International des Poids et Mesures for SI units

). In practice, we already have much of the needed technology – atomic clocks, time signal transmitters, relativity-aware synchronization (GPS) – so it’s a matter of agreement and gradual adoption. Initially, the system can run in parallel with legacy Earth time for convenience, but over time, one can imagine “Universal Time” (UT) becoming the primary timestamp for a spacefaring humanity. It is a logical step in our evolution to a multiplanetary civilization: just as we once standardized calendars and clocks across Earth’s longitudes, we now extend that standardization to the heavens, anchored not on any one world, but on the fundamental heartbeat of the universe itself.

Sources: The principles and data discussed are supported by references: atomic second definition

, decimal time proposals , Martian sol length , relativistic time dilation in GPS , and modern concepts of barycentric coordinate time , among others. Each illustrates aspects of why and how a universal, physics-based timekeeping system is both feasible and advantageous for future exploration and settlement.
You said:
Is the speed of light a useless measurement. Hours are popycock, and seconds, are they any better. Can we do away with seconds? Are seconds logical...weren't seconds a Babylonian derived value?
ChatGPT said:

You're raising an interesting point! The second, as currently defined, is based on atomic transitions, but historically, it was linked to Earth's rotation and the Babylonian base-60 system. Would you like research on:

  • A completely new fundamental unit of time independent of seconds?
  • Whether the speed of light is a better base for timekeeping?
  • The historical and logical basis of the second and whether it remains a good standard?

Let me know your preference, and I'll tailor the research accordingly!

You said:
A completely new fundamental unit of time independent of seconds
ChatGPT said:

Great! I'll research and propose a completely new fundamental unit of time that is independent of the second. This unit will be derived from fundamental physical constants rather than historical or Earth-based references.

The research will consider:

  • A new time unit based on universal principles, such as the speed of light, Planck time, or atomic transitions.
  • Logical scalability for practical use in science, engineering, and everyday life.
  • How to structure larger time intervals without relying on traditional hours, minutes, or seconds.
  • Comparisons with existing time units and the benefits of a new approach.

I'll let you know when the findings are ready!

Research completed in 5m · 10 sources
You said:
How to structure larger time intervals without relying on traditional hours, minutes, or seconds.
 

Would you like the new time intervals to be structured in a purely scientific way (based on fundamental constants like the speed of light or quantum phenomena), or should they also be designed for human practicality, such as aligning with biological rhythms or work cycles? Additionally, should the system be fully decimal-based for ease of calculation? Let me know your preferences so I can refine the research accordingly!

You said:
Fully decimal. get rid of seconds.
ChatGPT said:

Understood! I will develop a fully decimal-based system for structuring larger time intervals without relying on traditional seconds, minutes, or hours. This system will be based on fundamental physical constants rather than historical or Earth-centric divisions of time.

I will explore:

  • A new base unit of time derived from universal principles, such as atomic transitions, the speed of light, or Planck time.
  • A logical hierarchy of larger time intervals using a decimal structure for ease of calculation.
  • Practical implementation for science, engineering, and daily life in a multiplanetary civilization.
  • Comparisons with existing time systems and the advantages of the new approach.

I'll provide a detailed proposal soon!

Research completed in 4m · 10 sources

A Universal Decimal Timekeeping System

Rationale for a New Decimal Time System

Modern timekeeping is rooted in Earth’s cycles and ancient conventions. A day is divided into 24 hours, each hour into 60 minutes, and each minute into 60 seconds

. This sexagesimal (base-60) division dates back to the Babylonians and is not a decimal structure . While practical on Earth, it complicates calculations and is arbitrary for a spacefaring civilization. Converting between seconds, minutes, and hours requires handling 60 or 24 as factors instead of powers of 10. Moreover, Earth-based units like the day are not universal – one day only makes sense on Earth and even varies due to irregular rotation . For a civilization spread across planets and space stations, a more universal and calculation-friendly system is desirable.

Scientists and engineers already favor consistent, non-astronomical time measures for precision. The standard SI second was redefined in 1967 based on an atomic transition rather than Earth’s rotation, because Earth’s spin is irregular

. Astronomers use Julian Date, essentially a continuous count of days and fractions of days, and Unix-based systems count seconds continuously from a reference epoch . These are forms of decimal timekeeping, chosen because decimal numbers are easier to work with and share in scientific calculations . Adopting a fully decimal time system builds on these ideas, providing a single, uniform framework for measuring time anywhere in the universe.

Defining a New Base Unit from Fundamental Constants

At the core of the system is a new base unit of time, defined by unchanging physical phenomena so that it’s the same everywhere in the universe. One approach is to use the properties of atoms. For example, the current SI second is defined by the cesium-133 atom: “the duration of 9,192,631,770 periods of the radiation corresponding to the transition between two hyperfine levels of cesium-133”

. Our new base unit can adopt a similar definition to ensure stability and reproducibility. We can call this base unit a “chron” (from chronos, time) to distinguish it from the old second. By definition, 1 chron corresponds to a fixed number of oscillations of a chosen atomic transition or another fundamental process. For practicality, we might set 1 chron = the duration of 9,192,631,770 cesium oscillations (which is effectively the current second) . This ties our time unit to a universal constant of nature (atomic frequency) rather than any local planetary cycle.

Using an atomic reference (or the speed of light) ensures the unit is truly universal. We could equivalently define the chron via the speed of light c: for instance, the time light travels a specific distance in vacuum. (Since c is fixed at ~299,792,458 m/s, light travels about 299.8 million meters in one second

, so a chron could be defined as the time for light to travel a certain fraction of that distance.) In either case, the base unit is rooted in physics that any advanced civilization can replicate with precision instruments, no matter where they are. Extremely tiny “natural” units like the Planck time (≈5.39×10^–44 s) are known from theory , but those are far too small for practical use. Instead, a chron is chosen to be at a human‐useful scale (on the order of a current second) while still being fundamentally defined.

Decimal Hierarchy of Time Intervals

Building on the base unit (1 chron), larger time intervals are structured in powers of 10 for simplicity. This means each larger unit is exactly 10 times the smaller unit, creating a clean hierarchical ladder of time units. In the new system, time could be expressed with metric prefixes or new names that reflect these decimal multiples

. For example:
  • Decachron – 10 chrons. This is 10 times the base unit (roughly equivalent to 10 seconds).
  • Hectochron – 100 chrons. 100 times the base unit (≈ a few minutes; 100 seconds is 1 minute 40 seconds).
  • Kilochron – 1,000 chrons. 1,000 times base (on the order of 16.7 minutes, since 1000 seconds ≈ 16.7 min).
  • Megachron – 1,000,000 chrons. 10^6 times base (roughly 11.57 days if 1 chron = 1 second).
    (Intermediate factors like 10^4 or 10^5 can likewise be named or prefixed as needed.)

Each step is a neat power of ten, so conversions are trivial – you just shift the decimal point. For instance, if an event lasts 2530 chrons, that is the same as 253.0 decachrons or 25.30 hectochrons, etc., without needing awkward 60 or 24-based arithmetic

. This mirrors how the metric system handles lengths (where 1,000 millimeters = 1 meter, etc.), making time calculations as straightforward as moving between grams or meters in the metric system .

In everyday use, we might still use colloquial labels for convenience at certain scales. For example, a “day” in the new system could be redefined as a round decimal value for familiarity – perhaps 100,000 chrons – which would be about 1.157 old days (27.8 hours) if 1 chron is 1 second. Alternatively, we could slightly adjust the chron’s length so that 100,000 chrons exactly equals one Earth day

, aiding transition for Earth inhabitants. (This was the approach during the French Revolution: they defined 100,000 decimal seconds per day, making each decimal second ≈0.864 of a standard second .) However, a spacefaring society may not want to privilege Earth’s day. They could simply note that Earth’s rotation period is ~86,400 chrons, Mars’s rotation ~88,775 chrons, etc., without building those into the unit definitions. The key is that all larger units derive cleanly from the base by factors of 10, and any planetary cycles are just convenient reference counts, not fundamental units.

Practical Usage and Human Considerations

A fully decimal time system would greatly simplify timekeeping in science, engineering, and daily life. Clocks and timers could display a single running decimal value or a tuple of larger units (like “megachrons.kilochrons.chrons” for date-time). Because the base and representation share the same radix (10), a time of, say, 5 hectochrons 75 chrons can be understood instantly as 5.75×10^2 chrons, or 575 chrons total, without mental conversions

. This uniformity reduces errors and cognitive load when dealing with time intervals. Adding or subtracting times becomes as simple as normal decimal arithmetic, a boon for scheduling and navigation in space.

For everyday use, humans can adapt their routines to the new units. In daily life, people might refer to “kilochrons” as a rough quarter-hour block, or whatever mapping makes sense. Digital systems could easily show the time of day as a fractional day-count in chrons (similar to how 2025-02-14.54321 in a decimal date would mean 54.321% through that day

). Alarms, work shifts, and calendars could be set in nice decimal subdivisions of the day or other convenient period. Importantly, local cycles (like day-night on a colony planet or the work/rest cycle on a spaceship) can be accommodated by choosing an appropriate number of chrons for those cycles. For example, a spaceship might define a “ship day” of 50,000 chrons (~13.9 hours) if the crew prefers shorter cycles, or 120,000 chrons (~33.3 hours) if longer. These would just be locally used groupings – the underlying time measure remains the same everywhere.

The system is also practical for technology. Computers already count time in base units (SI seconds) and can easily switch to counting in chrons (which may be essentially the same magnitude). In fact, metric time is partly already in use: the SI second is the base unit, and we speak of milliseconds, microseconds, etc., in computing and science

. Using kilochrons or megachrons for longer durations would remove the need to ever convert to hours or days in computations. Engineering systems on different planets or spacecraft could use a single time standard for logging and synchronization, simplifying interoperability.

Benefits Compared to Traditional Timekeeping

1. Simplified Calculations: The decimal structure eliminates the mix of bases (24, 60, etc.) in favor of a single base (10). This makes it easy to convert any time value to a different scale or express it as a single number

. Planning a 2.5-hour spacewalk, for instance, is simply “250 hectochrons” instead of “2 hours 30 minutes,” and if it extends by 50 chrons, that’s just adding 50 to 250 to get 300 hectochrons (3.00 hectochrons = 300 chrons). No need to carry over 60-minute hours or 24-hour days in calculations.

2. Consistency with Metric System: All other SI measurements (length, mass, etc.) use decimal prefixes and units, and time would now fully align with that. Currently, units like minute and hour are accepted but not true SI units

. In the new system, time follows the same logical progression as meters or grams, which is more intuitive when teaching and using the system. It allows a seamless integration of time into formulas without special-case conversions (useful for physics equations, for example, when time is in chrons by default).

3. Universal Standard for a Spacefaring Society: A decimal time unit defined by physics is valid on any planet or in deep space. It frees timekeeping from Earth-centric definitions. As one commentary notes, basing time on Earth’s rotation “wouldn’t make any sense in outer space”

. With the new system, Mars, Jupiter, or an interstellar ship all use the same ticks of the clock. Coordination of events (meetings, data transmissions, navigation maneuvers) across planets becomes easier since everyone references the same time scale. There’s no need to juggle different local hour lengths or calendars for fundamental coordination – those become just localized conveniences on top of the universal time grid.

4. Precision and Stability: Because the base chron is defined by unchanging fundamental processes (like atomic vibrations or c), it is highly stable and precise

. Our current reliance on atomic clocks would carry over and ensure that the time standard doesn’t drift. This is crucial for navigation (e.g., GPS, deep-space communication) and scientific measurements. It also means the unit won’t arbitrarily change if humans relocate – unlike a “day” which would be different on another planet, a chron is always the same duration everywhere.

5. Simplified Record-Keeping and Conversion: Representing time as a single number (or a tidy tuple of decimal units) means timestamps and intervals are easy to store, compare, and convert. As noted, astronomers and computer systems already appreciate this advantage

. The new system would extend that ease to everyday contexts. For example, logging the time of an event can be one number (e.g., “Rover drill started at 2.4500 days” or “211,680 chrons since mission start”) which is straightforward to compute differences with. There’s less room for confusion about time zones or AM/PM; a universal reference time could be used throughout the galaxy, similar to how Coordinated Universal Time (UTC) is used worldwide now, but on a larger scale.

Implementation for a Spacefaring Civilization

Implementing this system for an interplanetary or interstellar society would involve establishing a “Galactic Standard Time” (GST) based on the new units. All clocks, whether on Earth, Mars, or starships, would count uniform chrons. An epoch (zero-point) would be chosen – it could be something arbitrary like the beginning of a mission, or a historical reference (for example, some have whimsically suggested using the moment of the Big Bang as time zero

, though in practice a nearer epoch like 1 January 2000 might be used for convenience). From that epoch, time would simply be a running count of chrons. This is analogous to how Unix Time counts seconds from Jan 1, 1970 , but now it would be an official standard for all civilization.

Each planet or habitat could still define local “days” or cycles for human activity, but these would be secondary. For instance, a Mars colony might say one local sol (Mars day) is ~88,775 chrons, and they might break that into 10 “Martian hours” locally for work scheduling. However, for any communication or record that leaves Mars, they’d convert to GST in chrons. Spacecraft traveling between planets would likely operate solely on GST (since they experience no natural day/night cycle in transit). Mission control, data logs, and calendars would refer to the decimal time units. Tools like conversion software or dual-display clocks (showing local time and GST) would aid the transition and daily use.

In practice, the rollout could mirror the adoption of the metric system. Just as metric units replaced many traditional measures, decimal time would replace legacy clocks. People might wear watches that display 10 “hours” in a day or directly show chrons elapsed since midnight. Education and training would help people acclimate (for example, learning that 50,000 chrons is roughly half a day, etc.). Over time, tasks like navigation, scheduling across time zones (or planets), and scientific data sharing would become more straightforward thanks to the common time language.

Conclusion

The proposed decimal time system provides a logical, universal framework for measuring time, built on fundamental constants rather than parochial celestial cycles. By defining a stable base unit (chron) from atomic or physical constants and scaling in powers of ten, it achieves consistency and simplicity. A spacefaring civilization using this system would benefit from having one cohesive timeline for coordination, unhindered by the idiosyncrasies of Earth’s rotation or the cumbersome 24×60×60 breakdown. Calculations involving time would be as clean as any other metric computation, reducing errors and confusion

. In comparison to existing methods, this system is more flexible (applicable anywhere), more rational (decimal-based), and remains practical for humans by choosing units at human-friendly scales. It highlights our movement away from Earth-bound thinking toward a truly cosmic perspective on time – a crucial step for a civilization that reaches to the stars.

A Universal Fundamental Unit of Time

Defining Time by Universal Constants vs. Earthly Cycles

Why a new unit? Our current time units (seconds, minutes, hours, days) are rooted in Earth-specific phenomena. The second was historically 1/86,400 of an Earth day

, and larger units like days and years are tied to Earth’s rotation and orbit . While practical on Earth, these are meaningless off-world – a “day” on Mars or a spaceship has no reason to equal 24 hours. For a spacefaring civilization, we need a time unit defined by universal principles rather than any planet’s cycles.

Principles to consider: A truly fundamental unit of time should be based on constants or phenomena any advanced civilization could reproduce or observe. Candidates include:

  • Planck Time – the interval derived from fundamental constants (gravity G, Planck’s constant ħ, and light speed c)

    . It’s extraordinarily small (about 5.39×10^−44 seconds) – the time light takes to travel one Planck length , which is incredibly shorter than any atomic process (roughly 10^−43 seconds, a hundredth of a millionth of a trillionth of a proton’s diameter) . This is a natural unit “independent of… any special body or substance,” as Max Planck envisioned in 1899 , and would “retain meaning for all times and for all civilizations, including extraterrestrial ones” . However, by itself it’s too tiny to be practical (so short that for decades scientists ignored it as “impractically small” ).

  • Speed of Light Distance – using c to define time via distance traveled. For example, G. N. Lewis proposed a “jiffy” as the time light travels 1 cm (≈33 picoseconds)

    . Likewise, one could use the light travel time for some fundamental length (say a specific number of wavelengths of some atomic emission). This ties time to c, a universal constant. But one must still pick a length unit to pair with c – if that length is arbitrary (like 1 cm), the result isn’t fully universal.

  • Atomic Transitions – using a stable atomic frequency as a clock. The SI second already does this: it’s defined as 9,192,631,770 cycles of cesium-133’s microwave transition

    . This yields a precise, reproducible unit (the atomic second), no longer based on Earth’s rotation. We could similarly pick another universal atomic or quantum phenomenon. For instance, neutral hydrogen’s 21-cm hyperfine transition is a natural choice: it has a known frequency (~1.4204 GHz) whose period is about 0.70 nanoseconds . In fact, the Pioneer plaque used this hydrogen transition’s wavelength (~21 cm) and period (~0.7 ns) as fundamental units of length and time to communicate with aliens . Any advanced species knowing hydrogen’s properties can understand that standard. The downside is that such base periods are extremely short for human use (nanoseconds), so we’d need to aggregate many cycles to get a human-scale unit (much as the cesium clock aggregates billions of cycles to define one second).

Choosing a base unit: To fulfill all criteria, we want a unit grounded in truly universal constants like Planck’s idea, but scaled up to something practical. Atomic transitions are universal in physics, but choosing a specific atom (cesium, hydrogen, etc.) is somewhat arbitrary and ties us to that atom’s properties. Planck’s natural units are more fundamental since they use only constants present in the laws of physics themselves

. Therefore, we’ll derive our new time unit from the Planck time – but not use the raw Planck time because it’s far too small. Instead, we’ll define a large multiple of it, so that the base unit lands in a convenient range (seconds or fractions thereof). This way, the definition remains rooted in universal constants, and any civilization with advanced physics could recreate it, but it’s also a manageable interval for everyday life.

The “Chronon” – A New Fundamental Unit of Time

Let’s introduce the Chronon as our fundamental unit of time (you could also call it a “Universal Time Unit”). One Chronon is defined by a fixed multiple of the Planck time. Specifically:

  • Definition: 1 Chronon = 10^43 × tₚ (Planck times).

Since the Planck time tₚ = √(ħG/c^5) ≈ 5.39×10^−44 seconds

, this means:

1 Chronon=1043×5.39×10−44 s≈5.39×10−1 s.1~\text{Chronon} = 10^{43} \times 5.39\times10^{-44}~\text{s} ≈ 5.39\times10^{-1}~\text{s}.1 Chronon=1043×5.39×10−44 s≈5.39×10−1 s.

In other words, one Chronon is about 0.54 seconds (just over half a second) in length. This magnitude is chosen so that the unit is on the order of a human heartbeat or the time to say a word – familiar and usable scales. We arrived at 10^43 as the scaling factor to get a convenient size; the Chronon could be tuned slightly with a different factor if needed (for example, 2×10^43 tₚ would be ~1.08 seconds), but the key is that it’s a simple power-of-ten multiple of a natural unit, not pegged to any Earth rotation or orbit.

Rationale: Using the Planck time ensures the Chronon is ultimately rooted in fundamentals of nature, satisfying universality. The huge multiplier (10^43) detaches it from the microscopic realm and brings it up to a human timescale. Any advanced society can measure ħ, G, and c to realize a Planck time (conceptually), then multiply by 10^43. In practice, they need not literally count 10^43 tiny intervals; they would use secondary standards like atomic clocks to realize the Chronon (more on implementation later). But conceptually, the Chronon is independent of Earth – it doesn’t reference seconds, days, or any planetary period, only nature’s constants.

Comparison to familiar units: 0.54 s is shorter than our current second but the same order of magnitude. For context, a Chronon is roughly the time for light to travel ~162 million meters (since light in 0.539 s goes 0.539×(3×10^8 m/s) ≈ 1.6×10^8 m). That’s about 0.54 light-seconds. It’s also about the duration of a moderate human heartbeat or a quick blink. So, while derived in an alien way, it’s quite usable for humans – you could almost count Chronons like you’d count seconds (saying “one… two…” would count ~2 Chronons). This makes it practical for daily life timing, unlike nanosecond or microsecond units.

Importantly, because the Chronon is defined via fixed constants, its length will never drift or change. It’s locked to the fabric of the universe. (By contrast, the old second sometimes needs “leap seconds” inserted to keep civil time aligned with Earth’s slowing rotation

– an issue we avoid entirely.)

A Logical Hierarchy of Time Intervals (No Hours or Minutes)

With the Chronon as the base, we can construct larger or smaller intervals using a consistent decimal scaling, rather than the irregular 60×60×24 scheme of hours/minutes/seconds. This is akin to a metric system for time. For example:

  • Millichronon (mCh) – 10^−3 Chronon, for fine fractions. (~5.39×10^−4 s or 0.000539 s). This would be used for high-speed physics or engineering events (milliseconds range).

  • Kilochronon (kCh) – 10^3 Chronon. This equals 1,000 Chronons, about 539 seconds. 539 s is about 9 minutes (since 600 s would be 10 min). So one kilochronon is a convenient interval on the order of minutes. Instead of “15 minutes”, one might say “~1.7 kCh” (since 1.7×539 s ≈ 915 s ~ 15 min).

  • Megachronon (MCh) – 10^6 Chronon. That is 1,000,000 Chronons, roughly 5.39×10^5 seconds. 5.39×10^5 s is about 6.24 days (a bit over six Earth days). A megachronon is a long interval, useful for multi-day spans or measuring weeks. For instance, an Earth week (~7 days) is about 1.12 MCh.

  • Gigachronon (GCh) – 10^9 Chronon. This equals ~5.39×10^8 s, which is about 17.1 years. So 1 GCh is on the order of decades. (A human lifespan ~80 years would be ~4.7 GCh.)

  • Terachronon (TCh) – 10^12 Chronon, ~5.39×10^11 s, ~17,100 years (on the order of historical epochs).

And so on (kilochronon, megachronon, etc. follow the standard SI prefix naming for 10^3 steps). For intermediate everyday use, we can also define deci- or centi- multiples if needed (e.g., 1 decachronon = 10 Chronons ≈ 5.39 s). In general, however, using base-10 multiples means we can express any time interval with a tidy number rather than mixing units.

For example, instead of saying “2 hours 30 minutes”, we would use one unit (Chronon) and perhaps scientific notation or a prefix: 2h30m = 9000 seconds, which is about 16700 Chronons, or 16.7 kCh. Instead of “a day” (24h), which is 160,000 Chronons (since 24*3600/0.539 ≈ 1.6×10^5), one could say 160 kCh. But note, in a spacefaring context we might not even use the concept of a “day” universally (since it varies by planet). One would just specify the number of Chronons or appropriate prefix unit for any duration or timestamp.

This decimal hierarchy has clear logical flow – each larger unit is just 1000× the smaller, making conversion and calculation straightforward. Gone are the hodgepodge factors (24 hours/day, 60 minutes/hour, 60 seconds/minute) which require mental conversion. The simplicity is akin to how metric units of length work (mm, m, km), but applied to time.

Human adaptation: Humans are used to roughly 24-hour cycles for sleep, so in daily life a person might informally refer to something like “my daily cycle is ~160 kCh long” (≈24 hours). But all official timekeeping and communication would stick to the standard units of Chronons and its multiples, not resetting every 24 hours as a “day” does. Think of it like abolishing separate hours and minutes in favor of a single running count (just as we don’t use separate units for distance – we use meters and then kilometers, rather than, say, feet and miles with odd conversion). This continuity and decimal structure make the system easy to work with, both for mental math and for high-precision science.

Practical Use in Science, Engineering, and Daily Life

A Chronon-based system would be beneficial across the board:

  • Scientific Calculations: By tying the unit to fundamental constants, we align with the systems physicists already use in theoretical work. In Planck units (which our Chronon is based on), many fundamental constants become dimensionless or unity

    , simplifying equations. For instance, if one also used the corresponding Planck-length unit for distance, the speed of light c would be 1 Chronon per appropriate length unit by definition. Even if we don’t fully switch all units, having time in Chronons means we can express quantities like particle lifetimes or orbital periods without referencing Earth seconds. It’s a truly universal language for time. An alien scientist on another planet would derive the same Chronon length if they chose the same 10^43 multiple of tₚ, and could immediately understand our measurements of time in their own terms of physics .

  • Engineering and Technology: All modern tech that relies on precision timing (GPS, telecommunications, computer clocks) could seamlessly adopt the Chronon. Since the Chronon is close to a second, existing systems wouldn’t face extreme redesign; it’s mostly a change of scale and terminology. Engineering calculations might even get simpler since we avoid odd conversions and leap-second corrections. For example, a spacecraft’s systems could use kilochronons for scheduling burns or maneuvers (1 kCh ~ 9 minutes, a nice unit for engine burns or orbits), and megachronons for mission durations. Because the unit is fixed by nature, high-precision synchronization across systems would remain as robust as with atomic seconds (we would realize Chronons using atomic clocks anyway). In fact, metrology labs could develop atomic clocks for Chronons – e.g. calibrating a device such that it counts a certain number of hyperfine transitions of an atom to equal 1 Chronon. Given 1 Chronon ≈0.54 s, that would be about 5 billion cesium cycles (since 1 second is 9.19 billion Cs cycles

    , so 0.54 s is ~4.97×10^9 cycles). A clock could be built or programmed to define Chronon by counting those cycles, or using another element’s frequency conveniently. The key is that once set, all engineers everywhere use the same unit.

  • Daily Human Use: On a personal level, people could wear watches or use timers that display Chronons and kilochronons. Initially it might feel odd (“What’s the time?” – “It’s 50 kCh since the reference epoch”), but humans can adapt just as we adapted to time zones or the metric system. Likely, common conventions would arise: for example, a work shift might be ~60 kCh (≈9 hours in old money), and a sleep period ~100 kCh (~15 hours). Or a colony on a spaceship might decide to stick to a 150 kCh awake / 50 kCh rest schedule (≈ day of 200 kCh, ~30 old hours) that suits their lifestyle. The advantage is that everyone’s clocks, regardless of where they are, tick the same units at the same rate. No more converting between “local times” when coordinating across planets – local “morning” might differ, but time is measured on one continuous scale. People would likely stop thinking in terms of Earth-specific units altogether after a while; “a second” or “an hour” would be replaced by fractions or multiples of Chronons which are just as intuitive once you’re used to them.

  • Ease of Calculation: With decimal units, everyday calculations (like adding durations) become simpler. Say a recipe needs to bake something for 2.5 kCh, and another step takes 500 Ch – that’s just 3,000 Chronons total (no need to convert minutes and seconds). Or if an event is in 50 kCh and now it’s 47.3 kCh, then you know it’s 2.7 kCh away. These are straightforward in base-10. In contrast, with hours/minutes, an event at 2:30 and current time 2:12 requires you to do a mix of base-60 math. Over large spans, the benefits grow – imagine calculating ages or deadlines in one unit rather than years/months/days.

In summary, the Chronon system would function much like an international metric time: scientifically precise, easy to convert by powers of ten, and still relatable for human activities with the right multiples.

Comparison to Existing Time Systems

How does our Chronon-based system stack up against the status quo and other proposals?

  • Versus the SI Second System: The current SI second is already derived from a universal phenomenon (cesium atoms), but it carries historical baggage. Its value (9.192631770×10^9 Cs oscillations) was chosen to match the old second

    , which in turn was Earth-based . In essence, the second is calibrated to Earth’s rotation period of 1900 . Our Chronon throws away that legacy calibration and starts fresh from physics. There’s nothing magic about 0.54 s versus 1.00 s except that one is a neat power-of-ten multiple of tₚ. By choosing a round figure in natural units, we emphasize conceptual clarity. The second could have been defined differently too – it’s somewhat arbitrary that it ended up as 9.19×10^9 cycles of Cs. Chronon chooses a round number (10^43) of the smallest time unit possible. Both systems use atomic clocks in practice and both are extremely precise; but Chronon is philosophically aligned with Planck’s vision of “natural units” that any civilization would deduce . An alien might wonder why 9.192631770×10^9 and not a round 10^x; Chronon would make more immediate sense to them (once they figure out the factor corresponds to fundamental constants).

  • Versus Earth Day/Year Units: As noted, days, years, months are hopelessly local

    . A Martian sol (day) is ~24.6 hours, a year on Jupiter is ~12 Earth years, etc. Using those as standard in a multi-planet society causes confusion and bias. Our system simply doesn’t use “days” or “years” as fundamental measures—those become derived or irrelevant. If needed, one can still say “sol” for a Mars local day, but it would be understood as ~164 kCh (if Mars day ~24h39m, convert to Chronons). The Chronon system benefits by not favoring any world’s cycle. It is the same everywhere, everywhen. This is a huge benefit when coordinating interplanetary events. For example, a mission timeline can be planned entirely in Chronons; whether an astronaut is on the Moon or Ceres, the schedule times mean the same duration for each. There’s no need for a plethora of local time conversions or calendars.

  • Versus Other “Metric Time” Ideas: Historically, people have proposed decimal time (like the French Republican Clock with 10 hours/day, 100 minutes/hour). Those still pegged the day length to Earth

    . Others, like Stardates in science fiction, use a continuous count but often lack a clear basis and end up arbitrary or inconsistent. Our approach is metric (powers of ten) and rooted in physics. It provides the regularity decimal time advocates wanted, but with a foundation that isn’t an Earth day. It also avoids the confusion of fictional time systems by giving a precise definition anyone can test. Another concept floated for a galactic empire is to use a pulsar as a universal clock (because pulsars emit periodic signals). Pulsar-based timekeeping has indeed been studied – e.g., the European Space Agency’s PulChron uses millisecond pulsars to keep time as an independent check on atomic clocks . While pulsars are cosmic and not Earth-specific, relying on one introduces issues: only those in communication with that pulsar can sync, and if you move far across the galaxy, the timing of pulses shifts (not to mention pulsars can slowly drift or glitch). By contrast, Chronon is locally realizable anywhere with lab equipment – no need for an external signal. It’s as if every planet carries its own “cosmic clock” because the recipe for the unit is coded in physics itself.

  • Precision and Adjustments: The second-based system requires leap seconds occasionally to adjust civil clocks, because Earth’s rotation is not constant

    . In a Chronon system, we do not tie civil time to any rotation, so no leap seconds are necessary. Timekeeping would be uniform and continuous. (If people on Earth still wanted noon to align with the sun overhead, they could adjust their work schedules, but the clocks would not reset or pause). Furthermore, atomic time (the basis of seconds now) is incredibly precise – cesium clocks drift only ~1 s in 100 million years . Chronon clocks would inherit this precision. If anything, using multiple atomic references (cesium, hydrogen, etc.) to define Chronon could make it even more robust: for example, the Chronon could be calibrated by a known combination of fundamental frequencies, reducing dependency on any single atom’s clock. In either case, both second and Chronon systems far exceed the precision humans need; but Chronon does so while remaining conceptually simpler and universally applicable.

Implementation in a Spacefaring Civilization

How would a spacefaring society actually adopt and use the Chronon system?

Establishing the Standard: First, an international (or interplanetary) standards body would define the Chronon officially, just as the second is defined today. They’d publish something like: “The Chronon is the base unit of time in the Universal System. It is equal to 10^43 times the Planck time (ħG/c^5)^1/2.” This gives scientists anywhere the recipe. In practice, they might also provide a secondary definition using atomic transitions for ease of realization: e.g. “One Chronon is the duration of 4.9685×10^9 cycles of the unperturbed Cs-133 hyperfine transition at 0 K” (if that number is adjusted to exactly match 0.539 s; or they could use hydrogen or another standard). Laboratories on various planets could then calibrate their primary clocks to this standard by tuning their atomic clocks accordingly.

Dissemination of Time: A spacefaring civ would need to synchronize clocks across vast distances. They could broadcast time signals in Chronon units via radio or laser. Because of the speed-of-light delay, there wouldn’t be a single “galactic now” everywhere (relativity forbids perfectly synced time across space), but they can establish a reference frame (say, a master clock on a flagship or a central planet) that others sync to when they receive the signal. For example, a colony on Europa might receive a time update from Earth that says “current time = 1.2345×10^12 Chronons since epoch.” They might be hours or days out-of-sync due to signal travel time, but they know the standard tick rate to keep locally. Each location would run its clocks continuously in Chronons and occasionally adjust if drifted from the reference (similar to how GPS satellites and ground stations share time updates now). Because all clocks use the same unit, comparisons are direct – no converting units, only accounting for signal delay or relativistic drift.

Epoch and Calendar: We haven’t discussed when “zero” time is. The Chronon is a unit, but for day-to-day use we’d also have a timeline or calendar (like how we use years AD/BC on Earth). A spacefaring society might choose an arbitrary epoch like the beginning of a universal calendar – perhaps the moment this new system was adopted, or a past event like the first moon landing, or something truly cosmic like the Big Bang (though “time since Big Bang” ~4.35×10^17 s would be an inconveniently large number to use). Let’s say they choose an epoch such that at a certain agreed moment, the time was 0 Chronons. From then on, all events are measured as timestamps in Chronons elapsed. This is analogous to Unix Time (seconds since Jan 1, 1970) but on a far grander, permanent scale. So a spaceship departure might be logged at time 1.0000×10^12 Chronons, and an arrival at 1.0003×10^12 Chronons, etc. Such a single number timestamp avoids any need for months or days names – it’s just increasing Chronons. If needed for human-readability, they could still format these into larger groupings (like breaking the continuous count into more human-friendly notation, e.g. “X megachronons since epoch”), but the underlying count is continuous.

Local Adjustments: On planets or habitats, people might still define a local “cycle” for convenience – for instance, Martians might informally say “one sol” for one rotation of Mars. They can use Chronons to measure it (one Mars sol ≈ 164300 Chronons). But critically, those are not separate units in the official system, just nicknames for certain number of Chronons. All clocks and official records use Chronon units. So a meeting time might be given as a specific Chronon count, which locals convert to realize it falls during their daylight or night. This is similar to how we handle time zones: e.g., a UTC time is given and each zone converts to its local hour. In the spacefaring case, “zones” might be entire planets, each with their own rotation period – but all tied to the standard timeline. This approach eliminates ambiguity. An engineer on Earth scheduling a video call with Mars simply gives the time in Chronons (or kCh), and their Martian colleague knows how that maps to their local schedule. No confusion of “is that Earth hours or Mars hours?”

Relativistic Effects: In interstellar travel at relativistic speeds, time dilation becomes significant – different ships will age at different rates. However, the coordinate time used for communication still can be the Chronon timeline. A ship traveling fast might experience, say, only 500 Chronons of proper time while 1000 Chronons pass on the standard timeline. This is no different than how we handle relativity with Earth’s clocks now (GPS satellites’ clocks tick slightly faster than ground clocks due to weaker gravity, and we correct for it). A spacefaring civ would similarly apply relativistic corrections to keep their clocks aligned with the master Chronon time. The benefit of a universal unit here is again clarity: whether you’re on a fast ship or a slow planet, you can report how many Chronons have elapsed by the standard frame’s count. Your local experience might differ, but it can be translated via physics to the common reference frame’s time. In essence, Chronon becomes the agreed “coordinate time” of the civilization.

Benefits Recap: By implementing the Chronon system, a spacefaring civilization gains a consistent, universal clock that all members can share. No matter where or who (human or alien) they are, time is measured the same way. It promotes scientific collaboration (everyone uses the same units), simplifies engineering (one common timing system for all devices and navigation), and eases cultural exchange (events can be universally dated and sequenced without converting calendars). It future-proofs timekeeping as well – even as humanity lives on different worlds or in deep space, the time standard remains valid and convenient, rooted in the fabric of the universe rather than the quirks of one world

.

Benefits of the New Approach

Adopting the Chronon as the fundamental unit of time offers several clear benefits:

  • Universality: The unit’s definition relies on immutable physical constants, making it valid “for all times and for all civilizations, including extraterrestrial and non-human ones”

    . Any advanced civilization would arrive at similar units when studying physics, facilitating communication. It’s a built-in common ground – much like mathematics, a truly universal language.

  • Neutrality: It frees us from the Earth-centric bias in timekeeping. No planet’s day or year dominates the system. This is important socially and politically in a multi-planet civilization – it puts all colonies on equal footing in terms of time standards (no one is stuck converting their lives to fit Earth’s clock). It also respects that not all intelligent beings (should we encounter or become them) will come from a 24h-day planet.

  • Consistency and Simplicity: The decimal hierarchy eliminates odd conversion factors, reducing mistakes and confusion. One can convert between any time scales by shifting decimal places. Scheduling, computing, and calculating durations all become more straightforward.

  • Scientific Elegance: Tying the unit to Planck time bridges the gap between daily life and deep physics. It subtly acquaints society with fundamental constants. It’s conceptually elegant that the speed of light, Planck’s constant, and gravity are etched into our time unit’s DNA. For a spacefaring culture that likely has a strong scientific backbone, this symbolic alignment with the universe’s fundamentals might be philosophically satisfying. It also means our time unit is directly connected to natural laws – something that wasn’t true for traditional units.

  • Practicality: Despite its exotic origin, the Chronon is sized for practicality. We ensured it’s in the ballpark of seconds so that existing technologies (clocks, timers, oscillators) can easily adopt it. Humans can perceive and use it without trouble. Indeed, the transition from seconds to Chronons could be as simple as updating software and dials, given their close magnitude.

  • Future-Proofing: As humanity ventures further into space, possibly encountering other intelligent life or establishing distant colonies, a universal time unit prevents the fragmentation of time standards. History shows standardizing units (like metric system) greatly boosted science and trade; a time standard extends that benefit to the chronometric realm. It will also avoid the messy corrections and redefinitions that the second had to undergo (leap seconds, etc.), because our unit is not pegged to any unstable astronomical cycle.

In conclusion, the Chronon-based time system provides a harmonious blend of scientific universalism and everyday usability. It liberates timekeeping from its terrestrial shackles and prepares the way for a cosmic era where time is measured on our terms, not Earth’s. A spacefaring civilization implementing this would enjoy seamless synchronization, easier communication, and the knowledge that their clocks tick in unison with the fundamentals of the universe. As Carl Sagan and colleagues hinted with the Pioneer plaque’s use of hydrogen’s frequency

, the key to interstellar understanding lies in universal benchmarks – and what better benchmark for time than one drawn from the very constants that govern time itself?

Sources:

  • Max Planck’s proposal of natural units for “all civilizations, including extraterrestrial” and values of Planck time .
  • Space.com – Discussion of Planck time’s magnitude and impracticality for daily use .
  • Pioneer Plaque explanation – using hydrogen 21-cm hyperfine transition as a universal length/time reference .
  • NIST and Wikipedia – Definition of the second via atomic cesium oscillations and its historical Earth-based origin .
  • Reddit (SciFiConcepts) – Issues with Earth-centric time (days, years) for space civilizations .
You said:
Continuing with this prior chat, where you came up with a solution for time. Can you come up with a solution for measuring height, length, and distance that does not involve any of the silly expressions like "foot" which was derived from somebody's foot? That ridiculous. We need a means of measuring the height of everything, the distance to something, and it could be light years from Earth, but don't forget that Light Years uses seconds and you have done away with that. If something logical exists already then please tell me about it.
ChatGPT said:

I see your goal is to establish a fully universal, logical measurement system for height, length, and distance, avoiding arbitrary Earth-based units like the 'foot' or even 'light-years,' which rely on the now-replaced second.

To refine the research, could you clarify:

  • Should the new unit be based on fundamental constants (e.g., Planck length, speed of light) or a physically reproducible standard (e.g., atomic properties)?
  • Do you want a fully decimal hierarchy for larger/smaller measurements, similar to the Chronon system for time?
  • Should this new length unit align with any existing scientific units (e.g., meters, astronomical units), or are you looking for something entirely new?

This will help ensure the solution is both practical and rigorously universal.

You said:
The new unit could be based on fundamental constants. I do not know much about them. A fully decimal hierarchy for larger/smaller measurements, similar to the Chronon system for time makes a lot of sense. Well, I don't know, where does the "meter" come from? Is it something silly like the outstretched arms of a King?
ChatGPT said:

Great! I will develop a new fundamental measurement system for length, height, and distance, eliminating arbitrary units like the foot and redefining large-scale cosmic distances without relying on the second. The system will be:

  • Based on Fundamental Constants: Rooted in physical constants rather than human body parts or historical artifacts.
  • Fully Decimal: Following the structure of the Chronon system to enable easy scaling up and down.
  • Universally Applicable: Usable for everything from microscopic to interstellar distances, avoiding Earth-centric biases.
  • Compared to Existing Systems: I'll analyze whether any current scientific units (e.g., meters) align with this goal or if a completely new system is needed.

I'll provide a structured proposal soon!

Research completed in 5m · 5 sources

A Universal Length Unit Based on Fundamental Constants

Rationale for a Universal, Non-Arbitrary Unit

Humanity’s traditional length units (feet, miles, etc.) grew from local quirks – often the size of a body part or a land measure – making them arbitrary and non-universal

. A spacefaring civilization spanning multiple worlds needs a system free of any one planet or culture’s idiosyncrasies. The goal is a truly universal unit of length defined by nature’s constants, not by historical accident. This mirrors the approach taken with time, where the Chronon replaced the second as a fundamental, decimal-based unit of time. By basing units on immutable physical constants, any advanced society (or even aliens) with knowledge of physics can reproduce the units, ensuring clear communication and consistency . The new length system must also be decimal for ease of scaling, just as the Chronon system uses a 10-based structure for time. This will allow seamless conversion from the microscopic to the cosmic scale by simply shifting decimal prefixes, without resorting to separate unit systems for different scales.

Basing Length on Fundamental Physical Constants

To eliminate anthropocentric references, the new unit is derived from fundamental constants of nature. One elegant choice is to use the Planck length, which is defined in terms of the speed of light c, the gravitational constant G, and Planck’s constant ħ (ℏ):

ℓP=ℏGc3≈1.616×10−35 m. \ell_P = \sqrt{\frac{\hbar G}{c^3}} \approx 1.616 \times 10^{-35} \text{ m}.ℓP=c3ℏG≈1.616×10−35 m.

This Planck length is an inherently universal (if tiny) length scale

. Of course, ℓP\ell_PℓP itself is far too small for everyday use – on the order of 10^−35 meters . To get a human-usable base unit, we scale it by a power of ten. For example, we can define the new base “unit of length” (let’s call it the UniLength for now) as:

1 UniLength=1035×ℓP.1~\text{UniLength} = 10^{35} \times \ell_P.1 UniLength=1035×ℓP.

Since ℓP≈1.616×10−35\ell_P \approx 1.616\times10^{-35}ℓP≈1.616×10−35 m, this makes 1 UniLength ≈ 1.616 meters

. This is on the order of a human body length, so everyday objects would be measured in single or tens of UniLengths. The choice of 103510^{35}1035 is deliberately a power of ten to fit a decimal system. In this scheme, all larger and smaller distances scale by factors of 10 (with standard prefixes like kilo-, milli-, etc.), providing a fully decimal hierarchy. Smaller scales like centimeters or kilometers are naturally handled as 0.01 or 1000 in these units, rather than requiring new names or conversion factors.

Why use Planck length? It ties the unit to the bedrock of physics – ensuring that any civilization measuring c,G,c, G,c,G, and hhh can derive the same length. It’s “free of arbitrary human-based units” by definition. Moreover, by also redefining the time unit (Chronon) in terms of Planck time or another fundamental interval, we can achieve simple relationships between units. For instance, if the time base is also chosen in powers of Planck time (about 5.39×10^−44 s), we might set 1 Chronon = 104310^{43}1043 Planck times ≈ 0.54 seconds

. In that case, light speed becomes a nice round number: c≈1.0×108c \approx 1.0\times10^8c≈1.0×108 UniLengths per Chronon . In other words, light would travel exactly 100,000,000 of our length units in one time unit. This is a huge simplification compared to c=299,792,458c = 299,792,458c=299,792,458 m/s in SI units , and it’s achieved by design through the fundamental scaling. Such elegance in constants is helpful in scientific calculations and reinforces the unit’s natural basis.

Another approach to base the length on fundamental physics is to use an intrinsic wavelength of a universal atomic phenomenon. For example, the 21-centimeter microwave hyperfine wavelength of hydrogen is the same anywhere in the universe and was even used as a reference on the Pioneer plaque for alien communication

. We could define the new unit such that it equals (or is a simple decimal multiple of) this wavelength. One option: 1 UniLength = 1 wavelength of the hydrogen 21 cm line (≈0.211 m). This ties the unit to a specific atomic constant that any advanced civilization could observe, without referencing human artifacts. Historically, the meter itself was once defined in a similar way – e.g. from 1960–1983, 1 meter was exactly 1,650,763.73 wavelengths of a krypton-86 atomic emission line . Defining our unit by a round number of wavelengths of a chosen spectral line (say exactly 1.000×10^6 wavelengths = 1 unit, to keep it decimal) would ensure it’s fundamental and easily reproducible with spectroscopy, without needing a time interval in the definition.

The New Unit and Its Decimal Hierarchy

Let’s assume we adopt the Planck-scaled definition (for maximal universality): 1 UniLength = 10^35 Planck lengths ≈ 1.616 m

. This is our base unit of distance, replacing the “meter” concept. All other distance measures are then powers of ten of this base:
  • 1 Deca-UniLength = 10^1 UniLengths (≈ 16.16 m)
  • 1 Kilo-UniLength = 10^3 UniLengths (≈ 1.616×10^3 m, i.e. ~1.6 km)
  • 1 Mega-UniLength = 10^6 UniLengths (≈ 1.616×10^6 m, ~1.6×10^6 m or 1,616 km)
  • 1 Giga-UniLength = 10^9 UniLengths (≈ 1.616×10^9 m, ~1.616 billion meters)

…and so on for Tera- (10^12), Peta- (10^15), etc., down to deci- (10^–1), centi- (10^–2), milli- (10^–3), micro- (10^–6), etc. This mirrors the Chronon time system’s decimal scaling for seconds, minutes, etc., but applied to space. Crucially, there are no odd conversion factors (like 12 inches = 1 foot, 5280 feet = 1 mile, or 1 astronomical unit = 149,597,870.7 km) – everything is a clean power of ten relationship.

Everyday scales: For a person’s height (~1.7 m), this is roughly 1.05 UniLengths. A coffee table (~0.5 m) would be 0.31 UniLengths (or 31 centi-UL). Such values are easy to handle or convert to sub-units. Common subunits might naturally arise: for instance, 0.1 UniLength (about 16.16 cm) could serve like a “decimeter” scale, and 0.01 UniLength (~1.6 cm) like a “centimeter” for finer measures. Because the base is close to a meter, human-scale distances remain in the 0.1–10 range of the base unit, which is convenient. If instead we had chosen the hydrogen wavelength basis (0.211 m), the base unit would be smaller – an average adult might be ~8 units tall – but still manageable with decimal prefixes (e.g. using tens of units or kilo-units as needed). The exact magnitude of the base is somewhat flexible; what’s important is that it’s decimally related to fundamental lengths, and reasonably sized for daily life.

Cosmic scales: The advantage of a single, decimal system is that even astronomical distances can be expressed without switching to specialized units like “light-years” or “parsecs.” We simply apply larger prefixes. For example, the distance from Earth to the Sun (~1 Astronomical Unit) is about 9.3×10^10 UniLengths (93 Giga-UL). The nearest star (~4.2 light years) would be on the order of 2.5×10^16 UniLengths, which we could call 25 Peta-UL. For intergalactic distances, we’d climb to Exa-, Zetta-, and Yotta- prefixes. A galaxy 1 million light years away would be roughly 9×10^21 UniLengths (~0.9 Zetta-UL). While these numbers are large, they are manageable with scientific notation or prefix naming, and crucially no new unit names are introduced – a scientist can convert a planetary survey (in kilo-UL) to an interstellar baseline (in tera- or peta-UL) by moving the decimal point. This continuity is ideal for a spacefaring civilization that deals with a vast range of distances.

Fundamental Realization and Practical Use

A unit defined by fundamental constants needs a way to be realized (measured) in practice. In our new system, this could be done in a few equivalent ways:

  • Via Fundamental Constants: If we choose the Planck-based definition, we are essentially setting a fixed combination of c,G,ℏc, G, \hbarc,G,ℏ. A standards laboratory in the spacefaring civilization would know the numerical values of these constants in the chosen unit system (some of which might be 1 or nice round numbers by definition). For instance, the act of defining 1 UniLength = 1035ℓP10^{35}\ell_P1035ℓP can be seen as fixing the value of GGG (or ℏ\hbarℏ) appropriately, since ℓP\ell_PℓP depends on them. With those constants defined, one can reproduce the length by experiment: for example, using an interferometer with lasers whose frequency (and thus wavelength) is known in terms of ccc and the Chronon. The length light travels in a given fraction of a Chronon can calibrate the unit length. Essentially, since ccc is known and fixed in our units (say 10810^8108 UL per Chronon by design

    ), a precise timing of light travel or counting of wave cycles yields the distance. This does implicitly involve the time unit (Chronon) for the realization method, but the definition of the length itself doesn’t rely on the second – it relies on c,G,ℏc, G, \hbarc,G,ℏ which are universal constants. In practice, time and length measurements often intermingle (as in the current SI), but what we’ve avoided is referencing any Earth-rotation or human calendar in defining the unit.

  • Via Atomic Wavelengths: Alternatively, the civilization can agree on an atomic or nuclear transition that produces a stable wavelength as a secondary standard. For example, they might decree: “The wavelength of the neutral hydrogen 21-cm hyperfine line is exactly 0.2110642… UniLengths.” (If the base unit was chosen as exactly that value, it’s 1.000 UL by definition; if not, it can be a known fraction.) Then by producing that spectral line (e.g. in a radio frequency cavity) and measuring out a known number of wavelengths (counting interference fringes), one can directly realize the base unit of length without any time measurement. This is akin to how the meter was realized with a krypton-86 lamp in the mid-20th century

    . The difference is that we ensure the number of wavelengths per unit is a round power of ten or 1, to keep it non-arbitrary. Using such a natural oscillator provides a practical way to implement the unit across different planets or ships – anyone, anywhere can generate hydrogen spectra or use a laser tuned to that frequency and verify their length measure matches the universal standard.

In daily life and engineering, the use of this system would feel much like a refined metric system. A builder on Mars might measure materials in UniLengths and millUniLengths, just as one on Earth might have used meters and millimeters – but they know these units are grounded in cosmic truth, not Earth alone. Instruments like laser rangefinders or radar could inherently use ccc and Chronon to display distances in these units immediately. For cosmic navigation, spaceship computers would handle distances in, say, Giga-UL or Tera-UL, avoiding confusion of switching to “light-minutes” or the like. The uniform decimal structure makes unit conversion trivial (a necessity when dealing with everything from nanotechnology to interstellar voyages).

Is a New Unit Necessary? (Comparison to the Meter)

It’s worth asking whether we truly need an entirely new length unit, given that the modern SI meter already has many of these features. The meter today is no longer defined by a human artifact or Earth’s geography; since 1983 it’s defined via the speed of light: “the length of path traveled by light in vacuum during 1/299,792,458 of a second”

. This ties it to the fundamental constant ccc. Moreover, the second is defined by an atomic constant (cesium-133 hyperfine frequency), not by Earth’s rotation. In that sense, the meter is already based on fundamental physics, and the SI system is largely free of old arbitrary bases. For scientific use, we can communicate the meter to extraterrestrials by referencing the cesium clock and ccc. So one could argue an entirely new unit isn’t strictly “necessary” – we could simply continue using the meter-kilometer system, and it would serve just fine in a spacefaring future (with perhaps more use of large prefixes for cosmic distances instead of units like light-year).

However, there are a few motivators for tweaking or replacing the meter in our new scheme:

  • Decoupling from the Second: Our meter definition still explicitly uses the second. In the Chronon time system, we’ve moved to a new base time unit, so it makes sense to redefine the length unit without referencing the old second. We could rephrase the meter in terms of Chronons (distance light travels in 1/299,792,458 of a second = distance light travels in X Chronons), but that X would likely be an awkward non-integer number of Chronons. A new unit lets us avoid such fractional ties. Instead, we pick a definition that either uses fundamental constants directly or an integral number of wavelengths, making the relation cleaner. This conceptually streamlines the unit system – each base unit (time, length, etc.) is defined on its own fundamental terms yet they remain consistent through physical laws.

  • Anthropocentric Value: The meter, while based on constants now, was originally chosen to be convenient for humans (one ten-millionth of a quadrant of Earth). Its size is somewhat arbitrary – it could have been a bit larger or smaller. In a universal redesign, we have the freedom to adjust the base length slightly for perhaps more elegant relationships. For instance, by choosing ~1.6 m as the base, we got c≈1×108c ≈ 1\times10^8c≈1×108 in our units

    . In SI units, c=2.99792458×108c = 2.99792458\times10^8c=2.99792458×108 m/s, which isn’t a round number. Also, many fundamental atomic scales end up as messy fractions of a meter. By contrast, in our proposed system the Planck length is exactly 10−3510^{-35}10−35 UniLength by definition – a nice power of ten – whereas in SI it’s 1.616×10−351.616\times10^{-35}1.616×10−35 m (a strange number). Similarly, the hyperfine hydrogen wavelength would be a simple 0.2110… UL instead of 0.2122… m, etc. These are admittedly subtle advantages; they don’t affect everyday carpentry or trade, but they make the unit system more mathematically neat for high-precision science. A spacefaring society might value a system where the fundamental constants and naturally significant lengths/time are expressed with clean, memorable figures rather than legacy ones .

  • Unified Scaling: While the metric system already provides decimal scaling, our new system doubles down on it for all scales of length, encouraging the use of standard prefixes up to the astronomical range. In practice, modern usage still introduces non-metric units for convenience (astronomical unit, light-year, parsec) because they tie to observational or historical contexts. In a future universal system, the preference would be to stick to one unit and simply apply, say, petalengths or exalengths. Technically, one can do this with meters (e.g. 1 light-year = 9.46 petameters), so this is more of a cultural shift than a necessity. But establishing a fresh system gives an opportunity to standardize cosmic measurements from the start.

In summary, the meter could be repurposed for this role by slight redefinition (especially if we express it in Chronons or fundamental constants differently). The decision to introduce a new name and exact length is partly philosophical and practical: it signals a break from Earth-bound thinking and ensures everyone adapts to a truly universal mindset. The improvements over the meter are incremental – the meter was a brilliant early attempt at a universal measure, and our proposal refines it further (removing any residual Earth-dependence and aligning it with a new time unit and neat constants). Whether those refinements justify a “new unit” in name is debatable, but for the exercise, we assume it does, given the spirit of creating a cohesive spacefaring SI.

Implementation in a Spacefaring Civilization

Adopting this new universal length system would involve education, infrastructure tweaks, and perhaps dual-marking during a transition from older units (just as we do when adopting metric). A spacefaring civilization might implement it as part of a broader move to Universal Standard Units for all measurements (time, length, mass, etc., all based on constants). The process could look like:

  • Establishing Standards: The governing scientific body defines the base length formally (e.g. via Planck length multiple or an atomic standard) and publishes the exact relationship to previous units for reference. For instance: “1 UniLength is exactly 1.616 255 (etc) meters” until people phase out the old reference. They would also fix constants like c,G,ℏc, G, \hbarc,G,ℏ or the chosen atomic wavelength frequency to exact values in these new units to solidify the definitions.

  • Dissemination of the Unit: Just as BIPM provides standard meter artifacts or calibration methods worldwide, the civilization would distribute reference instruments – perhaps a device that produces the hydrogen line and an interferometer so that any lab can realize the unit locally by counting 10^X wavelengths. Likewise, frequency standards tied to Chronon would ensure time and length standards stay in sync via ccc. Because the unit is based on nature, even a ship far from civilization could recalibrate by observing fundamental phenomena (for example, using a known laser frequency and timing light rounds with an onboard Chronon clock).

  • Integration into Technology: All new measuring devices, CAD software, navigation systems, etc., would use the new units by default. Spacecraft range-finding might naturally use the time-of-flight of signals in Chronons to output distances in UniLengths. Engineering drawings for interplanetary vehicles could be in milliyuli (milli-UniLengths) instead of millimeters. Over time, everyday language adopts the new terms (perhaps “units” for short, if a unique name isn’t given – e.g. “The doorway is 2.0 units high”).

  • Benefits Realized: Engineers and scientists quickly appreciate that formulas sometimes simplify. For example, if c=1.0×108c = 1.0\times10^8c=1.0×108 UL/Chronon exactly, then converting a signal travel time to distance is as simple as shifting a decimal. Communications with alien intelligences or between colonies are eased by referencing these fundamental units: one can transmit, “Our base length is defined such that the speed of light = 1×10^8; the wavelength of the hydrogen 21-cm line is 0.21106 in those units,” and any other civilization can decode our measurements without needing to know about Earth’s meters or seconds

    .

  • Accommodation of Human Scale: Because the base unit was chosen close to human dimensions, the switch wouldn’t drastically change the numbers people use day-to-day. A person who is 1.75 m tall would be ~1.08 UL tall – a different number, but of the same order, so the intuition for distances remains. This was a conscious design: picking a base that yields practical numbers for human life (unlike, say, using the raw Planck length or the light-year as the base, which would give wildly tiny or huge everyday figures). Thus, the system manages to be universal in principle yet practical in practice.

In conclusion, the new length measurement system centers on a universal length unit derived from fundamental constants, implemented in a fully decimal framework. It abandons arbitrary historical sizes in favor of nature’s yardsticks – whether via Planck units or atomic phenomena – ensuring any advanced being can replicate it. By comparing with the existing meter, we see that the change is an evolutionary step rather than a revolutionary departure: it fine-tunes our units to be even more universal (removing the last traces of Earth-specific definition and making certain constants conveniently form whole powers of ten). This system would serve a spacefaring civilization by providing a common language of measurement from the lab to the stars, simplifying science and engineering with a coherent, easy-to-scale unit for all distances large or small. Such a foundation helps bind together a galactic society with the precision of fundamental physics and the pragmatism of a decimal system, just as the Chronon did for time.

Sources:

  • History of length units and their human-centric origins
  • Modern SI definitions of the meter (Krypton-86 wavelength and speed of light)
  • Planck units derived from fundamental constants
  • impracticality of raw Planck units for everyday purposes
  • Proposal to scale Planck units (10^35 Planck lengths) to get a human-sized unit
  • Benefit of making speed of light a round number in new units
  • Use of the 21-cm hydrogen line as a universal reference in interstellar communication
  • Anthropocentric nature of current unit values despite fundamental redefinitions

 

 

 

 

 

 

Sensei

Sensei

Posted
Posted

What is the short version of your statement?

If someone uses the word "ChatGPT", I'm already sick of reading the rest..

 

Why should I waste my time on nonsense?

ps. The source/reference is reddit? Google search is too stupid to find the right phrase to name what I wanted to say, and I don't want to swear..

 

T Ivers

T Ivers

Posted
  • Author
Posted

"On another forum that is not science based I began a conversation regarding the fact that soon humans would be multiplanetary and most of the measurements that are in current use are based on silly and illogical Earth derived units.  I think we need to replace the time and distance measurements."


The topic gets pretty complex right away, and I thought that I would run the idea by this forum.  What will our systems of measurement be?  They cannot remain the same as they are right now.

I checked several other science based forums today and questions have been made over the last decade regarding the replacement of our current measurement systems for time and distance.  This is not a new question, and we need to do something soon.

The second, hour, day, week, month and year does not work on Mars, and they definitely do not work after leaving this solar system.  Does it make sense to use measurement systems based on 2,000 year old haphazard guesses or do we need new to create new systems for time and distance now that we are sufficiently advanced to do so and are about to become an interplanetary species?
 

Sensei

Sensei

Posted
Posted (edited)
14 minutes ago, T Ivers said:

The second, hour, day, week, month and year does not work on Mars, and they definitely do not work after leaving this solar system.  Does it make sense to use measurement systems based on 2,000 year old haphazard guesses or do we need new to create new systems for time and distance now that we are sufficiently advanced to do so and are about to become an interplanetary species?

If you go from England to the normal world, you switch from foots to meters, from yards to kilometers and so on. Does it count?

and I almost forgot: and from left-hand traffic to right-hand traffic..

 

 

 

btw, this is called unit conversion..

 

 

ps2. You are searching for this:

https://en.wikipedia.org/wiki/Planck_units

 

Edited by Sensei
T Ivers

T Ivers

Posted
  • Author
Posted

So what you are saying is that we should not have a universal measurement system, and we should have a different measurement system for each planet, moon and solar system?  

 

Markus Hanke

Markus Hanke

Posted
Posted
1 hour ago, T Ivers said:

So what you are saying is that we should not have a universal measurement system, and we should have a different measurement system for each planet, moon and solar system?  

 

To be honest, I don’t think it matters too much - the choice of units is arbitrary, in that the laws of physics don’t depend on that choice, and in the age of digital devices, unit conversion is a trivial task. The only important thing is that one is consistent with whatever choice one makes, so as to minimise potential sources of confusion.

So yes, one can of course use that system you describe, but I think ultimately people will stick with whatever units are most convenient for whatever task they have at hand.

exchemist

exchemist

Posted
Posted
2 hours ago, T Ivers said:

"On another forum that is not science based I began a conversation regarding the fact that soon humans would be multiplanetary and most of the measurements that are in current use are based on silly and illogical Earth derived units.  I think we need to replace the time and distance measurements."


The topic gets pretty complex right away, and I thought that I would run the idea by this forum.  What will our systems of measurement be?  They cannot remain the same as they are right now.

I checked several other science based forums today and questions have been made over the last decade regarding the replacement of our current measurement systems for time and distance.  This is not a new question, and we need to do something soon.

The second, hour, day, week, month and year does not work on Mars, and they definitely do not work after leaving this solar system.  Does it make sense to use measurement systems based on 2,000 year old haphazard guesses or do we need new to create new systems for time and distance now that we are sufficiently advanced to do so and are about to become an interplanetary species?
 

This seems rather a waste of time and effort to me. For a start the human race is not going to be a multiplanetary species "soon", if ever.

Secondly, even if we were, there is no reason to think a change to the system of units would be helpful. All units are arbitrary and the result of history. The metre, for instance was set up at the French Revolution as being one 10 millionth of the distance from the N Pole to the Equator. Does anyone today know or care about that? Of course not. We use the metre because it is a convenient size for human beings (actually very close to the yard), easy for us to visualise and able to express everyday objects and distances without a lot of decimal places or zeros.  

And then there is the process of changing units, which is very time-consuming and costly. 

So those are the reasons for not changing units. As far as I can see you have not explained what benefits you expect from a change (I have not read your long screed from ChatGPT since we all know Chat GPT produces any old crap to satisfy what the user has fed in. If there are benefits enumerated in that screed, you need to extract them and post a concise summary in your own words.)  

studiot

studiot

Posted
Posted
Just now, T Ivers said:

On another forum that is not science based I began a conversation regarding the fact that soon humans would be multiplanetary and most of the measurements that are in current use are based on silly and illogical Earth derived units.  I think we need to replace the time and distance measurements.

I have a degree in a non science area, so after starting the conversation,

Yes this is a discussion forum, not your blog.

So instead of coming preaching to real physicists, I respectfully suggest you ask if they already have such units.

 

Have you heard of the barn or the astronomical unit or the light-year ?

swansont

swansont

Posted
Posted
5 hours ago, T Ivers said:

I'm hoping to find some open minds here, and while I accept that the results from ChatGPT may not be well thought out or correct, that I leave to you to decide, debate amongst yourselves, and come up with logical systems for time and distance.

!

Moderator Note

And this is one of the reasons we have a rule (2.13) prohibiting the use of chatbots as a basis for discussion. You might be basing your proposal on a hallucination. It’s not up to others to sort through it and figure out what’s right and what’s crap.

It requires this to be moved to speculations

Posting a wall-of-text is also bad form

 

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