Without time.

[Strange]

It's a bit unorthodox, but what's wrong with it?

 

I don't know what it means. Are we talking lux, lumens, watts, joules ...

[swansont]

We're talking ct, which is distance. Just a new label. Nothing conceptual has changed.

[DimaMazin]

We're talking ct, which is distance. Just a new label. Nothing conceptual has changed.

Yes. Scientists use v/c as speed, but they don't understand that it is real speed without my definition of time.

[Mordred]

Yes. Scientists use v/c as speed, but they don't understand that it is real speed without my definition of time.

Sorry to burst your bubble but special relativity already uses ct.

 

[latex]ds^2=c^2 dt^2-dx^2-dy^2-dz^2[/latex]

The above equation is invarient

 

[latex] y = (ct,\acute{x},\acute{y},\acute{z})[/latex]=new coordinates;[latex] x = (ct, x, y, z)[/latex]=old coordinates

Edited May 6, 2015 by Mordred

[swansont]

Yes. Scientists use v/c as speed, but they don't understand that it is real speed without my definition of time.

 

And yet we seem to muddle on just fine.

[DimaMazin]

 

And yet we seem to muddle on just fine.

I see no sense when citizens of every planet use time of own planet. Time should be defined only by length of light way.

[ajb]

I see no sense when citizens of every planet use time of own planet. Time should be defined only by length of light way.

You mean the units of time?

 

You then have to worry about how you define the length you are going to time the light pulse over.

[swansont]

I see no sense when citizens of every planet use time of own planet. Time should be defined only by length of light way.

And how would you build a clock using this definition?

[DimaMazin]

And how would you build a clock using this definition?

I talk about units of time. Atomic clocks aren't build on Earth's rotation, but they show it. They can show length of light way with the same success. What is time which should be used by interplanetary nomads? And even light clock can exist.

You mean the units of time?

 

You then have to worry about how you define the length you are going to time the light pulse over.

System of calculations of distances and light receptions let you define age of the universe. Isn't it the clock?

[swansont]

I talk about units of time. Atomic clocks aren't build on Earth's rotation, but they show it. They can show length of light way with the same success. What is time which should be used by interplanetary nomads? And even light clock can exist.

Fine. Go build one.

 

System of calculations of distances and light receptions let you define age of the universe. Isn't it the clock?

Not a very precise one. How would you make GPS work with this kind of clock? 3ns of timing error sacrifices 1 meter of positioning precision.

[ajb]

System of calculations of distances and light receptions let you define age of the universe. Isn't it the clock?

So you want one unit of time to be the age of the Universe?

[DimaMazin]

So you want one unit of time to be the age of the Universe?

Unit of time should be 281374807m of length of light way. It is distance of balance of gravitational force and cosmological force of interaction of two bodies each of which has 1 kg of mass.

[ajb]

So translating that back into seconds you would use the speed of light; this is just the time light takes to travel 281374807m?

 

I am not quite sure what you mean by cosmological force, that does not really matter. The point is you fix some length and time light over that distance. Okay, no problem, but this is just using "x =ct" in what ever units you are using.

[DimaMazin]

So translating that back into seconds you would use the speed of light; this is just the time light takes to travel 281374807m?

 

I am not quite sure what you mean by cosmological force, that does not really matter.

Then how do you define interplanetary unit of time?

[ajb]

Then how do you define interplanetary unit of time?

What you have done is okay, once we all understand units of distance.

 

The definition of a second is

 

"The second is the duration of 9 192 631 770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium 133 atom."

 

This was calibrated to more-or-less agree with earlier definitions. The best thing for a universal unit of time would be something like this, maybe change the number of periods to maybe 10 000 000 000 or something.

[Strange]

Unit of time should be 281374807m of length of light way. It is distance of balance of gravitational force and cosmological force of interaction of two bodies each of which has 1 kg of mass.

 

Why is 1kg of universal significance? (Interestingly, the kg is the only unit that is still defined in terms of a physical object, rather than fundamental constants.)

[DimaMazin]

 

Why is 1kg of universal significance? (Interestingly, the kg is the only unit that is still defined in terms of a physical object, rather than fundamental constants.)

Only for example.

[ajb]

There should be a better way of defining a kg, one that is not dependent on having master objects. I don't know the details, but it is possible to use Planck's constant to define one kg. Doing so would give a universal definition.

[StringJunky]

There should be a better way of defining a kg, one that is not dependent on having master objects. I don't know the details, but it is possible to use Planck's constant to define one kg. Doing so would give a universal definition.

1 cm³ of water is 1.00000g at sea level and 4^oC. That's a standard anybody can replicate.

[Strange]

Only for example.

 

So, as you have chosen a completely arbitrary number why not stick with the definition of the second that we already have.

[swansont]

1 cm³ of water is 1.00000g at sea level and 4^oC. That's a standard anybody can replicate.

 

How precisely can that standard be realized?

[StringJunky]

 

How precisely can that standard be realized?

Is volume not standardised?

[swansont]

Is volume not standardised?

 

How well can you measure volume, stabilize temperature & humidity, and ensure isotopic composition? All of those factors (and probably others) would come into play in realizing a standard mass defined this way. Water is relatively incompressible, but ultimately not accounting for the local value of g will limit the measurement, as well.

[StringJunky]

 

How well can you measure volume, stabilize temperature & humidity, and ensure isotopic composition? All of those factors (and probably others) would come into play in realizing a standard mass defined this way. Water is relatively incompressible, but ultimately not accounting for the local value of g will limit the measurement, as well.

How many places of accuracy do you need for a standard? That number I pulled out was by the USGS. If you look at the table, it seems pretty fine to me. I'm not disagreeing with you really, I'll have to look into what goes into a deriving a standard. Using Litres as Kilos is how I check my fishing scales. Don't you have lots of variables to account for when measuring/standardising the second?

 

Edited May 11, 2015 by StringJunky

[swansont]

How many places of accuracy do you need for a standard?

 

Clocks go to better than a part in 10^15. There's seemingly always someone who wants a better standard, or finds a use for one. Form mass I'm not sure what the application is, but I assume it's out there.