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Posted

A Photon has kinetic energy. Yet, no rest mass. I may be wrong, but of a photon, I think (substance presented as a particle).

The Universe needs dark energy/matter. A lot of it. The Universes is expanding really fast, even accelerating. I am assuming space is also expanding, really fast, even accelerating. Is a defining particle of space needed to ask if the rapid expansion of space might create a lot of kinetic energy? Is the presence of energy enough to assume a link between the expanding space and the energy? Do I need a particle to assume substance?

Another question - A pie chart might show 68% Dark Energy,  27% Dark Matter, then show less than 5% as being ordinary energy/matter. My question is if we show the less than 5% as a combination of ordinary matter/energy, why make a distinction between dark matter, and dark energy on the chart?

Posted
18 minutes ago, jajrussel said:

The Universe needs dark energy/matter. A lot of it. The Universes is expanding really fast, even accelerating. I am assuming space is also expanding, really fast, even accelerating. Is a defining particle of space needed to ask if the rapid expansion of space might create a lot of kinetic energy? Is the presence of energy enough to assume a link between the expanding space and the energy? Do I need a particle to assume substance?

There is no "particle of space"; space is just the distance between things. Saying the universe expands is the same thing as saying space expands. It just means things are getting further apart (or the density is decreasing).

Quote

My question is if we show the less than 5% as a combination of ordinary matter/energy, why make a distinction between dark matter, and dark energy on the chart?

Because they are hypothesised to explain different things. Dark matter is required to explain the orbits of stars around, dark energy is required to explain the accelerating expansion. Apart from the "dark" in the name, there is no real connection between them.

Posted (edited)
7 hours ago, Strange said:

There is no "particle of space"; space is just the distance between things. Saying the universe expands is the same thing as saying space expands. It just means things are getting further apart (or the density is decreasing).

Because they are hypothesised to explain different things. Dark matter is required to explain the orbits of stars around, dark energy is required to explain the accelerating expansion. Apart from the "dark" in the name, there is no real connection between them.

 

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The quote feature isn't working the way I expected?

Thanks. But I am confused, one minute the world is expected to act relativistic, the next minute Mechanical is just fine. Space shrinks, expands, causes objects large and small to turn, ye has no substance, especially when it would be nice if it did.

If density is decreasing shouldn't there be an energy drop making it easier to move everything that exist within that space?

I saw a vid about the double slit experiment, where the repeated firing of a single photon fired over and over resulted in the same interference pattern presented by multiple photons emitted at the same time. If the interference pattern isn't coming from the other photons where is it coming from? Space not dense, yet with enough substance to direct the path of a photon? Just a question, not a statement.

I once, well maybe more than once tried to claim that relative effects were simply mechanical effects. The distance was simply longer or shorter thus presenting different observations even in simultaneity. I was soundly chastised, so i am not making that claim now. I'm just trying figure out when to use one or the other. Things simply getting further apart with density decreasing seems awfully Mechanical, and I am kind of afraid to go there. 

Edited by imatfaal
edited by Moderator to undo quote snafu
Posted
33 minutes ago, jajrussel said:

Thanks. But I am confused, one minute the world is expected to act relativistic, the next minute Mechanical is just fine.

Mechanics and relativity are comatible, so there is no problem there.

Quote

If density is decreasing shouldn't there be an energy drop making it easier to move everything that exist within that space? 

There is an energy drop. Which is why, for example, the temperature of the cosmic background radiation is redshifted to 2.3 Kelvin when it started out as 2,000 Kelvin.

Not sure why that would make it easier to move?

Quote

I saw a vid about the double slit experiment, where the repeated firing of a single photon fired over and over resulted in the same interference pattern presented by multiple photons emitted at the same time. If the interference pattern isn't coming from the other photons where is it coming from?

The probability of photons landing in particular places. That is the same whether they are single photons occurring individually or a mass of photons at the same time.

The description in terms of interference only applies to the classical "electromagnetic wave" description. It is less relevant when you use a description in terms of photons.

But this has nothing to do with expanding space.

Quote

Space not dense, yet with enough substance to direct the path of a photon? Just a question, not a statement.

The photon travels in a straight line - and in curved space it travels in the equivalent of a straight line (a null geodesic). There is no "substance" involved, just the effects of geometry.

Posted

Is dark matter another name for the aether, ether, diametric medium, electric fluid, dark energy and elastic fluid ? Or is the dark matter something new.

Posted
1 hour ago, ivylove said:

Is dark matter another name for the aether, ether, diametric medium, electric fluid, dark energy and elastic fluid ? Or is the dark matter something new.

Absolutely not, and I'm not sure why you would even think that. DM is simply what was needed to explain gravitational effects and rotational curves.

 

On 7/29/2017 at 6:13 AM, jajrussel said:

 Space shrinks, expands, causes objects large and small to turn, ye has no substance, especially when it would be nice if it did.

Space is simply what exists between mass/matter: If we had no space everything would be together. Time stops everything from happening at the same instant to put it as simply as possible. Spacetime on the other hand, is the  framework within which it is possible to locate events and describe relationships between them in terms of spatial coordinates and time. The concept of spacetime follows from the observation that the speed of light is invariant, i.e. it does not vary with the motion of the emitter or the observer. Spacetime allows a description of reality that is common for all observers  regardless of their relative motion. Intervals of space and time considered separately are not the same for all observers.

"The views of space and time which I wish to lay before you have sprung from the soil of experimental physics, and therein lies their strength. They are radical. Henceforth space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality".

— Hermann Minkowski, 1908, 1909

 

 

Posted

If by 'substance' you mean solidity or presence I would think not.

Elementary particles are dimensionless, and compound particles such as protons/neutrons are, as a result,essentially empty space, as are the atoms and molecules they make up.
It is the fields and interactions which give rise to those properties you inquire about.

As a matter of fact, QFT says the fields and interactions are even responsible for the particles.

  • 2 months later...
Posted

What effect does a field have on particles? dose it determine their path during the experiment? If you effect the field they pass through does it effect the pattern? As in warp the field, warp the space, change the pattern? If it works this way, note I’m asking, I don’t know, but if it does what is the difference between a field and the eather  that doesn’t exist? What would earlier scientist have expected from eather that the field doesn’t do?

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