About Hubble's Law

[Ignat]

If Hubble's law is fulfilled only in a certain narrow, by cosmic standards, area, then how can we rely on it when talking about the expansion of the universe?

 

[Catastrophe]

Of course, Hubble's Law, or Constant, is not fixed. It varies over time and distance.

I wonder why it was not realised earlier, that the proportionality which required FTL travel, could be countered by noticing that FTL travel might be used to invalidate Hubble's Law. And, imho, there is something a little dubious about FTL expansion of a space(time) universe . Does this not smack somewhat of the reinvention of the aether? Either space(time) is an empty nothing, devoid even of Newton's coordinate framework, or there is a "something", some substance, and one expanding at that.

I would welcome comment/correction on these points, but, please, not repetition of the problematic "explanations". I believe that the most likely answer is, at the present time, we do not understand (some of) the suggested "explanations". Please prove otherwise.

Cat

Addendum: I am currently reading "The Planets" by Andrew Cohen with Brian Cox. The Grand Tack of Jupiter, and movements of Saturn are mind--boggling to one brought up on a forever unchanging system. I mention this, certainly NOT in disbelief, but in the mammoth changes which are coming to light in very recent years. With Hubble and JWST, I think we must prepare ourselves for more stupendous discoveries. For starters, the Solar System is not rusting in eternal clockwork movements, as we have believed for hundreds of years.

 

[Gibsense]

I wonder why it was not realised earlier, that the proportionality which required FTL travel, could be countered by noticing that FTL travel might be used to invalidate Hubble's Law.

I did not know that FTL travel was possible. What evidence can you quote, please?

I would welcome comment/correction on these points, but, please, not repetition of the problematic "explanations"

The standard response is problematic (?). What response and how is it a problem, please?

 

[Ignat]

See post #2. If speed is proportional to distance, then at "infinite" distance you will get "infinite" speed. After approx. 14 bn years of increasing accelerating expansion, what is the speed of
the expanding material "universe"? What do you say iit is expanding into?
Can immaterial nothing expand? Did the aether expand.?

Cat

The question that puts supporters of the big bang in a stupor: where is the immaterial space expanding?

 

[Catastrophe]

I did not know that FTL travel was possible. What evidence can you quote, please?

The standard response is problematic (?). What response and how is it a problem, please?

• Explanation
  Hubble's law describes the relationship between the distance of a galaxy and how fast it's moving away from Earth. However, the expansion of space itself is not limited by the speed of light.

If speed is proportional to distance, then at "infinite distance, at what speed is it expanding?
Can immaterial nothing expand? Did the aether expand.?

Does Hubble's Law refer only refer to space itself? Are not galaxies supposed to be moving away from each other at a speed proportional to distance?

Can you please clarify by stating your understanding of Hubble's Law?
Are not (as stated) galaxies supposed to be moving away from each other at a speed proportional to their distance? Does space expand leaving the galaxies behind?
Let's start with agreed definitions. The above "explanation" is from Google.

Cat

 

[George²]

When we talk about empty, dimensionless, it is not a thing, it is not an object, it has no dimensions, nor any characteristics. It is problematic when our language, our way of thinking and communicating, forces us to give a name, a shell and characteristics even to nothingness.

 

[Catastrophe]

Can space exist by itself without matter or energy around?​

No. Experiments continue to show that there is no 'space' that stands apart from space-time itself...no arena in which matter, energy and gravity operate which is not affected by matter, energy and gravity. General relativity tells us that what we call space is just another feature of the gravitational field of the universe, so space and space-time can and do not exist apart from the matter and energy that creates the gravitational field. This is not speculation, but sound observation.

Gravity Probe B - Special & General Relativity Questions and Answers

 

[Gibsense]

If speed is proportional to distance, then at "infinite distance, at what speed is it expanding?
Can immaterial nothing expand? Did the aether expand.?

Does Hubble's Law refer only refer to space itself? Are not galaxies supposed to be moving away from each other at a speed proportional to distance?

Can you please clarify by stating your understanding of Hubble's Law?

Let's start with agreed definitions. The above "explanation" is from Google.

Are not (as stated) galaxies supposed to be moving away from each other at a speed proportional to their distance? Does space expand leaving the galaxies behind?
Let's start with agreed definitions. The above "explanation" is from Google.

FTL = Faster than Light, not "to travel faster than light". Galaxies that are so far apart that they separate faster than light travel through space at little speed if at all!
The point is space increases itself - nothing or very little is due to "travelling". You illustrate this yourself with a balloon blowing up separating dots (they do not move over the balloon skin but get separated).

You quoted thus (ex google):

• Explanation
  Hubble's law describes the relationship between the distance of a galaxy and how fast it's moving away from Earth. However, the expansion of space itself is not limited by the speed of light.

This is of course correct. The "moving away" is because space between is being added to separate a galaxy from Earth and not because of a galaxy's speed through space

 

[Gibsense]

If Hubble's law is fulfilled only in a certain narrow, by cosmic standards, area, then how can we rely on it when talking about the expansion of the universe?

This is an incorrect statement. Hubble's Law is supported by the whole Universe as indicated by the CMB (Cosmic Microwave Background).
However, there is something called Hubble Tension. This is where different but substantiated measurements disagree

 

[Gibsense]

Does this not smack somewhat of the reinvention of the aether?

Yes, a bit

 

[Gibsense]

I would welcome comment/correction on these points, but, please, not repetition of the problematic "explanations". I believe that the most likely answer is, at the present time, we do not understand (some of) the suggested "explanations". Please prove otherwise.

I suppose I am guilty of repetition. The reason is that no one has come near to a good logical explanation except for the one I have quoted which I guess can be proven as follows (bear in mind this is just my offering) -
Observe the wavelengths of the background radiation. If all are equal in every direction we are stationary in the universe. If there is a variation in say one direction compared to the opposite then this indicates movement through space.
This has been observed but is comparatively small and has nothing to do with spatial expansion in the FTL sense that you mention.