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Replying to otseng in post #1522]
The only way the expansion of space-time fabric could allow for clear images is that the expansion was perfectly uniform down to the last location of each subatomic particle in the universe and expanding at exactly the same rate with zero deviation.
Why would this be the case? The universe is mostly empty as far as physical matter, with an average density of just 5e-30 g/cm^3 (eg.
Here). The intergalactic medium is far less at only about 1 atom per cubic meter (eg. [url=
https://www.cfa.harvard.edu/research/to ... tic-medium]Here[/url). Spacetime pervades the universe but isn't "made" of anything. The matter that is embedded in space is the only thing we can take images of, and with telescopes that is limited to only very large things ...
very large. For us to get clear images of galaxies and distance objects it is only necessary to have a short observation time relative to the time period required for the object to change in some way.
Of course, you could argue that when we see an image of PoC in 1995 with Hubble, and a higher resolution version in 2022 with Webb, that both are misrepresentations of what is actually there 6,500 light years away. If there was some mechanism for the light we're capturing to be distorted in some way between PoC and here, during the minutes or hours of the observation (anything outside of that observation window is irrelevant as far as the image itself), we'd have no way of knowing it. All we can say is that over the 37 years for this example there is no apparent change in the light patterns reaching our solar system from PoC, so most likely the imaged object is changing so slowly as far as its emissions that 37 years isn't enough to matter.
But I don't see why any expansion would have to be perfectly uniform down to subatomic particle scales just to get clear images using telecopes which only can see giant objects like stars and galaxies at great distances. These are all riding along with the spacetime expansion at time scales that are gigantic compared to the time needed to record an image from a telescope. The telescope image is just an instantaneous snapshop in comparison. It is like taking a camera photo of a car moving down a highway with a shutter speed of 1 microsecond ... the car would appear to be dead still on that scale.
But, another major problem is there is no evidence the space-time fabric actually exists. Rather, it is only a mathematical model.
Yes ... but how does that relate to being able to get clear images of distant objects? Those objects exist as physical things as proven by the images, and from redshifts and other information across millions of distant objects we see a pattern of everything moving away from us, and the farther away the object is the faster it is moving away on large scales (Andromeda is moving towards the Milky Way, which is itself another piece of the puzzle showing that for closer objects gravity can dominate the movements). Whether these objects exist in something called spacetime, or in some other possible description of the "thing" the universe's contents exist in, their movement is on such large time frames compared to the time needed to acquire an image from a telescope that it may not matter whether the expansion were uniform or not ... we'd still get a clear image.
