Somewhere back in a previous discussion, I suggested that our Universe might not be the expanding spherical sphere that we all believe in, and accept.
I had suggested that there might be an uneven expansion of matter, which would show our accepted expanding sphere, as an expanding rubber glove, complete with 'fingers and depressions' instead.
http://www.scienceagogo.com/forum/ubbthreads.php?ubb=showflat&Number=25867&fpart=2In the above Scienceagogo thread, I wrote:-
"The accepted analogy for the expansion of the Universe, is the expansion of a balloon being blown up, or better, the currants within a cake that is being baked.
The Galaxys, or currants separate from each other as the cake expands during baking.
While this analogy is true, my personal opinion is that our Universe may not be expanding consistantly in every direction.
Its shape might not be like an expanding rubber balloon,.... but more like a rubber glove complete with fingers.I reasoned that this was due to the large Galaxy Andromeda, fast approaching our own MilkyWay galaxy, which will eventually merge with us.
Just this single merging of two large galaxies, must spoil the accepted "nice even" spherical picture we believe the expanding Universe shows us. With a million more Galaxies way-out there, that will eventually collide and merge, to spoil this constant and even expansion.? (In my view of things)
Stating the Red shifts that we see now, will not change, but to also remember there are also a few blue shifts as well.
All in all, this suggested to me, that our Universe is not such an even expanding sphere as we might believe?
I said that protruding fingers of matter, even depressions, probably exist all around us?
Yet another question for Astronomers to prove or disprove?"
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Well, Redenur pointed out that I may have put forward an incorrect idea as to why I think the Universe is not expanding evenly. His thoughts and ideas, I duly noted.
But I have now found a recent idea which supports my view.The problem is that we may have to wait another twenty years before 'An uneven expanding Universe' can be proved.
Pre-amble:-
"Convention suggests that Space Time is expanding at the same rate in every part of the universe, meaning that the distribution of matter is roughly the same.
Although this makes sense theoretically,
nobody has been able to test this assumption definitively.
However there is a test which can get around and solve this problem.
All you have to do is measure the light from objects such as Quasars, and
see if these frequency measurements change over time.Measuring the same 'Red Shift' of similar objects over say 10 years, would show if different parts of space are expanding at different rates.
If different parts of space are expanding at different speeds, then the Red Shifts of two objects that match initially for instance, would be out of kilter 10 years later.
If this is true, the case for Dark Energy would start to look shaky.
Unfortunately we will have to wait 10 years before the super sensitive red-shift spectrograph on the European E Large Telescope will be ready. Plus another 10 years to compare the minute Red-shift differences that are expected to be detected.
For a Complicated Url, read below (page 4)http://xxx.lanl.gov/PS_cache/arxiv/pdf/0801/0801.0068v1.pdf******
Another read, Also with suggestion that the necessary
sensitivity to detect differing Redshifts, again may take years to achieve.
>In another upcoming Physical Review Letters, Jean-Philippe Uzan of Pierre and Marie Curie University in Paris, along with Chris Clarkson and George Ellis of the University of Cape Town in Rondebosch, South Africa, suggest a different way to test the Copernican principle. They note that over time, as dark energy speeds up cosmic acceleration, the recession velocities of galaxies would change, as indicated by a change in their redshift — the shift in wavelength of light to redder, or longer wavelengths, due to a speedup.
By measuring both redshifts and distances to remote galaxies over a 10-year span, the researchers say that astronomers should be able to tell whether we live in a Copernican universe.
In a cosmos that is the same everywhere, “the expansion rate of the universe at distant objects and the distances we measure to those objects have to be related in a very precise way, notes Clarkson. That’s not the case in a universe with a special location.
“At the moment, any Redshift drift can't be measured at all, so very large telescopes are needed together with very sensitive spectrographs,” Clarkson says. “It's an extremely small effect.”
Caldwell says that “mathematically they may be justified, but the necessary precision and accuracy will not be achievable for many years.”< (sciencenews.org)
***Very easy read below- Newscientist.comIS OUR SPOT IN THE UNIVERSE SOMEHOW SPECIAL?
It is an age-old question, but now there's a way to answer it once and for all - as long as we're patient.
Convention has it that our neck of the woods is very ordinary, based on what's known as the Copernican principle, which states that the cosmos is pretty much the same wherever you go. It suggests space-time is expanding at the same rate in every part of the universe, meaning that the distribution of matter is roughly the same.
Although this makes sense theoretically, nobody has managed to test this assumption definitively.
Previous attempts have rested on further assumptions, such as the nature of gravity, or how matter is distributed through the universe -in other words, they rely on trusting our cosmological models, which were built on the Copernican principle.
Now Jean-Philippe Uzan of the Paris Astrophysics Institute in France, working with Chris Clarkson and George Ellis of the University of Cape Town in South Africa, have a test that gets around this problem.
All you have to do is measure the light from objects such as quasars, and see if these measurements change over time.
The paper will be published in Physical Review Letters.
Light shifts towards the red end of the spectrum on its journey to Earth because the expansion of the intervening space causes the light's wavelength to increase. Uzan and colleagues say that measuring the "red shift" of various objects over a period of say, 10 years would show whether the Copernican principle is false.
If different parts of space are expanding at different rates, then the red shifts of two objects that match initially, for instance, would be out of kilter 10 years later.
Dark energy is thought to be accelerating the expansion of the universe. But if expansion rates differ over areas of space rather than time, it would scupper dark energy models that assume acceleration is uniform.
Ruth Durrer of the University of Geneva in Switzerland likes the idea. "It could have a profound effect on the interpretation of the apparent acceleration," Durrer says. "It could help us get rid of dark energy."
We might be in for a bit of a wait before the test can be done, however. The only way to measure red shift accurately enough will be by using the CODEX spectrograph at the European 'Extremely Large Telescope', which won't be online for at least 10 years.
