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The large scale structure of the universe can be described with general relativity. Whether the structure of general relativity can be described with quantum mechanics is an unsolved problem. Many people certainly think so and have spent a considerable amount of effort on trying to formulate such a description. For the second part of your question, I would ...

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Is it possible that universe is not expanding but instead being dragged into singularity? Yes. That possibility is called the Big Rip. 'dragged into a singularity' can happen even while 'expanding', so they are not contradictory. It would occur if the rate of cosmic acceleration is exponential. In the Big Rip scenario, there is a finite time in the future ...

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The scientific paper linked in the article you read is saying that it seems that there's a clustering of mass beyond the reach of current all-sky galaxy redshift surveys that is pulling the local volume more to one side. Such clusterings are possible in the framework of the standard $\Lambda$CDM cosmology, but a clustering large enough to explain the data is ...

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Is it possible that universe is not expanding but instead being dragged into singularity? No. We see galactic redshift every where we look, the galaxies are moving apart like the raisin-cake analogy. There is no overall gravitational field in the universe. You may have heard about "the big crunch" but I'm afraid it's popscience. The universe didn't contract ...

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There are three types of matter/energy we consider when calculating how the universe expands: Matter - both normal matter and dark matter Radiation Dark energy We measure the expansion of the universe using a scale factor that we normally denote by $a$. The scale factor increases with time as the universe expands, and if we look backwards in time we see ...

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The expansion of space is like stretching a rubber sheet. (Don't take this analogy too seriously. It works for this explanation but fails elsewhere.) The mass of the rubber sheet stays the same as it gets bigger. Space expands, but mass does not increase with it.

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If you "run the clock backwards" using the Friedmann equations, you can avoid a singularity; you just need the pressure and energy to behave in the right way when the Universe was very hot and dense. The catch is that "the right way" in this case means that $\rho + 3 p < 0$; in other words, either the energy density or the pressure (or both) have to be ...

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The Big Bang was originally just the zero time limit of the FLRW metric. I'm not sure that Big Bang Theory has a meaning outside of CBS, but to the extent that it does have a meaning it is synonymous with the solution to Einstein's equations for a homogenous isotropic universe. Life is more complicated now because we believe the universe underwent a period ...

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The BAOs became imprinted in the background density of the Universe at the time of decoupling, which happened at the same time as recombination, i.e. when the linear scale of the Universe was a factor $z \sim 1100$ smaller. At this time, they had a characteristing wavelength given by the speed of sound in the plasma at that time. This happened to be ...

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I think, John Rennie's answer is far far better than anything I can do, but I'm going to give you the "universe for dummies" answer anyway. Mass of the observable Universe: 10^53 KG Density of the observable Universe: 9.9×10−30 g (equivalent to 6 protons per cubic meter of space - not very dense.) Source (Wiki): ...

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Can we talk about points in the intergalactic medium instead (i.e. between the galaxies and thus far from any gravitating matter), rather than two tennis balls? Because on such small scales, the Universe doesn't expand, instead being held together by gravity. Anyway, the present-day Universe expands at a rate of \$H_0 = ...

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Hubble Constant is about 70 km/sec per Megaparsec. Given the Milky Way Galaxy is about 34K parsecs in diameter, that means the velocity between the edges of the galaxy due to Hubble Flow is about 2.38 km/sec. With additional math, we can see two objects 1 meter apart are moving away from each other at about 2.26x10^-18 meters/sec. So after 10,000 years, ...

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