Sage-Tips

Why is it the overall expansion of the universe goes faster while the cluster of galaxies slows down?

The density of matter decreases as the universe expands because the volume of space increases. Currently the density of dark energy is higher than that of matter, but in the distant past the density of matter should have been greater, so the expansion should have been slowing down then.

Does the universe expand evenly?

Yet there is no centre to the expansion; it is the same everywhere. The Big Bang should not be visualised as an ordinary explosion. The universe is not expanding out from a centre into space; rather, the whole universe is expanding and it is doing so equally at all places, as far as we can tell.

What is the speed of Universe expansion faster than light?

Edwin Hubble was the first to measure the expansion rate. The number he got was way wrong, so I won’t bother mentioning it, but good on him for trying. The more modern value is 68 kilometers per second per megaparsec, plus or minus a couple, but close enough.

Is the universe expanding at the same rate everywhere?

Astronomers have assumed for decades that the Universe is expanding at the same rate in all directions. The rate of the Universe’s expansion, indicated in terms of the so-called Hubble constant, is shown in different colours, with purple hues indicating a slower rate and orange/yellow hues indicating a faster rate.

Is the universe expanding faster than we thought?

The number indicates that the universe is expanding at a 9\% faster rate than the prediction of 67 kilometers (41.6 miles) per second per megaparsec, which comes from Planck’s observations of the early universe, coupled with our present understanding of the universe. So, what could explain this discrepancy?

Are the boundaries of the universe continuously growing?

If all objects are moving outward at a constant speed, the boundaries defined by the outermost objects must be continuously growing. To be more precise about the expansion of the universe, we again resort to analogies.

What is the relationship between the universe’s expansion and formation?

On the largest scales, the Universe expands and galaxies recede from each other. But on smaller [+] scales, gravitation overcomes the expansion, leading to the formation of stars, galaxies and clusters of galaxies. On the largest scales of all, the expansion wins.

Why does the universe have underdense regions?

It has overdense regions, like planets, stars, galaxies and clusters of galaxies. It has underdense regions, like great cosmic voids where there are virtually no massive objects present at all. The reason for this is that there are other physical phenomena at play besides the Universe’s expansion.