Galaxies are not distributed randomly throughout the universe, but are grouped in graviationally bound clusters. These clusters are called poor or rich depending on how many galaxies they contain. Poor clusters are often called groups.
A: We've known since the early 20th century that the universe is expanding — after observations by Edwin Hubble and others showed that other galaxies are almost all moving away from us — and the greater their distance, the faster they're doing so.Apr 10, 2020
As the universe expands, the galaxies get farther from each other, and the apparent velocity will appear to be larger for the more distant galaxies. The Earth and the Milky Way are not special in seeing that all galaxies appear to be moving away from us.
There is enough matter in a galaxy, that the matter within the galaxy is not affected by the expansion of the universe. You can think of this as the gravity of the galaxy holding it together, but really it's more fundamental than that.Jun 27, 2015
Although the expansion of the universe gradually slowed down as the matter in the universe pulled on itself via gravity, about 5 or 6 billion years after the Big Bang, according to NASA, a mysterious force now called dark energy began speeding up the expansion of the universe again, a phenomenon that continues today.Jan 18, 2022
It took the same amount of time for all the dots to change their positions, so the more distant dots appeared to be moving faster. That's how it works with the Universe. Because space itself is expanding, the more further a galaxy is, the faster it seems to be receding.Apr 22, 2008
As the bread bakes, the raisins (which represent cosmic objects like galaxies and galaxy clusters) all move away from one another as the entire loaf (representing space) expands. With an even mix the expansion should be uniform in all directions, as it should be with an isotropic universe.Apr 7, 2020
Inhomogeneities in the early universe cause the formation of walls and bubbles, where the inside of a bubble has less matter than on average. According to general relativity, space is less curved than on the walls, and thus appears to have more volume and a higher expansion rate.