Astronomers aren't certain exactly how galaxies formed. After the Big Bang, space was made up almost entirely of hydrogen and helium. Some astronomers think that gravity pulled dust and gas together to form individual stars, and those stars drew closer together into collections that ultimately became galaxies.
People also ask, how do galaxies work?
A galaxy is a large system of stars, gas (mostly hydrogen), dust and dark matter that orbits a common center and is bound together by gravity -- they've been described as "island universes." Galaxies come in many sizes and shapes.
Beside above, what are the 4 types of galaxies?
In 1936, Hubble debuted a way to classify galaxies, grouping them into four main types: spiral galaxies, lenticular galaxies, elliptical galaxies, and irregular galaxies. More than two-thirds of all observed galaxies are spiral galaxies.
How many galaxies are in the universe?
100 billion galaxies
What galaxy do we live in?
the Milky Way