If the universe is expanding uniformly from a big bang. How do you get galaxies?

Answer 1

This is really a question for the astronomy section. Since you put it here, you're obviously hoping no one can answer it so you can claim no one knows.

Fortunately, there ARE astronomers hanging out here.

There was a small amount of anisotropy in the early universe, which lead to 'clumpiness' of material, eventually allowing atoms to form, then clouds of hydrogen, and then the early stars. And everything from there. It took about a billion years or so though. It's a slow process.

Answer 2

It was a live question in astronomy and cosmology, a few years back. If the big bang was perfectly uniform, galaxies would not have formed.

It only needed very small variation however, to produce the differences in gravitational attraction that would result in stars and galaxies.

Now it's got even more fun...
Observations in the cosmic background radiation, (perhaps the "oldest" piece of evidence that can actually be directly measured) have confirmed lack of uniformity, but not enough to account for galaxies. But this has tied into other data and observations, and prompted the search for dark matter and dark energy.

Answer 3

Do you remember the images of cosmic background radiation? The universe was not uniform in density following the big bang and those variations are still visible as slight temperature variations. The variations in density allowed large structures to develop once the universe cooled enough for matter to form.

Answer 4

Did u know that some galaxies spin backwards? True. Now when the Big Bang happened everything would have popped into place in a frictionless enviroment, how did they spin backwards, also 2 planets and 8 moons.

Conservation of Angular Momentum my friend

Answer 5

The initial singularity wasn't smooth. It had variable density and bits of nothing too. I like to think of it like a bolognese sauce. If you leave a cauldron of ragu' alla bolognese on the hob for 6 hours without stirring it, the air bubbles will expand, explode and blow the lid off ... then your kitchen will look something like the universe, with globby galaxy-like clumps on the wall and dark matter on the ceiling.

Answer 6

As the materials in the universe spread outwards, elements and chemicals interact with eachother which of course cause energy. This energy and form mass, and mass leads to gravity.
When you have a strong pulling object with many smaller particles around it, a galaxy starts to form itself.

Answer 7

There are many galaxies all moving out away from a center point just like we are in our galaxie, the Milky Way.

Answer 8

Most shops sell em! My kids prefer Mars and Milky Way but Galaxy is an old favourite.

Answer 9

As it cooled, atoms formed. Then gravity pulled things together. This made some stars, which produced heavier elements, and more stars. As it expanded, some stars hung together, and formed galaxies.

Answer 10

After the big bang, bits of matter got pulled into clumps by the gravity of each other. These clumps got pulled into bigger clumps, but sometimes their speed counteracted the pull, so they just ended up circling around a larger clump.