Why Did the Big Bang Create Irregular Bumps Instead of Expanding Uniformly?

[Sydius]

On the timeline of everything, at point 0, all matter was infinitely compressed and dimensionless, right? Then, it exploded, and produced the Big Bang…

We know that the original mass produced by the big bang should have been very bumpy to produce galaxies like it did, and this was confirmed by those microwave readings.

My question, though, is, if all matter was infinitely compressed and dimensionless at time 0, then why did it form irregular bumps, and not expand uniformly? Dimensionless implies no bumps, doesn't it?

 

[SpaceTiger]

On the timeline of everything, at point 0, all matter was infinitely compressed and dimensionless, right? Then, it exploded, and produced the Big Bang…

It's best not to visualize the Big Bang as an explosion because that gives the impression that it was some sort of event in a pre-existing spacetime. In fact, it was the origin of space and time itself.

We know that the original mass produced by the big bang should have been very bumpy to produce galaxies like it did, and this was confirmed by those microwave readings.

We don't think the universe started bumpy. In fact, if you go back far enough, matter as we know it didn't even exist. Rather, we think that there were fluctuations in a quantum field that eventually gave rise to the fluctuations in matter. These fluctuations were thought to have been frozen and expanded to large scales by a process known as inflation. Later, after inflation had long since ceased, these fluctuations were able to collapse under their own gravity and form the many structures (like galaxies and clusters) that we see around us today.

 

[Chronos]

Not exactly, Sydius. Space Tiger gave a wonderful explanation that I can only elaborate upon. The t=0 universe was extremely homogenous, but, unavoidably included quantum fluctuations in its energy density. Inflation froze and magnified those tiny fluctuations as the current universe unfolded. The denser regions collapsed to form stars and collections of stars [proto galaxies].