Question: after the big bang all these small dust particles were drawn together due to gravity and formed planets, stars, etc. Would the movement from dust to planets not decrease entropy, violating the second law of thermodynamics?

I how this is not a really ignorant question.

Good point but matter smashing into eachother is a lot different than it forming together. That and the 2nd law was used to show how the univers was before the big bang if you will. The explosion was such a great increase of entropy that the law was not violated