How did round planets form from the explosion of the Big Bang?

I hardly know where to stat, Aptera, other than to say hello and welcome to EvC.Are you aware that the universe was has been around for about three times as long as the planet we live on? That about 9,000,000,000 years passed between the Big Bang and the birth of our solar system?Planets and large asteroids/moons are round because of gravity. Rock is only so strong - a chunk of it 500 miles in diameter or so has enough gravity of its own to slowly deform it into a more-or-less sphere. The moons of Mars are similar sort of rock as, say, the asteroid Juno. But the moons are small enough that they can't pull themselves into a symmetric shape. Juno, Mars, and Earth can, and have. Stars and planets like Jupiter, where we only can see a gas atmosphere, are roughly spherical for the same reason. Gas deforms a lot quicker than rock, but the reasoning is identical - gravity does it.

Nope. Molecules get ripped apart and rearranged, but no mass is destroyed in the process of potato to poop. The heat is from the reassortment of bonds. Only.

A million tons per second is "lost" in the middle of the Sun. Four protons outwiegh one helium nucleus.

Ummm.....the 4 X 10^26 watts the Sun puts out? And the fact that there aren't any chemical bonds between what passes for atoms in the center of a star?