10 Simple Questions That Still Totally Baffle Scientists

4. Why Is There Stuff?

Speaking of matter in the universe, one of the biggest shrugs in the science world is why there is even stuff in the first place. In the very beginning, right after the big bang, the universe was just pure energy. There is a principle in physics that allows energy to be converted into matter so long as the debt is repaid. This happens because the matter is created alongside antimatter and they will annihilate one another, converting back into energy. This should mean that there are equal amounts of matter and antimatter in the universe, and all of our models for the big bang currently point to this being true, and they should be constantly cancelling one another out.

However, as far as we can tell, there's an overwhelming bias towards matter, hence the universe exists. We have no idea why this should be, by all rights, we should have all disappeared in a flash of energy before we'd even begun. This is amongst the many things that the scientists at CERN are trying to figure out.

There are two plausible theories for the asymmetry, the first of which being that antimatter is not a perfect mirror of matter and this slight difference caused the universe to favour matter, but the differences they have found so far appear to be too small to work on a large scale.

Another theory is that, in the chaos of the big bang, small amounts of matter and antimatter escaped annihilation and there is a mirror of our matter-based universe out there where all of the left over antimatter has coalesced into anti-stars and anti-planets, perhaps even anti-life.