10 Biggest Unsolved Mysteries In Science

4. Why Is There Stuff?

Or, more specifically, why is there more matter than antimatter?

As far as we can figure out, matter and antimatter are supposed to be equal and opposite and, when they meet, they should annihilate one another, leaving nothing behind.

However, a quick glance around you now will demonstrate that this has not happened and, what's more, there seems to be a lot more matter floating around than antimatter.

One possible solution for this could lie in a little subatomic particles called mesons. B-mesons are made of quarks and anti-quarks, but there is evidence to suggest that B-mesons decay slightly slower than anti-B-mesons, meaning that it's possible that some B-mesons survived the interaction and tipped the balance in favour of a matter universe.