Starts With A Bang #3: Why is there more matter than antimatter?

Everywhere we look in the Universe, we find that planets, stars, galaxies, and even the gas between them are all made of matter and not antimatter. Yet as far as we know, the laws of nature are symmetric between matter and antimatter: you can't create or destroy one without the other. So how did our Universe get to be the way it is? Come right up to the frontiers of our scientific knowledge and have a listen!