These days, we may take the stars for granted, but it's not hard to imagine the wonder early humans must have felt gazing up at those inexplicable points of light. Naturally, superstitions were bound to develop — some more fortuitous than others.
When a huge star collapses, it releases massive amounts of radiation in concentrated streams. If one of those streams hit Earth, it wouldn't be pretty. But where should we put "gamma-ray bursts" on our list of anxieties?
It wasn't so long ago that astronomers thought the universe contained normal matter, or baryonic matter, the base unit of which is the atom. But when it comes to the cosmos, there's always more than meets the eye. What else is hanging out in space?