Our new issue is on newsstands and in mailboxes (or beach bags or bathrooms or wherever it is you do your _flossing). This week we'll be sharing a few excerpts from the cover story, "The 50 Most Interesting Places in the Space-Time Continuum," by Jenny Drapkin and Ethan Trex, plus a few places that ended up on the cutting room floor.

28. Where Antimatter Still Exists
To wrap your head around what antimatter is, take everything you remember from high school science and reverse it. Matter is composed of positively charged protons and negatively charged electrons, whereas antimatter consists of positively charged electrons and negatively charged protons. When fast-moving matter collides with other fast-moving matter, antimatter is formed, releasing energy. After the Big Bang, some antimatter was formed, but it's pretty hard to find.

Antimatter does exist, though.

It usually occurs in places where particles of ordinary matter travel very quickly and collide with one another. In 1997, astronomers discovered a fountain of hot antimatter flowing in the center of the Milky Way. And in 2002, a solar flare—a powerful explosion emanating from the surface of the Sun—created about a pound of antimatter that was quickly annihilated.

Scientists have also tried to grow their own antimatter here on Earth, and they've succeeded several times. The problem is, the process is expensive. In 1999, NASA estimated that the price of producing a single gram of antimatter is about $62.5 trillion. All that cash doesn't buy you much time with your antimatter, either. It takes about 40 billionths of a second for antimatter to come into contact with matter and disappear. So why bother? Because even a small amount of antimatter would make an unbelievably potent fuel. In 2002, a NASA scientist told the press that a raisin-size amount of antimatter could generate enough energy to fuel a rocket to space.

See Also: The Final Resting Place of the Russian Mafia and The Final Moments of the Civil War. If you're in a subscribing mood, here are all the details.