1 . For years, planet-hunters have been searching for a planet other than Earth that can support life. They may have found one.

The planet is the sixth found orbiting a star called Gliese 581. Steven Vogt, one of the scientists involved, expects the new planet to have water. On Earth, when we find water, we find life.     1    

A planet that can support life has to be just the right size for its system and just the right distance from its star. Some planets orbit so close to their stars that they’re much too hot for liquid water—or for life as we know it.     2    

But a right-sized planet that's neither too close nor too far might be just right for water. Gliese 581 is probably just right. It is about three times as huge as Earth.     3     Because it’s so close, one side of it always faces its star, and the other side is always dark.

The new planet is 20 light years away, which is as far as 250 million trips to the Moon and back.     4     Only light can go that fast. So even at the fastest speed we could manage, it would take a spaceship from Earth more than 200 years to go that far.     5     But that doesn’t mean we can’t study it. Thanks to powerful new telescopes and new techniques for searching the skies, scientists can learn a lot about distant planets without even leaving Earth.

Gliese 581 is an exciting discovery—and astronomers are likely to find more soon, thanks to new, powerful telescopes specifically designed to look for planets.