planet

Kids, don't hula hoop, or else giant gaseous planets will descend into our atmosphere and kill everyone. This has been your PSA for the day.

Scanning the heavens, you might very well miss the star Kepler-62. It's a rather typical star, slightly smaller, cooler, and more orange than the Sun, much like tens of billions of other stars in our galaxy. But it holds a surprise: It's orbited by at least five planets… and two of them are Earth-sized and orbit the star in its habitable zone!

The Milky Way is teeming with billions of planets, including many that are similar to our own. But how many of these alien worlds have water, and do any host extraterrestrial life?

No answers to those questions just yet. But astronomers using a new infrared technique say they've discovered water vapor in the atmosphere of a nearby gas giant planet called "tau Boötis b."

The finding suggests that the technique may play an important role in identifying which exoplanets might be hospitable for life.

There once were two planets, new to the galaxy and inexperienced in life. Like fraternal twins, they were born at the same time, about four and a half billion years ago, and took roughly the same shape. Both were blistered with volcanoes and etched with watercourses; both circled the same yellow dwarf star—close enough to be warmed by it, but not so close as to be blasted to a cinder. Had an alien astronomer swivelled his telescope toward them in those days, he might have found them equally promising—nurseries in the making. They were large enough to hold their gases close, swaddling themselves in atmosphere; small enough to stay solid, never swelling into gaseous giants. They were "Goldilocks planets," our own astronomers would say: just right for life.