planet

This video explains the difference between a planet, like Earth, and a dwarf planet, like Pluto. 

Made up of rock and iron, this planet is thought to be tidally locked to it's parent star (meaning one side always faces the star), it is also much closer to it's host star than the Earth is to the Sun. This means that the "day" side of the planet is always molten, and that's just awesome.

Astronomers have found the first Earth-sized exoplanet within a star's habitable zone. The planet is the closest thing yet to the coveted 'Goldilocks' orb that scientists have long sought — a world roughly the size of Earth orbiting a star at a distance that is just right for liquid water to exist.

"We definitely think it's one step closer to finding a true Sun–Earth analogue," says study co-author Elisa Quintana, an astronomer at the SETI Institute in Mountain View, California, and at the nearby NASA Ames Research Center in Moffett Field. But because the star that the exoplanet orbits is a cool, dim one unlike the Sun, Quintana and her colleagues consider the planet more of a cousin to Earth than a twin.

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.

This planet, GJ 504b, is about the size of Jupiter, but has several times its mass. It's actually so far the smallest planet that's ever been directly imaged with a telescope, rather than being observed by eclipsing its parent star.

Astronomers have discovered an alien planet that wobbles at such a dizzying rate that its seasons must fluctuate wildly.

Throughout all of the planet's fast-changing seasons, however, no forecast would be friendly to humans. The warm planet is a gassy super-Neptune that orbits too close to its two parent stars to be in its system's "habitable zone," the region where temperatures would allow liquid water, and perhaps life as we know it, to exist.

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.