planet

About 500 light-years away in the constellation Cygnus lives a star, which, though smaller and redder than the sun, has a planet that may look awfully familiar.

With a diameter just 10 percent bigger than Earth's, the newly found world is the first of its size found basking in the benign temperature region around a parent star where water, if it exists, could pool in liquid form.

Scientists on the hunt for Earth's twin are focused on worlds that could support liquid surface water, which may be necessary to brew the chemistry of 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.

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.

Peering into the far reaches of the solar system, astronomers have spied a pink frozen world 7½ billion miles from the sun.

It's the second such object to be discovered in a region of space beyond Pluto long considered a celestial wasteland. Until now, the lone known resident in this part of the solar system was an oddball dwarf planet spotted in 2003 named Sedna after the mythological Inuit goddess who created the sea creatures of the Arctic.

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.

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.

A Japanese research team of astronomers and planetary scientists has focused their efforts on investigating the atmospheric features of one super-Earth, GJ 1214 b, which is located 40 light years from Earth in the constellation Ophiuchus, northwest of the center of our Milky Way galaxy.

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.

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