Astronomers have been at a loss to explain Mercury's excessively dark and unreflective surface. But a new study published in Nature Geoscience suggests the innermost planet was painted black by a steady stream of comet dust. The process took millions of years as comets disintegrated close to the sun, shedding carbon… » 3/31/15 2:40pm Today 2:40pm

Why Did A Group Of Medieval Monks See Part Of The Moon Explode?

In 1178, a group of monks at Canterbury saw the moon suddenly explode into sparks, "writhe," and "take on a blackish appearance." What the hell did they see? » 3/31/15 12:53pm Today 12:53pm

Ganymede's Bizarre Bulge Baffles Scientists

There's a strange bulge on the Solar System's largest moon, one that measures 375 miles wide and nearly two miles tall. Scientists aren't entirely sure why it's there or what caused it, but it may have something to do with the Jovian moon's subsurface ocean. » 3/27/15 9:20am Friday 9:20am

On Friday, asteroid 2014-YB35 is expected to make its closest approach to Earth. Traveling at over 23,000 mph (37,000 km/h), NASA says the 6.2 mile (1,000 meter) asteroid won't get any closer than 2.7-million miles (4.4 million km). That's nearly 12 times the distance from Earth to the Moon – so relax. » 3/26/15 2:40pm Thursday 2:40pm

Why the Length of Saturn's Day Is So Hard to Measure 

The length of a planet's day seems like such a simple number, a basic piece of information that should accompany any solar system diagram. But probes flying past Saturn have turned up oddly conflicting numbers. » 3/25/15 5:22pm 3/25/15 5:22pm

Last Week's Total Solar Eclipse – As Seen From 35,000 Feet

For last week's solar eclipse, astronomer Glenn Schneider chartered a plane to fly through the vast shroud of darkness temporarily cast by the the moon's shadow on the north Atlantic. Astrophotographer Stephan Heinsius was aboard the flight, with a video camera. Here's what he and the other passengers saw. » 3/24/15 1:30pm 3/24/15 1:30pm

As It Turns Out, We Really Are All Starstuff

"The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars," Carl Sagan famously said in his 1980 series Cosmos. "We are made of starstuff." » 3/24/15 10:00am 3/24/15 10:00am

Jupiter May Have Destroyed The Solar System's First Planets

It is becoming increasingly obvious that our Solar System — with its inner collection of small rocky planets and an outer region buffeted by gas planets — is quite uncommon. According to a remarkable new study, the reason may have to do with Jupiter and an ancient migratory journey that kickstarted the destruction of… » 3/24/15 8:00am 3/24/15 8:00am

Here's Your Opportunity To Help Name The Features Of Pluto And Charon

In July, New Horizons will pay a visit to Pluto and Charon. The historic flyby is expected to reveal surface features of these objects in extraordinary detail. Now, NASA and the SETI Institute, along with the International Astronomical Union, want your help naming these features. » 3/23/15 1:40pm 3/23/15 1:40pm

Nova in Sagittarius Is Brighter Than Ever - Catch It With The Naked Eye!

Great news about that new nova in Sagittarius. It's still climbing in brightness and now ranks as the brightest nova seen from mid-northern latitudes in nearly two years. » 3/21/15 3:30pm 3/21/15 3:30pm

Molecular Nitrogen On Rosetta Points To The Comet's Frigid Origins

For the first time ever, scientists have detected molecular nitrogen on a comet. The discovery is sheds light on the nature of the pre-Solar System environment in which Comet 67P/C-G formed. » 3/20/15 2:20pm 3/20/15 2:20pm

This Viral Photo Of Yesterday's Eclipse From Space Is Fake. Duh.

Yesterday's solar eclipse was one of the most spectacular in recent memory. So it's a shame that thousands of people were duped into thinking this image — supposedly taken from the International Space Station — was the real deal. It's obviously not, and here's why. » 3/20/15 9:45am 3/20/15 9:45am

How To Watch Friday's Total Solar Eclipse

Do you live inside the swath of red depicted in this map? If so, you're one of the few people on Earth able to directly witness Friday's total solar eclipse. For everyone else, your best bet is to watch online. Head over to to watch live, beginning at 1:30 AM PDT/4:30 AM EDT/8:30 UTC. » 3/19/15 7:00pm 3/19/15 7:00pm

Astronomers May Have Detected Rings Around Minor Planet Chiron

Researchers at MIT have detected features around Chiron — a centaur in orbit between Saturn and Uranus — that indicate a ring system, or possibly jets or a shell of dust. If confirmed, it would only be the second minor planet in our Solar System known to host rings. » 3/18/15 6:20am 3/18/15 6:20am

MESSENGER's Latest Shots Of Mercury Are Some Of The Best We've Seen

After four years in orbit around Mercury, NASA's MESSENGER mission is sadly coming to an end. But before it plunges to its doom, mission controllers are taking full advantage of the spacecraft's close proximity to the surface. Here are some of the most detailed and vivid images ever taken of the Solar System's… » 3/17/15 7:00am 3/17/15 7:00am

There May Be More Water On Jupiter's Largest Moon Than On Earth

By studying the subtle shifts of aurorae on Ganymede, scientists working with the Hubble Space Telescope have concluded that Jupiter's largest moon hosts a massive subterranean ocean. Quite suddenly, the outer reaches of our solar system appear to be a very wet place, indeed. » 3/13/15 12:50pm 3/13/15 12:50pm

The Quest To Find Another Saturn Just Got One Step Closer

If our solar system is any indication, planets with rings around them are quite common, but finding extrasolar ringed planets has proven difficult. Now astronomers have developed a surprisingly simple method for detecting these distant "exorings." It'll only be a matter of time before we find the next Saturn. » 3/11/15 7:30am 3/11/15 7:30am

9 Historical Mysteries Solved By Astronomy

History is filled with mysteries that can be answered by the position of the moon, the nature of the tides, and the time of year when an event occurred. Here are mysteries of battles, art, and literature, that were solved thanks to astronomical detectives. » 3/10/15 10:13am 3/10/15 10:13am

Here's What Happens When You Screw With Isaac Newton

Isaac Newton reached the level of genius in two different disciplines: physics and making people miserable. This is a tale of his accomplishments in the latter discipline. The object of his scorn, this time, is a poor astronomer named John Flamsteed,who made the mistake of not being agreeable enough. » 3/10/15 8:00am 3/10/15 8:00am

We Got to See This Supernova Explode Four Times Simultaneously

It's not every day we get to see a supernova, and a single exploding star split into four images is an absolute first. Here's how it happened. » 3/09/15 4:38am 3/09/15 4:38am