NASA scientists are now saying that Martian clouds may retain less water than expected. Planetary scientist Tony Colaprete reports that the clouds they are studying form at much colder temperatures than the ones here on Earth. It turns out that it's harder to start the cloud formation process at these temperatures—the cloud particles become larger and drop out of the sky more quickly, resulting in a drier atmosphere. Understanding its clouds, which play a key role in carrying water away from the ice cap at the north pole, helps scientists like Colaprete make sense of the larger water cycle on Mars and, in turn, its overall climate.—Gregory Mone

Solar storms affect Earth occasionally, if indirectly. The flares and tsunami-like waves that sweep over the sun's surface can disable satellites and down power grids. Now it seems they can have a more concrete impact on objects that cross their path. For the first time ever, NASA scientists captured images of a comet colliding with a coronal mass ejection and losing its plasma tail in the process. In the comet's case, the same ejections that disrupt radio communications triggered magnetic reconnection, shoving together opposing magnetic fields surrounding the comet and causing the tail to rip off during the subsequent burst of energy.

The image above isn't much to look out, but researchers spliced together a series of pictures taken by NASA's STEREO satellite into a terrific movie of the collision, check it out here.—Abby Seiff

In a few months, NASA scientists and the press will note the passing of the 30th anniversary since the launches of Voyagers I and II. By now, both interstellar probes have passed beyond Pluto's orbit and are speeding out toward neighboring star systems, carrying with them copies of the Golden Record, a phonograph record full of images, music and recordings of life on Earth intended for any extraterrestrials who might happen upon the probe and wonder who sent it. It's the same idea behind the plaque that was bolted onto the Pioneer 10 and 11 spacecraft, both of which are currently gliding out of the solar system behind the Voyager probes.

The region of Aries before (left) and after (right) the explosion, with the pinpoint of light created clearly visible. Courtesy NASA.

Scientists are in the midst of observing a supernova that's  in the act of exploding. GRB060218 is cooking right now in the constellation Aries. It’s quite exciting, but it helps underscore what is to me one of the eeriest aspects of astronomy: the fact that it's essentially looking back in time. GRB060218 is 440 million light-years away. That means this explosion actually happened 440 million years ago and is only now getting to us. This thing started waaay before the Internet. It even preceded the dinosaurs. Back then, all the continents were still shoved together in a giant Pangaea.  Makes you wonder what other amazing—or horrible—things are racing toward us at light speed right now. If, for example, our sun went prematurely bust, we wouldn’t know it for a full seven minutes! —Eric Adams

On December 27, 2004, while the world was focused on the Indian Ocean tsunami, a few astronomers were contemplating the possibility of an even deadlier disaster: that of a massive asteroid striking Earth. A fifth of a mile wide—heftier than the space rock that leveled a vast swath of Siberian forest in 1908—Near-Earth Asteroid 2004 MN4 had grabbed the attention of NASA scientists just before Christmas. They put the chance of an April 13, 2029, collision at 1 in 2,700 and two days later upped the odds to 1 in 165.

Partial transcript of a recent interview with ex-astronaut Sidney Gutierrez, veteran of two shuttle missions and leading advocate of a shuttle escape system (see "Get Out Now").



Sidney Gutierrez: On an earlier flight a window was hit by a little piece of something, and they concluded afterwards it was a piece of chicken the Russians had ejected and was just floating around in space.



Popular Science: How'd they know that it was chicken?