ESA Finds Liquid Water on Mars

Water has been found on Mars! (Yes, again.) In what’s turned into the biggest space news of the day, today ESA (and that’s pronounced “eesa”, you don’t need to spell it out) announced that the Italian-run radar experiment aboard its Mars Express orbiter has provided the first good evidence of liquid water present beneath the…

ESA Grabs Glimpses of Mars’ Groovy Moon

This animation is comprised of three images acquired by ESA’s Mars Express spacecraft on Sept. 12, 2017 with its High Resolution Stereo Camera (HRSC). It shows parts of the grooved and pitted surface of Phobos, the larger of Mars’ two natural satellites. The original images were captured in greyscale; I added color based on other…

Rolling Boulders on a Comet

See that big rock there? (It’s easy because there’s a big yellow arrow pointing to it.) That’s a 100-foot/30-meter wide boulder that was imaged sitting on the surface of Comet 67P/Churyumov-Gerasimenko by ESA’s Rosetta on May 2, 2015. Nine months later Rosetta captured another image of the same area in which that huge stone had…

Revisit Our First (and Only) Landing on Titan

When you think of spacecraft landings on other worlds, you probably first think of Mars, the Moon, Venus, and comet 67P (if you’ve been following along over the past couple of years.) But—in addition to the asteroid Eros and hard impacts on a comet and Mercury—Saturn’s moon Titan was also visited by an alien (i.e.,…

Could This Asteroid Hit Earth? Astronomers Go “Back in Time” to Find the Answer

Astronomers are always watching the skies for observations of near-Earth asteroids—”space rocks” that have orbits close to Earth’s and, in the case of potentially hazardous asteroids (aka PHAs), those whose orbits could actually cross Earth’s and are larger than 150 meters (500 ft) across. When a new one of these is discovered—no small feat considering that…

Light and Dark: the Two Faces of Dione

Saturn’s moon Dione (pronounced DEE-oh-nee) is a heavily-cratered, 700-mile-wide world of ice and rock, its surface slashed by signature “wispy lines” that mark the bright faces of sheer ice cliffs. But Dione has some strange colorations too, evident here in a global map created in 2014 from Cassini images. Its leading half—the side that faces “forward” as…

With One More Comet Landing Rosetta’s “Rock and Roll” Mission is Ended

Rosetta is down. I repeat: Rosetta is down. This morning, Sept. 30, 2016, just after 10:39 UTC (6:39 a.m. EDT) ESA’s Rosetta spacecraft ended its mission with an impact onto the surface of the comet 67P/Churyumov-Gerasimenko. The descent, begun with a final burn of its thrusters about 14 hours earlier, was slow, stately, and deliberate, but even…

Rosetta Finally Found Its Lost Philae Lander

Nearly two years after its historic landing on comet 67P/Churyumov-Gerasimenko, ESA’s lander has finally been spotted in an image from the orbiting Rosetta spacecraft—PHILAE HAS BEEN FOUND!

Venus’ Water Has Been Electrified Away

Using data gathered by ESA’s Venus Express researchers have determined what likely happened to Venus’ water: it was “zapped” away by a surprisingly strong electric field generated by the planet’s atmosphere and the incoming solar wind. Without a protective magnetosphere like Earth has, Venus’ upper atmosphere directly interacts with energetic particles streaming out from the Sun. The…

Europe’s Sentinel-3A Returns Gorgeous “First Light” Earth Images

Captured by the EU’s Copernicus Sentinel-3A satellite on Feb. 29, 2016, this beautiful composition of blacks, purples, and blues shows the twilight transition across the Norwegian archipelago of Svalbard, located north of the Arctic Circle between Norway and the North Pole.  The snow-covered and fjord-cut large island of Spitsbergen can be seen at the right edge, while sea ice…

Comet 67P Confirmed To Be a Contact Binary

Ever since we got our first good look at Comet 67P/Churyumov-Gerasimenko from the approaching Rosetta spacecraft in 2014 it has been considered to be a textbook example of a contact binary, with its “rubber duckie” double-lobed shape consisting of an oval “head” and flat-bottomed “body” joined by a “neck.’ Now, using data gathered by Rosetta’s…