Grand Canyon, meet your match—and then some. Mars's Valles Marineris (shown in a false-color composite picture released October 22 by the German Aerospace Centre) is the largest canyon system in the solar system.
Stretching across the equatorial Martian highlands for some 2,485 miles (4,000 kilometers), Valles Marineris yawns 124 miles (200 kilometers) wide and up to 6.8 miles (11 kilometers) deep. Earth's 1.25-mile-deep (2-kilometer-deep) Grand Canyon could easily fit into one of Valles Marineris's smaller side valleys.
Another measure of the Martian canyon's magnitude: It took 20 images from the High Resolution Stereo Camera (HRSC) aboard ESA's Mars Express spacecraft to represent Valles Marineris in glorious false color (as pictured above).
Freshly kicked up by the impact that created the crater, subsurface material shines bright against long-exposed rocks. But the bright, dandelion-like blast site should fade to match the surrounding ground relatively soon, by lunar standards—within hundreds of millions of years.
Image courtesy Arizona State University/NASA
Full of Stars
Star stalker Louie Atalasidis captured a stellar feature of the constellation Orion the Hunter from Bankstown, Australia—the Orion Nebula, a star-forming cloud of gas and dust.
Seen in several photos taken over a half hour, smoke from an Orionid fireball squiggles across the sky over a pond in northern Maine on October 19.
The Orionid meteor shower is caused when Earth slams into a debris field left behind by Halley's comet, which won't return to our neck of the woods for another five decades. (Find out why Halley's comet has been seen as an omen of doom.)
Photographs by Babak Tafreshi, TWAN
Art and science melt and merge in a new picture of the sun created October 19 at NASA's Goddard Space Flight Center in Greenbelt, Maryland. Scientists used a gradient filter—often used by photo editors to create dramatic effects.
By boosting contrast in the image, the gradient filter better reveals coronal loops, arcs of solar material whose paths are determined by magnetic fields in the sun's atmosphere. Studying those field lines, according to Goddard, "can help researchers understand what's happening with the sun's complex magnetic fields, fields that can also power great eruptions on the sun, such as solar flares or coronal mass ejections."