By combining information from the camera’s blue-green, red and near-infrared color filters, scientists confirmed that material around the rim of Phobos’ largest surface feature, Stickney crater, appears bluer than the rest of Phobos. The impact that excavated the 9-kilometer (about 5.5 mile) in diameter Stickney crater is thought to have almost shattered the moon.
“Based on analogy with material on our own moon, the bluer color could mean that the material is fresher, or hasn’t been exposed to space as long as the rest of Phobos’ surface has,” Bridges said.
The new view shows landslides along the walls of Stickney and other large craters: Phobos’ striking surface grooves and crater chains; and craters hidden on the moon’s dark side illuminated by “Marsshine.”
“Marsshine” is sunlight reflected by Mars onto the moon. The phenomenon is similar to “Earthshine,” where Earth reflects sunlight that illuminates the dark side of our moon. Like Earth’s moon, Mars’ moons Phobos and Deimos are “tidally locked” on their planet, that is, they always present the same side to the planet they orbit.
These images are among several new HiRISE images being released at: http://www.nasa.gov/mission_pages/MRO/multimedia/20080409.html. The images include an anaglyph, or 3D view of Phobos that can be viewed with red-blue glasses.
The Mars Reconnaissance Orbiter flies at about 4,800 kilometers per hour (7,800 mph) between 250 to 316 kilometers (155 and 196 miles) above the surface of Mars.
