Bright streaks crossing the floor of an unnamed Martian crater appear to be mineral veins, according to scientists who studied this newly released image from NASA's Mars Reconnaissance Orbiter. On Earth such sheetlike veins form when water flows through fractures in rock, leaving behind mineral deposits.
The region seen above is the central mound of a large impact crater, where bedrock was lifted up from deep inside the red planet. Scientists think heat from the impact could have melted ice in the Martian crust, allowing water to flow through the newly fractured rocks.
Also called the evening star, Venus is the brightest planet we can see with the naked eye, due in part to its thick, highly reflective atmosphere and its closeness to Earth.
Photograph courtesy Luc Perrot
Controlled from the ground, NASA's Robonaut 2 holds an instrument for measuring air velocity aboard the International Space Station on March 14. The robotic astronaut was handling the device as part of a series of dexterity tests, which included spelling out "Hello, world" in sign language.