Once Martian sand grains hop, they don’t stop.
That’s the conclusion of a new study that finds sand can move on Mars without much windy encouragement.
Mars’ sandy surface has clearly been shaped by wind. Its characteristic …

Santorini Panorama
This panorama shows the vista from which NASA’s Mars Exploration Rover Opportunity spent five weeks in November and December 2008 while the sun was nearly directly in between Mars and Earth.
Opportunity is approaching the …

Mercury was once seen as a cold, dead little world, spinning around the sun unchanged for the past 4 billion years.
No longer: Observations from the Messenger spacecraft say it’s anything but.
NASA’s orbiter is sending back …