The week in pictures: July 30–August 5, 2011
This week's news featured water on Mars, oxygen in space, a cratered asteroid, a spacecraft's launch, and more.
NASA/JPL-Caltech/Univ. of Arizona
NASA spacecraft data suggests water flowing on Mars
Dark, finger-like features appear and extend down some martian slopes during late spring through summer, fade in winter, and return during the next spring. Learn more »