Like strokes from a giant brush, dark streaks decorate the wall of a trough in the Acheron Fossae region of Mars, which lies about 620 miles (1,000 kilometers) north of the huge volcano Olympus Mons. Released February 24, 2010, the picture is among the latest from NASA's Mars Reconnaissance Orbiter program.
Such streaks are thought to be evidence of one of the only geologic processes currently active on the red planet. Scientists think the streaks form when dry sand or fine-grained dust flows down a slope like an avalanche, exposing darker material underneath. (See a picture of an active avalanche on Mars.)
Image courtesy NASA/JPL/University of Arizona
The Amazon River is a green line snaking across the otherwise orange rain forest in a map of "brightness temperature" in Brazil, created by the European Space Agency's Soil Moisture and Ocean Salinity (SMOS) spacecraft and released February 23.
Launched November 2, 2009, the SMOS probe measures radiation emitted by Earth's surface and uses that data to calculate variations in soil moisture and ocean salinity. The probe was designed to improve our understanding of Earth's water cycle so scientists can design more accurate climate models and make better weather predictions.
Image courtesy ESA
Cobweb in Space
Like a cobweb stretched across the sky, the wispy star cluster NGC 346 shines in unprecedented glory in a new picture from the European Southern Observatory in Chile, released on February 24.
Currently spanning about 200 light-years, the cluster's body of dust and gases has been shaped by powerful radiation from the young, massive stars within. But NGC 346 is a work in progress. New stars are still being born, and they'll continue to sculpt the cluster's glowing form.
Image courtesy ESO
Listening for Phoenix
As spring embraces northern Mars, surface ice has decreased around the Phoenix Mars lander, as seen in two aerial views taken February 8 (left) and February 25 by the Mars Reconnaissance Orbiter.
Phoenix, which arrived on Mars in May 2008, worked for five months before the onset of Martian winter left the solar-powered craft with too little sunlight to stay alive.
Image courtesy NASA/JPL-Caltech/University of Arizona
Final Firing Test
On February 25 glowing exhaust from a solid-fuel rocket motor lights up the snow in Promontory, Utah, during the last ever firing test of a NASA space shuttle flight-support motor. The motor burned for about 123 seconds—the same amount of time a motor needs to burn during an actual shuttle launch.
Since July 1977, NASA has run tests of the reusable rocket motors that carry space shuttles into low-Earth orbit. The planned April 5 launch of the shuttle Discovery will be one of the last four launches before NASA retires the space shuttle program at the end of 2010.