What's the weather like on Mars's south pole? The answer is blowin' in the wind.
As seen in a picture released yesterday and taken by NASA's Mars Reconnaissance Orbiter, dark dust streaks point in several directions across the red planet's carbon dioxide ice cap. The seasonal ice cap slowly vanishes during Martian spring, and winds kick up dust from patches of exposed soil, creating elongated fans of material.
Watching which directions the fans point over time can help scientists decipher local weather conditions around the planet's pole.
Unlike the sandy Sahara, the Gobi—Mongolian for "waterless place"—is made up of a series of small, gravelly basins within a larger basin. Conditions there have been ideal for preserving archaeological and paleontological evidence, including the remains of Stone Age settlements and fossils of dinosaur eggs, according to the European Space Agency.
A NASA engineer stands in front of what may be some of the coolest mirrors headed for space: These six mirror segments for the James Webb Space Telescope were recently tested at the Marshall Space Flight Center in Alabama to see how the structures change shape in extreme temperatures.
The polished beryllium mirrors need to operate at about -379 degrees F (-228 degrees C) to collect and reflect faint infrared light from distant galaxies. But the mirrors have to be kept cool artificially even in the chill of space, since heat from the telescope itself can warm things up and contaminate the data.
The James Webb's 18 mirror segments will each be temperature-tested twice before the telescope launches, which is slated for no later than 2014.
Photograph courtesy NASA
Bull's Eye on Mars
Did Martian geology carve this concentric impact crater, or did a second space rock make a bull's eye? Taken July 9 by the HiRISE camera aboard the Mars Reconnaissance Orbiter, the recently released picture shows an impact crater with a slightly off-center pit in its middle.
Mars experts aren't sure whether the pit formed due to erosion of icy and non-icy layers inside the crater or due to a second—and oddly lucky—impact event.
Image courtesy NASA/JPL/University of Arizona
Two bright stars light up clouds of "soot" in the outer edge of our Milky Way galaxy, as seen in an infrared picture from the Spitzer Space Telescope released July 28.
The false-color image can help astronomers study our galaxy's fog of compounds called polycyclic aromatic hydrocarbons, which are found on Earth in car exhaust and charcoal grills. In space, such compounds form in the clouds of matter where stars are born.
Spitzer has been collecting pictures of the far reaches of the Milky Way as part of the GLIMPSE360 project, which builds on a previous survey of the galaxy's center.
Image courtesy NASA
A thin red line shows where the Antarctic ice sheet starts flowing off land and over the ocean—a border called the grounding line—in a section from a new mosaic of satellite data released July 23.
Led by scientists at NASA's Goddard Space Flight Center, the ice-mapping project includes precise data on elevation, which has revealed that Antarctica is losing ice mass along its coasts faster than snowfall is building up in the continent's interior. The imbalance suggests that Antarctic ice loss is contributing to sea level rise.
Image courtesy Jesse Allen, NASA Earth Observatory