Bright material litters the floor of a trough in Noctis Labyrinthus, a maze-like region of deep valleys near one of Mars's volcanic plains.
The recently released image was snapped by NASA's Mars Reconnaissance Orbiter. Other data from the spacecraft suggest that the material is hydrated—that is, it contains water in its atomic structure.
Scientists think the hydrated material could have formed long ago, either from subsurface water upwelling in the trough or from surface ice melting from the heat of nearby volcanic activity.
Image courtesy U. Arizona/NASA
Resembling a primate head adrift in space, NGC 2174, also called the Monkey Nebula, shines in a new picture taken by a backyard astronomer in the U.K. and recently submitted to National Geographic's My Shot photo community.
The Monkey sits about 6,400 light-years away in the constellation Orion. The cloud of dust and gas surrounds a bright star cluster, which lights up the nebula and carves its simian shape with strong stellar winds. (See more nebula pictures.)
Seen via the Subaru Telescope in Hawaii, the Sombrero galaxy, aka M104, really lights up its local neighborhood. Now, new data hint at what was happening back when the seeds of such galaxies were deep in the universe's dark ages.
Shortly after the big bang, the universe was shrouded in an opaque fog of neutral hydrogen that absorbed the light from the first stars. These cosmic dark ages came to an end about 13 billion years ago, when enough stars and galaxies had formed to blast the fog with plenty of ultraviolet radiation, charging the hydrogen and making the fog transparent—a process called reionization.
In a new study, scientists looked for ancient signs of reionization in nearby galaxies—including the Sombrero. The results allowed the team to trace the path of reionization across the cosmos, offering an unprecedented glimpse at how the process swept away the galactic dark ages.
Swirls of teal and milky blue stain the waters of the Black Sea during a major phytoplankton bloom, as seen in a picture snapped earlier this month by NASA's Terra satellite.
Such colorful currents appear every year in the Black Sea, most often in the summer. The numbers of the microscopic marine organisms—and thus the intensity of the color change—vary depending on nutrient levels, water temperature, and other factors.
Image courtesy MODIS/NASA
Trick of the Light
This new NASA-ESA Hubble Space Telescope picture might look like a pair of colliding galaxies. But astronomers can tell that, in reality, the galaxies are separated by tens of millions of light-years.
One clue is that both galaxies in the pair—collectively known as NGC 3314—are still relatively intact. When galaxies collide, the intense gravitational forces usually pull the bodies out of shape long before they visibly merge. In addition, studies of the galaxies' motion show that they are not on a collision course.
Nevertheless, seen from Earth, the two galaxies overlap, offering scientists an opportunity to study a phenomenon called gravitational microlensing—when light from a background object is warped and magnified by the gravity of something massive in the foreground.
Image courtesy ESA/NASA and W. Keel, U. Alabama
Hole in the Sky
On June 5 NASA's Aqua satellite snapped an "antistorm"—a large circle of cloud-free sky over the ocean off Australia.
Spanning up to 620 miles (1,000 kilometers), the hole was created by a high-pressure system in a blanket of stratocumulus clouds. Winds tend to blow outward from high-pressure areas, causing air inside the regions to sink. Sinking air warms, boosting evaporation—and decreasing clouds.