Space Pictures This Week: Black Hole Ring, Moon Pit, More

Sparkling Ring

Image courtesy S. Rappaport, CXC/MIT/NASA

When two lovers decide to merge their lives, a shiny ring often comes into the picture. Apparently that's also true for the merging galaxies collectively known as Arp 147. A new composite picture from two NASA telescopes shows a ring of newborn stars decked out with hot-pink black holes that's formed around one of the interacting galaxies.

The collision of a spiral galaxy (right) with an elliptical galaxy produced the wave of star formation, shown in blue in visible-light images from the Hubble Space Telescope. Some of the massive stars lived fast and died young, collapsing to form black holes. As the black holes pull in surrounding material, they give off x-rays, captured in pink by the Chandra X-ray Observatory.

Published February 10, 2011

Black Hole Sun

Image courtesy SDO/NASA

The sun appeared to have a bald spot for a few days in early February, as a massive coronal hole was aimed at Earth. Seen in extreme ultraviolet by NASA's Solar Dynamics Observatory, or SDO, the dark hole stretched across the top of the sun on February 1.

Coronal holes are magnetically open regions on the sun that send out streams of high-speed charged particles. As SDO watched, this coronal hole rotated to face Earth, increasing the chance for aurora sightings.

(See pictures: "Huge Solar Storm Triggers Unusual Auroras.")

Published February 10, 2011

Lunar Void

Image courtesy ASU/NASA

A new satellite picture of a lunar pit proves that the gaping hole leads to an underground void—a potential boon for future astronauts on the moon, who could find shelter in the moon's deep caves. (See "First Moon 'Skylight' Found—Could House Lunar Base?")

NASA's Lunar Reconnaissance Orbiter (LRO) found the Marius Hills pit last March. Scientists suspected the pitch-black circle was a skylight on a lava tube, a tunnel under the lunar surface carved by flowing magma. The new LRO picture was taken at an angle, so that scientists could see sunlight hitting the floor of a tunnel that extends beyond the pit's maw.

Published February 10, 2011

Sands of Time

Images courtesy University of Arizona/Caltech/NASA

The sands of Mars are surprisingly shifty, according to a new analysis of pictures taken by NASA's Mars Reconnaissance Orbiter over two years.

Dune fields covering an area the size of Texas form a band around the edge of Mars's north polar ice cap. Scientists had thought these dunes were frozen in time, shaped long ago by much more powerful winds than the area experiences today.

But a series of three images of the same dune shows avalanches and noticeable changes in the ripple patterns between 2008 and 2010. The scientists think that, instead of by winds, the sand is being reshaped by carbon dioxide gas released as the seasonal ice cap vaporizes and reforms.

Published February 10, 2011