Highlighting Rhea’s Subtle Colors – New Cassini Images of Saturn’s Moon

Color-composite of Rhea (NASA/JPL/SSI/J. Major)

This is a color composite image of Rhea (pronounced REE-ah) I made from raw images acquired by the Cassini spacecraft on March 9, 2013, during its most recent — and final — close pass of the moon. The visible-light colors of Rhea’s frozen surface have been oversaturated to make them more apparent… even so, it’s still a very monochromatic place.

Rhapsody on an Impact Event: Mercury’s Rachmaninoff Crater

The peak-ringed interior of Mercury’s Rachmaninoff crater

Rachmaninoff is a spectacular double-ring basin on Mercury, and this color view is one of the highest resolution color image sets acquired of the basin’s floor. Visible around the edges of the frame is a circle of mountains that make up Rachmaninoff’s peak ring structure. The color of the basin’s floor inside the peak-ring differs from the darker material outside of it, and contains concentric troughs formed by extension (pulling apart) of the surface, likely as the molten surface solidified and cooled in the wake of the initial impact event.

This image was acquired as a high-resolution targeted color observation by MESSENGER on July 31, 2012. See a wider-angle view of the 140-km-wide Rachmaninoff crater here.

Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Carnegie Institution of Washington

Why It’s So Hard To Date a Crater

Panorama of a sunset-lit Giordano Bruno crater, imaged by LRO (NASA/GSFC/ Arizona State University)

The 13-mile (21-km) wide Giordano Bruno crater on the Moon’s far side was recently imaged by NASA’s Lunar Reconnaissance Orbiter at an angle at a time when the setting sun cast long shadows, creating the high-relief image seen above. It’s known that the brightly-rayed crater is relatively young (see the video below) but how young? It could be anywhere from 834 years old (if some Medieval accounts are to be accepted as accurate descriptions of the crater’s formation) to 2 to 4 million years old, up to even 10 million years old — of which there would obviously be no written documentation. So why is it so hard to date a crater?

Hit The Slopes!

Tracks of boulders down the northwest slope of Giordano Bruno crater

Things on the Moon don’t always stay put, as the tracks left by these large boulders show!

Ancient Ice Found in a Frigid Lunar Crater

Laser altimeter data from NASA’s LRO spacecraft shows water ice in a lunar crater’s surface material

NASA’s Lunar Reconnaissance Orbiter has found water ice lining a deep crater located on the Moon’s south pole — as much as 22% of the surface material of the crater appears to be composed of ice, NASA and university scientists report.

Mighty Melanthius

Raw image from Cassini acquired on April 14, 2012.

The 662-mile-wide Tethys is one of the most heavily cratered worlds in the solar system, tied with sister moons Rhea and Dione. In this recent raw image captured by Cassini on April 14, we can see some of the moon’s larger craters, including Melanthius with its enormous central peak.

Signs of Surprisingly Recent Volcanic Activity in Tycho

Tycho crater's central peaks may have evidence of recent volcanism (NASA Goddard/University of Arizona)

A team of researchers at India’s Physical Research Laboratory (PRL) claims it has found evidence of relatively recent volcanic activity on the Moon, using data from NASA’s Lunar Reconnaissance Orbiter and the Chadrayaan-1 spacecraft. According to the findings the central peak of Tycho crater contains features that are volcanic in origin, indicating that the Moon was geologically active during the crater’s formation a “mere” 110 million years ago.

Read more here.