New Discoveries at Mercury

Mercury's magnetic field is "alive." Volcanic vents ring the planet's giant Caloris Basin. And Mercury has shrunk in on itself more than previously suspected.
These are just a few of the new discoveries by NASA's MESSENGER spacecraft, which flew past Mercury on January 14, 2008. The results are described in a series of 11 papers published in a special July 4th issue of Science magazine.
Six of the papers in Science report studies of the planet's surface--its colors, mineralogy, and the shape of its terrain. For instance, the color enhanced image below reveals evidence of volcanic vents along the margins of Caloris basin, one of the Solar System's largest and youngest impact basins:
"By combining Mariner 10 and MESSENGER data, the science team was able to reconstruct a comprehensive geologic history of the entire Caloris basin interior," says James Head of Brown University, lead author of one of the Science reports. "The basin was formed from an impact by an asteroid or comet during a period of heavy bombardment in the first billion years of Solar System history. As with the lunar maria, a period of volcanic activity followed, producing lava flows that filled the basin interior. This volcanism is responsible for the comparatively light, red material of the interior plains intermingled with [newer] impact crater deposits."
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A world away, two planets somewhat like Earth

By Faye Flam
Inquirer Staff Writer

The most Earth-sized planet and the most temperate planet known beyond our solar system both circle a dim red star 21 light-years away. These discoveries, announced yesterday at a meeting in England, moved astronomers a step closer to their dreams of finding other planets capable of supporting life as we understand it.
Since 1995, scientists have found more than 350 planets orbiting other stars, but most suffer from the same problems that make our neighbors in the solar system so inhospitable.
Many of the so-called extrasolar planets orbit so close that their stars would sterilize their surfaces. Others are jumbo "gas giants," like Jupiter, and therefore unlikely to have solid surfaces.
Astronomers suspect that Earthlike planets are out there but that they are nearly impossible to detect with current technology.
This latest finding came from a Swiss and French team working at the European Southern Observatory in Chile. They announced this latest finding at an international conference at the University of Hertfordshire, in conjunction with the European Week of Astronomy and Space Science.
For the last four years, the team has been studying this relatively nearby solar system, called Gliese 581, named after Wilhelm Gliese, who cataloged this and other nearby stars. It now appears to have four planets. Read More.....