* Astronomy

Recent evidence suggests the vast disparity seen between the northern and southern halves of the planet is caused by the long ago impact of a gigantic space rock into Mars.

Read more

A new analysis of the topography and gravity of Mars by researchers at MIT and NASA has solved one of the biggest remaining mysteries in the solar system - why the planet Mars has two completely different kinds of terrain, in its northern and southern hemispheres. In the process, they have identified what appears to be by far the largest impact scar found anywhere.

The giant basin that covers about 40 percent of the surface of Mars, sometimes called the Borealis Basin, is actually the remains of a colossal impact very early in the solar system's formation, the new analysis shows. The basin, 8,500 km across and 10,600 km long, is about the size of the combined area of Asia, Europe and Australia, and about four times wider than the next-biggest impact basins known, the Hellas basin on Mars and the South Pole-Aitken basin on the moon.
The northern-hemisphere basin on Mars is one of the smoothest surfaces found anywhere in the solar system, and some geologists think it may once have contained an ocean in the early days of the planet. The southern hemisphere is high, rough, heavily-cratered terrain, which ranges from 4 to 8 km higher in elevation than the basin floor. Until now, nobody really knew why the two halves were so different.
The new findings are being reported in a paper in the journal Nature by MIT postdoctoral researcher Jeffrey Andrews-Hanna, Maria Zuber, MIT's E.A. Griswold Professor of Geophysics, and Bruce Banerdt of NASA-JPL. Accompanying this analysis of the elevations and gravitation of Mars, which shows clear signs of the impact basin, are two other papers that provide a theoretical analysis of the kind of impact that would have been required to create it.

Source MIT

Deposits of nearly pure silica discovered by the Mars Exploration Rover Spirit in Gusev Crater formed when volcanic steam or hot water (or maybe both) percolated through the ground. Such deposits are found around hydrothermal vents like those in Yellowstone National Park. That's the conclusion of planetary scientists working with data collected by the rover's mineral-scouting instrument, which was developed at Arizona State University.

Read more

A new online map lets visitors explore Mars past through a collection of high-resolution observations from one of the most powerful spectrometers ever sent to the Red Planet. Evidence of ancient bodies of water, flowing rivers and groundwater peeks out from beneath layers of hardened magma and dusttestaments to Mars progression through wet, volcanic and dry eras. Understanding the history of water on Mars will help scientists determine whether or not the planet could have supported life in its past.

Read more