Article Posted on : - Jun 18, 2012

WASHINGTON (PTI): It seems Mars is a beaten and battered planet in the solar system, as its surface has been pocked by more than 635,000 impact craters that are roughly a kilometre or more in diameter, a new study has found.

Using data gathered by several probes orbiting the Red Planet, researchers have tallied the impacts, at least those that gouged holes 500 meters wide or larger, for a grand total of nearly 635,000 craters.

The new Martian crater atlas, the largest single database ever compiled of impacts on a planet or moon, highlights the violent history of Mars and could help scientists address a number of questions about the planet, the researchers said.

"This database is a giant tool that will be helpful in scores of future Mars studies ranging from age-dating and erosion to planetary habitability, and to other applications we have not even thought of yet," study leader Stuart Robbins, from the University of Colorado, was quoted as saying by LiveScience.

Robbins and co-author Brian Hynek sifted through huge piles of data from a number of Mars orbiters and landers to compile the new database. The painstaking effort could help researchers learn more about Mars and its history, including its past potential to host life as we know it, they said.

"Many of the large impact craters generated hydrothermal systems that could have created unique, locally habitable environments that lasted for thousands or millions of years, assuming there was water in the planet's crust at the time," Hynek said.

"But large impacts also have the ability to wipe out life forms, as evident from Earth's dinosaur-killing Chicxulub impact 65 million years ago," Hynek noted.

Craters are used to date planetary surfaces and it is thought that the more craters pepper a region, the older it must be. So the new database, the researchers said, would help better understand Martian history and the role played by volcanic activity and erosion, which have resurfaced large parts of the planet.

"It can help us differentiate between craters that have been filled in versus those that have eroded by different processes over time, giving us a better idea about long-term changes on the planet's surface," Robbins added.

The new study appeared in the Journal of Geophysical Research -- Planets.

Scientists have catalogued just 200 or so impact craters on Earth, but that does not suggest that our planet hasn't been battered as badly as Mars over the ages. It's just that Earth's atmosphere, lifeforms and tectonic activity obliterate its craters or make them difficult to see, researchers said.

So the new Mars map, combined with data from the moon and Mercury, where craters are also relatively well-preserved, should provide a window into our own planet's past, they said.

Planetary scientists are particularly interested in a short span of time about 3.9 billion years ago, just 600 million years or so after the solar system formed.

In this period, asteroids as large as the state of Kansas rained down on Earth and the other rocky planets, dramatically reshaping their surfaces.