35-million-year-old crater offers hints to life on Mars
1 Jul 2008, 1041 Hrs

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Washington, July 1 (ANI): A new study has indicated that a 35-million-year-old crater under Chesapeake Bay in the US is offering new insights into possible locations for life on Mars.

According to a report in National Geographic News, the pit, discovered about 15 years ago, is considered one of the best-preserved examples of the roughly 200 known impact structures on Earth.

The full crater has a diameter of about 56 miles (90 kilometers).

"That's an oddly large size for a crater believed formed by a comet or asteroid only about 1.3 miles (2 kilometers) wide," said study co-author Gregory Gohn of the U.S. Geological Survey.

"At the time, the eastern shore of the U.S. lay near where Richmond, Virginia, sits today, so the object struck a 650-foot-deep (200-meter-deep) sea," he added.

The projectile vaporized upon impact, releasing intense heat for more than 100 miles (161 kilometers), according to Gohn.

The collision blew open a crater that was initially about 12.4 miles (20 kilometers) wide and 4.3 miles (7 kilometers) deep.

But the crater walls were not strong enough to support the massive pit and collapsed further, creating a larger pit and allowing salty seawater and broken rock to became trapped in a subsurface cavity.

The crumbling rock stirred up raw materials that allowed life to bloom inside the crater after the waters finally cooled, hinting that life on Mars may also have flourished because of impacts.

The findings could hold clues about the role craters played in the evolution of life on early Mars, said team member Mary Voytek, a USGS microbiologist. The red planet's surface is currently inhospitable to life because of high levels of ultraviolet radiation and frigid temperatures, but material and a suitable environment could have been introduced into the subsurface during impacts.

The new data suggests that "there's a higher probability we'll find life in the subsurface" on Mars.

According to David Kring of NASA's Lunar and Planetary Institute, "The recent drilling project is an excellent probe of the crater's geology, and this study reveals important details of the crater's formation."

"The crater is possibly an analog for impacts that may have occurred long ago on Mars, when the planet may have had intermittent seas," he added.

Elisabetta Pierazzo, a planetary physicist at the Planetary Science Institute in Tucson, Arizona, said, "This is very important for studying Mars, where a subsurface biosphere may have existed in the past." (ANI)