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A steamy cover-up on the Red PlanetMars Global Surveyor sees evidence for geologically recent volcanism that has covered over craters and may provide a niche for life |
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Space Science News home |
A steamy cover-up on the Red PlanetMars Global Surveyor sees evidence for geologically recent volcanism that has covered over craters and may provide a niche for life |
 Feb. 18, 1999:
Olympus Mons, the largest volcano in the solar system, towers a breathtaking
25 km above the surrounding plains on Mars. Until recently scientists thought that
Olympus Mons and other volcanoes on the Red Planet had been extinct for hundreds of millions, perhaps even
billions, of years. Now it appears they might have been wrong.
Right: Olympus Mons is an old Martian volcano that is very similar in style to the volcanic island of Hawaii on the Earth. It is 25 km high, making it the largest volcano in the solar system. More information and images from the JPL Planetary Photojournal. New images from NASA's Mars Global Surveyor spacecraft show that volcanoes were probably active less than 100 million years ago, and indeed may still be active today. One way that planetary scientists estimate the age of features or events on a planet's surface is by counting the craters left behind by meteorite and asteroid impacts. On a planet like Earth with weather or geological activity, craters tend to be quickly erased. On planets where nothing much happens, such as the Moon, the craters remain. The pock-marked surface of the Moon is considered "old" by planetary physicists whereas Earth's surface is dynamic and "young." By counting craters on surfaces with known ages, like lunar highlands and maria which have been dated by radioactive methods, it is possible to obtain a rough conversion factor between the minimum age of a planetary feature and the number of craters that are found on top of it. |
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In an article published today in Nature, a team led by William Hartmann (Planetary Science Institute) examined high resolution images of craters around a volcanic caldera called Arsia Mons. Previous pictures of the region did not show the detail necessary to identify the smallest craters, but the newer images made an analysis possible. What they found surprised them. Within the caldera, the researchers counted just one meteor crater per 100 square kilometers. A similar-sized area on the Moon contains more than 60. |
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They concluded that older craters must have been covered over by
lava as recently as 40 to 100
million years ago. By geological standards, that's very recent.
In fact, based on the statistical
distribution of crater sizes in the Global Surveyor images,
the authors suggest that volcanism
is continuing on Mars in current geological time.
Below: These hot springs at Yellowstone owe their vibrant colors to heat-loving microorganisms called Thermus Aquaticus, many of which can live and reproduce at temperatures near the boiling point of water. Photo courtesy Prof. Thomas D. Brock, University of Wisconsin. 
If these findings are correct it could have profound
implications for the
possibilty that life might exist on Mars. Here on Earth scientists
have
only recently learned that extreme-loving microorganisms (called extremophiles)
can thrive inside volcanoes and in near-boiling hot springs.
They can live without sunlight or organic carbon as food, and
instead survive on sulfur, hydrogen, and other materials that
normal organisms can't metabolize. It may sound like science
fiction, but many scientists are working rapidly to explore the
biology of these recently discovered life forms. If there are indeed
hot springs and geothermal vents on Mars today, as might be
expected if volcanism is ongoing,
then they could be prime
locations for future Mars missions to seek out life.
The results reported today in Nature will undoubtedly spur
new observations to find areas of active volcanism on the Red Planet.
Right:
The red of these volcanic rocks is produced
by sulfolobus solfataricus, extremophilic microorganisms
that thrive in the Solfatara volcanic area near Naples, Italy.
Malin Space Science Systems and the California Institute of Technology built the Mars Observer Camera using spare hardware from the Mars Observer mission. MSSS operates the camera from its facilities in San Diego, CA. The Jet Propulsion Laboratory's Mars Surveyor Operations Project operates the Mars Global Surveyor spacecraft with its industrial partner, Lockheed Martin Astronautics, from facilities in Pasadena, CA and Denver, CO. |
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Evidence for recent volcanism on Mars from crater counts -- from Nature
High-resolution Global Surveyor image of Arsia Mons -- from today's Nature article Mars Global Surveyor Web Site Bugs of Fire -- Spacelab crystallizes a protein from a very weird, and surprisingly common, volcano-loving bug. Scientists hope to discover how these bugs can survive in such extreme conditions. Sept. 16, 1998 NASA Space Science News The Sands of Mars -- Oct. 29, 1998 NASA Space Science News New NASA images of the Martian North Pole -- Oct. 23, 1998 NASA Space Science News New images of volcanoes on Mars and Io -- Oct. 14, 1998 NASA Space Science News The Planetary PhotoJournal -- the latest images from around the solar system JPL Press Release on Martian Sand Dunes Mars Global Surveyor Animations More NASA Space Science News |
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