Space Science News home |
Mars unveils a magnetic personalityMars Global Surveyor sees evidence for plate tectonics on the Red Planet that might have important consequences for ancient Martian life. |
|
Space Science News home |
Mars unveils a magnetic personalityMars Global Surveyor sees evidence for plate tectonics on the Red Planet that might have important consequences for ancient Martian life. |
April 30, 1999: Until recently scientists thought that Mars, like the Moon and Mercury, was a world
with an unbroken crust and a rather pedestrian geologic history.
Now it appears they might have been wrong.
Surprising new data from NASA's Mars Global Surveyor spacecraft have revealed a pattern of magnetic stripes on Mars similar to fields permeating the sea floors of Earth. It appears that Mars may have once had a rather dynamic geology, similar to activity on our planet today, with important consequences for ancient Martian life. Above: Magnetic bands on Mars in the southern highlands near the Terra Cimmeria and Terra Sirenum regions, centered around 180 degrees longitude from the equator to the pole. It is where magnetic stripes possibly resulting from crustal movement are most prominent. The bands are oriented approximately east - west and are about 100 miles wide and 600 miles long, although the longest band stretches more than 1200 miles. The false blue and red colors represent invisible magnetic fields in the Martian crust that point in opposite directions. The magnetic fields appear to be organized in bands, with adjacent bands pointing in opposite directions, giving these stripes a striking similarity to patterns seen in the Earth's crust at the mid-oceanic ridges. PHOTO CREDIT: NASA, Jack Connerney, Mario Acuna, Carol Ladd On Earth the banded pattern is created when molten lava wells up from the planet's interior. Along the divide where material cools to form new crust, iron-rich minerals preserve a record of the the magnetic field that prevails on the planet at the time. Earth's magnetic field reverses its polarity every million or so years, causing the alternating magnetic signature. The discovery of banded magnetic patterns on Mars suggests a similar process at work.
It's really too soon to say. Experts stress that while magnetic bands on Mars indicate past crustal spreading, they do not necessarily prove the existence of oceans or undersea vents. Furthermore, the tectonic activity seems to have ended billions of years ago. Life may have begun on early Mars and then faded away as tectonic activity subsided. These important questions can only be answered with additional research and, perhaps, trips to Mars to investigate conditions up close. 
Right:
The red of these volcanic rocks is produced
by sulfolobus solfataricus, extremophilic microorganisms
that thrive in the Solfatara volcanic area near Naples, Italy.
Even if global tectonic activity ended billions of years ago, as the magnetic data suggest, local volcanic activity might still be ongoing. In February, 1999, a team led by William Hartmann (Planetary Science Institute) announced that they had examined high resolution images of craters around a volcanic caldera called Arsia Mons and found something surprising. Previous pictures of the region did not show the detail necessary to identify the smallest craters, but the newer images from Mars Global Surveyor made an analysis possible. 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. 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 of that study 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.
|
| Web Links | |
|
NASA HQ press release - Apr. 29, 1999 The Planet Mars - from the SEDS Nine Planets web site Life on Mars - A review of evidence of signs of life in the Allen Hills meteorite Mars Global Surveyor - home page Mars at opposition - 1995 images from the Hubble Space Telescope Mars - by Percival Lowell, 1895 Related Stories:
|
|
 Join
our growing list of subscribers - sign
up for our express news delivery and you will receive a mail message
every time we post a new story!!! Headlinesreturn to Space Science News Home
|
