Mars: "The Water Planet" (Was There Life Too?)
"We can now say that the planet was altered on a global scale by liquid water about four billion years ago."
John Carter --The University of Paris
Minerals in northern Mars craters observed by two NASA orbiters suggest that a phase in Mars' early history with conditions favorable to life occurred globally, not just in the south.
Southern and northern Mars differ in many ways, so the extent to which they shared ancient environments has been open to question.
In recent years, the European Space Agency's Mars Express orbiter and NASA's Mars Reconnaissance Orbiter have found clay minerals that are signatures of a wet environment at thousands of sites in the southern highlands of Mars, where rocks on or near the surface are about four billion years old. Until this week, no sites with those minerals had been reported in the northern lowlands, where younger volcanic activity has buried the older surface more deeply.
French and American researchers report that some large craters penetrating younger, overlying rocks in the northern lowlands expose similar mineral clues to ancient wet conditions.
Other types of evidence about liquid water in later epochs on Mars tend to point to shorter durations of wet conditions or water that was more acidic or salty.
The researchers used the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), an instrument on the Mars Reconnaissance Orbiter, to check 91 craters in the northern lowlands. In at least nine, they found clays and clay-like minerals called phyllosilicates, or other hydrated silicates that form in wet environments on the surface or underground.
Earlier observations with the OMEGA spectrometer on Mars Express had tentatively detected phyllosilicates in a few craters of the northern plains, but the deposits are small, and CRISM can make focused observations on smaller areas than OMEGA.
"We needed the better spatial resolution to confirm the identifications," Carter said. "The two instruments have different strengths, so there is a great advantage to using both."
CRISM Principal Investigator Scott Murchie of Johns Hopkins University Applied Physics Laboratory, said that the findings aid interpretation of when the wet environments on ancient Mars existed relative to some other important steps in the planet's early history.
The prevailing theory for how the northern part of the planet came to have a much lower elevation than the southern highlands is that a giant object slammed obliquely into northern Mars, turning nearly half of the planet's surface into the solar system's largest impact crater. The new findings suggest that the formation of water-related minerals, and thus at least part of the wet period that may have been most favorable to life, occurred between that early giant impact and the later time when younger sediments formed an overlying mantle.
"That large impact would have eliminated any evidence for the surface environment in the north that preceded the impact," Murchie said. "It must have happened well before the end of the wet period."
Casey Kazan via NASA/JPL
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In recent years, the European Space Agency's Mars Express orbiter and NASA's Mars Reconnaissance Orbiter have found clay minerals that are signatures of a wet environment at thousands of sites in the southern highlands of Mars, where rocks on or near the surface are about four billion years old. Until this week, no sites with those minerals had been reported in the northern lowlands, where younger volcanic activity has buried the older surface more deeply.
French and American researchers report that some large craters penetrating younger, overlying rocks in the northern lowlands expose similar mineral clues to ancient wet conditions.
Other types of evidence about liquid water in later epochs on Mars tend to point to shorter durations of wet conditions or water that was more acidic or salty.
The researchers used the Compact Reconnaissance Imaging Spectrometer for Mars (CRISM), an instrument on the Mars Reconnaissance Orbiter, to check 91 craters in the northern lowlands. In at least nine, they found clays and clay-like minerals called phyllosilicates, or other hydrated silicates that form in wet environments on the surface or underground.
Earlier observations with the OMEGA spectrometer on Mars Express had tentatively detected phyllosilicates in a few craters of the northern plains, but the deposits are small, and CRISM can make focused observations on smaller areas than OMEGA.
"We needed the better spatial resolution to confirm the identifications," Carter said. "The two instruments have different strengths, so there is a great advantage to using both."
CRISM Principal Investigator Scott Murchie of Johns Hopkins University Applied Physics Laboratory, said that the findings aid interpretation of when the wet environments on ancient Mars existed relative to some other important steps in the planet's early history.
The prevailing theory for how the northern part of the planet came to have a much lower elevation than the southern highlands is that a giant object slammed obliquely into northern Mars, turning nearly half of the planet's surface into the solar system's largest impact crater. The new findings suggest that the formation of water-related minerals, and thus at least part of the wet period that may have been most favorable to life, occurred between that early giant impact and the later time when younger sediments formed an overlying mantle.
"That large impact would have eliminated any evidence for the surface environment in the north that preceded the impact," Murchie said. "It must have happened well before the end of the wet period."
Casey Kazan via NASA/JPL
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Image Credit: NASA/ESA/JPL-Caltech/JHU-APL/IAS
Comments
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In at least nine, they found clays and clay-like minerals called phyllosilicates, or other hydrated silicates that form in wet environments on the surface or underground.
Posted by: HMS Home Warranty | July 06, 2011 at 04:54 AM
John Carter speaking on Mars? Hilarious...
Posted by: Sad King Billy | July 06, 2011 at 08:07 AM
http://starchild.gsfc.nasa.gov/docs/StarChild/questions/question38.html
^ ^ then it slammed into earth and carved out the moon.
Posted by: John M. | July 06, 2011 at 09:37 AM
This makes a lot of sene dude. Wow.
www.total-privacy.ua.tc
Posted by: WuxRoo | July 07, 2011 at 07:17 AM
Wait really? There's a guy who studies mars, and his name is John Carter?
Posted by: Jacob | July 07, 2011 at 10:24 PM
Wait really? There's a guy who studies mars, and his name is John Carter?
Posted by: Jacob | July 07, 2011 at 10:24 PM
Wait really? There's a guy who studies mars, and his name is John Carter?
Posted by: Jacob | July 07, 2011 at 10:24 PM
Wait really? There's a guy who studies mars, and his name is John Carter?
Posted by: Jacob | July 07, 2011 at 10:24 PM
Wait really? There's a guy who studies mars, and his name is John Carter?
Posted by: Jacob | July 07, 2011 at 10:24 PM
Wait really? There's a guy who studies mars, and his name is John Carter?
Posted by: Jacob | July 07, 2011 at 10:24 PM
Wait really? There's a guy who studies mars, and his name is John Carter?
Posted by: Jacob | July 07, 2011 at 10:24 PM
Wait really? There's a guy who studies mars, and his name is John Carter?
Posted by: Jacob | July 07, 2011 at 10:24 PM
Wait really? There's a guy who studies mars, and his name is John Carter?
Posted by: Eric | July 07, 2011 at 11:05 PM
My first thoughts too. It's the job he was born for.
Posted by: Glen | July 07, 2011 at 11:06 PM
Yea, I had to look up to see if I got suckered into reading an Onion article when I saw the name.
Posted by: Kyle | July 07, 2011 at 11:07 PM
Yeah, I watched it on a color television! Then we took the Studebaker down to the soda shop and we all got cherry cokes....
Posted by: Kevin | July 07, 2011 at 11:08 PM
Wait really? There's a guy who studies mars, and his name is John Carter?
Posted by: Eric | July 08, 2011 at 01:11 AM
Mars is a dull, boring and lifeless Planet. I somehow don't like the idea of being overenthusiastic about that planet - not anymore.
Posted by: GodParticle | July 08, 2011 at 08:17 AM
Who the hell is John Carter?
Posted by: Grooms Speech | July 11, 2011 at 07:57 PM
Well we can't say that is there any life in mars.....Well The future of space exploration will witness a revolutionary change with a new breed of planetary explorer in design by engineers at the University of Glasgow...Thanks
Posted by: crowdSPRING | July 12, 2011 at 02:21 AM