Definitive Evidence For Ancient Lake On Mars
2009 06 22
A University of Colorado at Boulder research team has discovered the first definitive evidence of shorelines on Mars, an indication of a deep, ancient lake there and a finding with implications for the discovery of past life on the Red Planet.
This is reconstructed landscape showing the Shalbatana lake on Mars as it may have looked roughly 3.4 billion years ago. Data used in reconstruction are from NASA and the European Space Agency. (Credit: G. Di Achille, University of Colorado)
Estimated to be more than 3 billion years old, the lake appears to have covered as much as 80 square miles and was up to 1,500 feet deep -- roughly the equivalent of Lake Champlain bordering the United States and Canada, said CU-Boulder Research Associate Gaetano Di Achille, who led the study. The shoreline evidence, found along a broad delta, included a series of alternating ridges and troughs thought to be surviving remnants of beach deposits.
"This is the first unambiguous evidence of shorelines on the surface of Mars," said Di Achille. "The identification of the shorelines and accompanying geological evidence allows us to calculate the size and volume of the lake, which appears to have formed about 3.4 billion years ago."
A paper on the subject by Di Achille, CU-Boulder Assistant Professor Brian Hynek and CU-Boulder Research Associate Mindi Searls, all of the Laboratory for Atmospheric and Space Physics, has been published online in Geophysical Research Letters, a publication of the American Geophysical Union.
Images used for the study were taken by a high-powered camera known as the High Resolution Imaging Science Experiment, or HiRISE. Riding on NASA's Mars Reconnaissance Orbiter, HiRISE can resolve features on the surface down to one meter in size from its orbit 200 miles above Mars.
An analysis of the HiRISE images indicate that water carved a 30-mile-long canyon that opened up into a valley, depositing sediment that formed a large delta. This delta and others surrounding the basin imply the existence of a large, long-lived lake, said Hynek, also an assistant professor in CU-Boulder's geological sciences department. The lake bed is located within a much larger valley known as the Shalbatana Vallis.
"Finding shorelines is a Holy Grail of sorts to us," said Hynek.
In addition, the evidence shows the lake existed during a time when Mars is generally believed to have been cold and dry, which is at odds with current theories proposed by many planetary scientists, he said. "Not only does this research prove there was a long-lived lake system on Mars, but we can see that the lake formed after the warm, wet period is thought to have dissipated."
Planetary scientists think the oldest surfaces on Mars formed during the wet and warm Noachan epoch from about 4.1 billion to 3.7 billion years ago that featured a bombardment of large meteors and extensive flooding.
The newly discovered lake is believed to have formed during the Hesperian epoch and postdates the end of the warm and wet period on Mars by 300 million years, according to the study.
The deltas adjacent to the lake are of high interest to planetary scientists because deltas on Earth rapidly bury organic carbon and other biomarkers of life, according to Hynek. Most astrobiologists believe any present indications of life on Mars will be discovered in the form of subterranean microorganisms.
But in the past, lakes on Mars would have provided cozy surface habitats rich in nutrients for such microbes, Hynek said.
The retreat of the lake apparently was rapid enough to prevent the formation of additional, lower shorelines, said Di Achille. The lake probably either evaporated or froze over with the ice slowly turning to water vapor and disappearing during a period of abrupt climate change, according to the study.
Di Achille said the newly discovered pristine lake bed and delta deposits would be would be a prime target for a future landing mission to Mars in search of evidence of past life.
"On Earth, deltas and lakes are excellent collectors and preservers of signs of past life," said Di Achille. "If life ever arose on Mars, deltas may be the key to unlocking Mars' biological past."
Adapted from materials provided by University of Colorado at Boulder.
Article from: ScienceDaily.com
Mars May Still Be A Living Planet, Methane In Atmosphere Reveals
Is there a Life On Mars Conspiracy?
Mars: Windy, Wet And Wild: Victoria Crater Unveils More Of Mars' Geologic Past
Mars explorer says we'll find life on other planets within 10 years
Should Mars be treated like a wildlife preserve?
Latest News from our Front Page
Detekt: A New Malware Detection Tool That Can Expose Illegitimate State Surveillance
2014 11 21
Recent years have seen a boom in the adoption of surveillance technology by governments around the world, including spyware that provides its purchasers the unchecked ability to target remote Internet users’ computers, to read their personal emails, listen in on private audio calls, record keystrokes and passwords, and remotely activate their computer’s camera or microphone. EFF, together with Amnesty International, ...
New UK spy chief says tech giants aid terrorism, privacy not ‘absolute right’
2014 11 21
Robert Hannigan, the new head of GCHQ
The new head of Britain’s GCHQ, the UK equivalent of the NSA in the U.S., said he believes privacy is not an absolute right and that tech giants must open themselves up to intelligence agencies.
“GCHQ is happy to be part of a mature debate on privacy in the digital age,” Hannigan said. “But privacy ...
LOL: Atheist Feminist Pornographer Used as Moral Authority in T-shirt Row
2014 11 21
Dr. Matt Taylor was thrust into the headlines this last week, largely for his lead role in successfully landing a spacecraft on a comet 300 million miles from earth that travels at a speed of 85,000 mph. In short, Taylor and his colleagues pulled off one of the most amazing achievements in contemporary science and space exploration, and in a ...
Forty Years that Unmade France
2014 11 21
Eric Zemmour is a well-known French author and television personality. Of Algerian-Jewish origin, he may seem an unlikely spokesman for French tradition, but he has emerged in recent years as a prominent scourge of ideological orthodoxy. He is unquestionably the most prominent mainstream French commentator who speaks candidly about race.
This role comes with a price. In 2011 he was ...
Richard Spencer Under Fire
2014 11 21
The Flathead Beacon has a story on the mobbing of Richard Spencer consequent to the publicity over the Budapest conference. The city council is being asked to “an ordinance barring hate-group activities in the community.” As several of the comments note, the First Amendment seems to be of no concern to these activists. The article is interesting ...
|More News » |