Caves spotted on Mars

[L Roebuck]

Caves spotted on Mars
Dark 'skylights' could be openings to martian shelters

Some underground martian caves may have been spotted, thanks to 'skylight' holes into the caverns that have been photographed from above.

Glen Cushing, from the US Geological Survey (USGS) in Flagstaff, Arizona, got his first hint of the underground cave system from THEMIS (Mars Odyssey's Thermal Emission Imaging System) images of the Arsia Mons region near the equator of Mars. He spotted a system of pit craters, indicative of collapsed areas, and nestled among them half a dozen dark spots ranging in diameter from 100 to 252 metres.

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[Brian Roebuck]

Well this makes sense to me considering they have found lots of evidence of water on Mars now. Apparently though they can't explain where all the water they theorize used to be there went. Could it be down in Martian caves?

WASHINGTON (Reuters) -- A spacecraft orbiting Mars has scanned huge deposits of water ice at its south pole so plentiful they would blanket the planet in 36 feet of water if they were liquid, scientists said Thursday.

The scientists used a joint NASA-Italian Space Agency radar instrument on the European Space Agency Mars Express spacecraft to gauge the thickness and volume of ice deposits at the Martian south pole covering an area larger than Texas.

The deposits, up to 2.3 miles thick, are under a polar cap of white frozen carbon dioxide and water, and appear to be composed of at least 90 percent frozen water, with dust mixed in, according to findings published in the journal Science.

Scientists have known that water exists in frozen form at the Martian poles, but this research produced the most accurate measurements of just how much there is.

They are eager to learn about the history of water on Mars because water is fundamental to the question of whether the planet has ever harbored microbial or some other life. Liquid water is a necessity for life as we know it.

Characteristics like channels on the Martian surface strongly suggest the planet once was very wet, a contrast to its present arid, dusty condition.

www.cnn.com/2007/TECH/space/03/16/mars.water.reut/index.html

[Azurerana]

There is no need to theorize about liquid water on Mars. The Martian atomosphere is so thin that any water vapor in it escapes quickly to space. There isn't enough gravity or atmospheric pressure to hold it except transiently. CO2, being heavier than water vapor, will hang around, but even CO2 freezes under Martian temperatures, into a sort of dry ice snow.

Exposed water ice should sublimate fairly quickly at the high temperatures of Martian summer, but that trapped under a CO2 blanket would not.

They think water is below ground simply because the soil is also a protective layer.

[Sharon Faulkner]

No new information on this, just more articles being generated on the topic.
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March 17, 2007

Monitoring the temperatures of the caverns, scientists found that all of the seven caves provide a warmer climate during the night making them more hospitable to life.

Named the "seven sisters" the caves, dubbed Abbey, Annie, Chloe, Dena Jeanne, Nicki and Wendy, are at least 80 metres deep.

Yet little is known about the caverns due to the current equipment used which can only look directly down. However researchers believe using HiRISE, Nasa's high-resolution imaging science experiment could allow them to peek into the caves.

"When HiRISE looks from the side it will be able to see how thick the ceiling of the cave is, and whether it's a hole at all," said Glen Cushing from the US Geological Survey.

The new discovery comes just days after the Mars Express radar gauged the amount of water trapped in frozen layers over Mars' southern polar region. Scientists working on the project say the amount of water is equal to a liquid layer about 11 metres deep covering the planet.

Another Article

[L Roebuck]

Here's a Yahoo News Article....

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Possible New Mars Caves Targets in Search for Life

A Mars-orbiting satellite recently spotted seven dark spots near the planet's equator that scientists think could be entrances to underground caves.

The football-field sized holes were observed by Mars Odyssey's Thermal Emission Imaging System (THEMIS) and have been dubbed the seven sisters --Dena, Chloe, Wendy, Annie, Abbey, Nikki and Jeanne--after loved ones of the researchers who found them. The potential caves were spotted near a massive Martian volcano, Arisa Mons. Their openings range from about 330 to 820 feet (100 to 250 meters) wide, and one of them, Dena, is thought to extend nearly 430 feet (130 meters) beneath the planet's surface.

The researchers hope the discovery will lead to more focused spelunking on Mars.

Full Article

[Sharon Faulkner]

Another cave entrance found on Mars. To see the high-res picture from the Mars Reconnaissance Orbiter go to:
hiroc.lpl.arizona.edu/images/PSP/diafotizo.php?ID=PSP_003647_1745

[Robert Sewell]

azurerana said:

There is no need to theorize about liquid water on Mars. The Martian atomosphere is so thin that any water vapor in it escapes quickly to space. There isn't enough gravity or atmospheric pressure to hold it except transiently.

But if there once was water on Mars for a long enough time to form caves and other water-created patterns, what changed about its gravity and/or atmosphere since then to cause it to lose its water? I wouldn't think a planet would lose that much of its mass, even over millions of years.

[L Roebuck]

Spectacular images of possible caves on Mars found by NASA spacecraft

NASA's two spacecraft Mars Reconnaissance Orbiter and Mars Odyssey have found several possible caves on the planet Mars. Their fantastic images were made with two very powerful cameras onboard.

NASA’s Mars Reconnaissance Orbiter (MRO) was launched on August 12, 2005, was inserted into orbit about Mars on March 10, 2006, and began its scientific mission in November 2006.

Using its High Resolution Imaging Science Experiment (HiRISE) camera, the MRO spacecraft found a dark spot on Mars that measures about 100 meters (330 feet) in diameter. The dark spot is located in a bright dusty lava plain that is northeast of Arsia Mons, one of the four Tharsis volcanoes on Mars. The Tharsis area on Mars is a large volcanic upland found on the planet’s equator near the western end of Valles Marineris.

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1,200 images of Mars taken by the HiRISE Camera

[Mike Green]

Very interesting set of articles! Astronomy has always been a passion of mine, but second to caving of course . The need for understanding takes many different avenues.

My thoughts were that these caves are very close to the equator (the equivalent to Earth's Ring of Fire and no not the J. Cash song), and therefore are more likely formed by magma and not water; however, the pictures seem to tell a different story...

"But if there once was water on Mars for a long enough time to form caves and other water-created patterns, what changed about its gravity and/or atmosphere since then to cause it to lose its water? I wouldn't think a planet would lose that much of its mass, even over millions of years."

To answer this question, we must look to the center of the planet. Like our own, Mars was thought to have a heavy core that rotated. This rotation creates a magnetic field that deflects solar radiation. Whenever the core comes to a standstill, the protection from the solar wind stops. This in turn would turn a planet like Earth into a planet like Mars.

[Sharon Faulkner]

New photos from Mars:

HiRISE Camera Returns New View of Dark Pit on Mars
And Adds 930 More Images to NASA Space Mission Archive
By Lori Stiles, University Communications
August 29, 2007

The High Resolution Imaging Experiment (HiRISE) has confirmed that a dark pit seen on Mars in an earlier HiRISE image really is a vertical shaft that cuts through lava flow on the flank of the Arsia Mons volcano. Such pits form on similar volcanoes in Hawaii and are called "pit craters."

uanews.org/node/15715

Another article and photo of the pit on Mars