Posted on 09/15/2007 4:46:43 PM PDT by DogByte6RER
Mars, Like Earth, Has Cyclical Ice Ages, Study Says
Brian Handwerk
for National Geographic News
September 14, 2007
Mars has gone through 40 ice ages during the past five million years that regularly send the planet's permanent ice sheets cascading toward the equator, then melting backward, a new theory suggests.
The climate changes are likely driven by cyclical fluctuations in the planet's orbit that alter the amount of sunlight that falls on the planet's surface, says astronomer Norbert Schörghofer of the University of Hawaii at Manoa.
Understanding the sun's exact role in the Martian ice ages could help solve longstanding puzzles about the red planet.
It could also help scientists better understand Earth's complex climatic systems, which are also affected by orbital variations.
The new theory appears in this week's issue of the journal Nature.
Mystery of the Ice
In recent years extensive amounts of ice have been discovered below the surface of Mars. Much of the ice mysteriously survives far from the planet's poles.
Schörghofer suggests that this ice is newer than previously believed.
"Earlier theories have tried to explain this ice with snowfall that would have happened some five million years ago [but struggle] to explain how that ice could have stayed there," Schörghofer said.
"I'm saying it didn't stay. It went away and then came back many, many times."
According to Schörghofer, much of Mars's ice is formed by vapor diffusion—the seeping of gas directly into underground pockets during cold periods.
"The water cycle on Mars is very different than what we see on Earth," said Joshua Bandfield, a research specialist at Arizona State University's School of Earth and Space Exploration who was not involved in the study.
"Water vapor in the air basically diffused into the subsurface through pores in the soil and filled up that pore space with ice. It goes away by the same process—it heats up and goes from solid to gas and diffuses back out of the rock."
Schörghofer's theory may therefore reveal a very different recent history for the red planet than once thought.
"The surprise is how frequent Mars's ice ages are and how young some of the ice is," Schörghofer said. "[Some may be] only half a million years old, which is not very old for Mars because most of the surface is billions of years old."
"Wobbly" Theory
Mars, like all planets, experiences small "wobbles" in its axis as it orbits the sun.
Such variations change the amount of sunlight falling on a planet's surface, which can cause major climate shifts, Schörghofer said.
Earth's wobbles, known as Milankovitch cycles, occur in 20,000- and 100,000-year periods and are thought to impact the waxing and waning of the planet's ice ages.
According to Schörghofer, this means both planets have an ice record that tracks the activity of the sun.
"Mars's ice cores could tell us not only what the climate was on Mars but also changes in the sun, the same solar history that Earth was exposed to," he said.
"Understanding ice ages on Mars is an important step toward understanding the ice record on Mars," he added. "Samples of the Martian ice record could be used to interpret Earth's climate record.
In some ways, the Martian climate is easier to understand and model than Earth's.
Because Mars has no large moon to stabilize its orbit, the planet has much larger wobbles and thus greater climate shifts than Earth.
Mars also has more consistent weather and no oceans.
"Planets are sort of these huge lab experiments that were set up 4.5 billion years ago," Arizona State University's Bandfield said. "[Mars is an opportunity] to test how the physics work on a simpler system and get a better handle on how to apply it to a more complex system."
A first examination of the theory will arrive with the Phoenix lander, already en route to Mars for a 2008 landing. The craft will try to sample Martian ground ice, and the results could make or break Schörghofer's theory.
Wow! Melting backward? Global warming occurs on Mars.
Let's send Al Gore to Mars on a one-way ticket so he can lecture those greedy self-serving SUV driving Martians to stop their polluting behavior!
I have to be the first. BUSH’S FAULT!
Bush’s foibles have far reaching effects!!
Pass Kyoto now!
I guess this is probably not a good time to leak out the super highly classified info that SUV originally meant Solarsystem Universal Varmer (was a joint program with the Germans).
Who would a thought a planet known to not have water would have had 40 Ice Ages, ...except of course that all the ice is now below the surface, and temperatures are 80F in the summer and -200 in the winter at the poles on the surface??? Interesting hypotheses.
Pfft! The Martians have plenty water. Why do you think they built all those canals?
Algore doesn't have a clue. Poor Al is as stupid as a shoe. But that does not mean what's really happening is great news. 'Nuff said.
No wonder Gore doesn’t think and look human...he is a Martian in earthling’s clothing...
bfl
Stuff like this is why Algore is banging his head on that tree.
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regarding the lack of water on Mars:
‘Four-billion-year chill’ on Mars
BBC | 7/21/05 | David Whitehouse
Posted on 07/21/2005 4:57:09 PM EDT by LibWhacker
http://www.freerepublic.com/focus/f-news/1447845/posts
Report: Mars Cold, Bitter Planet for a Long, Long Time
space.com | 07/21/05 | Robert Roy Britt
Posted on 07/21/2005 10:09:04 PM EDT by KevinDavis
http://www.freerepublic.com/focus/f-news/1448047/posts
Rovers Find Evidence Mars Was Once Hostile
AP on Yahoo | 12/5/05 | Alicia Chang - ap
Posted on 12/05/2005 8:59:30 PM EST by NormsRevenge
http://www.freerepublic.com/focus/f-news/1534629/posts
Studies Cast Doubt on Idea of Life on Mars
Yahoo (AP) | Thu Dec 22, 8:37 AM ET | ALICIA CHANG
Posted on 12/22/2005 1:46:33 PM EST by The_Victor
http://www.freerepublic.com/focus/f-news/1545513/posts
Mars Takes a Fresh Pounding
space.com | 12/12/06 | Tarig Malik
Posted on 12/12/2006 10:31:08 PM EST by KevinDavis
http://www.freerepublic.com/focus/f-chat/1752633/posts
Red planet’s hue due to meteors, not water
New Scientist | September 4 2003 | Hazel Muir
Posted on 12/21/2006 3:27:00 AM EST by SunkenCiv
http://www.freerepublic.com/focus/f-chat/1756678/posts
methane on Mars — sign of biological activity (a la Thomas Gold):
Mars Express Confirms Methane in the Martian Atmosphere
European Space Agency via NASA Watch | Tuesday, March 30, 2004
Posted on 03/30/2004 12:25:47 PM PST by Frank_Discussion
http://www.freerepublic.com/focus/news/1108121/posts
New Mars data gives life clue
BBC News web site | September 20, 2004
Posted on 09/21/2004 1:35:25 AM EDT by RayChuang88
http://www.freerepublic.com/focus/f-news/1222131/posts
Mars Life Looms Closer
spacedaily.com | 23 Sep 04 | Phil Berardellie
Posted on 09/23/2004 11:53:43 AM EDT by RightWhale
http://www.freerepublic.com/focus/f-news/1224763/posts
Martian Water Vapor and Methane Overlap in Equatorial Regions (Formaldehyde!?)
Earth Files | 2004 | Linda Moulton Howe
Posted on 12/18/2004 10:56:02 AM EST by theFIRMbss
http://www.freerepublic.com/focus/f-news/1304121/posts
NASA Researches Claim Evidenc[e] of Present Life on Mars
Space News | Feb. 16, 2005 | Brian Berger
Posted on 02/16/2005 2:35:13 PM EST by PresbyRev
http://www.freerepublic.com/focus/f-news/1344592/posts
Scientist argues case for life on Mars
Australian Broadcasting Company | Thursday, 24 February 2005 | Anna Salleh
Posted on 02/24/2005 6:20:15 PM EST by Yo-Yo
http://www.freerepublic.com/focus/f-news/1350487/posts
Mars Life in Embalming Fluid?
CreationSafari.com | 03/01/05 | Creation Evolution Headlines
Posted on 03/03/2005 1:14:39 PM EST by DannyTN
http://www.freerepublic.com/focus/f-news/1355183/posts
NASA Scientist: ‘Mars Could be Biologically Alive’ (Methane Confirmed)
SPACE.com | April 19, 2005 | Leonard David
Posted on 04/19/2005 4:37:37 PM EDT by AntiGuv
http://www.freerepublic.com/focus/f-news/1386889/posts
If there were life on Mars wouldn’t it pass gas?
Waterbury Republican-American | April 30, 2005 | AP Wire
Posted on 04/30/2005 9:34:08 PM EDT by Graybeard58
http://www.freerepublic.com/focus/f-chat/1394490/posts
Methane on Mars: the plot thickens
New Scientist | 8/02/05 | Maggie McKee
Posted on 08/02/2005 3:00:01 PM EDT by LibWhacker
http://www.freerepublic.com/focus/f-news/1455509/posts
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