Geology Home Page physical geology historical geology planetary gems
Roger Weller, geology instructor
by Kim Ransford
Ice on Mars
For many years
now, there have been enormous amount of rumors and questions about outer space.
Many people have wondered if there were “humans” living on the other planets.
They were also extremely curious about water, oxygen, or land on the other
planets as well. Scientists and researchers have analyzed and looked deep into
the Red Planet, Mars. In the year of 2001, NASA’s Mars Odyssey spacecraft
discovered a large amount of water ice, large enough to fill Lake Michigan over,
NASA stated that this is the only known example of such an
amazing and unique existence in the solar system. Scientists used the
Mars Reconnaissance Orbiter
(MRO) Climate Sounder instrument, which
measures and records visible and red light in the Martian atmosphere.
Analysis of clouds of CO2 from pictures by the MRO, in the
Martian winter of 2006-2007, explains hydrogen dioxide snow, which was seen on
Mars in 2008 by the satellite, the Phoenix lander, the Red planet gets
snowstorms of frozen carbon dioxide.
NASA spent over $420 million to send the Phoenix Lander to Mars.
The rover was digging a trench nicknamed, “Dodo-Goldilocks” with its robotic arm when it hit some hard, reflective material. The scientists back on Earth who control Phoenix halted the digging, and spent the next couple of days taking photographs of the hole, trying to figure out what they were looking at in the ditch. Was the whitish material a kind of salt? But over those days of photography and scrutiny, something interesting happened to the marble-sized chunks. They evaporated. Long inhume beneath the iron-oxide surface of the red planet, the substance turns out to be part of a frozen layer of water just below the ground covered by Phoenix.
Any time water is discovered on other planets, the scientific
community pays full attention. Essential for life, the presence of any form of
water immediately raises the chances that biological material might be present
as well. Currently, Mission Control is taking another look at a different
trench, where the lander struck a hard layer at the same depth as the newly
discovered ice. With any luck, that layer is composed of the same frozen
treasure Phoenix unearthed today.
Scientists may be one step closer to unraveling the mystery of
Mars' current atmosphere thanks to a dry-ice discovery. Scientist Roger Phillips
of the Southwest Research Institute in Boulder, Colorado and his colleagues have
found a significant amount of dry ice on Mars' South Pole. This may show the
planet's atmosphere was once thick enough to have had large amounts of liquid
water on its surface.
These scientists detected a 300-mile-diameter cloud made of carbon dioxide over the South Pole, with measurements showing atoms falling all the way down to the surface. The scientists still aren't sure what process allows the carbon dioxide crystals to fall to the surface, or whether they simply form as frost on the ground. Mars Reconnaissance Orbiter (MRO) is still finding out all sorts of superior things about our nearest sibling in the solar system. Such as confirming the suspicion that Mars has instances in which it snows dry ice, carbon dioxide that has frozen at temperatures below -193 degrees Fahrenheit. The super-cold snowfall takes place at the Martian poles, where solid dry ice has been known to exist for some time. It has never been observed as falling snow, although suspected, remained uncertain, but not for long. While past studies have suggested that Mars' South Pole is covered in water with a thin top layer of dry ice, the team's study, which used radar measurements from MRO, proposes there is significantly more dry ice than previously suspected. Not only that, but the dry ice is atmospheric carbon dioxide deposited on the surface. The radar used by the team works by bouncing radio waves off reflectors at various depths on the planet, allowing the group to determine the velocity of the waves as they pass through material. For a particular repose, the group found a wave velocity corresponding to dry ice, which is very different from the wave velocity of liquid water.
But how did dry ice end up on the poles? It has to do with the
tilt of Mars' rotational axis. Like Earth's, Mars' tilt oscillates, moving from
a state of high tilt to low tilt and back again in roughly 100,000 years. Mars
at its highest tilt would create an atmosphere with twice as much carbon dioxide
by turning the dry ice from a solid immediately to a gas in a process called
sublimation. At low tilt, all the carbon dioxide would collapse onto the
Scientists initially believed there was a lot of dry
ice, enough to produce a massive atmosphere and a warm planet, but then went to
the opposite extreme to say there was very little - a tiny fraction of what's in
the current atmosphere.
Although the newfound store sounds like a lot, it's only enough carbon dioxide to double the mass of the feeble Martian atmosphere if released and not enough to warm up the planet substantially or allow water to pool. "The atmosphere would still be quite thin and would not have the density necessary to warm things up enough to have liquid water stable on the surface," said Peter Thomas of Cornell University, who had no role in the mission. The mystery of what happened to Mars' atmosphere has long intrigued scientists. NASA plans to explore the upper atmosphere and study how gases are lost to space with a new spacecraft in 2013.
1. Water on Mars
2. Ice on Mars more excessive than thought
3. 8 Most Surprising Mars Discoveries
4. Dry Ice on Planet Mars
5. Water Exposed on Planet Mars