News Brief Archives
Home > News Briefs > Watering Pole
Ice thickness at the Martian South Pole. Credit: NASA/JPL/ASI/ESA/Univ. of Rome/MOLA Science Team/USGS
Wednesday, March 21st, 2007--
Researchers looked deep into the Martian South Pole and found enough frozen water to cover the red planet in 36 feet of water, according to a recent study in the journal Science.
An ice cube the size of Texas may sound big, but it's not big enough to account for all the water that researchers think used to exist on the planet, leaving scientists still wondering where all the Martian water went.
To get a precise estimate of the ice, researchers analyzed data from the Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS), which flies aboard an orbiting satellite called Mars Express. MARSIS is the first radar to probe Mars. "Like any radar, it sends out pulses of radio waves and then waits and listens and detects the echoes that come back," says Jeffrey Plaut, a researcher at the Jet Propulsion Laboratory at the California Institute of Technology and lead author on the study.
When the radio waves hit the surface of Mars, some bounce back to the radar and others permeate the ice, bouncing back only after they hit another barrier--in this case, the crust of Mars. Researchers use the delay of the radio waves to calculate the depth of the ice. From the waves' energy loss, researchers can predict the composition of the ice: more energy is lost in dirty ice than pure frozen water.
This data may give scientists insight into Mars' climate history. At the Martian poles, the ice is layered. Darker layers correspond to dustier times on Mars. "Then, as conditions change, there may not be as much dust in the atmosphere, perhaps it was a period with very few dust storms, and the ice that gets deposited is cleaner," Plaut explains. These layers show up as white. "We're trying to understand how this layering is related to the climate history of Mars."
One puzzler from the data is that there are spots deep under the surface of Mars where the reflected radar waves are brighter than those reflected at the surface of the planet. These bright spots, in theory, could be explained by liquid water trapped below the surface. Is a Martian fish fry right around the corner? Not likely. The bright spots could also be explained by different properties of the ice. Plus, Plaut says, it is unlikely that liquid water exists in such a cold area.
The radar data also revealed that under the weight of the ice, Mars barely buckles. Compared to earth--which would sag under equivalent ice--Mars is firm. Plaut says this means Mars is probably colder inside and "more mature." In planetary speak, the temperature of the planet relates to its maturity. Plaut says: "Mars has lost a larger fraction of its heat. Its interior is a little bit colder, not quite dead, but not as active as the interior of Earth."
What did you think of the story? Send us some feedback.--Flora Lichtman
Jeffrey Plaut
Jet Propulsion Laboratory
California Institute Of Technology
Pasadena, CA
New Moon
The moon may not be as old as previously thought.
Liquid Mirror Lunar Telescope
Using liquid for the telescope's mirror could let scientists see deeper into the Universe than ever before.
Gravity Anomaly Solved
The gravitational pull near Hudson Bay, Canada is unusually weak. A new study explains why.
Ancient Dna Offers Clues About Climate Change
What can ancient DNA can tell us about the effects of climate change?
Mars Rovers Battle Storms On The Red Planet
In this segment, guest host Joe Palca checks in on the Mars rovers, and gets a preview of the Mars Phoenix mission.
Hurricanes, Climate and Weather
Researchers from the American Meteorological Society met this week in New Orleans, site of the Hurricane Katrina disaster just years ago. How much is known about the effects of climate change on hurricanes?
Mars Update
We get an update on the latest results from orbiting observations of Mars.
Sensing the Atmosphere of Distant Planets
Scientists using the Hubble Space Telescope have been able to detect the chemical signature of methane in the atmosphere of a planet orbiting a star 63 light-years away.
Turmoil in Planetary Exploration?
NASA's science chief, Alan Stern, announced his resignation this week. The announcement came the same week as threatened budget cuts to the popular Mars rover mission. Those cuts were later repealed by the NASA administrator.
What's a Planet, Anyway?
In 2006, astronomers voted to remove Pluto from the list of planets in our solar system -- but the controversy over just what should be called a planet lives on.
Countdown to Mars
The latest mission to Mars, Mars Phoenix, is scheduled to touch down on the Red Planet this coming Sunday. We'll talk about the mission and what the scientists behind it hope to achieve.
Mars Update
In this segment, we'll talk with the head of the Mars Phoenix mission and get an update on Mars research.
Print
Mail