Mars’ north pole, like a French parfait, comes in layers. Scientists analyzing radar images from NASA’s Mars Reconnaissance Orbiter spacecraft have found up to seven distinct layers of ice and dust beneath the north pole.
Roger J. Phillips, a scientist with the Southwest Research Institute in Boulder, said the layering probably was caused by changes in the planet’s orbit in the last 4 million years.
When the planet tilts strongly on its axis, the surface ice withers and is covered by a layer of dust mixed with ice, Phillips said. Then, “every million years or so,” he said, the planet tilts less, meaning less sunlight falls directly on the pole. At that point, a layer of clean ice is laid down.
The discovery, published today in the journal Science, comes as NASA’s Phoenix spacecraft closes in for a May 25 landing at the north pole. Phoenix carries a drill to dig into the surface ice. Based on this new research, any such life forms must be deep underground, close to the core, researchers said.
“Wherever they are, they are deeper than we thought,” Phillips said.
The Mars Reconnaissance Orbiter, built by Lockheed Martin Corp. in Denver, was launched in 2005 from Cape Canaveral in Florida. It has been orbiting Mars since 2006. The mission is managed by the Jet Propulsion Laboratory in Southern California.
