Some of Mars’ ice may have melted, orbiter finds
The ice at Mars’ south pole contains enough water to cover the planet in an ocean 36 feet deep, scientists said today.
Observations by the European Space Agency’s Mars Express orbiter determined the ice -- largely covered by dust and rock -- is more than two miles thick in places and is nearly pure water, according to research being published in the journal Science.
The latest findings also provide tantalizing indications that some ice beneath the planet’s surface may have melted, bolstering the possibility of finding life on the Red Planet.
Scientists have long hoped to find water, although they have suspected polar temperatures -- about minus 200 degrees Fahrenheit -- are far too low for the ice to melt.
The Mars Express orbiter and its lander, Beagle 2, were launched in 2003. The lander was designed to look for past or present life, but was lost. Controllers still don’t know its fate.
In late 2005, the scientific team unveiled its initial analysis of the north polar region, which showed an ice sheet more than a mile thick, as well as ancient geological structures.
The spacecraft scanned the south polar ice with an instrument known as the Mars Advanced Radar for Subsurface and Ionospheric Soundings over the course of 300 orbits, ending last April. The instrument turned up several unusually “bright” readings that resembled what a thin layer of water might look like to radar.
One of the study’s authors, Jeffrey Plaut of the Jet Propulsion Laboratory in La Canada Flintridge, said it was “highly unlikely” the readings were caused by melting ice because the south pole is one of the “coldest places on the surface of Mars.”
Nevertheless, the authors wrote, they could not rule out the possibility that “unusual geothermal conditions” were causing the subsurface ice to melt.
Data from Mars Express has also confirmed the long-held belief that the Red Planet is as dead inside as it appears on the outside.
On Earth, ice often alters the surrounding geology on the crust, in part because our planet has a molten core and thinner mantle.
But on Mars, the new research shows, the underground ice hasn’t warped the crust or mantle, proving that the planet’s internal structure “is strong and very hard,” Plaut said.
Earth’s molten core is why it is surrounded by a magnetic field. On Mars, the core has mostly solidified, leaving the planet with only remnants of its ancient magnetic field.
