Mars Express pictures action of glaciers

nature.com ^ | 04 November 2004 | Mark Peplow

[ckilmer]

Published online: 04 November 2004; | doi:10.1038/news041101-14 Mars Express pictures action of glaciers Mark Peplow Orbiter snaps martian canyons, while failed Beagle team fights for another chance.

Tithonium Chasma, looking east. The chasma is part of the Valles Marineris canyon system.

The Mars Express spacecraft has returned stunning images of mountains and valleys that show signs of past volcanic activity, and suggest that glaciers once shaped the red planet's surface.

Meanwhile, the craft's former travelling companion, the lander Beagle 2, is still making waves despite having made no contact with its handlers since separating from its mother ship on 19 December 2003.

The pictures from Mars Express show the western end of the Valles Marineris canyon system, which stretches for about 4,000 kilometres close to the martian equator.

In places, the main canyon is 10 kilometres deep, more than six times as deep as the Grand Canyon in Arizona. Mars Express's High Resolution Stereo Camera (HRSC) has now photographed this area in more detail than ever before, picking out features as small as 50 metres across.

"The images are showing us a lot more evidence for recent water activity, and probably recent ice deposits, than I'd previously thought," says John Murray, one of the HRSC team members based at the earth sciences department at the Open University, Milton Keynes, UK.

Larger features, such as U-shaped valleys punctuated by hillocks of rubble, indicate that glaciers may once have gouged their way through the canyons, he adds.

Tithonium Chasma, looking north-east. Dark rocks cover the canyon floor, possibly the result of volcanic activity.

The pictures also show that the canyon floors are covered in dark, layered material, which could be volcanic. Because the HRSC's stereovision provides three-dimensional pictures, geologists can analyse these exposed rock formations to unpick how the geology of the planet has changed over time. Mars may have been volcanically active very recently, says Murray, perhaps as little as a million years ago.

Although the HRSC is producing a continuous stream of data from the red planet, one of Mars Express's most useful tools remains firmly stowed and will not be used before March 2005.

The Mars Advanced Radar for Subsurface and Ionosphere Sounding, or MARSIS, the craft's 40-metre-long radar antenna, has the potential to detect underground stores of water a few kilometres below the martian surface. Mission scientists are worried it might damage the craft when it swings into position. They are now performing extra simulations to determine whether it is safe to deploy the instrument.

Beagle bounces back

Tithonium Chasma from above. The chasma's deepest point is 5.5 kilometres below the martian surface.

Colin Pillinger, the space scientist from the Open University who was the driving force behind Beagle 2, hasn't given up on his mission either. On November 3, he announced the team's plans for a new lander that could fly on an ESA mission in 2009 to look for life on Mars.

In particular, the team proposes installing a communication system that would allow the craft to keep in touch directly with Earth during its descent through the martian atmosphere. It would also use pillow-like airbags to cushion its landing.

As ESA did not ask the team to prepare its new proposal, there is no guarantee that the project, named Beagle 2: Evolution, will make it off the drawing board. But Murray, for one, supports the idea. "I'd like to see a Beagle type mission flown again in the near future," he says. "The Mars Express images have convinced me that the likelihood of life on Mars is far greater than I used to think."

[DJtex]

Beautiful pictures.

I've often wondered how Mars lost it's atmosphere, and with it, most of it's moisture. Even though there may be significant water-ice frozen in permafrost near the poles, it's a puzzle that Mars started, like Earth, with significant water for lakes, sedimentary formations, river canyons, even glaciers--but now it's gone.

The best explanation--aha!--is that Mars, which is half the size of Earth--lost it's magnetic field when it's iron core cooled and hardened. It seems that the fluid dynamics of a molten core are what generates the Earth's magnetic field. This field shields us from cosmic rays and also the vast majority of the solar wind. It was the solar wind that stripped off the atmosphere and water vapor of Mars once it's smaller iron core cooled and hardened.

[festus]

I find the words "Express" and "Glacier Action" in the same headline to be mildly amusing.....

;-)

[Dallas59]

Early Mars

[KamperKen]

For a possible answer to your question of what became of the atmosphere and oceans of Mars, I recommend you read Graham Hancock's "Mars Mysteries". He puts forth a very intriguing theory. This is not Erich von Danikan stuff, but all too plausible.