advertisement
Images of Mars Fuel Speculation on Planetary Life
In three reports published in the science journal Nature, an international team of researchers said images from the European Space Agency's Mars Express Mission and new data show glacial movement, climate change and volcanic activity.
"We're now seeing geological characteristics on Mars that could be related to life," said James Head of Brown University in Rhode Island and an author of one of the papers. "But we're a long way from knowing that life does indeed exist."
The new evidence, based on images of the planet's surface from the High Resolution Stereo Camera (HRSC), shows Mars is dynamic and had a watery past. Liquid water is seen as a prerequisite for earthly life.
Ernst Hauber, of the German Aerospace Center in Berlin, and his colleagues said eruptions that occurred 350 million years ago made depressions on the Hecates Tholus volcano. Five million years ago glacial deposits formed inside the depressions.
Head and his team said glaciers on the planet moved from the poles toward mid-latitude regions 350,000 to four million years ago.
In the final research paper, John Murray of the Open University in Britain reported evidence of a frozen body of water, about the size and depth of the North Sea.
The HRSC evidence suggests the water is still there as ice on the ground or deep below the surface.
Head said the glacial deposits that his team studied could be sampled in future space missions and may provide more data about life on the planet.
"If we had ice to study, we would know a lot more about climate change on Mars and whether life is a possibility there," he added.
Studies of Mars point to evidence of the presence of liquid water on the planet's surface and a vast amount of underground ice near the equator within the past few million years. Liquid water is believed to be a key ingredient for life, therefore the presence of water on Mars helps support chances of extraterrestrial life, reported the journal Nature today. In the studies, strong indications of glacial and volcanic activity were presented. The combined research on this subject, including a study in December 2004 indicating that five volcanoes were active as recently as two million years ago, justifies further search for signs of life on Mars scientists say.

A few million years is a mere minute on the geological timescale of Mars which has been around for 4.5 billion years.

The scarred surface of Mars cannot be attributed solely to asteroids. New images of the landscape taken by the High Resolution Stereo Camera (HRSC) on the European Space Agency's Mars Express Mission show that flowing water, large glaciers and active volcanoes have also taken their toll on the face of Mars.

Some evidence collected by two Mars rovers that NASA sent to explore the planet shows that Mars was hotter and more humid millions of years ago than it is today. Also important were active volcanoes that can stimulate the forming of microbial life as they do here on Earth. Scientists recently discovered bacteria near the mouths of undersea volcanic vents on Earth where bacteria live off sulfur instead of oxygen and discharge methane as a by-product of their life cycle. Though controversial, the discovery of signs of methane gas in Mars' atmosphere also interests researchers who believe it indicates the possibility of subsurface life.

Geologist James Head of Brown University led a group of researchers who examined landforms thought to be glacial during the Viking program in the 1970s. They found evidence that glaciers moved from the poles to the equator between 3.5 and 4 million years ago, suggesting that Mars is currently in an interglacial period. 

A third study looked at an area of frozen water roughly the size of the North Sea that formed near the equator around five million years ago. It is now thought that the ice was once liquid water carried along by volcanic eruptions in a region known as Cerberus Fossae.

Researchers have long assumed water on Mars had all evaporated into the Martian atmosphere. A 1991 hypothesis, then considered outrageous by suggesting Mars was no stranger to floods, is now supported by recent findings. The HRSC data suggests water is still present both in liquid form and ice. Mars Express will deploy a special radar instrument in early May which should be able to detect water and ice even several miles beneath the surface.

Should water be found on Mars, the chances of finding life are great. Many extremophiles, bacteria living under extreme conditions such as extreme salinity or heat, have already been discovered on Earth. In February 2005, scientists announced the discovery of bacteria that survived in a state of frozen suspension for 32,000 years. 

Likewise on Mars, a sample of ice could offer great insight into the evolution of the Martian environment and atmosphere. These discoveries may offer a great chance to get objective evidence for Mars research.