Saturday, October 20, 2007

Mars, Water and Life


The Spirit and Opportunity rovers were designed to last just three months. Having survived a huge dust storm, they are now projected to operate until 2009. Spirit suffered a locked wheel, which may have led to a big discovery! Humans could find much more walking on Mars, but that may not happen until 2037.

Presently Opportunity is slowly descending into Victoria Crater. The crater is 70 meters deep and nearly a kilometer wide. Rok layers within suggest sedimentation and ancient water. On the far side of the world, Spirit is exploring an region of basalt and ancient vulcanism.

Though our explorations have been limited to a few tiny probes, Mars continues to surprise. From time to time photos show tantalizing features of water flow that seem to come and go. A flow will be there in one photo and gone in the next. Scientists suggest that ice deposits erupt briefly into liquid before freezing again. Some inner source of heat may be required to melt the ice.

From the Toronto Star: Canadian researchers claim the strongest evidence yet for water on Mars. When one of Spirit's wheels became stuck, it churned up a white layer just beneath the surface. Careful analysis by the alpha particle X-ray spectrometer revealed that this salty layer may be 18 percent water. The white layer was seen in four separate sites in the Columbia hills, suggsting that it is quite common. Professor Iain Campbell of the University of Guelph was assisted by physicist Joanne O'Meara with students Mary Lee and Christianne Mallett.

Like characters in a Monty Python sketch, Mars volcanoes may not be dead, just sleeping. NASA-funded scientists have been comparing features on the Tharsis bulge (above) with shield volcanoes on our Big Island of Hawaii. Though no volcanic activity has been directly observed on Mars, a lack of impact craters suggests that the terrain is relatively new. Ascraeous Mons, Northernmost of the chain, has the most lava tubes and appears to be youngest. Tharsis volcanoes are EXTREMELY similiar to our Big Island. NASA Press Release

The Hawaiian Islands began far to our Northwest, with islands like Midway that have since subsided into atolls. The most recent activity in the Big Island is in our Southeast. The Big Island is less than a million years old, and still very active. Airborne eruptions (at least this week) are limited to a small vent at Pu'u O'o. Another big eruption could start at any time. Farther to sea the new island of Lo'ihi is already building and will emerge in a few thousand years.

Subsurface heat might explain the brief appearance of flow formations on the Martian surface. Just as volcanic eruptions fill Earth's atmosphere with greenhouse gases, volcanoes on Mars may resupply the thin CO2 atmosphere. If Mars began with a tiny Black Hole, it could still be giving off Hawking radiation. The Black Hole could still be inside Mars.

Paul Davies is author of many books and one of Australia's best-known scientists. Today he makes a home at Arizona State University and continues to study the Universe. In the latest issue of Cosmos magazine, Davies again wonders whether life on Earth originated on Mars. We have many examples of Martian meteorites that made the journey to Earth. Mars is "uphill" in the Sun's gravity well. The chemicals of life originated even further away, in explosions of supernovae. We and all life on Earth could be Martians! Exploration of Mars may lead to discoveries that will shed light on human existence.

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