07 December 2006
Water on Mars?
I know I am a little late in blogging this story but being a nerd I couldn’t pass it up. It may add up to nothing but if it does turn out that there is water on Mars then it is possibile that there could be life, albeit of a primitive kind.
Scientists appear to have discovered evidence of water gushing down gullies on Mars. If this is confirmed then it massively increases the possibility that some regions of the planet might still be capable of harbouring life.
Pictures taken by the Mars Global Surveyor, which has been orbiting the planet for 10 years, reveal distinctive streaks of what could be water bursting out of crater walls and flowing around boulders and other rocky debris strewn across the surface. Researchers have previously found evidence that ancient lakes once dotted the Martian landscape, and vast quantities of water ice are known to be locked up in sheets of permafrost at the planet's frigid poles. But this is the first evidence that liquid water, crucial to nurture life, might still be found on the planet.
Nasa scientists compared pictures of the Martian landscape taken between 1999 and 2006 and looked for signs of recent changes on the surface. They identified two craters where light streaks suggested water had erupted from the walls and poured down the slopes, leaving mineral deposits for hundreds of metres. The first crater was in a region on the planet's southern hemisphere called Terra Sirenum. Images of the crater taken in April 2005 revealed an apparent burst of water from the north-west wall of the crater that were not visible in an image taken in December 2001. The second crater was also in the southern hemisphere in a region called Centauri Montes. Here, images taken in February 2004 suggest a liquid flowed down the crater's north wall and left deposits that were not seen when the crater was previously photographed in August 1999. However, because of the extremely thin atmosphere on Mars, any water that did erupt from the ground would quickly boil and evaporate.
If they are right, the images add weight to the theory that liquid water remains buried beneath the Martian surface. Sudden impacts from asteroids would leave craters with cracked walls from which subsurface water could easily erupt. Another possibility is that the markings are caused by jets of liquid carbon dioxide, an explanation that some scientists favour because previous computer models suggested liquid water could only exist several kilometres below the crust.
Scientists have long wondered whether life ever existed on Mars and Nasa's mantra in the search for extraterrestrial life has been to follow signs of water. On Earth, all forms of life require water to survive. Among the planets in our solar system, only Earth has a more hospitable climate than Mars, and some scientists suspect Mars once sheltered primitive, bacteria-like organisms. Previous missions found evidence that the red planet at one time boasted ample quantities of water, and the question is whether liquid water is still present.