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Discovery means there could be life on Mars
By Nic Fleming, Science Correspondent
Last Updated: 2:38am GMT 07/12/2006
In pictures: Nasa's latest find on Mars
Dramatic new pictures suggest Mars has flowing liquid water on its surface, significantly increasing the chances that there could be life on the Red Planet.
Crisp before-and-after images of gullies on the planet taken by Nasa’s Mars Global Surveyor unexpectedly show liquid has flowed there in recent years.
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Scientists have previously pointed to features that suggest flowing water on the planet billions years ago.
The discovery is unexpected because the temperature and atmospheric pressure are too low to allow water to exist in liquid form for long.
It suggests geological activity could be heating water beneath the surface so that it is warm enough to flow for long enough to leave traces behind. Water and a stable heat source are considered keys precursors for the existence of life.
Dr Andrew Coates, of University College London's Mullard Space Science Laboratory, said: “This means there could be life on Mars now.
“Life can survive in very difficult situations so if there are places with liquid water under the surface with heating, it could mean there is life there now.”
Colin Pillinger, of the Open University who led the Britain-led Beagle 2 mission to Mars, said: “Water is a precursor of life. On Earth wherever there is water there is life.
“This is really significant. It means we now know where to look for life.”
Two gullies that were originally photographed in 1999 and 2001, and imaged again in 2004 and 2005, showed changes consistent with water flowing down the crater walls, according to the study published today in the journal Science.
Light-coloured deposits are seen in the later pictures that were not present in the original images.
Nasa researchers believe the deposits could be salt, mud or frost, and that they were left there when water recently flowed through the channels. |
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发表于 2006-12-7 12:37:38