We’ve long known that water once flowed on Mars, and it is currently abundant on the Red Planet in the form of ice. However, until recently it was thought that current temperatures and pressures were far too low for liquid water to exist today. A few years ago small, temporary patches of damp soil were detected on the planet, but more recently a large body of liquid water has been discovered on Mars for the first time.
In July this year, Italian scientists from the European Space Agency’s Mars Express Mission announced that a twelve mile wide liquid water lake had been detected by radar beneath an ice cap near the Martian south pole. It is thought to be about a mile deep.
With temperatures in this region of Mars estimated to be about minus 90 degrees Fahrenheit, how is it possible for it to harbor liquid water? The extreme pressure exerted by the overlying ice lowers the melting temperature. In addition, the ice acts as a blanket, helping to insulate the underlying region from the cold. However, these factors alone would not be enough to melt the ice. The only explanation for the presence of liquid water under these conditions is that the lake contains high concentrations of dissolved salts, which would lower the melting point enough to melt the ice.
We know that water is a prerequisite for life on Earth, so finding liquid water on Mars raises the possibility that life may exist there today. Enrico Flamini, who oversaw the research, says of the newly discovered water, “It is liquid, and it’s salty, and it’s in contact with rocks. There are all the ingredients for thinking that life can be there, or can be maintained there if life once existed on Mars.”
Here on Earth microbial life has been found thriving in extreme conditions, such as beneath the Antarctic ice in a dark, frigid lake with similar radar signatures to the one discovered on Mars. In this Antarctic lake and in other bodies of water on Earth, we know that microbes can and do live off minerals derived from underwater rocks, so the rocks in the Martian lake could potentially provide life forms there with energy. Another factor favoring life in the Martian lake is that the ice covering it would shield it from the damaging radiation that bombards the planet’s surface. However, the water in the Martian lake is thought to be extremely salty. Is it too salty for some form of life to survive? We don’t know.
The Martian lake was found in a basin where liquid water might once have flowed at a time when the planet was warmer and could potentially have harbored life. As Mars cooled and dried out might any life on its surface have migrated to the underground lake and survived there to this day?
Does life exist on Mars today or did it ever? As of now we don’t know. All we can say is that some of the preconditions for life exist there. However, NASA plans to send another rover to the Red Planet in 2020 to look for signs of past life there and to collect samples for future return to Earth. While drilling beneath the ice that covers the newly discovered lake is not on its agenda, who knows what treasures it may uncover?
Join the Springfield Stars Club on Tuesday, November 27th at 7pm at the Springfield Science Museum for a talk by Grant Wilson on “Peering into the Dusty Universe,” a new look at the formation of stars throughout the cosmic ages. Wilson is a professor in the Department of Astronomy at the University of Massachusetts. He has worked at NASA’s Goddard Space Flight Center and has discovered hundreds of new galaxies with the AzTEC camera. He chairs the Science Advisory Board of the Large Millimeter Telescope and leads a multi-national collaboration of scientists in the development of the TolTEC telescope camera. Refreshments will be served, and the public is welcome. The meeting is free of charge for members, with a suggested donation of $2 per non-member.
Also, on Friday, December 7th at 7:30pm, the Stars Club and the Springfield Science Museum will host “Stars over Springfield,” an astronomy adventure for the whole family. Amateur astronomer Alan Rifkin will give a talk on “Telescope Ideas for the Holidays.” A fee of $3 for adults and $2 for children under 18 will be charged.
Copyright © Amanda Jermyn