Forget life on Mars… look to the moon
Scientists have made a remarkable discovery – the moon may have once supported life on its cratered surface.
They say there could have been two early windows of lunar habitability on Earth’s desolate airless companion. US astrobiologist Professor Kirk Schulze-makuch, from Washington State University, said: “If liquid water and a significant atmosphere were present on the early moon for long periods of time, we think the lunar surface would have been at least transiently habitable.”
The “man in the moon” may not be so far from reality after all.
Scientists believe the Earth’s desolate airless companion could once have supported life on its cratered surface.
In fact there may have been two early windows of lunar habitability, according to new research.
Conditions would have been suitable for simple life shortly after the moon’s birth four billion years ago and again during a peak in lunar volcanic activity half a billion years later.
At both times the moon is thought to have spewed out large amounts of superheated gas and water vapour from its interior.
The out-gassing could have wrapped the moon in an atmosphere dense enough to have lasted millions of years, with pools of liquid water forming on the surface.
US astrobiologist Professor Kirk Schulze-makuch, from Washington State University, said: “If liquid water and a significant atmosphere were present on the early moon for long periods of time, we think the lunar surface would have been at least transiently habitable.”
Prof Schulze-makuch and British colleague Professor Ian Crawford, from Birkbeck, University of London, analysed results from recent space missions and studies of lunar rock and soil samples.
Evidence from both show that the moon is not as dry as previously thought.
In 2009 and 2010 an international team discovered hundreds of millions of tonnes of water ice on the moon.
Strong evidence was also found of large amounts of water in the lunar mantle, deep below the surface, thought to have been deposited soon after the moon’s formation.
A magnetic field surrounding the young moon would also have shielded anything living on its surface from deadly solar radiation, said the sci- entists writing in the journal Astrobiology.
They speculate that simple organisms could have been carried from the Earth to the moon on chunks of the planet blasted into space by meteorites.
The oldest evidence of life on Earth comes from the fossilised remains of cyanobacteria dated to between 3.5 billion and 3.8 billion years ago.
During this time, the Earth and other planets in the solar system were being heavily bombarded by meteorites. “It looks very much like the moon was habitable at this time,” said Prof Schulzemakuch.
“There could have actually been microbes thriving in water pools on the moon until the surface became dry and dead.”
Future space missions could search for markers of life in volcanic lunar rocks, he added.
“It looks very much like the moon was habitable at this time. There could have actually been microbes thriving in water pools on the moon.” KIRK SCHULZE-MAKUCH Washington State University professor
Little did Oliver Postgate and Peter Firmin know that, when they created the delightful children’s TV show the Clangers in the 1960s, it might not have been entirely fictional.
OK, so probably any life that did exist on the moon during the time it was theoretically “habitable” several billion years ago probably did not communicate by whistling and survive on a diet of soup delivered by the Soup Dragon.
But the idea that there might have been any kind of life at all on the moon would have seemed almost equally ridiculous not that very long ago. The hunt for extraterrestrial life has so far found tantalising hints but nothing concrete.
The focus has been on Mars in recent years – because it is the most Earth-like of the known planets and also because of the plan to send astronauts to explore it – and perhaps we have overlooked the potential of the apparently barren moon. Could life still be clinging on somewhere beneath the surface? Microbes in the moondust might seem small, but they could help answer one of science’s biggest questions – whether life is rare or abundant in the universe.