By 
July 23rd, 2018
NASA’s Galileo spacecraft took this Moon image on Dec. 7, 1992, on its way to explore the Jupiter system in 1995-1997. Credit: NASA/JPL/USGS
Two space researchers are suggesting that, while Earth’s Moon is uninhabitable today, there could have been life on its surface in the distant past.
They suggest that two early windows of habitability for Earth’s Moon might have been sufficient to support simple lifeform: shortly after the Moon formed from a debris disk 4 billion years ago and again during a peak in lunar volcanic activity around 3.5 billion years ago.
During both periods, the Moon was spewing out large quantities of superheated volatile gases, including water vapor, from its interior. This outgassing could have formed pools of liquid water on the lunar surface and an atmosphere dense enough to keep it there for millions of years.
That prospect has been outlined by astrobiologist Dirk Schulze-Makuch at the Technical University in Berlin, Germany and adjunct professor at Washington State University, along with Ian Crawford, a professor of planetary science and astrobiology at the University of London.
Sensitive analyses
The study is online today in the journal Astrobiology and draws on results from recent space missions and sensitive analyses of lunar rock and soil samples that show the Moon is not as dry as previously thought.
Credit: NASA
In 2009-2010, an international team of scientists discovered hundreds of millions of metric tons of water ice on the Moon. Additionally, there is strong evidence of a large amount of water in the lunar mantle that is thought to have been deposited very early on in the Moon’s formation, Schulze-Makuch and Crawford point out.
The early Moon is also likely to have been protected by a magnetic field that could have shielded lifeforms on the surface from deadly solar winds.
Cyanobacteria touchdown
The earliest evidence for life on Earth comes from fossilized cyanobacteria that are 3.5-3.8 billion years old. During this time, the solar system was dominated by frequent and giant meteorite impacts. It is possible that meteorites containing simple organisms like cyanobacteria, the researchers suggest, could have been blasted off the surface of the Earth and landed on the Moon.
“It looks very much like the Moon was habitable at this time,” Schulze-Makuch said in a press statement. “There could have actually been microbes thriving in water pools on the Moon until the surface became dry and dead.”
International Space Station.
Credit: NASA
Future research
Whatever the case, determining if life arose on the Moon or was transported from elsewhere can only be addressed by an aggressive future program of lunar exploration, the researchers add. A promising line of inquiry for any future space missions would be to obtain samples from deposits from the period of heightened volcanic activity to see if they contained water or other possible markers of life.
Also, experiments could be conducted in simulated lunar environments on Earth and on the International Space Station to see if microorganisms can survive under the environmental conditions predicted to have existed on the early Moon.
To view the research — Was There an Early Habitability Window for Earth’s Moon? — go to:
Posted in Space News
