The Moon continues to enthrall us. Scientists now believe that it may have supported simple lifeforms twice in its existence. The arid, cold and cratered surface was potentially habitable 3.5 billion years ago. This was because water from lunar volcanoes was trapped under the Moon’s surface. It could have been there for up to 70 million years, shielded by an atmosphere which has also now disappeared. So early forms of bacteria could have survived.
These would have arrived in clouds of debris caused when huge meteorites smashed into Earth. While now they would be blitzed immediately by deadly solar winds and cosmic radiation, at that time, the churning volcanic magma is thought to have created a protecting magnetic field on the lunar surface. With the presence of water, carbon and a thin atmosphere, the main building blocks for life were in place, according to Professor Dirk Schulze-Makuch, from the Technical University in Berlin. The astrologist, who has worked with Professor Ian Crawford from Birkbeck University, London, to analyse data from recent probes and rock samples, 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 study, published in journal Astrobiology, suggests the water came as amounts of hydrogen and carbon dioxide were released in a molten magma similar to what happened during volcanic lunar eruptions. So for life to exist, it only needed a meteor strike to transfer bacteria from Earth, which 3.5 billion years ago was much closer to the Moon.
The authors identify a second – less likely – time life could have survived, shortly after the Moon formed 4 million years ago. Until a decade ago most experts thought the Moon had always been dry – possibly because any channels formed by water, as seen today on Mars, were eroded by solar winds. Experts now say it may once have been home to vast lakes.
New theories such as these will probably lead to further expeditions to the Moon to unravel more discoveries, which will give more credence to their suppositions so far.