© Muhammad Hamed / Reuters
The research, published in the Astrobiology journal this week, does not say definitively that there was ever life on the Moon, but argues that the conditions which would have made life possible existed there during two different time periods, for tens of millions of years at a time.
The study’s authors write that at least some of the key conditions existed simultaneously on the Moon for long stretches of time. “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,”said Dirk Schulze-Makuch, co-author of the study and a Washington State University astrobiologist.
Discoveries made in recent years have shown that the Moon is not as dry as was previously thought. One study even showed that there was probably still ice or water trapped within the Moon’s interior at the lunar poles – but the new study suggests that there could have been a significant amount of water on the surface of the Moon; many moons ago, so to speak.
The first time, the scientists say, could have been about four billion years ago when a proto-Earth collided violently with another planetary body, creating a “gigantic impact” and a massive, donut-shaped cloud of vaporized rock and liquid. Eventually, it cooled, forming the Moon and the Earth, according to the theory. That first event could have created an atmosphere conducive to hosting life, the scientists explain.
A whopping 500 million years later, during a peak in lunar volcanic activity, conditions for harboring life could have once again been created. In fact, liquid water could have been present on the surface of the Moon for about 70 million years, according to the study.
The study says that the most likely theory for how life developed on the Moon – if it did – was that it was brought there by meteorites which “blasted off the surface of the Earth and landed on the moon” bringing with them microorganisms which could have survived the journey and then evolved into lifeforms over millions of years.
Despite all the hypothesizing, however, there are still doubts about life on the Moon. The study’s authors said it would require an “aggressive future program of lunar exploration” to figure out if the conditions ever did all come together to support life.
They also acknowledge that there is a high chance that any evidence of such life could now be destroyed after approximately four billion more years of “pounding by solar wind, cosmic radiation, and micrometeorites”.