Did the moon once support life? It’s likely, according to a new scientific study

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.”

The second article cited above, Life on the Moon? – ends with: “There’s abundant evidence that the early lunar water is still trapped within rock now. So, digging a little deeper under the surface of the Moon — in, say, a lunar exploration program — could yield greater evidence for lunar life, including the possibility of fossilized microbes trapped in rock.”

Areas of the moon locked in permanent shadow, like those shown here, can still harbor water. But long ago, water was abundant across the Moon.

NASA’s Goddard Space Flight Center Scientific Visualization Studio

This article originally appeared on Discovermagazine.com.