many moons many moons Could our moon just be the most recent one? (Photo: Vadim Sadovski / Shutterstock)

The mystery of Earth’s lost moons

Scientists think the moon we see today may not have been the first.

When you look up at the night sky and write poetry or howl at the moon (depending on your species), you probably feel a sense of awe. How did this beautiful orb get here? Well, a team of scientists from Israel have a new theory, and it has something to do with ... other moons.

The old theory of how the moon was created went thus: A small planet slammed into early Earth, and the collision formed today's moon.

But scientists from Israel's Weizmann Institute and The Technion, two of the country's research powerhouses, were not convinced. They knew that lots of objects had likely slammed into early Earth ... what happened to them?

The scientists created a computer program that simulated how the Earth and moon formed. They ran 800 simulations and came to a pretty interesting conclusion: Indeed, many objects probably hit early Earth, and many of these could have joined Earth's orbit. According to the new theory, these became different moons at different times.

"Our model suggests that the ancient Earth once hosted a series of moons, each one formed from a different collision with the proto-Earth," explained Professor Hagai Perets, a Technion professor who coauthored the study.

Some of these "moonlets" in turn may have been drawn toward each other and combined into today's moon.

"It's likely that small moons formed through the process could cross orbits, collide and merge," went on Professor Raluca Rufo, a Weizmann Institute professor and this study's lead author. "A long series of such moon-moon collisions could gradually build-up a bigger moon – the moon we see today."

If we could go back billions of years and stand on Earth without melting or suffocating, we'd see a different moon ... and maybe more than one.


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The mystery of Earth’s lost moons
Scientists think the moon we see today may not have been the first. Discover what happened to the others.