We Asked a NASA Scientist: Where Did Our Moon Come From?

Moon Formation

Artist’s impression of the Moon-forming event. Numerous moon formation theories have been suggested by researchers. Nonetheless, the most widely-accepted explanation, backed by the available evidence, posits that the moon resulted from a massive collision between the proto-Earth and another protoplanet approximately the size of Mars, often referred to as “Theia.” Credit: NASA/JPL-CalTech/T. Pyle

Where did our Moon come from?

Well, actually, there have been several theories over many decades. Earlier versions of lunar formation theories included capture, where the Moon would have been a strayed planetoid. Another version was fission, where the Earth was spinning so fast that it would have ejected out of the Earth and then formed its own body.

This led to our current theory, the giant impactor theory. So this collision was during the late stages of planetary formation throughout our entire solar system, when planets were still very new and very much forming. So this happened when Earth was just an embryo — a baby planet, and this was actually in a crash course collision with Theia, which is a Mars-size planetoid. And this collision ripped apart early Earth’s crust. And that crust then coalesced. It snowballed into a wholly separate entity, which we now call the Moon.

So where did our Moon come from? Well, currently, our understanding is that the Earth had collided with a Mars-sized object named Theia. But once we send future astronauts to the lunar surface again, who knows? We may actually have a whole new theory in the coming decades.


Where did our Moon come from? Over the years, there have been several theories, but most scientists think it’s likely that a Mars-sized object smashed into Earth, creating what we now see in the sky. NASA scientist Caitlin Ahrens shines a light on the Moon’s mysterious origins. Credit: NASA

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2 Comments on "We Asked a NASA Scientist: Where Did Our Moon Come From?"

  1. Listen to who built the moon on audible then ask this question.

  2. The Aboriginal explanation is that it was towed into orbit by the “gods”. It’s interesting that the moon apparently rang like a hollow bell when the lunar module was dropped on it. If it were actually artificial, it certainly would make a very good observation location for life on Earth without interfering. Given the “tic-tac” videos declared real by the Pentagon, one does have to wonder if the Ancient Alien hypothesis might potentially have at least some measure of truth to it, after all.

    Sadly, we seem to be heading for self-destruction as the World Wide Web and Internet with smart phones have enabled more extremist elements in society to unite together towards all or nothing scenarios. We see the separation and extremism from various groups both far left and right these days while the middle stays quiet and does nothing. Sadly, this may lead to our ultimate destruction as nuclear and biological weapons have made it possible to destroy ourselves entirely. This may explain why the Universe is so quiet out there (along with the transition to lower power digital signals). A civilization may reach a certain technological level and blows itself up (or at least sends itself back to the stone age) within one or two hundred years or reaching the nuclear level of technology.

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