In just a few days, November 14, the Moon is going to be a Supermoon. There are lots of opportunities to see a Supermoon but the super-super-super-ness of this particular Supermoon won’t happen again for 70 years. What better time to pen a post that explains just how our Moon ended up in the orbit it’s in around our pretty, blue planet? You see, despite the fact that we are all accustomed to that big, gray rock circling us every day, how it got there to begin with is actually a mystery. Earth and her moon have not always been a couple.
Scientists think that Earth had a major smackdown with a protoplanet millions of years ago that resulted in it becoming our Moon. A protoplanet is a large body orbiting around a sun, or star, that eventually develops into a regular planet. In other words, it’s a hunk of rock that eventually transforms into creating its own motion that affects the events and natural environment of its surface. So, although the Moon has its own motion, it is controlled by the Earth’s gravity. Interestingly, although the Moon is not yet a planet in its own right, it does affect environmental events on Earth, our ocean tides.
But the gringa has gotten sidetracked. Back to just where the heck the Moon came from. So, a protoplanet slams into Earth yet is not obliterated. Researchers suspect that for a hunk of rock to survive such a collision it would have had to have originated from a protoplanet the size of Mars. Scientists have named this theoretical Moon-producing protoplanet Theia. Here’s a picture of Earth next to Mars and Mars next to the Moon. Picture the middle guy slamming into the big guy and ending up the little guy.
Now, the gringa wants to know that if this is how it happened, how did the Moon become so perfectly round? I don’t know about you, but whenever I have seen any rock get pulverized, I don’t find any fragments that are spherical. So, the gringa takes her skepticism further. What kind of rock is the Moon?
Well, the Moon actually consists of geological material that can be found on Earth. What this means is that an impact theory between Earth and Theia doesn’t really make sense. The Moon would then consist of Earth stuff and foreign Theia stuff. But, the Moon’s just made of Earth stuff.
Another thing that keeps scientists scratching their heads about the Earth-Theia impact theory is where the Moon is. If it was a piece of space debris from an impact, the Moon should orbit around Earth’s equator. Instead, it orbits elliptically at a tilt, five degrees off our equator.
Scientist Sarah Stewart at the University of California thinks she has solved these problems. She theorizes that:
- Number one, the clash between Earth & Theia involved much more energy than previously thought.
- This caused the Earth to spin like crazy, much faster than it does now.
- Some of the debris was vaporized, meaning melted Earth material fused with Theia and Theia material fused with Earth. The Earth and Moon are actually mixed together. So, when it seems that the Moon is only comprised of Earth materials, in a way that’s true but yet not all true. The Earth and the Moon are BOTH made up of Earth & Theia stuff.
- When the collision first happened, causing the Earth to spin wildly, our axis pointed right at the Sun and we only had a 2 hour day.
- As Theia a.k.a. the Moon stabilized in its orbit around the Earth equator, its affect was to gradually slow the rapid spinning of the Earth by affecting the tidal movements of the oceans.
- As the Earth slowed down the Earth’s axis also shifted which caused Theia a.k.a. the Moon to no longer orbit around our equator.
Now, it would have taken more than 10 million years for all of this to happen. But, it all makes perfect sense to the gringa. Except for the round bit. Why is there not a big dent still visible in the Earth and the Moon? And despite the fact that I really like the name Theia, I don’t have any plans to call the Moon anything other than the Moon.
Image Credit: www.space.com