written by: Atlee Hargis•edited by: RC Davison•updated: 7/19/2011
From the effects of meteorites and asteroids, to the tides and even the bizarre origin of the Moon itself -- all of these are significant answers to the question: "How does studying the Moon help us learn more about Earth?".
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Earth and Moon, Mother and Daughter
The only time you'll hear about the Moon in casual conversation is usually when it's full or when it's being used as an excuse for crazy behavior. However, the Moon is in fact very important to the Earth, not simply because of the physical connection between the two objects, but also because of the things we can learn about our own planet from its only natural satellite.
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The Moon: Closer to the Earth Than You Might Think
For many, the Moon is simply regarded as being a large, luminous rock hanging over our heads. Yet, few are aware that the Moon, at one time, was a part of the Earth. That is, according to the most popular theory for the origin of the Moon. This theory states that, during the early history of the Earth, a massive object the size of Mars collided with the molten rock we now call Earth. This collision was so powerful that it knocked a chunk out of the Earth, this enormous chunk of rock eventually cooled and continued to orbit the Earth and today it is known as the Moon.
Why is this important and how does studying the Moon help us learn more about the Earth? Well, because it is essentially a part of the Earth, it means that we can study it and gain an understanding of how the Earth existed millions of years ago, when it was in its early stages of formation. Everything from the elements that make up the lunar crust to the way in which the moon evolved following its expulsion from the Earth gives us more insight into planetary evolution, as well as the effects of space on an "unprotected" body like the Moon.
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A Warning Sign of Imminent Danger
With its millions of years of history behind it, the Moon has endured a number of significant and devastating meteor strikes, ranging from the countless pebble sized meteorites that fall to the surface everyday to the monstrous collisions that occur once in a very long while. This is significant for research purposes, because it gives us a look at how much damage a meteorite can do when it comes within range of our planet. One might assume that studying the Moon's meteor craters wouldn't be worth it, but given how quickly Earth deteriorates the quality of an impact crater it makes it much more difficult for scientists to study the impacts. On the Moon, with no wind or rain to erode them, craters are preserved for millions of years. Additionally, these craters are far easier to study because of the simplicity of pointing a telescope at the lunar surface as opposed to sending a satellite into space to take pictures of the craters here on Earth.
As our ability to detect different sizes of meteors and asteroids at further distances improves, we must also be more aware of the effects these space rocks can have on our home. This is the main significance of studying craters on the Moon, because it becomes possible to distinguish which meteors and asteroids can be considered harmful to life here on Earth.
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The Tides and Other Interesting Relationships
Finally, one of the most important aspects of the Moon-Earth partnership is the Moon's effect on our tides. It is the main cause for the high and low tides experienced at beaches and harbors everyday around the world. This is obviously important to us, because with the tides go the fish and when the tides are low, the fishing is going to be poor in that area. If we know when the tides are going to change we can properly relay this information to fishermen so that they may efficiently do their business.
A secondary issue on this topic is the slowly increasing distance between the Moon and the Earth. Every year the Moon gets further from the Earth by about 1.5 inches, according to measurements taken using retroreflectors left on the lunar surface by Apollo 11 astronauts. This means that eventually its effect on our planet will be drastically different than they are now, which requires further study to ensure those changes aren't harmful to ourselves or the planet itself.
Another relationship between the Moon and Earth's oceans is the supposed effect ithas on spawning cycles for various ocean creatures. A suggested theory on how and why corals mass spawn at specific times is believed to be because of the lunar cycle. Whether or not this is true is still up for debate, but it's one more effect which we've only recently discovered that the Moon has on our planet.
Through countless decades of research, we've gained a large catalog of knowledge about the Moon, arguably more than any other object in space, yet we still have more to find, all the more reason to grab your own telescope and peer up at that pearly, crescent rock in the sky, because who knows what you might learn about your own planet one day.
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Daniels, Patricia. The New Solar System Ice Worlds, Moons, and Planets Redefined. National Geographic Society, 2009.