4 months ago
Last edited at 2:18PM on 11/3/2013
The most widely accepted explanation comes from the Giant Impact hypothesis. While the planets were forming 4.5 billion years ago through accretion, a planetesimal dubbed "Theia" collided with the young Earth at an angle that spared our planet. (Collisions were very common during the formation of the solar system...about a hundred or so planetesimals are believed to have initially formed.) The collision ripped off part of the Earth's crust, hurling the debris into orbit around Earth, forming a ring system. The debris eventually coalesced to form what is now the Moon. Pieces of Earth's crust have been discovered in rock samples collected by the Apollo missions.
Scientists today have a theory on it. They say that while the earth was still forming and getting rounder an asteroid hit it. the asteroid broke off a piece of the earth that went all the way doen to the mantle. This piece drifted into space and got caught in the earth's orbit. In then began to orbit the earth and get rounder. This is now known as our moon.
There are several theories on how the moon was formed. The most accepted theory, is that an object, roughly the size of Mars, impacted the Earth. The result was catastrophic and flung debris everywhere... That debris later formed together to create the moon. However, many object to this theory, because the moon's rocks are quite similar to the Earth's, and this would not be true if rocks had to take so much time to form together. This led to another theory: that the Earth was moving much faster than it is today. So fast that the days would only last a few hours. This would, thus, make matter from earth clump together more rapidly resulting in a similar composition of both objects.
The theory is that when the Earth was still forming, a giant asteroid almost as big as Mars collided with the Earth and the collision was so powerful that it blew a chunk out of the Earth and eventually became the moon
Zechariah Sitchin believes the earth...then a huge planet orbiting between Mars and Jupiter called Tiamat with it's moon Kingu, was slammed into by some of the moons of the watery planet Nibiru as it came rushing in on its elliptical orbit around the sun. It was on a collision course with Tiamat coming head-on from the opposite direction. Tiamat was knocked out of its orbit and a giant gouge was sliced out. This later filled in as the Pacific Ocean. The moon was well on its way to becoming a planet but the catastrophe killed it. The part that was gouged out was broken up and remained in the same orbit that Tiamat used to be in. All of those broken up pieces are now the asteroid belt.