No concrete evidence explains why there is a moon. The best hypothesis presented is the Giant Impactor hypothesis: It suggests that around 4.45 billion years ago, while the Earth was still forming, a large object hit the Earth at an angle.Continue Reading
How Stuff Works explains the Giant Impactor or Ejected Ring hypothesis: When the large object that was around the size of Mars hit the Earth, it threw debris into space from the Earth's mantle region and overlying crust. After the impact, the object of impact itself melted; and, it merged with the interior of the Earth. The hot debris merged to create the moon.
This hypothesis explains certain things, such as: why the moon has rocks that have a composition similar to the Earth's mantle, why the moon has no iron core, and, why moon rocks look as if they have been baked, although they have no volatile compounds. Computer simulations demonstrate that this hypothesis is possible.
Throughout the years there have been other theories to suggest why there is a moon. Some believe that the moon was made through fission and the Earth moved so rapidly on its axis that a large part of it during the molten stage spun off and formed the moon. Another theory is that the moon and Earth just happened to form at the same time. However, both of these theories have been proven wrong over time.Learn more about Our Moon
In 2003, a hoax circulated around the Internet predicting that at 12:30 a.m. on Aug. 27, 2003, Mars would appear in the night sky the same size as the moon. The hoax took advantage of the Mars close approach, the time at which Mars and Earth come the closest.Full Answer >
According to NASA, a full moon technically only lasts for the moment when the Earth is directly between the sun and the moon. However, full moons appear to last for approximately three days.Full Answer >
The moon completes one full rotation about its axis in the same time it takes Earth to complete a full revolution, resulting in one side always turning to face the parent planet in sync with its orbit. This phenomenon is known as tidal locking.Full Answer >
The moon accelerates or decelerates because the pull of gravity between it and the earth changes as it moves closer or farther from earth. As the moon orbits the earth, it moves closer in one half of its cycle and away in the other half. As the moon approaches the earth, mutual gravity increases its speed.Full Answer >