Selene is the goddess of the moon in Greek mythology. In this post, we will talk about how scientists think the Moon came to be. Before we go onto the most accepted theory by the scientific community, let's take a look at some rejected theory’s:
1. The Sister Theory: This theory states that the Earth and the Moon have always formed together since the time of the early solar system and have ever since been in orbit with each other. This theory was rejected because no one was able to create an actual mathematical model which could support this theory.
2. The Capture Theory: This theory states that the Moon actually formed as a separate planet around the Sun but got captured by the Earth into orbit. This theory has been rejected because an object the size of the Moon being captured into orbit without any loss of energy and collapse into the Earth is a scenario near impossible and violates orbital mechanics and momentum laws.
3. The Fission Theory: This theory states that when the Earth was a young protoplanet, it was spinning so fastly that a chunk of it actually ripped off the main surface and went into orbit. The remainder of this chunk which was ripped off is what we now observe as the Ring of Fire, around the Pacific Ocean. This theory also was rejected because such a high rotational speed wasn't something that could be achieved by a protoplanet (a planet during its formation).
Now, let's talk about the most widely accepted theory in the Scientific Community which explains the origins of the Moon, the Giant Impact Hypothesis. This hypothesis states that young Earth was struck by a planetesimal (an object found during the early solar system) the size of Mars. This resulted in a stream of ejecta (loose material after a collision) to stream out and form a ring around the Earth. This material eventually over time coagulated into a spherical object, which is the Moon.