Well, frankly speaking; there is no way we can be cent percent sure about the fact that how was the moon formed. I mean, theories related to the origin of the moon dates back to some four billion years ago. In fact, we are not even sure that the formation of the moon took place at what exact timeline. (we will talk about it in a later section).
In other words, if we could not know the exact date about the fact that when was the moon formed? Therefore, how could it be possible to know how was the moon formed? For this reason, we can never be sure about the birth of the moon. That’s why all we can do is hypothesize or simply predict different moon formation theories.
In this article, I will give you a little moonly glimpse of the different theoretical predictions related to the question we are asking here i.e how was the moon formed? Here is the list of moon formation theories that I will be discussing with you today. So, just buckle up for this nasty ride.
- Giant Impact Hypothesis
- George Darwin’s Fission Theory
- Moon Capture Theory
- Co-formation Theory
Giant Impact Hypothesis
One of the most prevailing theories about the origin of the moon is the Giant Impact Hypothesis. According to the giant impact theory, scientists think the moon was formed when young earth and mars sized planet named Thea struck each other. That’s why this impact theory is also known as the big splash.
Well, you would have noticed that I called earth as young earth. Simply because Earth and Thea impact could have happened approximately 4.5 billion years ago. On the contrary, the latest research suggests that the Thea impact could have happened some 4.425 billion years ago.
In other words, the Giant impact hypothesis would have happened 85 million years before the previously claimed timeline i.e 4.51 billion years. Now, You see, why I was saying that we can never be sure about the birth and formation of the moon.
Apart from that, this Thea impact theory is the most favored hypothesis by the scientific community for the formation of the moon theories. Simply because almost all the questions related to the origin of the moon can be explained with the help of the Giant impact hypothesis. Well, Don’t Forget, I said almost all, Not all….!!!!
Pros And Cons Of Giant Impact Hypothesis
On one hand, with the help of the giant impact hypothesis, we can explain why the moon has a low density and a smaller core relative to the earth. Plus, we can also explain why the moon is moving away from earth. In fact, we can also easily explain how the earth got its 23.4 degrees of axial tilt.
On the other hand, the Giant impact hypothesis drastically fails to explain why the debris formed due to Thea Impact only formed a single moon rather than having multiple smaller moons orbiting around the earth. Well, before the arrival of the giant impact hypothesis, the most favored prevailing theory was George Darwin’s Fission theory. Let us check how darwin’s theory explains the fact that how was the moon formed?
George Darwin’s Fission Theory
Is the moon a piece of earth? Well, YES. I mean if you are thinking in terms of George Darwin’s fission theory. According to Darwin’s hypothesis, there was a time when the earth and the moon were once a single entity. Darwin suggested that a molten moon had been spun away or simply fissioned out from the parent earth.
In order to support his claim, he suggested that just because of the Earth’s centrifugal force, a chuck of earth fissioned out from the parent earth. In other words, in his younger days, Earth was spinning so fast that a piece of it got played out from the earth. Hence, became the only natural satellite of earth i.e Moon.
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Don’t get confused between Charles Darwin and George Darwin. To clarify, George Darwin is non-other than the son of the famous Charles darwin. YES, Charles Darwin – who gave Darwin’s theory of evolution.
Rise And Demise Of Darwin’s Fission Theory
The rise and demise of Darwin’s fission theory are somehow related to each other. I will tell you how. Well, on one hand, with the help of his assumptions, he was able to explain the fact that why the moon is moving away from earth. In fact, his calculations of the moon’s drift were later confirmed by American and soviet scientist’s experiments.
On the other hand, he could not calculate the mechanics required to trace the moon back to its parent entity i.e earth. And for this reason, (and obviously some other reasons too), Darwin’s fission theory was spun away from the heart of the scientific community. That why I said that the rise and demise of Darwin’s Fission theory are somehow related to each other.
Moon Capture Theory
The next one in the list of How was the moon formed is the Moon Capture Theory. Well, where did the moon came from? According to the capture hypothesis, the moon was captured by the earth. Scientists claim that in the early solar system, there were so many stellar bodies that never get the status of planetary bodies. Hence, our earth somehow captured one of these leftover bodies of the early solar system.
Pros And Cons Of Moon Capture Theory
This capture hypothesis became popular because it was able to explain the size of the moon. Well, it was also able to explain the tidal locking between the earth and the moon. On the other hand, the biggest drawback of the moon capture hypothesis was its capture mechanism. Scientists were scratching their heads by thinking that how could earth capture the other planetary body in its younger days.
I mean, in order to capture the moon by aerobraking, there has to be a large and dense atmosphere around the surface of the earth. But, it was practically impossible for the earth to have a large and dense atmosphere some 4 billion years ago. Plus, even the earth was somehow able to capture the moon, the moon could not have an elliptical or circular orbit as it has right now.
Therefore, by taking accounts of these drawbacks, scientists discarded the capture hypothesis for the formation of the moon. Well, maybe, the capture hypothesis can perfectly work for the irregular orbits of the moons of Jupiter or Saturn. But, definitely not in the case of the earth-moon system.
The next one in the list of How was the moon formed is the earth and the moon’s Co-formation Theory. According to the Co-formation theory, the formation of the earth and the moon took place at the same time and the same place. Meaning, they would have formed together at the same time and even from the same accretion disk.
Well, scientists claim that the accretion disk could be the center of the solar system. On the other hand, it could also be a black hole. In other words, both the center of the solar system and a black hole shares an equal possibility for the formation of the earth-moon system. As you can see, this hypothesis is related to the accretion disk, therefore also known as accretion theory.
Pros And Cons Of Co-formation Theory
The only advantage of the co-formation theory was that it was able to explain the similar composition of the earth and the moon. On the other hand, this hypothesis drastically failed to explain the high angular momentum of the earth-moon system.
must read, Our Sun Will Never Become A Black Hole: WHY?
Plus, the Co-formation theory was also not able to explain the lower density as well as the smaller core of the moon relative to earth. In other words, if they would have formed together then they should have had the same density and core too. But, you can see that the density of the moon and its core is quite lower and smaller relative to the earth’s density and its core.
Apart from the above-explained moon formation theories, there are a few more general predictions related to the formation of the moon. But, the fact remains the same. I mean, none of them (not even the above-explained ones) are completely able to explain the fact that in actuality how was the moon formed?
Well, who knows, maybe in the near coming future we could have another theory related to the formation of the moon. Or, maybe you would have something in mind related to the origin of the moon. Do You? Enlighten me with your thoughtfulness in the comment section.
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