June 7, 2014
Knowing Moon’s Origin A Step Closer?
How the moon came to exist is still in dispute. Recent findings by scientists in Germany are claimed by some experts to further support the most popular theory that the moon was formed from a collision of Earth and another, smaller planet, but the significance of this evidence is itself in question.
The UK’s Natural History Museum explains that there are three major theories for the formation of the moon. The Accretion Theory, that the moon was created at the same time as the Earth and from the same material, or was possibly a break away chunk which made off on its own as the earth was formed. The Impact Theory says that the moon was created around 4.5 billion years ago as a result of impact between the Earth and a smaller planet about the size of Mars, with the debris collecting in orbit and forming the moon. And the Capture Theory — that the moon formed entirely independently elsewhere in the universe and was pulled into the Earth’s orbit as it passed by.
Meanwhile, the BBC tells us, “An alternative, controversial, theory proposed by Prof Rob de Meijer of Groningen University in the Netherlands was that the Earth’s crust and mantle was blown into space by an accumulation of nuclear material 2,900km (1,800 miles) below the surface. It was this debris that clumped together to form the Moon.”
The Impact Theory, though, has been the most popular since astronauts were able to bring back samples of moon rock during the NASA Apollo missions. Analysis revealed that the rock was similar in composition to the Earth’s, but not exactly the same. If the moon had formed elsewhere, things would be completely different, whereas if the moon was just a rogue chunk of the Earth, then there would be no difference at all between the two materials. This left the Impact Theory as the most likely.
However, one problem stood in the way of total confidence in the Impact Theory, to the point where, according to the lead researcher with the German team, Dr. Daniel Herwartz from the University of Goettingen, “It was getting to the stage where some people were suggesting that the collision had not taken place.” The problem was that no chemical evidence of the planet Theia, the planet that it is believed collided with Earth, existed. Now, with better analysis of lunar material, it does. The researchers have found traces of Theia, and Herwartz tells us, “we have now discovered small differences between the Earth and the Moon. This confirms the giant impact hypothesis.”
There is still much disagreement, though. The tiny nature of the findings are, some say, a cause for question, and the discoveries are too small to be conclusive. Professor Alex Halliday of Oxford University told the BBC, “What you are looking for is a much bigger difference, because that is what the rest of the Solar System looks like based on meteorite measurements.” While the crazy Dutchman with the nuclear explosion theory says, “We don’t know how the Moon was formed. What we need are manned missions to the Moon and a search for rocks deeper under the lunar surface, that have not been polluted by meteorite impacts and the solar wind.”
Other planets in the solar system are believed to have different ‘fingerprints’ and should therefore show less similarity to one another than the Earth/Theia material. However, as yet unavailable samples from Mercury or Venus may prove that there are more similarities between planets in our solar system than previously thought. Alternatively, even if that turns out not to be the case, Theia could have been very similar to the Earth because it was formed so close to it.
All very exciting stuff, whatever the final analysis, should such a thing ever exist. One thing that is proven once again, though, is how science is always unwilling to fully commit to anything without conclusive evidence, and that the search for the truth is more important than the glory in being believed to have found it.
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