Alien origin

Now a more refined analysis of Moon rock has found evidence of material thought to have an alien origin.

One mystery replaced alexander hera by another: Traces of Theia have been found on the Moon but its composition is very similar to that of the Earth

According to the lead researcher, Dr Daniel Herwartz, from the University of Goettingen, no-one has found definitive evidence for the collision theory, until now.

"It was getting to the stage where some people were suggesting that the collision had not taken place," he told BBC News.

"But we have now discovered small differences between the Earth and the Moon. This confirms the giant impact hypothesis."

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What you are looking for is a much bigger difference, because that is what the rest of the solar system looks like”

Prof Alex Halliday

Oxford University

But the difference, some say,alexander hera pre wedding could be explained by material absorbed by the Earth after the Moon formed.

And Prof Alex Halliday of Oxford University, is among many scientists who are surprised that the difference between the Theian material found in the Moon rock and the Earth is so small.

"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," he said.

Dr Herwartz measured the difference in what is called the isotopic composition of the oxygen contained in rocks on Earth and Moon rock. This is the ratio of different forms of oxygen.

Studies of meteorites from Mars and the outer solar system show that these ratios are markedly different - rather like a fingerprint. So Prof Halliday and others are puzzled by the fact that the fingerprints of Earth and Theia seem almost identical.

Similar composition

One possibility is that Theia was formed very close to the Earth and so had a similar composition. If that was the case, it raises the possibility that the assumption that each planet in the current Solar System has a markedly different fingerprint needs to be revisited, according to Prof Halliday.

"It raises the question of how alexander hera價錢 well the meteorites from Mars and the asteroid belt in the outer Solar System are representative of the inner Solar System? We do not have samples from Mercury or Venus.

"They may well be similar to the Earth. If that is the case then all the arguments over the similarities of the Earth and the Moon fall away," he told BBC News.