"The abundance of water on Earth is one of the most important
parameters that make our planet finely tuned for life. But how did Earth come to be so rich in this vital resource? That is a question that has vexed scientists for some time.
As a result, many have proposed that water was delivered to Earth by asteroids or comets. Comets, being giant balls of ice (and rock), are the preferred candidate. However, the Rosetta Probe that landed on Comet 67P last month found that the isotopic signature of the water on 67P is very different from the signature found in water on Earth.
Water, as everyone knows, is composed of two hydrogen molecules and one oxygen molecule. Hydrogen atoms typically have a single proton and no neutron. But hydrogen also has an isotopic variant known as deuterium which has one proton and one neutron. In Earth's oceans, about one in every 6420 hydrogen atoms is deuterium. According to Professor Kathrin Altwegg of the University of Bern in Switzerland, quoted in the BBC article, the prevalence of deuterium on Comet 67P is "more than three times higher than on the Earth, which means that this kind of comet could not have brought water to the Earth."
Other comets studied also have different deuterium concentrations than in water on Earth." EN&V
P.S.--a BBC Headline:
Rosetta results: Comets 'did not bring water to Earth'
Scientists have dealt a blow to the theory that most water on Earth came from comets.
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| Spacecraft nearing comet 67P |
As a result, many have proposed that water was delivered to Earth by asteroids or comets. Comets, being giant balls of ice (and rock), are the preferred candidate. However, the Rosetta Probe that landed on Comet 67P last month found that the isotopic signature of the water on 67P is very different from the signature found in water on Earth.
Water, as everyone knows, is composed of two hydrogen molecules and one oxygen molecule. Hydrogen atoms typically have a single proton and no neutron. But hydrogen also has an isotopic variant known as deuterium which has one proton and one neutron. In Earth's oceans, about one in every 6420 hydrogen atoms is deuterium. According to Professor Kathrin Altwegg of the University of Bern in Switzerland, quoted in the BBC article, the prevalence of deuterium on Comet 67P is "more than three times higher than on the Earth, which means that this kind of comet could not have brought water to the Earth."
Other comets studied also have different deuterium concentrations than in water on Earth." EN&V
And the Spirit of God moved upon the face of the waters.
Genesis 1:2
P.S.--a BBC Headline:
Rosetta results: Comets 'did not bring water to Earth'
Scientists have dealt a blow to the theory that most water on Earth came from comets.
