First comet found with ocean-like water
A recent discovery may add support to the theory that the water on Earth was brought by a rain of comets. Scientists have analyzed the comet Hartley 2, and discovered that ice found on it has the same composition as ocean water. The discovery was made utilizing an orbiting telescope on the Herschel Space Observatory, which can observe organic molecules by reading their far-infrared wavelengths.
"At the time of the Solar System formation there may have been a large reservoir of such comets with the correct ratio that bombarded the earth," says Paul Hartogh of the Max Planck Institute for Solar System Research in Katlenburg-Lindau, Germany.
"Life would not exist on Earth without liquid water, and so the questions of how and when the oceans got here is a fundamental one," added University of Michigan astronomy professor Ted Bergin, "It's a big puzzle and these new findings are an important piece." Bergin is a co-investigator on HiFi, the Heterodyne Instrument for the Infrared on the Hershel Space Observatory.
Hartley 2 comes from the Kuiper Belt, a zone that is found near Pluto at the edge of the solar system, where there are many more comets which we know little about. The source of Earth's water has been disputed for a long time, with previous theories believing that asteroids where the original water carriers. However, this new discovery strengthens the theory that the water present on Earth was most likely transported by comets from the Kuiper Belt.
"The results show that the amount of material out there that could have contributed to Earth's oceans is perhaps larger than we thought," Bergin said.
Source: Nature Journal
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Are we to presume the tiny amount of water that arrived through even an enormous rain of comets then multiplied like amoebas?
I used the example that I am familiar with. But talking about seawater and ignoring the salt content at least borders on lunacy.
The \'similarity\' to sea water is in the Deuterium to Hydrogen ratios. Salt has nothing to do with it. The deuterium/Hydrogen ratio is dependent on the conditions when the ices formed. We already know that these icy bodies contain amines, cyanogens, and other nucleic acids and amino acids.
The need to bring some mechanism into the supply of water comes from the recently established fact that there was a major collision around 4 Billion Years ago that resulted in the Moon. This collision was great enough to strip away all the water and air from the young Earth. Yet, within two or three Hundred Million Years, the rock evidence shows the presence of large quantities of water. Around two Hundred Million Years after that, there was oxygen in the atmosphere. A sure indication that life was at work.
After the collision that resulted in the Moon, the entire surface of the Earth was as barren as the Moon is today. It was also molten. The oldest rocks are not sedimentary, there was no water to form them. But, there \'soon\' was.
The work reported here is looking where the water could have come from. The water involved in the formation of the Earth would be quite rare. Sunlight started, and the ice was vaporized inside the orbit of Jupiter. Like the Moon and Venus, then, Earth should have been an environment with mostly Carbon Dioxide with small amounts of Nitrogen. Earth then should be much like Venus is today. But, it isn\'t. Also, the oceans have a different ratio of Hydrogen to other isotopes such as Duterium and Tritium to the lava that comes up from inside the Earth.
Yes, the work reported here is important, but it really doesn\'t mean what the Article\'s author and the commentators assume. Please read the referenced Nature Journal article if you want to understand what is being talked about.
Of course that assumes that the ratios of isotopes in the volcanic water released today is the same as it was previously.