Rosetta Mission has raised doubts as to the origin of water on the … – Money.pl

2014-12-11 17:10

[Photo: sxc / cc / Diana34]

The most recent data from the Rosetta mission indicate that the steam coming from the comet 67P / Churyumov-Gerasimenko is significantly different isotopic composition in relation to the water in Earth’s oceans. This seems like a comet exclude tested as a major source of water on Earth – informs the European Space Agency (ESA).

The question of the origin of water, in the seas and oceans is one of the major puzzles in research the creation of the Earth and life on it. The most popular hypothesis suggests that the source of water were comets and asteroids that hit in the early Earth.

Scientists are largely agree that the water must be supplied to Earth early in its formation. However it is not known what the category of small bodies in the solar system has contributed to this process. There are three main possibilities: asteroids in the main asteroid belt between Mars and Jupiter, comets from the Oort cloud (a hypothetical reservoir of comets at the very far edge of the solar system), comets from the Kuiper belt outside the orbit of Neptune.

Researchers able to verify that the water present in the data objects is similar to that occurring on the Earth, analyzing its isotopic composition. Measured the levels of deuterium (D) relative to the normal hydrogen (H) and compares it with the ratio of these components in the Earth’s oceans. On Earth, the content of deuterium to hydrogen ratio is equal to D / H = 0.00015.

In 1986, nearly 30 years ago, Halley’s comet measurements made by the European Giotto probe made it possible for the first time to designate the ratio of deuterium to hydrogen for the comet. It turned out that it is twice the size of the Earth. Measurement in subsequent years in the case of several other comets from the Oort cloud showed a very similar level as in the case of Halley’s comet. As a result of adopting models of the Oort cloud comets as a source of water on Earth became less and less popular among scientists.

However, in 2011, working in the space telescope Herschel, who was also sent by the European Space Agency, has examined the level of deuterium terms of hydrogen for comet 103P / Hartley 2, which is considered the property belonging to another group of comets – the Kuiper belt comets (or Jupiter family comets). In this case, the level of deuterium was very similar to that of the Earth’s water, which was a surprise.

The latest measurements were made from 8 August to 5 September within the Rosetta mission, which launched the European Space Agency in 2004, and which is now located near the comet 67P / Churyumov-Gerasimenko. Was used for the measurement of instrument called ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis), built by an international consortium led by the University of Bern (Switzerland).

Made using ROSINA spectrometer measurements of the isotopic composition of water vapor gave value more than three times superior to the results of the Earth’s water (D / H = 0.00053). This means that like a comet 67P / Churyumov-Gerasimenko rather not be a source of water on Earth.

As the scientists from the Rosetta mission, in the light of the most recent measurements, it appears that the main source of water on Earth were rather asteroids, not comets, but the topic requires further investigation. (PAP)

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