Rosetta poured cold water – BBC

The first scientific data from the probe Rosetta puzzled astronomers – water from the comet was much “heavier” the earth’s water. This will add fuel to the fire of disputes about the origin of the oceans on our planet.

After a month after the world subsided passion about landing on the surface of the device comet Churyumov-Gerasimenko, experts have published the first scientific article based on the received data from the probe Rosetta. And the importance of these results is difficult to overestimate – we are talking about the origin of no less, and water on Earth. The answer to this question, along with other fundamental issues were among the main goals of the mission Rosetta.

According to one of the dominant theories in the early stages of the Earth was so hot that it simply could not survive any amount originally had water.

According to this hypothesis, the water that now occupies two-thirds of our planet’s surface, was introduced to the already chilled Earth by comets and asteroids.

The only way to shed light on the origin of the Earth’s water – compare it with the water on the other bodies of the solar system. Here, scientists are at an opportune methods of nuclear physics by which we know,

that a liter of water and the earth’s molten pounds Martian ice can be distinguished not only chemically.

The fact is that the distinguishing feature of any water is not only the presence of impurities in it but its isotopic composition. In the molecule H ₂ O may include not only ordinary hydrogen (H), but also its “heavy” isotope deuterium (D).
For example, in the world in 10 th. Of water molecules there are only three, including the heavy atoms of deuterium. Comparing the ratio of deuterium to hydrogen in water, scientists can judge the origin of water on those or other bodies of the solar system. That is why the study of the isotopic composition of water – one of the main objectives of many space missions to study comets, planets and asteroids.

Comets in this quest stand out – it is believed that they are fragments of the original substance from which the solar system formed 4.6 billion years ago, and therefore look similar to terrestrial isotopic composition must be on them.

It is believed that the comet Churyumov-Gerasimenko, like most of the Jupiter-family comets, was formed in the Kuiper Belt – the ring of ice blocks beyond the orbit of Neptune. Due to the gravitational perturbations of these comets were pushed into the inner regions of the solar system and their orbits become determined by the impact of a massive Jupiter.

During the previous years, scientists were able to measure the isotopic composition of water 11 comets.

And only one of them, the comet 103P / Hartley 2 family of Jupiter using a space telescope was determined isotopic composition of the water, similar to the earth. Unlike comets, meteorites water, fallen to the ground from the main asteroid belt between Mars and Jupiter, is similar in isotopic composition from the Earth, so scientists are not in a hurry to discount the hypothesis of meteoric origin of the Earth’s water. And because scientists have been waiting for the results from the set on the unit Rosetta spectrometer ROSINA (Rosetta Orbiter Spectrometer for Ion and Neutral Analysis), which determines the composition of the comet’s atmosphere.

Analysis of samples of water evaporating from the surface of the comet showed

that the ratio of D / H to it more than three times higher than that of water or earth from the same comet 103P / Hartley 2. Furthermore, it is even higher than the measured ratio D / H for all the studied comets, arrived from the far more “distant” – the Oort cloud is a huge repository of ancient ice blocks on the margins of the solar system.

«Our discovery eliminates the version that the Jupiter-family comets contain only similar to the Earth’s water, and adds weight to a model assuming participation in the asteroid entering of water on Earth, “- says Katherine Altwegg, a research team leader ROSINA, author of a paper published in the Science .

According to her, the result points to a different origin Jupiter-family comets, which occurred at different distances from the sun.

«We knew that the analysis of this comet will be surprises in terms of exploration of the solar system, and it outstanding discovery definitely will add fire to the debate on the origin of water on Earth, “- says who became famous all over the world, Matt Taylor, head of the landing probe” Fila “on the comet’s surface.