A new study suggests that the water in the oceans comes from asteroids

Une célèbre image de la Terre et de ses océans prise par les astronautes d'Apollo 17. © Nasa

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[EN VIDÉO] 42 large asteroids in the main belt were scanned by the VLT
The VLT’s SPHERE instrument has observed the largest main belt asteroids between Mars and Jupiter.

Assignments Apollo And interplanetary probes launched in the 1970s were able to broadly confirm a scenario of planets and exoplanets forming in previous decades. Comets A Protoplanetary disk Rich gas And dust around a young the sun About 4.56 billion years ago.

This scene is emerging and growing Rocky planets like earth, mercury Or by March AggregationWith a bomberAsteroids and comets, traces of which are still visible in the form of lunar craters. The water in Earth’s oceans must come from this blast, but debate has continued for decades about the exact nature of the smaller celestial bodies responsible for this contribution. In other words, water has been key Comets Or asteroids?

Futura has devoted several articles to this debate, and today brings a new section to it via In an article Natural Astronomy. It reports some conclusions from the analysis of the samples matter Earth was reported by the end of 2020 by a Japanese probe Hayabusa-2. These models come from Asteroid Ryugu (“Dragon Palace”, in Japanese), belongs to the Apollo family of meteorites, the C type. Chondrites It is found on Earth and is located 300 million kilometers from our planet.

With a diameter of less than 900 meters, examination of its samples confirmed the presence of original material from the time of its formation. The Solar System And it’s little changed despite traces of heat and water circulation Liquid But its temperature should not exceed 30 degrees Celsius.

Hydrogen isotopes as cosmogonic tracers

Cosmochemists study samples Ryuu Explain today that the analysis of Hydrogen and nitrogen isotopes are abundant Point out once again the relationship between asteroid water and Earth’s oceans.

To understand what it is, remember that naturally there are two types of water, one, normalAtoms ofHydrogen H with single Proton to the center; The other, called heavy, is made up of deuterium D atoms, so one proton and a Neutron.

became part of the water on earth Molecules A hydrogen atom is replaced by deuterium. We can thus define the D/H isotopic ratio of origin of seawater in cosmochemistry.

By comparing this relationship with that Meteorites and comets, so it can be determined who is the parent of the waters of the oceans. Over the years, the thesis of the origin of this water Volcanic outgassing The young Earth was abandoned and the pendulum never stopped swinging alternately to the side of comets or to the side of meteors.

A study of meteorites on Earth—mostly from the main asteroid belt—was able to establish that, on average, the D/H ratio was on the order of 140. BPM Whereas this ratio, when determined in some comets, was between 150 and 300 ppm. On Earth it is about 150 ppm, ruling out the comet hypothesis, or at least, that comets are not the main source of Earth’s water.

Ryuku’s analyzes therefore support the asteroid hypothesis.

The Solar System is a laboratory for studying the formation of giant planets and the origin of life, which can be used in conjunction with the rest of the observable universe for the same purpose. Mojo: Modeling the origin of the Jovian planets, namely modeling the origin of the Jovian planets, is a research project that resulted in a series of videos presenting the theory of the origin of the Solar System, and in particular the origin of the gas giants, by two renowned experts, Alessandro Morbidelli and Sean Raymond. Click on the white rectangle in the lower right for a more accurate French translation. Then the English subtitles should appear. Then click on the nut to the right of the rectangle, then “Subtitles” and finally “Auto Translate”. Select “French” © Laurence Honnorat

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