Earth is the only planet that has liquid water on its surface, which is a basic characteristic when it comes to explaining the origin of life. However, was this water always present in the rocks that formed our planet? Alternatively, it was later delivered by asteroids and comets that bombed the Earth? Or is the earth’s water flowing from a combination of the two sources?
In the journal ScienceScientists from the Center de Richars Petrographics and Nancy in Gémિકેkિકેmens (CNRS / University de Lorraine) have contributed to this discussion by suggesting that most of the water present on Earth today has probably been there since the beginning. And even though the Earth is formed in a region of the solar system where the temperature was too low for water and was mixed with other solids as ice, the hypothesis of adding water at the end is no longer supported.
A Sahara 97096 meteorite about 10 centimeters long, studying encyclopedic chondritis. A water concentration of about 0.5% was measured by the mass, and a portion of the hydrogen was found to be located in the condrules (white spheres seen in the photograph). Samples related to the French National Museum Natural and Natural History (Paris). Credit: Christine Finney / Lauret Piani
However, the amount of water in the rocks formed on Earth was never accurately estimated. Scientists have focused on meteors with a similar structure to Earth, called ascetite chondritis[1], And more specifically on a small number of these that made them a little warmer during their lifetime and so they still exhibit primitive composition. Using two complementary techniques, they measured their content in hydrogen and determined where part of this was.
Their results show that the Earth’s ancient rocks probably had enough water to supply at least three times as much water as the Earth’s oceans, and probably much more.
In addition, the hydrogen of this meteorite has a similar isotopic composition[2] Like water stored in the Earth’s crust, the isotopic composition of the oceans is consistent with a mixture of 95% water from anastatite chondrites and only 5% water delivered by comets or water-rich asteroids. So the Earth seems to have got most of its water from its constituent objects.
Notes
[1] This is very rare, making less than 2% of meteors. Although thirteen were brought together for this study, some of them were modified, and only eleven of them were believed to have the original content of water. [2] The water molecule is made up of two hydrogen atoms and one oxygen Atom. Like many chemical elements, hydrogen exists in many different forms called isotopes, which differ in their mass.For more on this research, read:
Reference: “Earth’s water can be inherited from the same material as the Ansetite chondrite meteorites” Vachcher, Dorian Thoma Massin and Bernard Marty, 28 August Gust 2020, Science.
DOI: 10.1126 / Science
