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Artist impression of a very young star surrounded by a disk of gas and dust. Scientists suspect that rocky planets such as Earth are formed from these materials. Credit: NASA / JPL-Caltech
Water trapped in dust grains from which the Earth has formed can explain the current large amount of water on Earth.
This is suggested by scientists from the Netherlands, Germany and the United Kingdom based on calculations and simulations. The search will appear in two articles of the journal Astronomy and astrophysics.
For a long time, scientists have struggled to explain the large amount of water on Earth. A first scenario indicates that water is delivered by comets and asteroids that hit the Earth. According to a second scenario, the Earth was born "wet" and the water was already present on blocks of ten kilometers wide from which the Earth was built. However, the amount of water that these large rocks can contain is limited.
Now an international team of scientists has designed and calculated a variant of the "boulder-with-water" scenario. The team shows that in the region of the Earth's origin, small or millimeter-sized dust grains may contain enough water. The water-rich dust grains then agglomerate to form pebbles and rocks of several kilometers. These blocks can then contain large amounts of water and eventually form the Earth.
The new calculations also show that small dust particles can collect enough water in "only" a million years to explain the amount of water on Earth. A million years easily matches the time it takes to form big rocks.
Explore more:
From dust to pebbles to planets – overview of the birth of a solar system
More information:
Surface chemistry of hot dust in protoplanetary disks – Formation of phyllosilicates. Astronomy and astrophysics, 2018.
On the distribution of water in the internal solar nebula – Monte Carlo simulations of the hydration of forsterites. arxiv.org/abs/1808.06183
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