Meteorites brought water to Earth in the first two million years

Meteorites brought water to Earth in the first two million years

A parent body resembling an asteroid, Vesta, studied by the Dawn mission. Vesta pulled out to 525 km in diameter

A new study of angrites (rare basaltic meteorites) suggests that volatile substances with relatively low boiling points (like water) could arrive on Earth with meteorites during the first two million years of our system.

Elements like carbon and water are important ingredients for life, so scientists want to understand when they arrived on our planet. They are now examining the parent bodies of meteorites to find out where they were located in the early system and how much water they had. That is, the researchers create a map of the earliest system.

Water History

Angry meteorites appeared about 4.56 billion years ago in the internal system. At that time, the Earth reached only 20% of today's size, but Mars was developing faster, therefore, more like a modern version.

During this period, the inner part of the solar system was characterized by dryness and high temperatures. The surfaces of protoplanets and asteroids were red-hot, and in magma even carbon (boiling point - 4800 ° C) is considered unstable. Therefore, it is unclear how water could remain in such an environment. Was hydrogen present in this early period in the internal system?

Meteorites brought water to Earth in the first two million years

Basalt meteorites are scattered throughout the system. This specimen arrived from Mars in northwestern Africa. He was nicknamed “Black Beauty”. It has a relatively large water volume. The researchers measured the total mineral in basalt meteorites (olivine) for volatile elements — hydrogen, carbon, fluorine, and chlorine. Basalt is formed by cooling of igneous rocks, so volatile elements are easily converted into the composition of the basalt melt. You just need to know the composition, and you can calculate the amount of water.

Scientists have found that the Angrites parent asteroid had 20% of the current water volume. For modern conditions, this is a low percentage, but for the early system, this suggests that there were a lot of water 4.56 billion years ago.

Water Arrival on Earth

When searching for water sources in the system, we focus on the terrestrial water, measuring the ratio of isotopic hydrogen deuterium to hydrogen (from D to H). An analysis in 2017 showed that the water of the Angrites ideally corresponds to the aquatic composition of our planet.

It is easiest to assume that water entered Earth very early, before the planet had time to form. So, at the time of cooling the water was already on the surface. By the period of the final formation of the Earth, Mars was ahead of us by 20 million years, so the water on it could also appear earlier.

Using calculations on water and carbon, the scientists decided to simulate the parameters of the angritic asteroid. It was supposed to resemble the asteroid Vesta and reach a diameter of 525 km.

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