Water may have been brought to our planet by meteorites during the first two million years after the birth of the solar system, according to a study.
Since elements such as water and carbon are essential ingredients for life on Earth, researchers are eager to know when they arrived on our planet.
"We are seeing as many meteorite bodies as possible at this time to find out where they were in the early solar system and how much water they had," said Adam Sarafian, of the Massachusetts Institute of Technology (MIT) in I know. UU
Angrite meteorites formed in the extremely early inner solar system, approximately 4.56 billion years ago. At that point, Earth is probably still only 20 percent of its current size, while Mars, which formed more quickly, is probably close to its current size. Scientists are not sure how fast Mercury and Venus formed.
During this time, the inner solar system was a warm and dry place. Protoplanets and asteroids have fused surfaces and, when they are in magma, even an element such as carbon, which has a boiling point of 4,800 degrees Celsius, is considered volatile. Therefore, it is not clear when delicate elements of low boiling point, such as water, were incorporated, especially because the hydrogen required to make water molecules would have evaporated due to the high temperatures.
Researchers measured a common mineral in basaltic meteorites, called olivine, for the volatile elements hydrogen, carbon, fluorine and chlorine.
"Once we know the composition of the melt, we can calculate the water content of a planetary body," Sarafian said. The team discovered that the asteroid father of angrites probably had about 20 percent of the Earth's current water content.
Although the percentage is low in modern terms, this amount of water in the initial solar system indicates that water was quite abundant at 4.56 billion years ago, even when the inner solar system was still warm. Different sources of water in the solar system are commonly compared to Earth's water by measuring the ratio of the deuterium hydrogen isotope to hydrogen (D to H).
Previous research has shown that the water in the parent's body matches perfectly with the composition of Earth's water. This suggests that both the water found in angrites and the early water of the Earth come from the same source.
"It is a fairly simple assumption to say that the Earth's water at least began to accrete to the Earth extremely early, before the planet was fully formed," Sarafian said. "This means that when the planet cooled enough so that the liquid water could be stable on the surface, there was already water here," he said.
When the Earth was fully formed 4.540 million years ago, Mars already had a 20 million year initial advantage as a stable mass with water and other volatiles on its surface, such as carbon, fluorine and chlorine, Said Sarafian.