Our planet Earth has a unique place in the solar system. Besides being the only terrestrial planet having a high quantity of water, it also has a large moon which helps in stabilizing the axis of the Earth. These factors have been very crucial for the development of life on Earth.
A group of scientists from the University of Münster in Germany have been able to show that water on Earth first came due to the formation of the Moon nearly 4.4 billion years ago. The formation of the Moon occurred when the Earth was struck by a body nearly the size of Mars known as Theia.
Scientists assumed till now that the formation of Theia took place in the inner solar system close to the Earth. But the scientists from Münster showed that Theia actually came from the outer solar system and it delivered huge amounts of water to Earth. The results of study has been published in the journal Nature Astronomy.
The formation of the Earth took place in the inner solar system which is dry. Hence it is quite amusing that there are large amounts of water on Earth.
According to earlier studies the ‘wet’ materials or the carbonaceous meteorites have come from the outer solar system and the ‘dry’ materials or non-carbonaceous meteorites have come from the inner solar system. It was previously unknown as to how this ‘wet’ material ever came to Earth and how the Earth contains so much water.
Dr. Gerrit Budde of the Institute of Planetology in Münster who is the lead author of this study had used the molybdenum isotope which allows us to clearly distinguish between carbonaceous and non-carbonaceous material and represent a genetic fingerprint in classifying material from outer or inner solar system. Studies have shown that Earth’s molybdenum isotope lies between carbonaceous and non-carbonaceous zone and is believed to be originated from outer solar system.
Molybdenum is mostly present in the Earth’s core and whatever we can access today from the mantle was from the late stages of the formation of the Earth. This shows that carbonaceous material arriving from outer solar system arrived late on Earth. It is known that molybdenum from Earth’s mantle has originated from the protoplanet Theia around 4.4 billion years ago which leads us to the fact that Theia itself originated from outer solar system.
This collision and the deposition of carbonaceous material from Theia is to account for the water on our planet. We have now been able to associate the origin of water with the formation of moon through a unique approach.