Without the Moon and water, life on Earth would not be possible . New research suggests both were made possible by the protoplanet Tea (Theia), which collided with Earth 4.4 billion years ago.
Scientists have long puzzled over the true origin of Earth’s water. Earth was formed in the inner solar system yes, but the inner solar system was dry. The wet materials of the solar system were relegated to the outer solar system.
Water-rich carbonaceous meteorites, for example, come from the outer solar system. Non-carbonaceous meteorites in the inner solar system have no water. At some point during Earth’s early history, carbonaceous materials supplied large amounts of water. But the details and timing of this process are not well understood.
Where did water come from?
We already know that Earth is unique in our solar system: it is the only terrestrial planet with a large amount of water and a relatively large moon, which stabilizes the Earth’s axis. Both components were essential for the Earth to develop life.
Now, planetologists from the University of Münster (Germany) have been able to demonstrate, for the first time, that water reached Earth with the formation of the Moon about 4.4 billion years ago.
Until now, scientists had assumed that Tea originated in the inner solar system near Earth. However, experts have been able to show that Tea comes from the outer solar system and that it supplied large amounts of water to Earth. The results are published in the journal Nature Astronomy.
“ We have used molybdenum isotopes to answer this question ,” Gerrit Budde, a researcher at the Institute of Planetology at the University of Münster, said in a press release. “Molybdenum isotopes allow us to clearly distinguish carbonaceous and non-carbonaceous material, and as such represent a ‘genetic fingerprint’ of outer and inner solar system material.”
Analysis by Budde and his team showed that some of the Earth’s moly comes from the outer solar system. Because molybdenum is an element that loves iron, most of it is found in the Earth’s core, but not all of it.
“Molybdenum, which can be accessed today in the Earth’s mantle, therefore, originated in the later stages of the Earth’s formation, while molybdenum from earlier phases is in the core“, clarifies the planetary scientist Christoph Burkhardt, co-author of the work.
The new research shows large amounts of water reached our planet after Earth’s building blocks had merged. The study authors suggest that much of this water-rich material was supplied by Tea, the Mars-sized planet that scientists theorize struck Earth about 4.4 billion years ago.vaporizing much of the Earth and causing the formation of the Moon.
“Our data show that the Earth increased carbonaceous bodies at the end of its growth history, probably through the impact of the formation of the Moon,” the authors wrote.“This late delivery of carbonaceous material was likely due to orbital instability of the gas giant planets, and shows that Earth’s habitability is strongly linked to the late stages of their growth.”
“Our approach is unique because, for the first time,allows us to associate the origin of water on Earth with the formation of the Moon.In short, without the Moon there would probably be no life on Earth, “concludes Thorsten Kleine, a co-author of the study.
Referencia: Gerrit Budde et al, Molybdenum isotopic evidence for the late accretion of outer Solar System material to Earth, Nature Astronomy (2019). DOI: 10.1038/s41550-019-0779-y
