Scientist have a new suggestion about the formation of the Earth. Astronomers studying the way the Moon formed have found new evidence showing that it formed after a smaller planet hit us directly about 4.5 billion years ago. According to scientists, the collision was so fierce that the “embryo planet” that hit us (Theia) eventually merged with both the Moon and Earth, writes Science Alert.
The idea that our planet’s satellite formed as a result of a collision in the Solar System is not new. Until now, however, scientists have suggested that Theia simply “wiped” the Earth and pushed the Moon into our orbit. And then – she continued on her way into space. Today, however, a team of scientists from the University of California, Los Angeles, say that Theia has never abandoned us.
To reach this conclusion, the researchers studied seven lunar rocks brought by the Apollo missions, as well as six volcanic rocks from the Earth’s mantle.
They wanted to see how many oxygen isotopes were in the rocks. In other words – they were counting protons and neutrons in the oxygen atoms. This is important because the rocks of each planetary body in our solar system have a unique imprint of oxygen isotopes. That’s how we can find out where they actually came from.
For example, nearly 99.9 percent of the Earth’s oxygen is O-16. This means that each atom contains 8 protons and 8 neutrons. However, there are also small amounts of O-17 and O-18 on our planet. And it is the ratio between O-16 and O-17 that can be used to understand where rocks (and other substances) actually came from.
If Theia simply wiped the Earth and formed the Moon, as was thought until recently, our satellite would have been built primarily by Theia. Accordingly, the ratio between the oxygen isotopes of the Earth and the Moon would be different.
“We do not find any differences between the oxygen isotopes of the Earth and the Moon. They are indistinguishable, “said Edward Young, the study’s lead author.
Moreover, the findings support the hypothesis proposed in 2012 that Thea and Earth collided and eventually merged.
“Thea merged with the Earth and the Moon and was distributed in both bodies,” Young commented. “That explains why we don’t see a different Theia signature on the Moon and Earth.”
We still don’t know much about Theia. Young and his team believe that this planetary embryo was about the size of Earth. According to others, it was as big as Mars. However, Young explains that there is evidence that Theia was growing and that if she had survived the collision, she would have become an entire Planet.
If confirmed, the study, published in Science, will change our understanding of how our planet formed and evolved. It can also provide us with additional information about the origin of the water. A head-on collision with Theia most likely resulted in the destruction of all water supplies. If this really happened, then the water returned to us through the collisions of small asteroids and comets tens of millions of years later.
On the one hand, the very fact that our planet has destroyed another so that we can exist today is quite sad. But on the other hand – the series of random events that led to the birth of life is truly remarkable.