It inspired poets, mystics and musicians throughout history. Our natural satellite. Not many people often wonder how it came about. It was about 4.5 billion years ago. It arose from the collision with the Earth of another body the size of Mars, which was baptized as Theia. That is the general theory. However, the details vary in the various hypotheses on how this could be done. A new theory aims to explain the day the moon collided with the earth.
The research is led by the University of Durham. He has recreated the various proposed scenarios. And it came to the conclusion that, depending on the type and force of impact during the event, the earth would have been fired from 10 to 60 percent of its atmosphere.
The researchers performed more than 300 simulations. To do this, they used a supercomputer. He studied the consequences of various large collisions on rocky planets with thin atmospheres. Factors such as the mass, size, angle or speed of the impactor played a role. Even if it was made of iron, stone, or both.
“How the moon was formed and what other consequences a huge collision with the early Earth would have is a great mystery. Scientists are working hard on this, ”says Jacob Kegerreis. It belongs to the Institute for Computational Cosmology in Durham.
The simulations were described in “Astrophysical Journal Letters” (the research was prepublished in arxiv). They show that the atmospheric loss would depend on the type of impact. Changing a variable can lead to a loss of atmosphere. Until the complete destruction of the affected planet. And sometimes it happens the other way around, there is a profit. Everything changes with the slow giant impacts between young planets and massive objects. They could give a world a meaningful atmosphere if the impactor also has a considerable one.
How was it in the case of the earth? “We believe it suffered at least one huge late impact that formed the moon. And we know that its atmosphere has a complicated history of loss and growth that culminates in that which houses life today, “says Kegerreis.” The erosion of the atmosphere from giant bumps is an exciting piece of the puzzle. Maybe there are five or six popular ideas for the type of impact scenario. Our results show how much atmosphere would have been lost at any given time. Around 10% for the mildest, up to 60% for the most violent, ”he explains.
The consequences depend entirely on the nature of the impact. “Fast frontal collisions can easily remove an entire atmosphere. A very shallow impact could allow much of the atmosphere to survive relatively calmly, “he describes. These collisions also have a dramatic impact on the rest of the planet. They scatter the debris into orbit where it could form the moon. And usually by merging of the impactor with the main body of the earth.
The day the moon collided with the earth, it could make us disappear or change the course of the planet’s existence. But it had exactly the intensity that we have this moon in the sky today. Aren’t we really lucky?