Why does Earth have a Moon? Perhaps we should thank one solar system giant for that

by times news cr

2024-05-01 21:53:27

What’s more, scientists believe that migrating planets—primarily Jupiter—may have led to the formation of Earth’s moons—by destabilizing the orbit of a Mars-sized protoplanet called Theia. This destabilization could have led to a collision with Earth, sending debris into space. Scientists believe that it is these debris that could have formed the Moon.

After studying the composition and location of various types of asteroids and comets, scientists know that this event occurred early in the solar system’s history. However, to understand exactly how it all happened, several puzzles need to be solved, according to Live Science.

For example, scientists know that the objects in the Solar System that we see today, including Earth, formed around the Sun from a disk of gas and dust. However, some of these objects – namely asteroids and comets – appear to be made of material that was not present in the disk – at least the material should not have been present in the places where these objects are now. Instead, it would make more sense for these objects to have formed closer to the Sun and then spread further away. If Jupiter and the other giant planets migrated from where they formed, perhaps asteroids and comets could have migrated as well.

In the young solar system, the four gas giant planets—Jupiter, Saturn, Uranus, and Neptune—were closer together. Eventually, Saturn, Uranus, and Neptune migrated outwards due to gravitational interaction with the planets beyond Neptune. Meanwhile, Jupiter migrated inward, where scientists believe it may have destabilized the inner Solar System bodies.

“The idea of ​​this orbital instability is well established in the planetary community, but the timing of when this instability occurred is still a matter of debate,” Chrysa Avdellidou, a planetary scientist at the University of Leicester, told Space.com.

Scientists call this theory of orbital instability the “Nice model,” after the French city where the Côte d’Azur observatory is located and where scientists first developed the idea.

At first, those scientists thought that this instability occurred between 500 and 800 million years ago. years after the birth of the solar system. If true, it would have coincided with the late heavy bombardment, during which the inner planets would have been pelted by comets pushed out of their orbits by migrating gas giants.

However, evidence has disproved the late heavy bombardment concept, and scientists now believe that the instability occurred no later than 100 Ma. years after the formation of the Solar System – considering when Jupiter could have accumulated the Trojan asteroids at its L4 and L5 Lagrangian points.

“Scientists seem to agree that an instability similar to the Nice pattern probably occurred less than 100 million years ago. years since the beginning of the solar system, but several different camps are emerging,” Kevin Walsh of the Southwest Research Institute in the US told Space.com. Representatives of one camp say that the instability should have happened very quickly, within four million years of the birth of the solar system. The other camp believes that it happened later, around 60 million years later. years.

So, Ch. Avdellidou, with the help of Walsh and other planetary scientists, set out to find an answer.

The team focused on a meteorite called EL enstatite chondrite, which is low in iron and has a composition and isotopic ratio very similar to that of the material from which Earth was formed. This suggests to scientists that Earth and EL chondrites likely condensed from the same part of the planet-forming disk.

However, it appears that the EL chondrite’s parent body is no longer near Earth. In fact, astronomical observations from ground-based telescopes have linked these meteorites to the Athor family of asteroids, which are located quite far in the asteroid belt between Mars and Jupiter. To be clear, the Athor family and the EL chondrites were once part of a single large asteroid that collided around 3 billion years ago. crashed after colliding – this event is not related to major instability.

Something must have scattered the Athor family pioneer into the asteroid belt, and that “something,” the team says, must have been the instability that caused Jupiter to wander. Thus, EL chondrites are excellent chronometers for this event – because they should clearly record what must have happened.

“The thermal history of EL meteorites in particular tells a rich story that constrains both the size of the original parent body and the time it had to cool before it was broken up,” Walsh said.

Using dynamic modeling, Ch. Avdellidou’s team was able to model various scenarios for a migrating Jupiter – and concluded that Jupiter could have dispersed Athor’s progenitor to an asteroid as early as 60 million years ago. years after the birth of the solar system. Combined with data from Jupiter’s Trojan asteroids, scientists can now say that the Great Instability occurred between 60 and 100 million years ago. years.

“Ch. Avdellidou specifically determined that the Nice model itself, the perturbation of the giant planet’s orbits over a short period of 10 or 20 million years. year period was the best and perhaps only time to ‘send’ asteroids into the region of this particular Athor family of asteroids,” Vals said.

And what is intriguing – around this period, the Earth and Theia collided, during which the Moon was formed. “We understand that proto-Earth had a huge collision with Thea, which had a very similar composition,” says Ch. Avdellidou. – From samples [iš Mėnulio] research has an estimated age, and other colleagues have shown that this collision may have been the result of the instability of the giant planet.”

However, this cannot be proven. “Proof” is a strong claim, and hardly possible when we’re talking about events 4.5 billion years ago. years”, says Ch. Avdellidou, though, acknowledges that the collision that formed Earth’s moon coincides with the Great Instability.

“In our study, these events fall into a nice, tight time frame,” she says. Although it may not be possible to definitively prove that Jupiter contributed to the formation of the Moon, the evidence is certainly suggestive.

So the next time you look at the moon’s silver face in the night sky, think of it as a holdover from the early solar system when Jupiter was lurking around.

Research results were published in the journal Science and presented at the General Assembly of the European Union of Geologists in Vienna.

2024-05-01 21:53:27

You may also like

Leave a Comment