It seems that the so-called 'great instability' event that caused chaos among the planets and the gas giants their journey through space until they settled into the orbits we know today took place between 60 and 100 million years after the birth of the solar system. This is the conclusion of careful scientific detective work that has established a connection of sorts meteorite to a asteroid that was once pushed around by those marauding planets.
Moreover, scientists primarily believe in the migrating planets Jupiter - could have led to the formation by Soil'S Moon by destabilizing the orbit of a Mars-large protoplanet called Theia. This destabilization may have led to a crash with Earth sending debris into space. It is this debris, scientists believe, that may have formed the moon.
Related: What happened billions of years ago when the moon 'turned itself inside out'?
Thanks to research into the compositions and locations of different types of asteroids and Come eat Scientists know that the aforementioned massacre occurred early in the solar system's history. Still, there are still some puzzles to be solved when it comes to exactly how everything went down.
For example, scientists are aware that the solar system objects we see today, including Earth, are formed around the sun from a disk of gas and dust. However, some of those objects, namely asteroids and comets, appear to be composed of material that was not present in the disk - at least, the material should not have been present in the locations where these objects currently reside. It would make more sense if these objects had formed closer to the sun before spreading further away. If Jupiter and the other giant planets migrated away where they formed Maybe asteroids and comets could have done that too.
In the young solar system are the four gas giant planets - Jupiter, Saturn, Uranus And Neptune - were nestled closer together. Over time, gravitational interactions with planetesimals outside Neptune led Saturn, Uranus, and Neptune to migrate outward. Meanwhile, Jupiter migrated inward, where scientists believe it was in turn able to destabilize bodies in the inner solar system.
"The idea of this orbital instability is now well established in the planetary community, but the timing of this instability is still a matter of debate," planetary scientist Chrysa Avdellidou of the University of Leicester told Space.com.
Scientists call the theory behind this orbital instability the "Nice model," after the French city home to the Côte d'Azur Observatory, where scientists originally developed the idea. Initially, these scientists thought this instability occurred between 500 and 800 million years later birth of the solar system. If that were true, it would coincide with an event known as the Late heavy bombardment, in which the inner planets would have been littered with comets that had been expelled from their orbits thanks to the migrating gas giants. However, evidence has turned against the concept of the Late Major Bombardment, and scientists now believe that the instability occurred no later than 100 million years after the solar system's formation, based on when Jupiter placed its Trojan asteroids at its L4 and L5 could have collected. Lagrange points.
"People seem to agree that the Nice model-like instability probably occurred less than 100 million years after the formation of the solar system, but there are a few different camps emerging," says Kevin Walsh of the Southwest Research Institute in Boulder, Colorado. told Space.com. One camp argues that the instability would have occurred very quickly, within four million years of the birth of the solar system. The other camp thinks it happened later, after about 60 million years.
So Avdellidou, aided by Walsh and other planetary scientists, set out to find an answer.
The team focused on a type of meteorite called EL enstatite chondrite, which contains a low amount of iron and is very similar in composition and isotope ratio to the material from which Earth formed. This tells scientists that Earth's and EL's chondrites likely condensed from the same part of the planet-forming disk.
However, the parent body of EL chondrite appears to no longer be near Earth. Astronomical observations with ground-based telescopes have even linked these meteorites to the Athor family of asteroids, which are found quite far out in the asteroid belt between Mars and Jupiter. For context, the Athor family and the EL chondrites were once part of one large asteroid that broke apart in a collision about three billion years ago, an event unrelated to the major instability.
Something should have scattered the Athor family progenitor into the asteroid belt, and that "something," the team says, must have been the instability that caused Jupiter to wander. Thus, EL chondrites are the perfect chronometers for this event because they should contain a clear record of what must have happened.
"Specifically, the thermal history of the EL meteorites tells a rich story, constraining both the size of the original parent body and the time it took to cool before breaking down," says Walsh.
Using dynamical simulations, Avdellidou's team was able to model the different scenarios involving a migrating Jupiter, concluding that Jupiter could have dispersed the Athor precursor into the asteroid as early as 60 million years after the birth of the solar system. Combined with data from Jupiter's Trojan asteroids, scientists can now say that the major instability occurred between 60 and 100 million years ago.
"Avdellidou specifically finds that the Nice model itself - the giant planet's orbits going wild over a short period of 10 to 20 million years - is the best and perhaps only time to move asteroids into the region of this particular Athor asteroid family to send," says Walsh.
And, intriguingly, the collision between Earth and Theia that formed the moon occurred around this period. "We understand that a giant collision occurred on proto-Earth by Theia, which had a very similar composition," Avdellidou said. "From examination of samples [from the Moon] there are age estimates, while other colleagues have shown that this collision could have resulted from the instability of the giant planet."
Although there is no way to prove it. "'Proof' is a strong statement and something difficult when we are dealing with events from 4.5 billion years ago," Avdellidou said, although the scientist admits that the collision that formed Earth's moon appears to coincide with the great instability.
Related stories:
- Part of the 'protoplanet' that created the moon may be stuck near Earth's core
- The moon could be 40 million years older than we thought, samples from Apollo 17 show
- Moon rocks fired from the moon's surface can become near-Earth asteroids
"Our research put these events into a nice, tight time frame," says Avdellidou. While it may not be possible to conclusively prove that Jupiter had a hand in the formation of the Moon, the evidence is certainly suggestive.
So, the next time you look at the moon's silvery face in our night sky, consider it a throwback to the early solar system, when Jupiter plagued it.
The findings were published April 16 in the journal Science and presented at the General Assembly of the European Geological Union in Vienna.
