The solar system was born in chaos, and the moon’s scars led many planetary scientists to believe that the storm occurred about 3.95 billion years ago. But a new timeline appears to have overturned the theory, bringing the chaos ahead of schedule, Science reported.
As primitive gases and dust form planets, giant planets slowly begin to pull each other, causing them to lose their orbits, pushing not only Pluto and others into the distant Kuiper Belt, but also possibly triggering smaller objects to crash into the inner planets. Planetary scientists believe the turmoil occurred 650 million years after the formation of the solar system, but the theory has one flaw: Mercury, Venus, Earth and Mars may not survive the attack.
Now, a new timeline is beginning to appear, pushing the chaos forward to less than 100 million, or even 10 million, years after the birth of the solar system.
Twenty years ago, scientists realized that the migration of planets created the modern solar system. Models by planetary scientist Alessandro MorbiDELLi of the University of the French Cote d’Azur and his collaborators show that after the giant planet formed from the gas disk, Jupiter pulled its planet”, the Little Companion, into a resonant orbital chain;
Now, in a paper published by Icarus, Morbidelli et al. point out that the “late” chaos may not work. Computer models show that if the chaos comes too late, there will be a huge gap between Neptune and the disk of planets orbiting beyond its orbit. But the gap rarely appears in the model, Morbidelli said, suggesting that disaster cannot be delayed.
In addition, Matthew Clement of the Carnegie Institution for Science and others have shown in computer simulations that instability that began less than 10 million years after the formation of the solar system, it would allow inner planets to merge peacefully and wash away planetary formations near Mars and the asteroid belt. This explains their strangely low quality.
A recent paper published in the Monthly Journal of the Royal Astronomical Society: Letters suggests that near the end of the period of instability, Saturn begins to move away from Jupiter, and that the last pull between them could throw asteroids away from the orbital plane, creating the current compact structure of the asteroid belt.
Still, Thomas Kruijer, a geochemist at Lawrence Livermore National Laboratory, believes there is little direct evidence that the period of instability occurred in the early days of solar system formation, and that there are at least two scenarios that explain how rocky planets survived. But Kruijer also believes it is possible to have an impact in the first 100 million years of the solar system.
Scientists are looking for more observations to analyze what happened in the first 100 million years, possibly from asteroid samples, primitive asteroid clusters, or craters on the moon and Mars.