The migration of the planets from asteroids told
New research on the objects orbiting in the main asteroid belt shows a wide variability in their composition and size, a sign of the great planetary upheavals during the first billion years of the Solar System. The study is published in Nature.
The turbulent history of the chaotic evolution of the Solar System has left traces revealing the asteroid belt between Mars and Jupiter, according to a new study, published yesterday in Nature, in which Francesca DeMeo (Harvard-Smithsonian Center for Astrophysics) and Benoit Carry (Paris Observatory) have mapped the composition and distribution of main belt asteroids.
Credit: David A. Aguilar (CfA)
The incredible variability of size and composition of the belt asteroids is not a surprise. For the past ten years, several studies have refuted the previous hypothesis that wanted celestial objects in the asteroid belt have formed on site and they were the remains of a planet never born, failed because of the strong gravity of nearby Jupiter.
The broad spectrum emerging from the mapping of the asteroids implies instead that their current spatial distribution is the result of the migration of planets during the first billion years of the solar system. A period of great agitation, during which, according to modern physics models, the giant planets went migrating to the inner solar system and outside before finding peace and settle in present orbits. During these upheavals have shaken the planets and asteroids moved “like flakes in a glass ball with snow,” said DeMeo.
We have the exemplary case of Jupiter. The distribution and composition of the asteroids in the belt suggest in fact that during its migration the gas giant has approached the Sun to reach the orbit of Mars today. Doing so would have wiped out the asteroid belt almost completely, leaving only one-tenth of one percent of its original population. Then reversing the route to the outer solar system Jupiter would have repopulated the belt with new material. The main asteroid belt would contain so now basically samples from the entire solar system.
DeMeo and Carry browsing in their recent article advances in the discovery and catalogue the rocks of the belt. But the mapping of the asteroids also suggests some new and interesting line of investigation. Such as the evolution of the systems of extrasolar planets, in connection with the history of the Earth. The water of our oceans could in fact just come from asteroid impacts occurred in the period of strong agitation of the migration of the planets. If it were, there would be a condition more to put on the suitability of exoplanets, or just the accidental impact of a sufficiently large number of asteroids, and Earth-like worlds could then be rarer than we think.
Despite all the studies, analyzes and mappings, much remains to be discovered about these celestial bodies and their internal structure. Waiting to send the first man on an asteroid, NASA look with high expectations approaching the probe Dawn to Ceres, the asteroid more massive band, where, according to a recent study, there should be at least a bit of water .