Jupiter may have once migrated closer to the Sun

Washington: MIT scientists have developed a map of more than 100,000 asteroids throughout the solar system which suggests that Jupiter may have once drifted much closer to the Sun.

The map found that `rogue` asteroids are more common than previously thought. Particularly in the solar system`s main asteroid belt - between Mars and Jupiter - the researchers found a compositionally diverse mix of asteroids. Previously, scientists believed that asteroids that formed near the Sun remained near the Sun and those that formed farther out stayed on the outskirts. However, in the last decade, astronomers have detected asteroids with compositions unexpected for their locations in space: Those that looked like they formed in warmer environments were found further out in the solar system, and vice versa. Scientists considered these objects to be anomalous "rogue" asteroids. The map developed by researchers from Massachusetts Institute of Technology (MIT) and the Paris Observatory charted the size, composition, and location of more than 100,000 asteroids throughout the solar system. The map suggests that the early solar system may have undergone dramatic changes before the planets assumed their current alignment. For instance, Jupiter may have drifted closer to the Sun, dragging with it a host of asteroids that originally formed in the colder edges of the solar system, before moving back out to its current position. Jupiter`s migration may have simultaneously knocked around more close-in asteroids, scattering them outward. "It`s like Jupiter bowled a strike through the asteroid belt," said Francesca DeMeo, who did much of the mapping as a postdoc in MIT`s Department of Earth, Atmospheric and Planetary Sciences. "The trickle of asteroids discovered in unexpected locations has turned into a river. We now see that all asteroid types exist in every region of the main belt," researchers wrote in their paper in the Journal Nature. The compositional diversity seen in this new asteroid map may add weight to a theory of planetary migration called the Grand Tack model, researchers said. This model lays out a scenario in which Jupiter, within the first few million years of the solar system`s creation, migrated as close to the Sun as Mars is today. During its migration, Jupiter may have moved right through the asteroid belt, scattering its contents and repopulating it with asteroids from both the inner and outer solar system before moving back out to its current position - a picture that is very different from the traditional, static view of a solar system that formed and stayed essentially in place for the past 4.5 billion years, researchers said.