For years, the solar system seemed to follow a simple organizational pattern. Planets formed where they are today and the asteroids nearest the sun had been formed at hot temperatures.
“It seemed like a kind of orderly and neat and static solar system,” said Francesca DeMeo, a postdoctoral researcher at the Harvard-Smithsonian Center for Astrophysics. In a review paper published last week in Nature, DeMeo and her colleague Benoit Carry of the Paris Observatory describe a solar system that more closely resembles a snow globe that was shaken up.
Newer asteroid maps, fed by data from two projects — the Sloan Digital Sky Survey and the WISE survey — highlight a fact that surfaces again and again in scientific research, whether scientists are trying to understand DNA or the structure of the universe. Once you think you have the answer, nature will probably reveal more complexity.
“I was always told once you find the answer, stop looking further, because it’ll just get messier from there,” DeMeo said, laughing.
Different types of asteroids are being found in spots they weren’t supposed to be, helping support new theories of a dynamic solar system.
According to the Grand Tack theory, for example, within the first 5 million years of the solar system, Jupiter might have swung around where Mars sits today before boomeranging back out. DeMeo compares Jupiter with a giant bowling ball, knocking asteroids out of its path.
The planet Neptune would have started at half the distance it is today from the sun, and 700 million years later, it would have moved out to its present position. All this planetary musical chairs might have helped boot some asteroids out of the solar system altogether and sent others careening inward.