Are you Trying to Suggest that Jupiter Migrates?

Jupiter may be the largest planet in our Solar System (by far!), but that doesn’t mean it hasn’t traveled. Astronomers have long postulated that the gas giants, Jupiter and Saturn, formed far from the Sun, and traveled inward, to their current positions between Mars and Uranus. New computer simulations from researchers at Lund University in Sweden now provide some of the best evidence yet this theory is correct.

Jupiter is accompanied by two groups of asteroids, called Trojan asteroids, which travel around the Sun in the same orbit as the King of the Planets, just ahead and a little behind that massive world. One bizarre aspect of their behavior, found by the WISE spacecraft, is that the cluster of asteroids ahead of Jupiter is roughly 50 percent larger than the grouping of Trojans traveling behind the planet. This population density could best be explained, researchers concluded, if Jupiter formed far from the Sun and migrated inward, closer to our parent star.

“This is the first time we have proof that Jupiter was formed a long way from the sun and then migrated to its current orbit,” Simona Pirani, doctoral student in astronomy at Lund University, explains.

An artist’s impression of Trojan asteroids, as they accompany Jupiter in its orbit around the Sun. Image credit: NASA/JPL-Caltech

The Tale of an Ancient Journey

As the planets of the Solar System were forming from a cloud of gas and dust 4.5 billion years…