Distances in the solar system are vast, and it typically takes millions of years for small bodies to migrate from one orbit to another. But researchers recently discovered a “super highway”, where interactions among the planets are capable of sending comets and asteroids from Jupiter to Neptune in as little as a decade.
When you travel amongst the planets of the solar system, you’ve got to pay attention to the road. The gravity of the giant planets (Jupiter, Saturn, Uranus, and Neptune) dictate how objects in the outer system move. Where those planets are in their orbits, and when they coincidentally line up and when they don’t, determine how quickly you can navigate to the outer reaches.
Typically, small objects like comets and asteroids take millions of years to navigate from orbit to orbit. They will only occasionally suffer interactions with the giant outer worlds, slowly nudging them here or there. Usually, they can spend eternities in a single stable orbit, and only after countless little nudges do they begin to drift off course.
But by analyzing millions of computer simulated orbits, researchers have recently been able to identify shortcuts in the outer solar system. These shortcuts take advantage of peculiar alignments and positions of the outer worlds to maximize their gravitational influence and interactions, quickly moving small objects in a complex orbital dance.
If you know where you want to go, and if position yourself just right and give yourself the exact right starting velocity, you can ping-pong around the solar system, leaping from Jupiter’s orbit to Neptune’s in under a decade, and to the edge of the solar system in less than a century. All without using a single ounce of fuel.
The network of gravitational super-highways gives us clues to how the outer system shapes itself, because occasionally the random comet or asteroid can get in one of these special trajectories, allowing it to migrate much, much faster than its friends. And it also has implications for the exploration of the outer solar system, by providing a cheap, fast way to travel to the giant planets of our system…and beyond.