JUPITER has long been thought to defend the inner planets by kicking dangerous comets and asteroids out into interstellar space. Now it seems the planet could have been responsible for the greatest pounding in Earth’s history.
Kevin Grazier of NASA’s Jet Propulsion Lab in Pasadena, California, and colleagues built a computer model comprising 40,000 small objects in circular orbits between the outermost planets, similar to the disc of material present in the early solar system. As the simulation progressed, Jupiter hurled over 95 per cent of the objects out of the solar system. But in the process its gravitational tug stretched their circular orbits into loops…
