Wandering Jupiter could have swept inner solar system clean

On its way out, infant planet left only enough debris for four small planets, simulation suggests

Jupiter

GREEDY GIANT  Jupiter, seen in this Hubble Space Telescope image, might have once robbed the inner solar system of planet-building material

NASA, ESA, and A. Simon/GSFC

A wandering baby Jupiter could help explain why there are no planets closer to the sun than Mercury and why the innermost planet is so tiny, a new study suggests.