The shattered remnants of a dwarf planet may have bombarded the inner planets in the early solar system, suggests a new analysis of craters on the moon.
Several large impact scars on the moon appear to be around 3.9 billion years old, suggesting that the Earth and other objects of the inner solar system were heavily pounded at that time. Most astronomers believe that the bombardment was caused by shifts in the orbits of the giant planets, which destabilised the asteroid belt, hurling giant rocks our way.
But the distribution of small and large lunar craters does not match the numbers of small and large objects in the asteroid belt today, says a team led by Matija Cuk of Harvard University, who spoke at a meeting of the American Geophysical Union in Toronto, Canada, last week.
Cuk says one possible alternative is that a dwarf planet or single large asteroid "hundreds or maybe 1000 kilometres across" did the damage after being ripped apart by gravity when it came too close to Earth or another inner planet. It then littered the inner solar system with impactors.
Several large impact scars on the moon appear to be around 3.9 billion years old, suggesting that the Earth and other objects of the inner solar system were heavily pounded at that time. Most astronomers believe that the bombardment was caused by shifts in the orbits of the giant planets, which destabilised the asteroid belt, hurling giant rocks our way.
But the distribution of small and large lunar craters does not match the numbers of small and large objects in the asteroid belt today, says a team led by Matija Cuk of Harvard University, who spoke at a meeting of the American Geophysical Union in Toronto, Canada, last week.
Cuk says one possible alternative is that a dwarf planet or single large asteroid "hundreds or maybe 1000 kilometres across" did the damage after being ripped apart by gravity when it came too close to Earth or another inner planet. It then littered the inner solar system with impactors.
Full story on New Scientist
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