A small fraction of the rocks blasted off Mars by asteroid or comet impacts could have reached Earth in just a few years.
A small fraction of the rocks blasted off Mars by asteroid or comet impacts could have reached Earth in just a few years.
小行星或彗星在撞击火星时，所轰出的岩石之中，有少数可以在仅仅数年之内就抵达地球。