An impact (on the Mars) capable of ejecting a fragment of the Martian surface into an Earth-intersecting orbit is even less probable than such an event on the Moon, in view of the Moon's smaller size and closer proximity to Earth.
一個能夠把活性表面的碎片射入地球交叉軌道的碰撞發(fā)生的可能性甚至小于這種事件在月亮上發(fā)生的可能性，考慮到月亮更小的尺寸及其與地球接近的程度。