英语翻译

英语翻译
But the minimum close-approach distance is zero.Comets do not move smoothly on their tracks like ball bearings or planets.The gases that blow off their surfaces as the sun warms them up push them hither and yon,changing their trajectories.So,though the odds are strongly against it (how strongly no one can yet say) the comet has a real if small chance of actually hitting the planet.
请问这段话中最后一句联系上下文应该怎么翻译,很别扭的感觉..