Halley's comet has had a greater impact than any other upon astronomy. The period of its orbit was discovered first, and sightings of it can be traced with certainty to more than 2000 years ago. It is mainly Chinese records that allow us to do so.
哈雷彗星是所有彗星中對天文學影響最大的一顆，週期建立比任何彗星都早，能準確的追蹤到兩千年以上，主要憑藉的也就是中國的紀錄。