The Earliest Sighting of Comet Halley

240 B.C. Chinese astronomers observe a new broom-shaped "star" in the sky. It's the first confirmed sighting of Halley's Comet.

Some have made the case that a sighting in the third millennium B.C. is responsible for the alignment of the Sphinx and the pyramids of Giza. Interesting. Even a supposed Chinese sighting in 613 B.C. would be seven years later than the calculated 620 B.C. for a Halley's passage. Was that a record-keeping error or a different comet?

The 240 B.C. observation coincides with Halley's computed orbit, but its exact date is a matter of some imprecision. The existing Chinese record is the Records of the Grand Historian, or Shiji (or Shi Chi), written more than a century later around 100 B.C. What the Chinese called a "broom star," because of its bristly tail, appeared first in the east and then later in the north.…

See Wired Top Stories for links to further info.