Halley's [HAL-lee] Comet has been know since at least 240 BC and possibly since 1059 BC. Its most famous appearance was in 1066 AD when it was seen right before the Battle of Hastings. It was named after Edmund Halley, who calculated its orbit. He determined that the comets seen in 1531 and 1607 were the same object that followed a 76-year orbit. Unfortunately, Halley died in 1742, never living to see his prediction come true when the comet returned on Christmas Eve 1758.
Halley's Comet put on bright shows in 1835 and in 1910. Then in 1984 and 1985, five spacecraft from the USSR, Japan and Europe were launched to make a rendezvous with Halley's Comet in 1986. One of NASA's deep space satellites was redirected to monitor the solar wind upstream from Halley. Only three comets have ever been studied by spacecraft. Comet Giacobini-Zinner was studied in 1985, Comet Halley in 1986, and CometGrigg-Skjellerup on July 10th, 1992. The nucleus of Halley is ellipsoidal in shape and measures approximately 16 by 8 by 8 kilometers (10 by 5 by 5 miles).

Halley's Comet Statistics

  • Perihelion distance: 0.587 AU
  • Orbital eccentricity: 0.967
  • Orbital inclination: 162.24°
  • Orbital period: 76.0 years
  • Next perihelion: 2061
  • Diameter: 16 x 8 x 8 km