Halleys

Halleys may refer to several subjects associated with the name Halley, most prominently Halley's Comet. The term is most often encountered in the possessive form Halley's Comet, the periodic comet that visits the inner solar system.

Halley's Comet, officially designated 1P/Halley, orbits the Sun about every 75 to 76 years. It was named after Edmond Halley, who, in the 17th and 18th centuries, used Newtonian gravity to show that a single object observed in multiple historical passings could be a periodic comet. Records of a bright object in the sky appear as far back as 240 BCE, with notable returns in 1066, 1835, 1910, and 1986. When near the Sun, its nucleus—estimated around 15 kilometers in diameter—sheds material, creating a coma and two tails directed away from the Sun. The comet’s visibility and scientific interest have spanned centuries, contributing to the understanding of cometary physics and planetary perturbations.

Predicted next perihelion is around 2061–2062, though exact dates vary due to gravitational influences, especially from Jupiter and Saturn.

Other uses: The plural Halleys can refer to multiple people with the surname Halley, or to places or entities named after Edmond Halley. In common usage, the standard forms Halley or Halley's are preferred for individuals and the comet.