History of Halley's Comet

Halley's Comet, officially designated 1P/Halley, is the most famous of all periodic comets and has been observed by humans for over two millennia. Its regular appearances have marked significant moments in human history and helped advance our understanding of the cosmos.

Ancient Observations

The earliest confirmed observation of Halley's Comet dates back to 240 BCE, recorded by Chinese astronomers in the Shih Chi and Wen Hsien T'ung K'ao chronicles. They described it as a "broom star" sweeping across the sky.

Throughout antiquity, the comet appeared regularly in historical records:

• 164 BCE: Babylonian astronomers recorded the comet on clay tablets
• 12 BCE: Chinese records note a "broom star" visible for 56 days
• 66 CE: Jewish historian Josephus described it as "a star resembling a sword" over Jerusalem
• 451 CE: Appeared during Attila the Hun's defeat in Europe

The Norman Conquest - 1066

One of the most famous appearances of Halley's Comet occurred in 1066, just before the Battle of Hastings. The comet is immortalized in the Bayeux Tapestry, where it's depicted as an omen. King Harold II of England saw it as a bad sign, while William the Conqueror interpreted it as a favorable portent for his invasion.

"You've come, have you? You've come, you source of tears to many mothers. It is long since I saw you; but as I see you now you are much more terrible." — Eilmer of Malmesbury, 1066

Edmund Halley's Discovery

The comet is named after English astronomer Edmund Halley (1656-1742), who was the first to recognize that comets could be periodic. Using Newton's newly formulated laws of motion and gravitation, Halley calculated the orbits of 24 comets observed between 1337 and 1698.

He noticed that the comets of 1531, 1607, and 1682 had remarkably similar orbital elements and concluded they were the same object returning approximately every 76 years. In 1705, he published his findings and boldly predicted the comet would return in 1758.

Halley died in 1742, but his prediction proved correct when the comet was recovered on Christmas Day 1758 by German farmer and amateur astronomer Johann Georg Palitzsch. This successful prediction was a triumph for Newtonian physics and established comets as members of our solar system.

The 1910 Panic

The 1910 return of Halley's Comet caused worldwide panic when spectroscopic analysis revealed the presence of cyanogen gas in its tail. As Earth was expected to pass through the tail, sensationalist newspapers predicted mass poisoning, despite scientists' assurances that the gas was too diffuse to pose any threat.

Entrepreneurs sold "comet pills" and gas masks, while others threw "comet parties" to celebrate what they feared might be their last night on Earth. The panic highlighted both the public's fascination with and misunderstanding of astronomical phenomena.

The Space Age Encounter - 1986

The 1986 return marked the first time spacecraft could study a comet up close. An international fleet of spacecraft, nicknamed the "Halley Armada," was launched to intercept the comet:

• Giotto (ESA): Passed within 596 km of the nucleus
• Vega 1 & 2 (USSR): Flew by at distances of 8,890 km and 8,030 km
• Suisei & Sakigake (Japan): Studied the comet from greater distances
• ICE (USA): Observed from 28 million km away

These missions revealed that Halley's nucleus is a dark, peanut-shaped object about 15 km long and 8 km wide, composed of ice and dust - confirming Fred Whipple's "dirty snowball" hypothesis.

Cultural Impact

Halley's Comet has left an indelible mark on human culture:

• Italian artist Giotto di Bondone included it as the Star of Bethlehem in his 1305 fresco "Adoration of the Magi"
• Mark Twain was born during the 1835 appearance and correctly predicted he would die with its return in 1910
• The comet has inspired countless works of literature, music, and art throughout history
• It appears in numerous historical chronicles as an omen of significant events

Next Return: 2061

Halley's Comet will next reach perihelion on July 28, 2061. This return is expected to be particularly favorable for observers, as the comet will pass relatively close to Earth and be well-positioned for viewing from both hemispheres.

Future technology may allow for even more detailed study of the comet. Some scientists have proposed sample-return missions or even a long-duration rendezvous mission to accompany the comet through part of its orbit.