One of the most famous comets is Halley’s Comet, the only known short-period comet that is regularly visible to the naked eye from Earth. The comet was named after the English astronomer Edmond Halley (1656-1742) because he managed to calculate its orbit. Halley calculated that the comet will be visible once again at the end of 1758. He was right, but Halley was dead when the comet made its appearance on the sky.
Regular appearances on the sky
A comet’s appearance on the sky was seen as a bringer of destruction and diseases for many ancient cultures. Starting with sixteenth century, comets were considered bad omens of deaths of kings or noblemen or even attacks by heavenly beings. It is clear that comets have been observed on the sky for thousands of years.
However, there were a few people who had the courage to step outside of the box. Edmond Halley was one of them. He managed to gather most of the records found in history (also from people who step outside of the box) about the appearance of the comets and other celestial objects. He studied the comets for several years and when Newton published his book “Principia” Halley managed to calculate the Halley’s Comet trajectory.
The first mention of the Halley’s Comet was in 611 BC in China, but is uncertain. Also a comet was recorded in ancient Greece between 468-466 BC, and the details of the comet suggest that it was Halley. As far as we know, the first certain appearance of Halley’s Comet in the historical records is from the Chinese chronicle “Records of the Grand Historian” from 240 BC. The interesting fact is that the only ancient record of Halley’s comet that still exists is the Babylonian tables from 164 BC (owned by the British Museum).
If we look back in history, the appearance of Halley’s Comet on the sky is mentioned almost every 70-80 years.
The approach in 1910 was notable for at least two reasons: it was the first approach of which photographs exist and the first for which scientific data were recorded. Even more, Halley’s Comet was especially close to the Earth and because of the media coverage back then it created curiosity, but also fear. On May 19, the comet’s long tail was carried on Earth’s orbit for six hours, earning the story on the day’s banner headline in The New York Times.
Despite the fact that most people understood the phenomenon, there were reporters who have fuelled the fears that the end of the world was imminent: the comet’s tails were poisonous. However, the studies spectroscopic studies of comet tails revealed that among the organic molecules, there was also cyanide.
This was the trigger of speculation that people would be asphyxiated by the cyanide molecules. So, people took it further: they panicked and bought gas masks, “anti-comet pills” and “anti-comet umbrellas”. In some places from the Earth, on certain days many people did not even drink water as it was rumored the cyanide was in it.
On the other hand, other astronomers explained that the gas is too diffuse and the Earth will not feel any effects. “Somehow” the Earth survived once again without scars passing through a small part of the comet’s tail.
When we look in the sky we see the past. The light from the star that reaches our retina has travelled for millions of years and probably the star is already gone. The Halley’s Comet is a memory of our ancestors.
Facts about Halley’s Comet
- The comet also troubled the Xinhai Revolution which would end the last dynasty in 1911;
- The comet takes 75-76 years to complete an orbit around the Sun;
- Halley’s Comet is darker than coal and reflects 4% of the sunlight it receives, it shines brightly only when it is close enough to the Sun;
- Is shaped like a peanut and is about 15 km long and 8 km wide and thick;
- Mark Twain’s birth and death “brought” the Haley’s Comet in 1835 and 1910;
- The last apparition was in 1986, which was the least favorable on record;
- The next return is expected in July 28, 2061;