Here are some facts about Halley’s Comet.
- Halley’s Comet is the best known of the short period comets and last appeared in 1986. A short period comet is one that completes its orbit in less than 200 years.
- Comets consist of a mixture of frozen gases and solid materials and are usually irregular in shape. Halley’s comet contains water, iron, ammonia, sodium and carbon monoxide.
- The English astronomer Edmond Halley officially calculated its orbit in 1705. However, the comet was seen and documented by the ancient Babylonians and Chinese, as far back as 240 BC.
- In 87 BC, an Armenian king had an image of the comet engraved on his coins.
- Some people believe that the ‘star’ the Three Wise Men followed to find Jesus was actually Halley’s Comet.
- The comet was seen over England in 1066 and it was believed to be a bad omen. It is shown on the famous Bayeux Tapestry, which documents the Battle of Hastings (which saw William the Conqueror and the Normans defeat the Saxons led by Harold Godwinson.)
- In 1456, the Turkish army attacking Belgrade saw the comet and were afraid. They described it as a long sword or the tail of a dragon.
- The writer Mark Twain was born the same year the comet appeared, 1835. He predicted he would die when it next appeared and died the year after that happened, in 1910.
- The orbital period of the comet is about 75 years, meaning it can be seen about every 75 years. It is next scheduled to appear in the sky and be visible from earth in 2061.
- The orbit of the comet is opposite to the orbits taken by the planets, making Halley’s Comet retrograde. The exact orbit time can be affected by the gravity of other celestial bodies.
- It is estimated that Halley’s Comet is about 4.5 billion years old. It is shaped rather like a peanut and is about 15 km long and between 7 km and 10 km wide.
