837 A.D.

On this date, 837 AD, Halley's Comet reached it's 15th perihelion (recorded) in its ongoing journey between the inner and outer solar system. The first recorded visit of Halley's Comet to the inner solar system took place at 240 BC. The most recent visit took place in 1986. The next will take place in 2061 and I won't be alive to see it. The comet returns every 75 to 76 years.

The 837 passage was very close to earth (about 3 million miles) and the tail may have stretched half-way across the night sky. Astronomers in China, Germany, Japan and the Middle East recoded the event. It created panic in Christendom portending the end of the world.

Several hundred years later in 1066, it passed close as well. The Bayeaux Tapestry recorded it as a fiery star that dominated the night sky. It was held as a bad omen, confirmed later in the year when Harold Godwinson lost England to Norman invaders at the Battle of Hastings. (It was a good omen for William the Conquerer, who won)