Ninety nine years ago today, the Earth passed through the tail of Halley's comet. This must have been a spectacular event and it was the first time that the comet was spotted on camera. There was also considerable panic amongst the Earth's population, as many feared the tail of the comet contained noxious gases, particularly cyanide. Another comet, known as the Great Daylight Comet of 1910, also passed within Earth's range that year, and was much more spectacular than Halley's. Halley's comet appears every 76 years or so and was last seen in 1986 and will reappear again in 2061. For more information on Edmund Halley see a previous blog post on his life and works by clicking here.