Halley's Comet in May 1910, coloured image. This appearance of Halley's Comet is the first for which photographs exist. The approach was relatively close, and on 18 May the Earth passed through the comet's tail (red and yellow). Despite astronomers stating that there would be no noticeable effect, sensational and incorrect reports predicted global cyanide poisoning. Halley's Comet is the only naked-eye comet certain to return within a human lifetime (every 75 years or so). It derives its name from the English astronomer Edmond Halley (1656-1742) who computed its orbit. The comet has been observed since at least 240 BC.