When Comet Halley approached Earth in 1910, with the use of a scientific process called spectroscopy French astronomer Camille Flammarion detected cyanide gas in its tail that incited real panic. Flammarion was quoted as saying the gas could “impregnate the atmosphere and possibly snuff out all life on the planet.” His theory got very little support in the scientific world, but it was published in the New York Times.
Panic ensued. People were buying gas masks, sealing up their homes, and preparing for the end of the world. Scammers took advantage of the mass hysteria and began selling sugar pills marketed as “anti-comet pills.”
The comet came and went without incident, save for the death of King Edward VII which only those still holding onto the old superstitions linked to the comet.
It has made one more visit since then, this time in 1986 and scientists were prepared with new technology which allowed the release of unmanned space probes to fly by the comet, sending back images and providing the closest look at the comet to date.
Halley’s Comet last appeared in 1986. Next appearance will be July 28th 2061.
Two photos attached: First (Library of Congress – 1910) Second (NASA)