The 1910 Return of Halley's Comet

Halley's Comet is one of the best known comets, returning regularly enough to be known but with such long gaps between that seeing it is a chance that comes only once a lifetime. The last appearance was in 1986, and the next will not be until 2061. This makes every appearance of the elusive comet memorable, but one of the best known returns was in 1910, which was notable both because it was studied in some detail for the first time and because it caused conflicted feelings of fear and excitement among the world's population.

The returning comet first became visible on strong telescopes in August of 1909, and the recordings of these first viewings became the first ever photographs of the comet. At that point, the comet was easily 480 million miles (770 million km) away from Earth. It was a milestone in the study of comets in many ways, as more powerful telescopes and more advanced techniques were able to learn more than had ever been revealed about comets before. Through examination of the comet, scientists were able to see how it reflected light and decipher some of the composition of the tails. It was an amazing opportunity for astronomy.

What's more, this particular pass of the comet was an especially close one. The comet came within 14 million miles (21 million km) of Earth at one point during its May approach, and Earth briefly passed through the tail of the comet. This, of course, was amazing for scientists, allowing them to study many details of the comet ‘up close' as it were. The close pass was reportedly spectacular in the sky, the comet easily visible.

The downside of this close pass and the new observations made was that a panic briefly overtook much of the world's population. Scientists had noticed a poisonous gas known as cyanogen that was present in the composition of the tail, and while they assured the public that the gas would be much too diffuse to have any effect during Earth's pass through the tail, many people still panicked and assumed the worst. In addition, the comet was connected to several events that it could not possibly have caused, such as the death of King Edward VII in England and the death of Mark Twain. This brief hysteria faded when the Earth passed through the comet's tail without problems, but many people were coerced into buying expensive comet protections or otherwise suffered from the panic.

Still, despite this mar on the event, the 1910 return was still spectacular, lighting up the skies and providing new knowledge on Halley's Comet and others of its kin. This one-time opportunity was not wasted by observers or by scientists, and many records of the event still preserve its awe-inspiring nature. Hopefully by 2061 scientists will have still more tools with which to discover more about our infrequent visitor.