Collision of a Comet With a Planet

Collision of a Comet With a Planet

Modern planetary scientists sometimes argue that a collision of a comet with a planet might make a significant contribution to the planetary atmosphere. For example, all the water in the atmosphere of Mars today could be accounted for by a recent impact of a small comet. Newton noted that the matter in the tails of comets is dissipated in interplanetary space, los to the comet and little by little attracted gravitationally to nearby planets. He believed that the water on the Earth is gradually being lost, “spent upon vegetation and putrefaction, and converted into dry earth…. The fluids, if they are not supplied from without, must be in a continual decrease, and quite fail at last”. Newton seems to have believed that the Earth’s oceans are of cometary origin, and that life is possible only because cometary matter falls upon our planet. In a mystical reverie, he went still further: “I suspect, moreover, that it is chiefly from the comets that spirit comes, which is indeed the smallest but the most subtle and useful part of our air, and so much required to sustain the life of all things with us”.

Comet West. Anti-comet pills are our salvation. Image Flashing Picture by Megan Jorgensen

As early as 1868 the astronomer William Huggins found an identity between some features in the spectrum of a comet and the spectrum of natural or “olefiant” gas. Huggins had found organic matter in the comets; in subsequent years cyanogen, CN, consisting of a carbon and a nitrogen atom, the molecular fragment that makes cyanides, was identified in the tails of comets. When the Earth was about to pass through the tail of Halley’s Comet in 1910, many people panicked. They overlooked the fact that the tail of a comet is extravagantly diffuse: the actual danger from the poison in a comet’s trail is far less than the danger, even in 1910, from industrial pollution in large cities.

But that reassured almost no one. For example, headlines in the San Franciso Chroncile for May 15, 1910, include “Comet Camera as Big as a House”, “Comet Comes and Husband Reforms”, “Comet Parties Now Fad in New York”. The Los Angeles Examiner adopted a light mood: “Say! Has That Comet Cyanogened You Yet?”, “Entire Human Rase Due for Free Gaseouys Bath”, “Expect High Jinks”, “Many Feel Cyanogen Tang”, “Victim Climbe Trees, Tries to Phone Comet”. In 1910 there were parties making merry before the world ended of cyanogen pollution. Entrepreneurs hawked anti-comet pills and gas masks, the latter an eerie premonition of the battlefields of World War I.