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Did A Comet Trigger The Great Chicago Fire?
Alien54 writes "Perhaps it was not Mrs. O'Leary's cow kicking over a lantern that sparked the Great Chicago Fire of 1871, which destroyed the downtown area and claimed 300 lives. New research lends credence to an alternative explanation: The fire, along with less-publicized and even more deadly blazes the same night in upstate Wisconsin and Michigan, was the result of a comet fragment crashing into Earth's atmosphere."
The interesting thing about objects that enter the atmosphere is that the rate at which the outer shell ablates away from friction exceeds the rate at which heat conducts through the material. If a chunk of such a comet were to reach the surface without breaking up during the process and land nearby, you could immediately find it see (and touch if you really are up for touching *really* *really* cold stuff) that the object was still frozen.
Project Steve
It is worth noting that Chicago fire was not typical in many ways. The fire was unusually hot. One factory that burned melted pig iron 200 feet away. Buildings burned on a timescale of minutes, it was reported. Unlike your normal everyday fire, nothing was left half-burned. It also burned INTO the wind, which is contrary for usual fires. A guy in the New York Evening Post wrote, "buildings far beyond the line of fire, and in no contact with it, burst into flames from the interior". The other facts I noted may be referenced in The Annual Record of Science and Industry for1876, pg. 84 and History of the Great Conflagration Sheahan & Upton, Chicago, Illinois, 1871