Hildebrand says the meteor could likely be seen up to 700 kilometres away, into the northern United States. It contained about a tenth of a kiloton of energy when it entered the earth's atmosphere, equal to 100 tons of the chemical explosive TNT. “It would be something like a billion-watt light bulb.” Besides sonic boom sounds, he said witnesses also reported hearing hissing or crackling noises like frying bacon. Fireballs can act as radio transmitters, Mr. Hildebrand said, causing odd sounds.







