Great 1972 FireballIn the broad daylight of mid-afternoon, an asteroid measuring somewhere between 10 and 50 feet in diameter plows through Earth’s atmosphere over North America, creating a long-tailed fireball across the sky. Undetected before its close pass – only 35 miles from Earth’s surface – asteroid US19720810 skips off of the atmosphere and back into space, having lost half of its mass to the frictional heating of plummeting through the atmosphere. The spectacle lasts only a couple of minutes, and US19720810 will make another pass by the Earth in 1997 (though not at such a close distance).