For those that are not familiar with some of our government acronyms - E.L.E. refers to an "Extinction Level Event".On March 23, 1989 an asteroid named 1989FC came to within 690,000 km, and was not discovered until after it had passed through the orbit of the Earth. Its size was estimated to be about 0.5 km. An impact of this mass would have released energy greater than that released in a nuclear war, and enough to cause a "Nuclear Winter Event". Although 690,000 km seems like a long distance, it translates to a miss of the Earth by only a few hours at orbital velocities.In other words - we may have come within hours of extinction.