zlacker

>>Brajes+(OP)
"but this one was unique because it was first detected by scientists roughly three hours before impact — only the eighth time that researchers have spotted one of these space rocks before it hit."

Maybe I did not read close enough but how is it "first"?

>>tocs3+QV
"first detected", meaning this asteroid wasn't detected before. They don't claim anything about earlier detection of other asteroids.

>>kvdvee+5X
They do claim that this asteroid is somehow unique.

The best I can guess is that 8 of these have been detected before they hit, but only this one was detected 3 hours before it did. The rest must have been detected with longer or shorter times before impact (presumably longer).

Alternatively, perhaps it is unique because of its small size, at only 1 meter.