Astronomers are predicting that the 2012 LZ1 asteroid will be visible tonight. If you lack the proper fancy equipment for such an adventure, you can also watch it online with SLOOH Space Camera. The site has a handy count-down so you won't miss out and can build anticipation of the big event.
2012 LZ1 is similar in size to the 2005 YU55 that came dangerously close to Earth last November. How close is “dangerously close?” Near-Earth asteroids generally have to be at least 500 feet wide and come within 4.65 million miles of our planet to be classified as potentially hazardous.
Astronomers think 2012 LZ1 is about 1,650 feet wide, which is more than 10 football fields long, and will come within 14 lunar distances of Earth Thursday evening. That’s not close enough to be dangerous, but is close enough to be classified as a near-earth event.
This video is of a similar near-earth asteroid fly-by: