Near-Earth asteroid 2011 MD was found by the LINEAR project. Asteroids stick out against the field of stars because they move through the sky at a different rate. LINEAR photographs patches of the sky five times a night.
Nothing’s going to strike us. The asteroid will be about 7,500 miles away Monday at 9:30 AM. That’s still awful close.
Scientists at NASA/JPL’s Near-Earth Object Program Office says something like this happens every six years or so.