An asteroid did not hit the Earth today.
An object known as 2010 AL30 was discovered by NASA on Monday. Today at 7:47 a.m. ET, it passed (will pass for those of you who were up early) by us with 80,000 miles to spare.
However, being only 10 meters across, it would have posed little danger even if it were to hit us. Most likely, it would have disintegrated in the atmosphere.
There is some possibility that 2010 AL30 is a manmade object, perhaps a spent rocket booster, or some other kind of space junk. However, the trajectory of the object suggests that it is indeed a naturally occurring asteroid.
For an idea of how close a miss this is, look here. The Earth is at one end, the moon at the other, and the yellow arrow indicates where 2010 AL30 passed by. Click to enlarge.