You may be interested to know that at 8:45 Eastern Time a hunk of rock the size of a ten story building will go whizzing past Earth at about 18,000 MPH. This asteroid, 2009 DD45, will pass a mere 45,000 miles away from us.
At that speed, it could reach Earth in just 3 hours from the point of closest approach -- if it had a slightly different trajectory.
Fortunately, it is going to go past us. Unfortunately, we won't be able to see it. Fortunately, DD45 is only dozens of meters across. By comparison, the asteroid that wiped out the dinosaurs was several kilometers across. If DD45 did hit us, it would be spectacular but it wouldn't wipe out all life on Earth. Unfortunately, there are plenty of bigger pieces of rock whizzing around out there with our name on it. That's a problem.
I point this out because we are going to be treated to a lot of noise over the next several days about the "threat" from Iran. Unlike that "threat," the rock with our name on it really could wipe us out faster than you can say "Cretaceous/Tertiary extinction event." It would be nice if we could get our priorities straight before the party's over.