In case you didn't have enough to worry about, NASA says there are over 1400 Potentially Hazardous Asteroids (PHAs) orbiting our sun. If it makes you feel any better, this visualisation of their orbits is kinda pretty. The beauty of impending destruction.
If you're really wondering, Asteroids fall into the PHA category when they get relatively close to our planet's orbit, but in NASA speak "relatively close" means within 4.7 million miles. PHAs are big enough to cause unprecedented damage if they hit land, or massive tsunamis if they hit the ocean. Thankfully, they only do so about once every 10,000 years. And NASA says "none of these PHAs is a worrisome threat over the next hundred years."
If you just need to satisfy your morbid curiosity, you can read more about each one of those asteroids here on NASA's Near Earth Object database. Or just look at the pretty pictures and pray NASA comes up with something better than sending oil drillers into space to save us from one of these things. [NASA Photojournal via PopSci]
Image by NASA