Well, not for another 10,000 years or so.
Back in the summer of 1998, Hollywood spawned two asteroid movies, Armageddon, and Deep Impact. In both of these movies, astronomers discover an Earth-bound object, and must destroy or move it to save the human race. While those movies were fictional, the chance of a large asteroid hitting the Earth is small, but real.
In a study published in the journal Nature, scientists simulated, with computers, what would happen if an asteroid were hit by a force equivalent to a 17-kiloton bomb. Their subject was the 1-mile wide asteroid Castalia. They projected what would happen if it were hit by a 50-foot-wide asteroid traveling at 11,000 mph. If Castalia were made of solid rock, it would've been blown to many small pieces, but the 90% of the pieces would remain on the same path. In a different situation, assuming that Castalia is really two large pieces, the piece hit by the projectile would be shattered into little bits, which would be drawn towards the other, almost unaffected half. In a third scenario, assuming that this asteroid is a group of many large rocks, the one rock that was hit exploded, but the others were unaffected. In all three situations, if the asteroid were headed towards Earth, it would still hit. Only if the object were detected decades before it came close to Earth would such a minute course adjustment steer it clear of us.
What implications does this have? Well, it casts doubt on the chances of using nuclear warheads to successfully deviate an Earth-bound object. It also points out a possible need to rethink our priorities in space. $3 million a year in NASA's budget is allocated to detecting possible doomsday asteroids. To compare, the entire NASA budget is 13.6 billion dollars. It is possible to track most large objects that will cross our orbit, but in order for any effective action to be taken against an Earth-bound object, it must be detected early. Keep watching the sky.
Hannibal Courier Post
Destroying asteroids may be difficult task harder than it looks in the movies:
Do what you will with this document. Feel free to plagiarize. No, seriously, I mean it.
Credit to fuzzy and blue for catching my spelling error.