Asteroid stories circulating the internet have rekindled fears that the Deep Impact plot will play out in real life. Based on NASA projections, there is indeed a chance that such an asteroid will impact Earth this year.
It is 1 in 2,518,072
This number is derived from NASA calculations of the likelihood of a strike by any one of the six substantial Near-Earth Objects (NEOs) whose current course could intersect our planet's the next year. The most likely of the bunch has a 1 in 4,000,000 chance of impacting Earth. In other words, there's a 99.999975% chance the thing will miss the planet, let along you.
What do these numbers mean? Here's some context. Based on National Safety Council data, the chances are less that you will be killed by an asteroid than by the following:
Motor vehicle accident: 1 in 6,539
Exposure to noxious substances: 1 in 12,554
Assault by firearm: 1 in 24,005
Accidental drowning: 1 in 82,777
Exposure to smoke, fire or flames: 1 in 92,745
Exposure to forces of nature (lightning, flood, storms, etc.): 1 in 136,075
Falling out of bed or off other furniture: 1 in 329,819
Choking on food: 1 in 343,179
Air and space transport accidents: 1 in 502,554
Exposure to electric current, radiation, temperature, and pressure: 1 in 705,969
Being bitten, stung or crushed by another person or animal: 1 in 1,841,659
Conclusion: There's not much reason to worry about asteroids. But be careful with your choice of space travel provider.
Related Link: 7 Grams of Lead