A few days ago, NASA reported that Asteroid 2004 MN4, discovered back in June, had a tiny chance of hitting the Earth on April 13, 2029, but considered it extremely unlikely. Well, on Friday they actually upgraded the chance on the Torino scale from level 2 to level 4. It's still in the Yellow part of the scale, so all that means is an Elevated threat of asteroid attack.
Am I worried? Not at all. Chances are very likely that within the next few weeks, astronomers will work out the orbit precisely and discover that the asteroid will miss the Earth completely. And Torino Yellow 4 refers to a chance of impact at only about 1%. From NASA's own press release:
"2004 MN4 is now being tracked very carefully by many astronomers around the world, and we continue to update our risk analysis for this object. Today's impact monitoring results indicate that the impact probability for April 13, 2029 has risen to about 1.6%, which for an object of this size corresponds to a rating of 4 on the ten-point Torino Scale. Nevertheless, the odds against impact are still high, about 60 to 1, meaning that there is a better than 98% chance that new data in the coming days, weeks, and months will rule out any possibility of impact in 2029."
Furthermore, if the asteroid is shown to be a real threat, we've already got people working on trying to deflect an asteroid by the year 2015. So again, I'm not worried.
But...the news does emphasize the need for the entire human race to take the threat of asteroid collision seriously. As Larry Niven is fond of saying, the dinosaurs died out because they didn't have a space program.
Articles and webpages of interest:
The Torino scale can be found here
Asteroid has 1-in-60ish chance of Earth hit (USA Today)
Former Astronaut, Engineers Hope to Deflect Asteroid (VOA)