According to the latest data from NASA, an asteroid has been detected and tracked with that chance of hitting the Earth on that date.
If it happens, the impact would be the equivalent of an explosion of about 2,200 Megatonnes of TNT.
This is the first time that any asteroid has been detected with a Torino Scale Threat Rating of greater than 1. Until the latest measurements earlier today, the rating was 2. It's now 4.
Here's the definition of what Torino 4 means :
A close encounter, with 1% or greater chance of a collision capable of causing regional devastation.Note: this is not a "Dinosaur Killer", and anyone on a different continent from the impact will likely only be aware of it from news broadcasts, spacetacular sunsets, and a few slightly colder than normal seasons - much the same as if a number of major volcanos let rip simultaneously.
On the other hand, anyone within a hundred miles of the impact would likely have a tough time. The crater will be nearly 4 miles across. Anyone within 50 miles will get 200 mph winds, a bombardment of rocks ranging from golfball size to football size, and the equivalent effects of a magnitude 6.8 earthquake. (Data from the Impact Effects Calculator, with parameters of Velocity 12.59 km/sec, 0.44 km diameter size, Dense Rock, 45 degree impact angle).
More calculations based on earlier data over at A Voyage to Arcturus
Looks like I was ten days early with my post on this subject.. the point is though, that even if this one doesn't hit, nor the next, nor the next, eventually one is going to, and it may not be nearly so minor.
The newly created NASA Impact Risk page has a table that puts the thing into perspective. They also provide a useful visualisation tool, a Java applet that gives a simulation of the asteroid's orbit.
UPDATE: Jay Manifold at A Voyage to Arcturus now has more calculations and analysis based on the latest data. If you want the numbers, he's the man.
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