Disappointed at the lack of end o’ the world action today? Here are few items that aren’t world-enders but would cause considerable trouble.
Apophis, an asteroid approximately 270 meters long, is currently given 1 in 250,000 chance of striking the earth on April 13, 2036 with the effect of a 510 megaton explosion. (Note: biggest H-bomb ever exploded was 50 megatons*). After a close approach of Apophis next month on January 9, and another close approach in 2029, there should be more accurate measurements of its chances of actually colliding with us.
Asteroid 2007 VK184, approximately 130 meters long, is currently given a 1 in 1,820 chance of hitting the Earth on June 3, 2048 with the force of 146 megatons. A close approach in 2014 will allow for observation and a more accurate prediction.
These are pretty long odds, and are likely to get longer the more we know. But consider that there are unpredictable factors that can affect an asteroid’s trajectory, like its spin, the way it reflects or absorbs sunlight, and gravitational interactions with other asteroids. Also, about 90% of near-earth asteroids that are more than one kilometer in size have been tracked and there is no immediate danger from them, leaving a 10% fear factor. There’s more: smaller asteroids that might, say, only destroy a city or a region, have not been tracked yet. Keep your eyes out for these.
*Tsar Bomba (1961) created a fireball five miles in diameter and a mushroom cloud 40 miles high.