April 13, 2029

Twenty one years from today, we'll know for sure if 99942 Apophis—a meteor a quarter of a kilometer wide—is going to collide with Earth in 2036.

To paraphrase the above article, if 99942 Apophis hits Earth, it would release more than 100,000 times the energy of the Hiroshima explosion with a blast affecting thousands of square kilometers: everyone on Earth would see the dust released into the atmosphere. (I actually wrote about Apophis some time ago.)

Sadly, we cannot wait until 2028 to act. If we did, it would already be too late. To design and test the necessary equipment to deflect an asteroid takes decades. And this should be a global mission because the potential consequences would affect everyone on Earth. Most scientists are waiting until 2013 to observe Apophis' pass and collect further data on its trajectory. After that, they'll know a lot more.

Below is the "path of risk" of the meteor's possible impact, which would mean 10 million deaths in Central and South America alone, not including the gargantuan tsunamis sure to hit North America's West Coast:


By 2029, Apophis will pass so close to Earth as to be visible to the naked eye. In fact, it will even pass beneath our geosynchronous satellites. If we're lucky, Apophis will miss a 600 square meter "keyhole"—if it passes through that keyhole, Earth's gravitational pull would alter Apophis' trajectory enough to swing back and hit Earth eight years later.

And if luck has anything to do with it, or if you're superstitious at all, you really don't want to know which day of the week April 13th, 2029 is.