Phil Plait, astronomer, lecturer, and blogger at Bad Astonomy gives a humorous and informative talk about asteroid impacts both in the past and in the future. He touches on the asteroid that wiped out the dinosaurs 65 million years ago, and the 50 meter-wide asteroid that created Meteor Crater in the Arizona desert 50,000 years ago, and the rocky bolide that exploded with the force of 1000 atomic bombs above the Tunguska river region in Siberia in 1908. Each impacted with Earth, and lucky for us, they all took place safely in the past. But you know it’s bound to happen again. It’s not a question of if, but one of when. And when could be sooner than you think. Plait ratchets up his talk’s anxiety level with the information that an asteroid discovered in 2004 and known as Apophis is headed toward Earth. This thing isn’t anywhere as huge as the 6-mile wide space rock that ended the reign of the dinosaurs, but at over 250 meters across it could still do some serious damage.
In 2029, Apophis will pass so close to Earth it will come inside the orbit of some of our weather satellites. It won’t strike our planet at that time but if it manages to pass through a small kidney-shaped region in known as a gravitational keyhole, Earth’s pull would redirect Apophis orbit into one that would set it on a path of collision with us the next time it comes around on April 13, 2036. Sure the odds are slim everything will actually line up right for this to happen, but Plait sees it as an opportunity for us to learn how to deal with such events. We know impacts happened in the past, and we can assume they'll continue to happen in the future. Apophis is a good example of that. So it makes sense to start planning on how we can defend against such an event. Scientists from organization such as the B612 Foundation and NASA are already trying to raise public awareness of the dangers asteroids and other near Earth objects may pose to the future of our planet. And Plait explains some interesting counter offensives already being considered. It won't be an easy task but it's probably one that needs planning just in case. Besides, look at what could happen if we don't. It's a no-brainer.