Asteroid Detection

It is widely believed that a large asteroid collision was responsible for the event that caused dinosaurs to suddenly go extinct after ruling the planet for millions of years.  They were not capable of foreseeing the event, but humans are.  So we spend time, effort, and money scanning the sky for these dangerous objects.

Even so, recently an asteroid exploded in an air-burst above the city of Chelyabinsk, Russia.  The asteroid wasn't detected until it slammed into the atmosphere at a speed of tens of kilometers/second.

I recently watched this fascinating video about the tremendous difficulty of detecting earth-crossing asteroids, and thought I'd share it.

 

Now look at the soup of asteroids we have discovered that we are swimming in.

 

In many ways it seems amazing that we aren't struck by house-sized asteroids on a daily basis.

If you are inclined, you can go to this website.  Scroll down far enough, and it will list the *known* near-earth asteroids as they approach earth's orbit, and the expected closest approach in Lunar Distances.  The moon is 1 Lunar Distance away - roughly 25,000 miles.  

Fun fact:  Many of the asteroid names begin with the year of discovery.  A startling number of them are discovered right before they would have hit the earth if they were on a collision course.  When I started visiting the spaceweather.com website, there were just over 600 known asteroids.  As of this blog post, there are 2018 of them.