First, let's put this into perspective. This Russian meteor was a bolide, or in layman's terms an air-burst, meaning most of it broke up on impact with Earth's atmosphere. It was reportedly about 10 tons, or roughly the size of a dump truck, and according to NASA, is totally unrelated to the asteroid 2012 DA14 passing through Earth's atmosphere today. It was traveling in the opposite direction, and thus was not a part of any debris traveling in the asteroid's wake. It was also traveling at 10-20 miles a second.
It exploded over the city of Chelyabinsk, east of the Ural Mountains, and just over a thousand miles due east of Moscow. It's a city of about 1.1 million people, and almost a thousand of them so far have sought medical attention as a result of the meteor, mostly those injured by shattered glass and building debris from the sonic boom.
For a better understanding of the effects of a bolide explosion, watch this next video. I recommend cranking your speakers to full volume to get the full effect. (No, don't do that - it's friggin' loud! Understandably, it also contains a lot of swearing in Russian.)
This pales in comparison to the meteor that struck the Tunguska area of Siberia in 1908. That one was the largest recorded impact event in history, and struck with the force of a 5.0 earthquake as measured on the Richter scale. The Tunguska meteor is also largely considered to be a bolide, meaning most of it didn't even hit the ground. Even so, it flattened everything within an area 830 square miles wide, with a blast estimated at between 10-15 megatons of TNT, or about 1,000 times the size of the atomic bomb dropped on Hiroshima.
So how did we not see this most recent one coming? How did it escape attention until it impacted our atmosphere, far too late for any warnings or advisories? Well, scientists say size has a lot to do with it. Space is a pretty big place to look for something the size of a dump truck. That, and if it's coming at us from the direction of the sun, rather than from dark space, it could be very difficult to see even if we were looking for it.
These events of course fuel our imagination, and propelled by the media's infatuation with hyperbole, can lend themselves to some pretty interesting speculation. It's not hard to imagine the chaos and destruction involved with a meteor or series of meteors that actually impact the earth.
The more of these events that happen, and are inevitably filmed and recorded from every possible angle, the more we understand them. We see firsthand accounts of their destruction, and hear how they affected common people.
Just imagine for a moment that the 2012 DA14 asteroid that passes by Earth today was actually on a trajectory to impact Earth. The Russian meteor earlier was a dump truck-sized rock of about 10 tons; Astroid 2012 DA14 is about 190,000 tons, and 160 feet long. That seems gigantic, but the size and speed of it would put it lower than the lowest estimates of the one that struck over Tunguska in 1908, with the kinetic energy of only about 3.5 megatons of TNT.
So we're safe. For now. But there's still hope, doomsdayers. Asteroids of this size are expected to hit Earth about every 1,200 years. Better get your affairs in order. The year 3108 is just around the corner!