updated the projected size of the meteor from 49ft (15m) to 55ft (17m) and from 7,000 to 10,000 tons. It was believed to enter the atmosphere 6,500 miles away above Alaska travelling at 33,000mph and took 32 seconds for it to disintegrate in Earth’s atmosphere at an altitude of 13 to 31 miles above the surface, causing an explosion equivalent to a 500 kiloton nuclear warhead. Approximately 1,200 people were injured, mostly from the glass and other damage to over 4,000 buildings that was caused by the shockwave of the explosion. This type of event is considered a once in a hundred year event and the largest since the 130ft (40m) Tunguska meteorite event which occurred in Russia in 1908.
There is good news and bad news about this event. Let’s start with the bad news. According to the WISE asteroid survey there are roughly 4,700 plus or minus 1,500 Potentially Hazardous Asteroids with diameters above 330ft (100m), of which only a small fraction of 20 to 30 percent have been found (shown on left as orange dots, blue dots are smaller asteroids around the green orbit of Earth). Although these asteroids need only pass within 5,000,000 miles of Earth to be considered hazardous, many of these asteroids pass much closer, even passing between the Earth and the Moon. An asteroid of this size would cause major destruction to the Earth that would be considered a Global Catastrophe and may cause shifts in climate plus possible tectonic disruptions that could cause extinctions of anywhere from a few species to almost all life on Earth. These big, bad asteroids are out there, as shown in Hollywood films like “Armageddon” and they do pass by close to Earth with their orbits occasionally being changed by passing by massive objects like the Earth / Moon system or collisions with other large asteroids. We have not spotted them all and events like the Chelyabinsk meteor show that sometimes we don’t see them coming until they have already entered the atmosphere and there is nothing at all that we can do about them. There could be a killer asteroid headed right for your house as you read this article.
OK, enough doom and gloom. There is plenty of good news to go around. While there are still about 50 people hospitalized from the Chalyabinsk meteor with minor injuries, nobody has died from this incident. Broken windows and minor building damage can easily be repaired. It is thought that the remnants of the mostly disintegrated meteor landed safely in a frozen lake, as most meteors do land far away from populated areas causing little to no damage to anything man made. Possibly the best news is that this event has brought world attention to a problem that could possibly be solved. Tracking asteroids costs money that many think is a frivolous waste. By showing that asteroids do pose a real threat, investors, donations, and government funds can be allocated to track and find ways to prevent such things from happening in the future. Several countries have expressed desires not only to shift orbits of asteroids to protect Earth but also to visit, mine, and colonize asteroids. The more funding for projects like these, the more information and experience we will receive about the asteroids that may someday threaten us. With enough time and experience, it is possible to protect the Earth from all major asteroid impacts while at the same time mining them for resources and using them as bases for exploration.
There isn’t an asteroid bearing down on your house right now. These events occur very infrequently and there is no need for panic. At the same time, we can’t just ignore what is going on in space. It may be difficult to understand why we spend money launching things into space when we could let people pay less taxes or have better education for our kids. If we were alone on our planet with nothing else out there to threaten us, that might be a good idea but we have to remember that we are on a tiny planet with a huge amount of dangerous threats from space that aren’t going to wait for us to get our act together. Russia’s President, Vladimir Putin, has already called upon the U.S. and Europe to join them and China in developing an Anti-Asteroid Defense System to prevent disasters like this from happening in the future. Perhaps this could be a venture that might unite traditionally independent nations against the common enemy of dangerous space rocks. There are going to be more meteorites causing damage and some people might get hurt but hopefully this event has awakened us to the perils which all humans face so that we can learn how to defend ourselves against this deadly threat.