Well, thanks to Russia’s corrupt cops and dodgy insurance, we have an abundance of footage of the most damaging (and spectacular) meteorite impact in at least a century:
Inevitably, there is a bigger, more damaging asteroid out there with our name on it, and sooner or later one will hit a major city.
While there is some dark amusement in certain political circles at conservatives suggesting that funding for climate change mitigation be cut to pay for asteroid defence, that shouldn’t preclude some more serious consideration of whether we can or should be doing anything about the risk.
The Chelybinsk meteor strikes, according to Wikipedia, were caused by an object around 17 metres in diameter. According to our current estimates, something around that size collides with the Earth every few decades. While it’s the only one to have caused extensive injuries to people, it’s not the largest in recorded history – that honour goes to the Tunguska impact, also in Siberia, back in 1908. While they are not common, therefore, they do occur, and they do pose some risk. Were something of this magnitude to occur directly over a major city, of course, it would be a catastrophe.
Larger collisions with asteroids and comets capable of causing planet-wide devastation do and will occur, but they are much rarer events. The odds of us facing one within any of our lifetimes are very small.
In the more likely scenario of a relatively small object on a collision course with Earth, there are any number of strategies that could be used to deflect it. Setting off nuclear weapons on or near such an object is the favourite of sci-fi writers, but there are more subtle strategies. Again, Wikipedia summarizes a few – ramming it with kinetic impacts, attaching some kind of propulsion system to the asteroid itself, a “gravitational tug”. If an object is detected early enough, deflection is actually pretty easy. And, furthermore, even if deflection wasn’t achieved, early warning – just a few days or weeks – along with a precise trajectory would be enough to save people from a “city-killer” by evacuating.
So – how much would it cost to build a system that gave us a good chance of detecting “city-killer” asteroids in enough time to at least evacuate? Not a lot. In fact, there is a partial, prototype system under construction right now at the University of Hawaii. This one wouldn’t provide enough warning for deflection, but it does provide enough warning for evacuation of between a few days and a few weeks, and the program cost is around 5 million USD for five years.
However, there is one rather important limitation of this system as far as Australians are concerned – it doesn’t cover much of the southern sky.
A million dollars a year to look for city killer asteroids? Sounds like a reasonable use of money to me, particularly if other Southern Hemisphere countries could be convinced to share the cost.