The Pan-STARRS PS1 system just recently spotted an asteroid due to come within four million miles of Earth. The discovery has revealed just how sensitive and accurate the tracking system truly is, far beyond what was previously possible with other systems of its kind. And with the Pan-STARRS PS1 system scanning the skies, we can rest a little easier. But even this system tracked a distant and potentially hazardous asteroid only one month before it neared Earth and largely by chance. Is even this system not sensitive enough to protect major cities from asteroid falls?
Of course the Pan-STARRS PS1 system is only one of several including amateur astronomers who scan the skies in an attempt to get a clear image of what incoming asteroids will look like. But with a new system such as this, asteroids will be reaching the news that would have gone by entirely unnoticed before. And the definition of the term ‘potentially hazardous’ should be examined to ensure it is not overused. The 2010 ST3 detected on September 15th of this year is only 150 meters across. While the asteroid could wipe out several city blocks if it hit the wrong area of the country with its incredibly fast descent, it will not be ending civilization as we know it by any means.
But how dangerous is an asteroid impact big enough to cause massive devastation on Earth? Astronomers and officials from NASA have suggested the chances of a planet killing asteroid hitting Earth in our lifetime is slim, and far less likely than the destruction of civilization by nuclear war. Even virulent superviruses are considered largely more dangerous than an asteroid impact (and even they are fairly low on the list). But the real danger, as humans expand more and more across the globe is the possibility of a smaller asteroid smashing into an area and changing the landscape or triggering a chain reaction that could affect the rest of the world.
For example, the Yellowstone Caldera is an area 34 miles by 45 miles in diameter. If an asteroid of any appreciable size were to impact near the Caldera, is it possible it could erupt and cause a massive eruption the likes of which have not been seen for a hundred thousand years? Of course because such an eruption has not taken place in over a hundred thousand years, this only suggests how unlikely it is. But it is an example of a place even a small asteroid could create a big problem. New York, a city with an area of around 7,000 square miles is home to almost twenty million people. An asteroid impact here, even a small one could be the most devastating event in the history of the United States.
The simple fact of the matter is, cities and towns cover approximately 0.29% of the planet’s surface. If an asteroid were to impact the Earth’s surface, the chance of a one mile blast hitting a city at random is extremely slim unless the blast itself was huge.