Invading Our Space

As of October 28, the newly discovered asteroid 2013 TV135 – which now occupies the top slot on NASA’s near-earth object watch list – has a 1-in-28,000 chance of striking Earth. While Eric Holthaus assures us that “we are almost assuredly safe from this errant geological space wanderer,” he nevertheless wonders what a direct hit would look like:

According to the Earth Impacts Effects Program, a joint project of Imperial College London and Purdue University, 2013 TV135 would carry the energy of about 3,300 megatons of TNT if it were to strike. That’s roughly equivalent to 60 percent of the world’s remaining nuclear weapons detonated at the same time, in the same place. The result would surely be impressive:

The crater would be about twice the width of Manhattan, and about as deep as the newly constructed Freedom Tower in New York is tall. More than one hundred million cubic meters of rock would be instantly vaporized on impact. The shaking produced would be equivalent of a 7.0 earthquake. If you were standing about 60 miles (100 km) from the impact site, within two minutes you’d be pelted with debris up to about two inches in size. Within five minutes, the air blast generated by the heat of the impact would create hurricane force winds, shattering your windows. If you were standing within about 20 miles away (30 km) – for reference, New York City is roughly 20 miles wide – the effects would be much more serious. The average fragment size headed your way would be about the size of a dishwasher, and within 90 seconds wind speeds would top 500 miles per hour.

The good news:

Thankfully, in the very unlikely case that NASA can’t rule out this kind of a strike in 2032, we’ll have nearly two decades to deflect 2013 TV135 onto a safer course. Scientists have been investigating ramming dangerous objects with spacecraft, among other tactics. If it comes to that, let’s just hope world governments can agree more quickly about exactly what to do than they have on the much more real threat of climate change.