Cuz We Said So

An asteroid named 2004 MN4 is heading in the general direction of Earth. It is due to get here on Friday, April 13, 2029, and while the odds of it hitting the Earth are low, the possibility can not at present be ruled out. The odds are estimated at 1 in 62.

2004 MN4 is 420 meters in diameter. According to the Earth Impact Effect Program here, that's not a big enough impact to shift the Earth's orbit or rotation, but it wouldn't be something you'd want to be near. Impact would release an energy of 1.9 gigatons of TNT. Assuming the asteroid is dense rock, and strikes sedementary rock, it would create a crater 4 miles across, generate a 7.0 earthquake, and an air blast that would knock over buildings 30 miles away. It would kill, on average, a million people.

Given the current odds, I'm not too worried about this... but it did get me thinking. What if the rock were bigger, and we knew for sure it would strike us? What if we were to wake up tomorrow to learn that on that April day, 24 years from now, all life on Earth would end?

How would knowing that, so far in advance, change us? It would certainly make arms races, and terrorism, and global warming seem less relevant. Would this knowledge change the way we treat each other? Would humanity rise to the occasion, and find a way to survive? Would we find a way to divert or destroy the rock? Would we get people off the planet? How many, and to where? Or would we fail, and cease to be?

Statistically speaking, the question isn't whether that extinction-level impact is going to come one day, but when. I wonder if we'll see it coming, and I wonder what we'll do about it?