Somewhere out there in the deepness of space is the object that is on course to cause the next great extinction event on Earth. The space rock passing by today is probably not that object, but it has the potential to be a real continent-killer. Asteroid 1998 QE2 is nearly 2 miles in diameter, and it’s going to pass within 3.6 million miles of Earth. In astronomical terms, that’s a close call.If you’re looking for a yardstick of sorts, the asteroid is going to be about 15 times farther away than the moon is. The object is going to approaching close enough that astronomers all over the world are pointing their telescopes at 1998 QE2, and NASA is even planning to have a live webcast of the asteroid’s passing at about 4:59PM EDT today. Before that, there will be a White House Google+ Hangout to talk over the event at 2PM EDT.1998 QE2 was (as its name suggest) discovered in 1998 by the Massachusetts Institute of Technology’s Lincoln Near Earth Asteroid Research Program near Socorro, NM. Given its size and nearness of its orbit to Earth, researchers have been keeping tabs on it.The light from the asteroid will be less than 1% as bright as the dimmest visible stars. Observers on the ground won’t be able to make out 1998 QE2 without a telescope, but planetariums around the world are going to be watching.This particular space rock might not be on a collision course with our planet, but it is inevitable Earth will get in the way of an object this size or bigger in the future. It has happened before, and if we don’t prevent it, the same will happen again. An object the size of 1998 QE2 would create an impact crater over 10 miles wide, and rain molten rock across thousands of square miles while also throwing up enough dust to drastically alter the Earth’s climate. Might be a good idea to keep an eye out, right?