If an asteroid were speeding toward a calamitous collision with Earth, we might be able to knock it off track by ... painting it white. The PopSci blog picks up on the novel idea by MIT grad student Sung Wook Paek: Let's say scientists determined that an asteroid were going to smash into us in 20 years. We send up a spacecraft and hit it with five tons of white paint pellets. That alone would knock it a bit off course, but the paint also would increase the rock's sunlight reflectivity, which would cause more photons to bounce off its surface, and, in theory, steer it out of harm's way. The paper just won a UN competition on the subject for students and young scientists.