phase

"The moon shuts off the beams of the sun as it passes across it, and darkens so much of the earth as the breadth of the blue-eyed moon amounts to." -Empedocles, ~450 B.C. Less than two weeks ago, I saw my first annular eclipse, with some spectacular results at the moment of maximum eclipse. From my first eclipse expedition, to False Klamath Cove, on the coast in northern California. This happens, of course, because -- from our point of view -- the Moon appears to pass in front of the Sun, blocking a fraction of the light coming from it. Image credit: NASA / Solar Dynamics Observatory. And…
Let's say we're having a nice day here on Earth; the Sun is shining, the clouds are sparse, and everything is just looking like a peach: And then Lucas goes and tells me, Oh my God, Ethan! It's Armageddon! An asteroid is coming straight for us! You've got to stop it! Really? Me? Well, how would I do it? Let's say we've got some reasonably good asteroid tracking going on, and we've got about 2 months before the asteroid is actually going to hit us. We'd like to do something with the situation on the left, to avoid the situation on the right: Well, what we really have to do is change the…