Over at the XKCD blag, Randall discusses solar sails and levitating squirrels. And he’s absolutely right — the Back-to-the-Futuresque 1.21 Gigawatts will levitate about a kg, assuming perfect reflection. Assuming absorption, you vaporize the squirrel in a couple of milliseconds.

(1 kg of water requires about 2.5 million Joules to boil away, starting at body temperature. Or not — the latent heat of vaporization is the dominant term)

I think the XKCD cartoons are often quite funny, BTW. A link, if by some odd chance you were unaware of them. I just got a new light box to replace my broken one. Must find time to draw cartoons.