I think the really cool and compelling thing about math and physics is that it opens up entry to all these hypotheticals - or at least, it gives you the language to talk about them. But at the same time, if a scenario is completely disconnected from reality, it's not all that interesting.

I argue that for every country to have an independent fuel cycle is the wrong way to go. Because any country which has a complete fuel cycle is a latent nuclear weapons country, in the sense that it is not far from making a nuclear weapon.

In Einstein's equation, time is a river. It speeds up, meanders, and slows down. The new wrinkle is that it can have whirlpools and fork into two rivers. So, if the river of time can be bent into a pretzel, create whirlpools and fork into two rivers, then time travel cannot be ruled out.

Odd arrangements and funny solutions are the proof of evolution - paths that a sensible God would never tread but that a natural process, constrained by history, follows perforce.

So if the worth of the arts were measured by the matter with which they deal, this art-which some call astronomy, others astrology, and many of the ancients the consummation of mathematics-would be by far the most outstanding. This art which is as it were the head of all the liberal arts and the one most worthy of a free man leans upon nearly all the other branches of mathe matics. Arithmetic, geometry, optics, geodesy, mechanics, and whatever others, all offer themselves in its service.

And I don't care what else anyone has ever told you, the Sun is white, not yellow. Human color perception is a complicated business, but if the Sun were yellow, like a yellow lightbulb, then white stuff such as snow would reflect this light and appear yellow-a snow condition confirmed to happen only near fire hydrants.