The central idea of string theory is quite straightforward. If you examine any piece of matter ever more finely, at first you'll find molecules, atoms, sub-atomic particles. Probe the smaller particles, you'll find something else, a tiny vibrating filament of energy, a little tiny vibrating string.

I've seen children's eyes light up when I tell them about black holes and the Big Bang.

General relativity is in the old Newtonian framework where you predict what will happen, not the probability of what will happen. And putting together the probabilities of quantum mechanics with the certainty of general relativity, that's been the big challenge and that's why we have been excited about string theory, as it's one of the only approaches that can put it together.

So: if you buy the notion that reality consists of the things in your freeze-frame mental image right now, and if you agree that your now is no more valid than the now of someone located far away in space who can move freely, then reality encompasses all of the events in spacetime.

Energy is the ultimate convertable currency.

The revelation we've come to is that we can trust our memories of a past with lower, not higher, entropy only if the big bang - the process, event, or happening that brought the universe into existence - started off the universe in an extraordinarily special, highly ordered state of low entropy.

Nature's patterns sometimes reflect two intertwined features: fundamental physical laws and environmental influences. It's nature's version of nature versus nurture.