In physics, one of the most exciting areas is in nanotech. With computers exhausting the power of silicon, Silicon Valley could become a Rust Belt, unless we can find replacements, such as quantum computers and molecular computers. To be a leader in any field, one has to have a great imagination. Sure, we have to know the basics and fundamentals. But beyond that, we have to let our imagination soar.

To become a theoretical physicist ... you need to have a passionate love affair with the universe.

One problem with politics is that it is a zero sum game, i.e. politicians argue how to cut the pie smaller and smaller, by reshuffling pieces of the pie. I think this is destructive. Instead, we should be creating a bigger pie, i.e. funding the science that is the source of all our prosperity. Science is not a zero sum game.

Modern thinking is that time did not start with the big bang, and that there was a multiverse even before the big bang. In the inflation theory, and in string theory, there were universes before our big bang, and that big bangs are happening all the time. Universes are formed when bubbles collide or fission into smaller bubles.

Growing new organs of the body as they wear out, extending the human lifespan? What's not to like?

Physicists often quote from T. H. White's epic novel The Once and Future King, where a society of ants declares, "Everything not forbidden is compulsory." In other words, if there isn't a basic principle of physics forbidding time travel, then time travel is necessarily a physical possibility. (The reason for this is the uncertainty principle. Unless something is forbidden, quantum effects and fluctuations will eventually make it possible if we wait long enough. Thus, unless there is a law forbidding it, it will eventually occur.)

It's risky to allow radiation to constantly go up into the atmosphere. The main criticism of this approach of entombing it is that it would cost too much, involve too many resources and people. But think of the cost of having all the crops impounded by the government, all the milk being thrown into the river, people's livelihoods destroyed.