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.)

You cannot create new science unless you realise where the old science leaves off and new science begins, and science fiction forces us to confront this.

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.

Science is given almost no visibility in the media. If a Martian came down to Earth and watched television, he'd come to the conclusion that all the world's society is based on Britney Spears and Paris Hilton. He'd be amazed that our society hasn't collapsed.

There is so much noise on the Internet, with would-be prophets daily haranguing their audience and megalomaniacs trying to push bizarre ideas, that eventually people will cherish a new commodity: wisdom.

In some sense, gravity does not exist; what moves the planets and the stars is the distortion of space and time.

We are not at the end but at the beginning of a new physics. But whatever we find, there will always be new horizons continually awaiting us.