Energy is liberated matter, matter is energy waiting to happen.

You may not feel outstandingly robust, but if you are an average-sized adult you will contain within your modest frame no less than 7 X 10^18 joules of potential energy—enough to explode with the force of thirty very large hydrogen bombs, assuming you knew how to liberate it and really wished to make a point.

If you've never done anything wrong it's probably because you have never tried anything new.

Physics is really nothing more than a search for ultimate simplicity, but so far all we have is a kind of elegant messiness.

When Einstein died, his greatest rival, Bohr, found for him words of moving admiration. When a few years later Bohr in turn died, someone took a photograph of the blackboard in his study. There’s a drawing on it. A drawing of the ‘light-filled box’ in Einstein’s thought experiment. To the very last, the desire to challenge oneself and understand more. And to the very last: doubt