The pinpoints of starlight we see with the naked eye are photons that have been streaming toward us for a few years or a few thousand.

I think the relationship between memory and time is a very deep and tricky one, to tell you the truth. I don't consider memory another sense. I do consider memory that which allows us to think that time flows.

Over the centuries, monumental upheavals in science have emerged time and again from following the leads set out by mathematics.

I’ve spent something like 17 years working on a theory for which there is essentially no direct experimental support.

Einstein comes along and says, space and time can warp and curve, that's what gravity is. Now string theory comes along and says, yes, gravity, quantum mechanics, electromagnetism - all together in one package, but only if the universe has more dimensions than the ones that we see.

Science is the greatest of all adventure stories, one that's been unfolding for thousands of years as we have sought to understand ourselves and our surroundings.

In my own research when I'm working with equations, I never feel like I really understand what I'm doing if I'm solely relying on the mathematics for my understanding. I need to have a visual picture in my mind. I'm constantly translating from the math to some intuitive mind's-eye picture.