Maybe dark matter is denser than we usually assume, kind of like the Milky Way plane.

You have to be careful when you use beauty as a guide. There are many theories people didn't think were beautiful at the time but did find beautiful later—and vice versa. I think simplicity is a good guide: The more economical a theory, the better.

I did not set out to explain the extinction of the dinosaurs. I'm a particle physicist, and I was actually thinking about dark matter along with some collaborators.

There is real confusion about what it means to be right and wrong - the difference between what spiritual beliefs are and what science is.

If such external influences are intrinsic to religion, then logic and scientific thought dictate that there must be a mechanism by which this influence is transmitted. A religious or spiritual belief that involves an invisible undetectable force that nonetheless influences human actions and behavior or that of the world itself produces a situation in which a believer has no choice but to have faith and abandon logic--or simply not care.

I considered going into business or becoming a lawyer - not for the money, but for the thrill of problem-solving.

There are many aspects of time we just do not understand. That’s the thing about writing a popular book: You realize the things you understand because for those you can give a really simple explanation. But some things about time I just don’t know how to give simple explanations for, even though I can tell you mathematically what’s going on.