In 5 billion years, the expansion of the universe will have progressed to the point where all other galaxies will have receded beyond detection.

Metaphysical speculation is independent of the physical validity of the Big Bang itself and is irrelevant to our understanding of it.

The one experience that I hope every student has at some point in their lives is to have some belief you profoundly, deeply hold, proved to be wrong because that is the most eye-opening experience you can have, and as a scientist, to me, is the most exciting experience I can ever have.

The ultimate arbiter of truth is experiment, not the comfort one derives from one's a priori beliefs, nor the beauty or elegance one ascribes to one's theoretical models.

The real thing that physics tell us about the universe is that it's big, rare event happens all the time — including life — and that doesn't mean it's special.

For many, to live in a universe that may have no purpose, and no creator, is unthinkable.

We all trust each other to some extent. We have to rely on experts to some extent, but we should learn to be sceptical.