There are plenty of dead scientists I admire, but I can't think of any living ones. This is probably because it is only in retrospect that one can see who made the important contributions.

When the going gets tough, the tough take a coffee break.

I don't think the human race will survive the next thousand years, unless we spread into space. There are too many accidents that can befall life on a single planet. But I'm an optimist. We will reach out to the stars.

If it [the universe] was expanding fairly slowly, the force of gravity would cause it eventually to stop expanding and then to start contracting. However, if it was expanding at more than a certain critical rate, gravity would never be strong enough to stop it, and the universe would continue to expand forever.

One of the basic rules of the universe is that nothing is perfect. Perfection simply doesn't exist.....Without imperfection, neither you nor I would exist

If time travel is possible, where are the tourists from the future?

The concern here is that financial services become a kind of tech-led Wild West.