I never said it. Honest. Oh, I said there are maybe 100 billion galaxies and 10 billion trillion stars. It's hard to talk about the Cosmos without using big numbers. I said 'billion' many times on the Cosmos television series, which was seen by a great many people. But I never said 'billions and billions.' For one thing, it's imprecise. How many billions are 'billions and billions'? A few billion? Twenty billion? A hundred billion? 'Billions and billions' is pretty vague... For a while, out of childish pique, I wouldn't utter the phrase, even when asked to. But I've gotten over that. So, for the record, here it goes: 'Billions and billions.'

Humans may crave absolute certainty; they may aspire to it; they may pretend, as partisans of certain religions do, to have attained it. But the history of sci…

If we keep on with business as usual, the Earth will be warmed more every year; drought and floods will be endemic; many more cities, provinces, and whole nati…

Education on the value of free speech and the other freedoms reserved by the Bill of Rights, about what happens when you don't have them, and about how to exer…

In science one tries to tell people, in such a way as to be understood by everyone, something that no one ever knew before. But in the case of poetry, it's the…

[W]e believe that failing to call a spade a spade is not scientific.

Every sentence I utter must be understood not as an affirmation, but as a question.