Stephen Hawking Quotes

With 'Extinction Machine,' I wanted to start some conversations about whether we're alone in the universe and what that might mean.

Within the scientific community, there is healthy skepticism. And the question is, 'How do you ever get to a meaningful null result? How long and how hard do SETI scientists have to look for extraterrestrial intelligence and find nothing before they say, 'There is nothing. We are alone.'

To my mathematical brain, the numbers alone make thinking about aliens perfectly rational.

Perhaps we've never been visited by aliens because they have looked upon Earth and decided there's no sign of intelligent life.

I believe that there may be intelligent life on other planets.

Spectroscopy can probably answer the question, 'Is there anybody out there?' Are we alone?

This planet seems to be in such sorry shape. And I can't ever think about the rest of the universe without coming back home and thinking what the implications for life here would be if we were to really have some definitive proof of extraterrestrial life.

We can never prove that we're alone in the universe. But the Allen Telescope Array could prove that we're not.

I actually think the chances that we'll find E.T. are pretty good.

Should we find a second form of life right here on our doorstep, we could be confident that life is a truly cosmic phenomenon. If so, there may well be sentient beings somewhere in the galaxy wondering, as do we, if they are not alone in the universe.

I think it quite likely that we are the only civilization within several hundred light years; otherwise we would have heard radio waves.

Ethan Allen was convinced that every planet out there has its own intelligent extraterrestrials. And this, as you can imagine, is a radical, inspiring, but very unsettling, idea.

People quite often think of the question 'Are we alone in the universe?' in terms of other civilizations out there: life forms that have reached at least our level of technological development.

There must be other races out there, watching our tiny yellow sun glimmering in their unknown field of the sky. Do they desire us as we desire them?

I think there's all kinds of life out there, including intelligent life, but the reason we haven't found each other is because of vast distances.

I believe there's other forms of intelligence in the universe. I've seen and heard some pretty convincing UFO stuff. Besides, if we're the most intelligent things in the universe... well, that's just depressing.

Galactic plankton is undoubtedly out there, but it's statistically highly likely there's also another intelligent civilisation out there somewhere. Unfortunately, the distances and time differences are so great, communication might remain impossible.

I think obviously there is some kind of life form somewhere else. Whether it looks like the creature in 'Alien Autopsy,' I'm not sure.

I believe that these extra-terrestrial vehicles and their crews are visiting this planet from other planets. Most astronauts were reluctant to discuss UFOs.

Will searching for distant messages work? Is there intelligent life out there? The SETI effort is worth continuing, but our common-sense beacons approach seems more likely to answer those questions.

I believe that we're not alone. How can we be alone in an infinite universe? I'm using the word 'alien' with a little trepidation because I know that sparks so many different versions of that word, and there are so many different images that come into one person's head when someone says it.

The Moon and Mars were the two most likely candidates for life in the solar system; what exists beyond our solar system is mere guesswork.

I believe alien life is quite common in the universe, although intelligent life is less so. Some say it has yet to appear on planet Earth.

We don't know how to identify intelligence over interstellar distances, so what we do instead is use technology for a proxy.

The one way to discover about aliens is to tune your radio telescope and listen to the signals.