Harold Urey Quotes

No planet is more earth-like than Earth itself, so if life really does pop up readily in earth-like conditions, then surely it should have arisen many times right here on our home planet? And how do we know it didn't? The truth is, nobody has looked.

So how can we test the idea that the transition from nonlife to life is simple enough to happen repeatedly? The most obvious and straightforward way is to search for a second form of life on Earth. No planet is more Earth-like than Earth itself, so if the path to life is easy, then life should have started up many times over right here.

We think that life develops spontaneously on Earth, so it must be possible for life to develop on suitable planets elsewhere in the universe. But we don't know the probability that a planet develops life.

The life we have on Earth must have spontaneously generated itself. It must therefore be possible for life to generate spontaneously elsewhere in the universe.

I should say we know that there are many, many other Earths out there. We're almost certain that there will be upwards of a billion Earth-like planets in our galaxy alone, so there is no lack of real estate where life might happen, but what we don't know is how likely it is given the real estate, given a wonderful pristine planet like Earth how likely is it that life will pop up inhabited? We don't know the answer to that.

The discovery and investigation of life on other planets is likely to change many of our ideas about how life arose on the Earth and even what is life and its natural development.

We know too little about how life began on Earth to lay confident odds. It may have involved a fluke so rare that it happened only once in the entire galaxy. On the other hand, it may have been almost inevitable, given the right environment.

We do care about planets like the Earth because by now we understood that life as a chemical system really needs a smaller planet with water and with rocks and with a lot of complex chemistry to originate, to emerge, to survive.

The fact that life evolved out of nearly nothing, some 10 billion years after the universe evolved out of literally nothing, is a fact so staggering that I would be mad to attempt words to do it justice.

If we do discover more than one type of life on Earth, we can be fairly certain that the universe is teeming with it, for it would be inconceivable that life started twice here but never on all the other earth-like planets.

The origin of life is one of the great outstanding mysteries of science.

Man was not breathed into the earth. Man came out of the earth.

Since the universe must contain millions of appropriate planets, consciousness in some form - but not with the paired eyes and limbs, and the brain built of neurons in the only example we know - may evolve frequently. But if only one origin of life in a million ever leads to consciousness, then Martian bacteria most emphatically do not imply Little Green Men.

The probability of life ever evolving on Earth was slim to none. It's insane that we're all walking around and talking.

In short there is not a shred of objective evidence to support the hypothesis that life began in an organic soup here on the Earth.

From the scientific view, the theory of karma may be a metaphysical assumption -- but it is no more so than the assumption that all of life is material and originated out of pure chance

The universe is almost 14 billion years old, and, wow! Life had no problem starting here on Earth! I think it would be inexcusably egocentric of us to suggest that we're alone in the universe.

The assumption that nature is all there is, and that nature has been governed by the same rules at all times and places, makes it possible for natural science to be confident that it can explain such things as how life began.

Life began three and a half billion years ago, necessarily about as simple as it could be, because life arose spontaneously from the organic compounds in the primeval oceans.

Why, for example, should a group of simple, stable compounds of carbon, hydrogen, oxygen and nitrogen struggle for billions of years to organise themselves into a professor of chemistry? What's the motive?

I do definitely believe that there is life away from this planet. I mean, we've kind of established that with the fact that we found bacteria on meteorites, and we've kind of used that to backtrack and show how this Earth, this planet, could have formed the ability to sustain life in the first place.

Life exists throughout the cosmos and is a consequence of matter in the universe.

From a personal perspective, I am disappointed that we have yet to really achieve a full understanding of the origins of life on Earth. What was the spark that, billions of years ago, kickstarted the process of evolution that has brought us life as we know it today? I hope that we will get some answers to that in my lifetime.

The universe is large and old, and the ingredients for life as we know it are everywhere, so there's no reason to think that Earth would be unique in that regard. Whether of not the life became intelligent is a different question, and we'll see if we find that.

We haven't yet found a speck of evidence for biology on another world, so we have no objective way to judge whether life is a onetime fluke or a near-inevitable phenomenon.