Top 153 Quotes & Sayings by Brian Greene - Page 3

Most people don’t question the practice of eating meat. Many of these people care about animals and the environment, some deeply. But for some reason-force of habit, cultural norms, resistance to change-there is a fundamental disconnect whereby these feelings don’t translate into changes of behavior.

I wouldn't say that The Fabric of the Cosmos is a book on cosmology. Cosmology certainly plays a big part, but the major theme is our ever-evolving understanding of space and time, and what it all means for our sense of reality.

I believe that through its rational evaluation of truth and indifference to personal belief, science transcends religious and political divisions and so does bind us into a greater, more resilient whole.

You should never be surprised by or feel the need to explain why any physical system is in a high entropy state.

Quantum Mechanics is different. Its weirdness is evident without comparison. It is harder to train your mind to have quantum mechanical tuition, because quantum mechanics shatters our own personal, individual conception of reality

Energy is the ultimate convertable currency.

Understanding requires insight. Insight must be anchored.

Time allows change to take place and the very evolution of the universe is what requires some conception of time. Mathematically can we write down a universe that doesn't have time? Sure. Do we think that would be realised in the larger reality that is out there? None of us take that possibility seriously.

Physicists have come to realize that mathematics, when used with sufficient care, is a proven pathway to truth.

Cosmology is among the oldest subjects to captivate our species. And it’s no wonder. We’re storytellers, and what could be more grand than the story of creation?

...things are the way they are in our universe because if they weren't, we wouldn't be here to notice.

I’ve spent something like 17 years working on a theory for which there is essentially no direct experimental support.

General relativity is in the old Newtonian framework where you predict what will happen, not the probability of what will happen. And putting together the probabilities of quantum mechanics with the certainty of general relativity, that's been the big challenge and that's why we have been excited about string theory, as it's one of the only approaches that can put it together.

The beauty of string theory is the metaphor kind of really comes very close to the reality. The strings of string theory are vibrating the particles, vibrating the forces of nature into existence, those vibrations are sort of like musical notes. So string theory, if it's correct, would be playing out the score of the universe.

Far from being accidental details, the properties of nature's basic building blocks are deeply entwined with the fabric of space and time.

But if you think about a practical implication of enriching your life and giving you a sense of being part of a larger cosmos and possibly being able to use this [gravitational waves] as a tool in the future maybe to listen not just to black holes colliding, but maybe listen to the big bang itself, those kind of applications may happen in the not too distant future.

We do not know whether there are extra dimensions or multiverse. Let's go forward with the possible ideas that come out of the mathematics. It's hard for us to imagine a universe that would have no time at all.

In essence, we string theorists have been trying to work out the score of the universe, the harmonies of the universe, the mathematical vibrations that the strings would play. So musical metaphors have been with us in science since the beginning.

In quantum mechanics there is A causing B. The equations do not stand outside that usual paradigm of physics. The real issue is that the kinds of things you predict in quantum mechanics are different from the kinds of things you predict using general relativity. Quantum mechanics, that big, new, spectacular remarkable idea is that you only predict probabilities, the likelihood of one outcome or another. That's the new idea.

So: if you buy the notion that reality consists of the things in your freeze-frame mental image right now, and if you agree that your now is no more valid than the now of someone located far away in space who can move freely, then reality encompasses all of the events in spacetime.

...quantum mechanics—the physics of our world—requires that you hold such pedestrian complaints in abeyance.

Evidence in support of general relativity came quickly. Astronomers had long known that Mercury’s orbital motion around the sun deviated slightly from what Newton’s mathematics predicted. In 1915, Einstein used his new equations to recalculate Mercury’s trajectory and was able to explain the discrepancy, a realization he later described to his colleague Adrian Fokker as so thrilling that for some hours it gave him heart palpitations.

Assessing existence while failing to embrace the insights of modern physics would be like wrestling in the dark with an unknown opponent.

So many galaxies, so many planets out there in the universe circling so many stars... it just feels like there's a very good chance that there is another Earth-like planet out there that is able to support some kind of life similar to what we're familiar with.

We are living through a remarkably privileged era when certain deep truths about the cosmos are still within reach of the human spirit of exploration.

That is, you can have nothingness, absolute nothingness for maybe a tiny fraction of a second, if a second can be defined in that arena, but then it falls apart into a something and an anti-something. And that something is then what we call the universe. But can we really understand that or put rigorous mathematics or testable experiments against that? Not yet. So one of the big holy grail of physics is to understand why there is something rather than nothing.

When I give this talk to a physics audience, I remove the quotes from my 'Theorem'.

The revelation we've come to is that we can trust our memories of a past with lower, not higher, entropy only if the big bang - the process, event, or happening that brought the universe into existence - started off the universe in an extraordinarily special, highly ordered state of low entropy.

The real question is whether all your pondering and analyses will convince you that life is worth living. That's what it all comes down to.

If string theory is right, the microscopic fabric of our universe is a richly intertwined multidimensional labyrinth within which the strings of the universe endlessly twist and vibrate, rhythmically beating out the laws of the cosmos.

Einstein comes along and says, space and time can warp and curve, that's what gravity is. Now string theory comes along and says, yes, gravity, quantum mechanics, electromagnetism - all together in one package, but only if the universe has more dimensions than the ones that we see.

When you know the answer you want, it is often all too easy to figure out a way of getting it.

According to inflation, the more than 100 billion galaxies, sparkling throughout space like heavenly diamonds, are nothing but quantum mechanics writ large across the sky. To me, this realization is one of the greatest wonders of the modern scientific age.