Quotes from Brian Greene

Rather than despair because a unique universe seems not to emerge, we are encouraged to celebrate: string theory makes the least plausible part of Weinberg's explanation of the cosmological constant-the requirement that there be many more than 10^124 different universes-suddenly seem plausible.

According to special relativity, no longer can space and time be thought of as universal concepts set in stone, experienced identically by everyone. Rather, space and time emerged from Einstein's reworking as malleable constructs whose form and appearance depend on one's state of motion.

The principle of relativity rests on a simple fact: Whenever we discuss speed or velocity (an object's speed and its direction of motion), we must specify precisely who or what is doing the measuring.

The big bang is a theory, partly described in the last two chapters, that delineates cosmic evolution from a split second after whatever happened to bring the universe into existence, but it says nothing at all about time zero itself.

In this scenario, the universe as we know it would merely be the latest in a temporal series, some of which may have contained intelligent life and the culture they created, but are now long ago extinguished. In due course, all of our contributions and those of any other life-forms our universe supports would be similarly erased.

Witten's result showed that much as the Wizard of Oz's frightening visage was produced by an ordinary man, a rapacious black hole is the holographic projection of something equally ordinary: a bath of hot particles in the boundary theory (Figure 9.6). Like a real hologram and the image it generates, the two theories-a black hole in the interior and a hot quantum field theory on the boundary-bear no apparent resemblance to each other, and yet they embody identical information.

In Plato's parable of the cave, our senses are privy only to a flattened, diminished version of the true, more richly textured, reality. Maldacena's flattened world is very different. Far from being diminished, it tells the full story. It's a profoundly different story from the one we're used to. But his flattened world may well be the primary narrator.

In every collection of 10^10^122 cosmic patches, we thus expect there to be, on average, one patch that looks just like ours. That is, in every region of space that's roughly 10^10^122 meters across, there should be a cosmic patch that replicates ours-one that contains you, the earth, the galaxy, and everything else that inhabits our cosmic horizon.

the universe, according to quantum mechanics, participates in a game of chance.

the Nobel Prize–winning particle physicist Isidor Isaac Rabi greeted the discovery of the muon with a less than enthusiastic Who ordered that? Nevertheless, there it was. And more was to follow.

I think I thought, therefore I think I was.

a) The probability wave for a macroscopic object is generally narrowly peaked. (b) The probability wave for a microscopic object, say, a single particle, is typically widely spread.

The implications of these features of quantum mechanics for our picture of reality are a subject of ongoing research. Many scientists, myself included, view them as part of a radical quantum updating of the meaning and properties of space.

Since gravity and acceleration are equivalent, if you feel gravity's influence, you must be accelerating. Einstein argued that only those observers who feel no force at all—including the force of gravity—are justified in declaring that they are not accelerating.

The predictions of general relativity have been uniformly confirmed. There is no longer any doubt that Einstein's description of gravity is not only compatible with special relativity, but yields predictions closer to experimental results than those of Newton's theory.

Namely, each messenger particle is a string that's executing a particular vibrational pattern. A photon is a string vibrating in one particular pattern, a W particle is a string vibrating in a different pattern, a gluon is a string vibrating in yet another pattern. And, of prime importance, what Schwarz and Scherk showed in 1974 is that there is a parti Table

After all, the reasoning goes, at the big bang everything emerged from one place since, we believe, all places we now think of as different were the same place way back in the beginning.

These frozen moments are grouped into nows—into events that happen at the same time—in different ways by observers in different states of motion.

Many find it fatuous and downright repugnant to claim that the wonders of life and the universe are mere reflections of microscopic particles engaged in a pointless dance fully choreographed by the laws of physics.

Each moment—each event or happening—exists, just as each point in space exists. Moments don't momentarily come to life when illuminated by the "spotlight" of an observer's present; that image aligns well with our intuition but fails to stand up to logical analysis. Instead, once illuminated, always illuminated. Moments don't change. Moments are. Being illuminated is simply one of the many unchanging features that constitute a moment.

General relativity provides the choreography for an entwined cosmic dance of space, time, matter, and energy.

the right slit—and since

all events making up the history of the universe are on view; they are all there, static and unchanging. Different observers don't agree on which of the events happen at the same time—they time-slice the spacetime loaf at different angles—but the total loaf and its constituent events are universal, literally.

In (highly) colloquial terms, the law declares that the production of waste is unavoidable.