Sep 28, 2018 04:22 PM
http://nautil.us/issue/64/the-unseen/the...revolution
EXCERPT: . . . The same fundamental laws apply throughout the entire domain we can survey with telescopes. Were that not so—were atoms “anarchic” in their behavior—we’d have made no progress in understanding the observable universe. But this observable domain may not be all of physical reality; some cosmologists speculate that “our” big bang wasn’t the only one—that physical reality is grand enough to encompass an entire “multiverse.”
We can only see a finite volume—a finite number of galaxies. [...] Even conservative astronomers are confident that the volume of spacetime within range of our telescopes—what astronomers have traditionally called “the universe”—is only a tiny fraction of the aftermath of the Big Bang. We’d expect far more galaxies located beyond the horizon [...] each of which (along with any intelligences it hosts) will evolve rather like our own.
It’s a familiar idea that if enough monkeys were given enough time, they would write the works of Shakespeare [...] But the number of “failures” that would precede eventual success is a number with about 10 million digits. [...] To produce a specific set of letters as long as a book is so immensely improbable that it wouldn’t have happened even once within the observable universe. When we throw dice we eventually get a long succession of sixes, but (unless they are biased) we wouldn’t expect to get more than 100 in a row even if we went on for a billion years.
However, if the universe stretches far enough, everything could happen—somewhere far beyond our horizon there could even be a replica of Earth. This requires space to be VERY big—described by a number not merely with a million digits but with 10 to the power of 100 digits [...] Given enough space and time, all conceivable chains of events could be played out somewhere, though almost all of these would occur far out of range of any observations we could conceivably make.[...]
All this could be encompassed within the aftermath of “our” big bang, which could extend over a stupendous volume. But that’s not all. What we’ve traditionally called “the universe”—the aftermath of “our” big bang—may be just one island, just one patch of space and time, in a perhaps infinite archipelago. There may have been many big bangs, not just one. Each constituent of this “multiverse” could have cooled down differently, maybe ending up governed by different laws. Just as Earth is a very special planet among zillions of others, so—on a far grander scale—our big bang could have been a rather special one. [...] Our current concept of physical reality could be as constricted, in relation to the whole, as the perspective of the Earth available to a plankton whose “universe” is a spoonful of water.
Could this be true? A challenge for 21st-century physics is to answer two questions. First, are there many “big bangs” rather than just one? Second—and this is even more interesting—if there are many, are they all governed by the same physics?
If we’re in a multiverse, it would imply a fourth and grandest Copernican revolution; we’ve had the Copernican revolution itself, then the realization that there are billions of planetary systems in our galaxy; then that there are billions of galaxies in our observable universe. But now that’s not all. The entire panorama that astronomers can observe could be a tiny part of the aftermath of “our” big bang, which is itself just one bang among a perhaps infinite ensemble.
[...] At first sight, the concept of parallel universes might seem too arcane to have any practical impact. But it may (in one of its variants) actually offer the prospect of an entirely new kind of computer: the quantum computer, which can transcend the limits of even the fastest digital processor by, in effect, sharing the computational burden among a near infinity of parallel universes....
MORE: http://nautil.us/issue/64/the-unseen/the...revolution
EXCERPT: . . . The same fundamental laws apply throughout the entire domain we can survey with telescopes. Were that not so—were atoms “anarchic” in their behavior—we’d have made no progress in understanding the observable universe. But this observable domain may not be all of physical reality; some cosmologists speculate that “our” big bang wasn’t the only one—that physical reality is grand enough to encompass an entire “multiverse.”
We can only see a finite volume—a finite number of galaxies. [...] Even conservative astronomers are confident that the volume of spacetime within range of our telescopes—what astronomers have traditionally called “the universe”—is only a tiny fraction of the aftermath of the Big Bang. We’d expect far more galaxies located beyond the horizon [...] each of which (along with any intelligences it hosts) will evolve rather like our own.
It’s a familiar idea that if enough monkeys were given enough time, they would write the works of Shakespeare [...] But the number of “failures” that would precede eventual success is a number with about 10 million digits. [...] To produce a specific set of letters as long as a book is so immensely improbable that it wouldn’t have happened even once within the observable universe. When we throw dice we eventually get a long succession of sixes, but (unless they are biased) we wouldn’t expect to get more than 100 in a row even if we went on for a billion years.
However, if the universe stretches far enough, everything could happen—somewhere far beyond our horizon there could even be a replica of Earth. This requires space to be VERY big—described by a number not merely with a million digits but with 10 to the power of 100 digits [...] Given enough space and time, all conceivable chains of events could be played out somewhere, though almost all of these would occur far out of range of any observations we could conceivably make.[...]
All this could be encompassed within the aftermath of “our” big bang, which could extend over a stupendous volume. But that’s not all. What we’ve traditionally called “the universe”—the aftermath of “our” big bang—may be just one island, just one patch of space and time, in a perhaps infinite archipelago. There may have been many big bangs, not just one. Each constituent of this “multiverse” could have cooled down differently, maybe ending up governed by different laws. Just as Earth is a very special planet among zillions of others, so—on a far grander scale—our big bang could have been a rather special one. [...] Our current concept of physical reality could be as constricted, in relation to the whole, as the perspective of the Earth available to a plankton whose “universe” is a spoonful of water.
Could this be true? A challenge for 21st-century physics is to answer two questions. First, are there many “big bangs” rather than just one? Second—and this is even more interesting—if there are many, are they all governed by the same physics?
If we’re in a multiverse, it would imply a fourth and grandest Copernican revolution; we’ve had the Copernican revolution itself, then the realization that there are billions of planetary systems in our galaxy; then that there are billions of galaxies in our observable universe. But now that’s not all. The entire panorama that astronomers can observe could be a tiny part of the aftermath of “our” big bang, which is itself just one bang among a perhaps infinite ensemble.
[...] At first sight, the concept of parallel universes might seem too arcane to have any practical impact. But it may (in one of its variants) actually offer the prospect of an entirely new kind of computer: the quantum computer, which can transcend the limits of even the fastest digital processor by, in effect, sharing the computational burden among a near infinity of parallel universes....
MORE: http://nautil.us/issue/64/the-unseen/the...revolution
