Entire universes might hide nearby, offset from our own by a microscopic distance along a compactified dimension. We just need to find our way...
Oh, my aching brane
String theory, as though it isn't esoteric enough, has a generalization called M-theory, M for membrane (a string being a one-dimensional membrane). M-theory characterizes our familiar universe as a 4-D island adrift in a higher-dimensional space. Everything we have traditionally considered the Universe is wrapped, at least conceptually, in a membrane, or "brane," that separates us from those other dimensions and the larger Universe.12 Physical laws beyond the membrane may differ dramatically from laws within the membrane.13
Nothing in M-theory precludes the existence of islands in addition to our own.
Suppose that two or more islands nestle together within the higher-dimensional bulk, and that any encounters between them are gentle. Voilà! Nearby universes ripe for exploitation (setting aside the pesky unanswered detail of just how one would make the trip) and for storytelling.14
It sounds, in fact, much like Isaac Asimov's novel The Gods Themselves.
Universe in my pocket
The parallel universes that can be extrapolated—which is not to say, have been proven!—from quantum mechanics, string theory, and M-theory would all arise naturally. What about mere mortals creating a universe?
Robert A. Metzger did just that in his novel Picoverse. His protagonist used highly focused energy to create an artificial singularity, from which, in a mini-Big Bang, his pocket universe developed.15
On a lighter note, the Futurama episode "The Why of Fry" has our everyman hero vanquish an existential threat into a pocket universe to protect our own Universe.
Can one create a universe? Sure. But it takes...
An inflated ego
The birth of the Universe in a Big Bang is perhaps the best known concept of modern cosmology, but the Big Bang alone does not explain the nature of the visible Universe.
A case in point (and simplifying furiously): regions of the visible Universe very distant from one another—still separating, almost 14 billion years later, in the aftermath of the Big Bang—look remarkably similar in structure. Such homogeneity would be expected if the very early Universe were well-mixed. Alas, the universe's observed rates of expansion, coupled with Big Bang theory, suggest expansion proceeded faster than would allow early mixing to be sufficiently thorough.
Enter the theory of cosmic inflation.
To start, forget the rates of cosmic expansion that astronomers observe. Assume the earliest expansion was slow enough to accommodate thorough mixing. Follow that initial phase with a period of extremely rapid expansion. Finally, slow to a third rate, the expansion as astronomers now observe it.16
That middle stage is cosmic inflation.
The math works if, in that middle stage, the Universe inflates much faster than the speed of light. Such expansion wouldn't violate relativity's well-known light-speed limit. Objects can't move through space faster than light— but space-time isn't a thing.
Inflation theory, because it explains the Universe's large-scale homogeneity (and several more otherwise troublesome observations about the Universe), is widely accepted by cosmologists. And inflation raises new questions, as all good theories do, such as: what drives the inflation process? What starts and stops inflation?
Cosmologists envision a universal "inflaton" field that drives inflation. Just as electric fields have a complementary relationship with electrons, the inflaton field has a complementary relationship with (the yet to be detected) inflaton particles. And particles have these pesky quantum indeterminacies...
A discussion of cosmic inflation would require an essay in its own right, so we'll keep things at a high level. It suffices for our purposes to note that a quantum fluctuation in the (still purely hypothetical) ever-expanding inflaton field can create a region in which inflation spontaneously halts. A region within which natural quantum fluctuation—or a clever protagonist—might later create a new region of expansion....
In sum, cosmic inflation theory suggests an ever-expanding number of universes embedded within an ever growing larger multiverse. Picture it (per astrophysicist's Brian Greene's evocative turn of phrase) as the Swiss cheese cosmos.
One bit at a time
And with cheap humor, we segue from physical to digital alternate realities.
Many of us interact with other worlds—programmed worlds—all the time. We have a wide choice. Shoot-'em-up worlds, as in the game franchises BioShock and Warhammer. Roll your own worlds, as in the game Sim Earth. Hang-with-the-denizens worlds, like the virtual community Second Life.
Suppose computers and simulation software continue to improve. Why wouldn't they? Might not simulated domains come to seem entirely real?
Do you accept that possibility? Then it's not a big leap to suppose a civilization only slightly more advanced than ours would already have developed such a virtual world. And once you accept that premise, how do you know we don't live inside the simulation? That we don't live in the Matrix?17... As, long before The Matrix, Daniel F. Galouye's hero came to wonder in Simulacron 3 (the basis of the movie The Thirteenth Floor ).
At least Galouye's hero was a human simulation developed by a human being. Matters aren't as straightforward when the virtual-world "ents" in James P. Hogan's Entoverse find a way to impinge on the outer/physical world.
Meet the Sims
Suppose our Universe is a simulation. Can we find that out?
Maybe.
Before we dive into the nature of computer simulation, we'll consider an analogy: representing a real-world scene on a TV screen.
From a distance your hi-def TV looks, well, awesome. That's not to say its picture is perfect. It doesn't present the totality of the object on the other side of the camera (even if you have a 3-D TV). A finite number of pixels can represent only a finite amount of visual detail.
Imagine a car commercial. That sleek sports car has a lustrous finish, and each paint molecule receives and reflects the ambient light slightly differently. That paint coat is comprised of many more molecules than the screen's ~2 million pixels (or your retina's ~120 million photoreceptors). So: the reflections off nearby paint molecules have been aggregated. Averaged values determine the color and brightness levels of each pixel. Detail has been lost, although (for this example, anyway), likely not enough detail for you to notice any difference.
Now we'll consider a sophisticated digital simulation. Just as a TV doesn't (can't!) represent the reflection from each molecule in a scene, a climate simulation doesn't model the behavior of every gas molecule in the atmosphere. Climate models treat great expanses of atmosphere as though each were a single entity. A conceptual box of air kilometers on a side is represented by an average temperature, pressure, humidity, etc.18
To recap, the TV screen simplifies the detail of a physical scene to map the scene into the available pixels. A climate model likewise makes simplifying assumptions to render its calculations manageable. Perhaps a universe simulator doesn't attempt to calculate the behavior of every photon, electron, and quark in that universe. That is, perhaps the universe simulation is only precise to the resolution of its own representational grid.
Do we live inside a simulation? If it can be shown that the behavior of the Universe is artificially simplified or constrained (and—a high hurdle—that there is no other explanation for the observation), then yes.
Scientists at the University of Bonn have made one such search. Just maybe, the distribution across astronomic distances of high-energy cosmic rays denotes the presence of an underlying simulation grid.19
And greater (simulated) fleas have lesser (simulated) fleas...
As technology improves, our simulations become so much more realistic. If that's not self-evident, compare high-end videogames from, say, ten years ago to the latest games.
How close are humans to constructing a simulation that would seem realistic to its resident Sims
?
I'll venture to say, fairly close—and that has an interesting implication.
Humanity has learned, time and again, that nothing is special about our place in the Universe. Earth isn't the center of existence. Neither is our Sun, nor our galaxy. Now let's extend that Mediocrity Principle.
Suppose that, in the near future, humans develop simulations complete and detailed enough to seem real to their (simulated) inhabitants. In time, mightn't those Sims accomplish the same? Then their next-generation Sims? And theirs?
As soon as one envisions that sequence of simulations, it's hard to see on what basis we would suppose our existence is the first in the chain. And if we are anything but the first in the chain, then our Universe isn't physical.
Whodunit?
Suppose we exist in a simulated universe. Who built it, and why?
Brilliant and ethical scientists, one would hope, if merely to salve our already bruised (simulated) egos.20 To accomplish an important—if not revealed to us—purpose.
(I am reminded of Douglas Adams's The Hitchhikers Guide to the Galaxy. Remember the transdimensional mice who commissioned the construction of a planet-sized biological computer? Earth, it was called. Humanity's purpose—entirely unbeknownst to us—was computing the Question to the Answer to the Question of Life, the Universe, and Everything. Humanity was scant minutes from completing that eons-long calculation when the reflexively bureaucratic Vogons destroyed Earth to make way for a hyperspace bypass.)
If not brilliant scientists, then who? Über-dimensional hackers, perhaps. Students enrolled in Universes 101—or Psych 101. An ad agency dry-running possible marketing campaigns (as in Galouye's Simulacron 3 ). An entertainment company crafting a more realistic virtual-reality game (as in my short story here, in the June 2010 issue, "A Time for Heroes").
Like any technology, universe simulation will become easier with practice. The hard work will be done by tools, with the user contribution reduced to specifying a few key parameters or picking options from a list.
One final analogy...
To unleash nasty computer malware into the world once required great skill. To launch an original virus, worm, or Trojan horse still does. To tweak malware is much easier, and cybersecurity experts speak dismissively of copycat attack software as the product of "script kiddies."
Was our Universe built by a script kiddie, for no lofty purpose? Per the Mediocrity Principle, that seems plausible.
At least, before losing interest, he/she/it let me finish writing this article.
To Read Further:
The Hidden Reality: Parallel Universes and the Deep Laws of the Cosmos, Brian Greene.
Hiding in the Mirror: The quest for alternate realities, from Plato to String Theory (by way of Alice in Wonderland, Einstein, and The Twilight Zone), Lawrence M. Krauss.
Uncertainty: Einstein, Heisenberg, Bohr, and the Struggle for the Soul of Science, David Lindley.
The Trouble with Physics:The Rise of String Theory, the Fall of a Science, andWhat Comes Next, Lee Smolin.
Taking the Red Pill: Science, Philosophy and the Religion in the Matrix, Glenn Yeffeth (editor).
"Is Our World Just a Computer Simulation?", John G. Cramer, Analog, July/August 2013.
http://en.wikipedia.org/wiki/List_of_fiction_employing_parallel_universes.
Footnotes:
1 Here's a twist: Inferno by Larry Niven and Jerry Pournelle. The hero, a science-fiction author, after plummeting from a hotel window, awakens into (Dante's) Inferno- like surroundings. He spends most of the novel trying—and failing—to explain this place in scientific terms, only to conclude he is in Hell. The story is supernatural, not SF.
2 See http://en.wikipedia.org/wiki/Counter-Earth#Greek_philosophy.
3 Begun with "Audubon in Atlantis" ( Analog, December 2005) and "The Scarlet Band" ( Analog, May 2006).
4 It's the case Stanley Schmidt, Analog 's previous editor, did make. See "Alternatives Past and Future," in the January/February 2011 issue.
5 Two of my favorite paratime stories appeared in this magazine: "Gunpowder God" (November 1964 issue) and "Down Styphon" (November 1965 issue).
6 Per the Joss Whedon TV series Buffy the Vampire Slayer and its spin-off, Angel.
7 Einstein made similar comments on several occasions. In a more complete statement, he said, "Quantum mechanics is certainly imposing. But an inner voice tells me that it is not yet the real thing. The theory says a lot, but does not really bring us any closer to the secret of the 'old one.' I, at any rate, am convinced that He does not throw dice."
8 "Why quantum mechanics is an "embarrassment" to science," Washington Post, February 7, 2013 ( http://www.washingtonpost.com/blogs/wonkblog/wp/2013/02/07/quantum-mechanicsis-an-embarrassment/ ).
And the plurality winner? The Copenhagen Interpretation, named after the venue where many of the theory's early luminaries debated these issues. Or, as I like to call it, QM's "Don't ask" interpretation.
9 "The Most Embarrassing Graph in Modern Physics," Sean Carroll ( http://www.preposterousuni verse.com/blog/2013/01/17/the-most-embarrassing-graph-in-modern-physics/ ).
10 The paradox: if I travel back in time and kill my own grandfather, how did I come to exist? But if I never existed, then clearly I didn't kill my grandfather. So I do come to exist, and can travel backward in time. So... (Great authorial fun, in any event. See my Probability Zero story "Grandpa?" in Analog 's July/August 2001 issue.)
The paradox goes away when the time traveler commits murder in someone else's universe.
11 Despite similar names, the strings of string theory and the cosmic strings of cosmology are unrelated.
12 Eleven dimensions aren't too many for some theorists, but two syllables are. Go figure.
13 One of those differing characteristics being, perhaps, the speed of light. That's why I touched on M-theory in an earlier essay in this series: "Faster than a Speeding Photon," January/February 2012 issue.
14 And if the encounters aren't gentle? Colliding branes offer a competitive model to the Big Bang for the origin of our Universe. See: "Questioning the Big Bang: Could universe follow a cycle without end?" at http://www.nbcnews.com/id/3077357/.
15 A singularity is a point in space-time at which mass/energy has been compressed to infinite density. Like a black hole. Or (reversing your mental image of galaxies flying apart) the origin from which the Big Bang emerged.
(Alas, the Universe's pre-Big Bang nature is nothing as simple as a single point. Everywhere in the Universe is flying apart from everywhere else. When someone in a distant galaxy runs the cosmic clock backwards, it looks to her as though everything originated there.)
16 More precisely, the time-varying rate of expansion for the era of the universe accessible to astronomy. The period of cosmic inflation had long concluded before the post-Big Bang particle soup cooled enough to end the Universe's so-called Dark Ages. There is no light old enough for astronomers to see the era of cosmic inflation.
17 I speak to the overall concept of that movie franchise, of a world-spanning simulation. Don't get me started on the more comic-book-like aspects, such as humans used as batteries!
18 In contrast with the loss of precision in how that shiny car appears in the commercial, a climate model's loss of resolution can have consequences. These models can't accurately take into account the climate effects of clouds smaller than the grid's granularity.
19 See "Cosmic rays offer clue our universe could be a computer simulation," Ian Steadman, http://www.wired.co.uk/news/archive/2012-10/11/universe-computer-simulation.
20 Almost certainly those progenitors are also virtual, merely an iteration earlier in the sequence than we are.
Remembering
FREDERIK POHL, 1919-2013
Frederik Pohl, one of the most versatile and influential individuals in the history of science fiction, died on Monday, September 2, 2013, hours after entering a hospital near his home in Palatine, Illinois with respiratory distress. Born November 26, 1919
, in Brooklyn, New York, he did just about everything there is to do in the field of science fiction, and quite a bit outside it.
In his teens, he was one of the founders of the Futurians, one of the first prominent science fiction fan organizations, with influence extending beyond fandom into the development of science fiction itself. Like many of the group's members, Fred became an important professional author, winning multiple Hugo, Nebula, and other awards for both short fiction and novels such as Gateway and Man Plus. He also received a Grand Master Nebula and served as president of the Science Fiction Writers of America. His stories and novels, some of which appeared in this magazine, often featured mind-stretchingly imaginative ideas and innovative approaches to storytelling. His nonfiction was as diverse as Encyclopaedia Britannica articles on the Roman emperor Tiberius and his own autobiography The Way the Future Was. He remained an active writer to the end of his life, and, unlike many of his generation, adapted easily to changing technologies and publishing ways such as blogging.
In addition to his own solo writing, he worked well with others in many capacities. He often collaborated with other writers, notably Cyril M. Kornbluth and Jack Williamson. Sometimes he acted as literary agent for other authors, and was an award-winning editor of both magazines and books. Much in demand as a lecturer on topics such as futurology, he was always ready to point out that the future can't really be predicted and, while science fiction is often said to be about the future, "it's not about the future."
He will be missed greatly by his wife, Dr. Elizabeth Anne Hull, several children and grandchildren, and a great many others whose lives he touched in a wide variety of ways.
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