Sunday, March 3, 2019

Parallel Universes

Could there really be parallel universes?  Whole other universes that exist somewhere, somehow outside or alongside or within our own universe or in some mysterious relationship to our universe?  Can we find out anything about them? Can we get to them? Can we communicate with sentient beings inside them?  I believe your guess is as good as anyone’s.  Which is to say, I think no one really knows.  Which is also to say all of the above might just be possible!  

There are certain premises in science fiction that are dead letters because they are

1. beaten-to-death clichés, or

2. pernicious because of what they imply, or

3. simply stupid to speculate about because of what scientists have repeatedly shown us.  Among these are , faster than light travel, time travel, and, in my opinion, as of 2019, space travel (see my blog post). 

You might think the parallel universe premise would fall into at least one of the above categories.  I don’t think so.

Let’s examine the parallel universe premise from the standpoint of the three criteria I’ve imperiously defined above.  Are parallel universes dead horse clichés?  They do show up a lot. They have featured in some of the very best science fiction. If anything about P.K. Dick’s writing can be described as a “staple,” it’s the parallel universe. In Dick’s writing, people move between parallel universes, they create parallel universes (The World Jones Made), and they join each other in secret trysts in the same parallel universe by taking a certain drug at the same time (The Three Stigmata of Palmer Eldritch). Dick’s parallel universes sometimes even bleed into each other.  One of Dick’s little-known influences, Frederic Brown, spun out one of the best parallel universe stories in his 1949 novel What Mad Universe.  These are some of my favorite science fiction stories of all time.  These stories aren’t clichés because the parallel universe is used as an effective literary device, providing opportunities for characters to do things and compare things they otherwise couldn’t.  But the idea of a parallel universe is not a cliché for another reason as well: it is such a broad idea.  It’s not just an expedient like time travel.  All fantasy worlds and alternate histories could be considered parallel universes.  A huge variety of alternative reality stories have been written.1 Indeed, the very idea of writing a fictional story might be considered creation of an alternative universe. 

But the science fiction parallel universe I’m talking about, in my opening paragraph above, is more limited.  It’s one that can have some kind of interaction with the reader’s everyday universe.  These universes are “parallel” rather than simply “other” because they have some kind of relationship to our own. That’s what is in Dick’s and Brown’s universes, and those contemplated by Heinlein, Zelazny, Moorcock, Borges, Lewis Carroll and many others.  And even thus limited, there is still a huge variety.  Whole universes worth. 

Is there anything pernicious about promoting the idea of a parallel universe? The idea of such a universe is not pernicious in itself, as I believe promoting space travel currently is, because the parallel universe idea encompasses so much territory. Some might consider escapism pernicious, or at best a waste of time. Maybe so. But in any case, the better parallel universe stories are not simply escapist. They allow us to bring into focus contrasts among real things, and real potential things, in unique ways. 

What does science say about the reality of parallel universes?  To me, the most interesting parallel universes are those that might be real instead of just effective literary devices. Scientists working at the limits of what we can know, the biggest things and the smallest things, have proposed two kinds of parallel universe. 

At the small end of things, the most fundamental interactions of matter and energy, those among photons, atoms and their constituent parts are governed by the equations of quantum mechanics.  These equations come from the results of real experiments (usually real expensive too) with these fundamental particles and forces.  They imply some bizarre things, like instantaneous correlation of distant events, and things existing in two mutually exclusive conditions until they interact with something else. One of the interpretations of quantum behavior that is supported by some very reputable physicists is called the “many worlds” theory.2  It is controversial because it has not been either proved or disproved, yet it provides elegant solutions to the quantum equations. Some highly respected physicists consider it plausible, if bizarre.  It postulates that every physical interaction that has an element of quantum uncertainty generates separate realities for each possible outcome.  That means an unfathomable number of separate universes.  For science fiction, that means infinite speculation territory. 

At the biggest end of things there’s cosmology, the study of the universe as a whole. We normally think of the universe as being everything, including all space, matter, energy, thought, and all people.  Cosmologists have reduced the universe we know to a thing that can be looked upon from outside, in our imaginations. They describe the whole thing’s behavior in a single equation.3 They measure a wide variety of things across the sky, from changes in stars’ light spectrums that show they are all moving away from each other, to space-filling microwave radiation that could only have come from the hot soup of electrons and nuclear particles giving off energy as they cooled and settled into ordinary atoms in the early universe, to the ratio of hydrogen and helium in stars and space, that confirms how that hot soup formed the atomic nuclei that everything is made of. The data show that the whole universe has been expanding and cooling since its creation. Cosmologists, using their observations, trace the expansion back to a very tiny and very hot space from which the whole universe exploded, and call the explosion the big bang.  They can trace it back to an age of one trillionth of a second after creation, during which time the entire universe expanded from less than a millimeter in size to about the size of our current solar system, and had an average temperature of 10 quadrillion degrees Celsius.4  And using these same data, cosmologists propose that the big bang, the beginning of this universe we know, may have spawned not just the universe we know but a multiverse, an infinite number of co-existing universes.5 

How could there be interactions with these hypothesized parallel universes? At the quantum level, the many worlds seem to be blossoming in some kind of very close proximity, since multiple realities are spawned by the same microscopic events.  Who is to say there couldn’t be some collective interactions?  And for the separate universes of the multiverse, it’s been suggested that they could each have different basic laws of nature than our own.  Who can say this wouldn’t allow some kind of interaction in specific cases?  The point here is we don’t know at all.  There is nothing that says how likely or unlikely interactions between parallel universes could be.  It’s wide open for speculation.   
Parallel universes are not hackneyed science fiction crutches as are space travel, time travel and faster-than-light travel.  All of those crutches rely on assumptions which scientists tell us are highly unlikely.  That’s not the case for parallel universes. Both the quantum many worlds idea and the cosmic multiverse idea are based on careful reasoning from experimental data and from cosmological observations, and have been vetted by many respectable scientists in these fields.  The verdict for both is: plausible but unproven.  Plausible but unproven is what science fiction is all about.  There are so many ways to think about parallel universes. 

[1] The Wikipedia Article on Parallel Universes is amusing and replete, to the extent of irritating the Wikipedia editors.

[2] Penrose, Roger, The Road to Reality (2004), Section 21.11

[3] The Friedmann equation, which uses Einstein’s general relativity theory to describe the behavior of the entire universe.  See Weinberg, Steven, The First Three Minutes (1977), Chapter 11 The Expansion of the Universe. It’s old but still valid and a good explanation.

[4] Ryden, Barbara, Introduction to Cosmology, 2nd ed. (2017), Chap. 10 Inflation and the Very Early Universe.

Saturday, January 5, 2019

Mysteries Still Abound

The public face of science focuses on its accomplishments: what it has nailed down about our universe.  There is an understandable tendency to de-emphasize the unknown, especially for those issues that persist in being mysterious despite long and costly efforts. For some of us, particularly science fiction lovers, this tendency to put a cork in the mystery bottle is sad because we love the unknown.
Media reports on science give the impression that science has erected a solid framework for understanding the universe, except for a few interesting issues yet to resolve.  A “standard model” has been constructed for all of the elementary forces and sub-atomic particles that make up our world, and the universe has been reduced to a tidy pie-chart that shows how little of ordinary matter makes up our universe.  “Dark matter” and “dark energy,” which gobble up most of the pie, are presented as things we have a handle on, understand well enough to put a precise percentage on them in the big pie chart of the universe.
Reports of the discovery of the Higgs boson in 2012 said that it put the last building block into the standard model and confirmed its validity.  Confirming the Higgs boson, which was predicted by standard model physics, was a great achievement, but there are wide dark patches in elementary physics that aren’t explained at all by the standard model.  In fact, darkness overwhelms the light. One of the dark areas is the “dark energy” of the universe. What is termed “dark energy” is whatever is causing everything in the universe to accelerate away from everything else.  Because it’s accelerating, it means there is some force driving everything away from everything else, some kind of energy, like when you step on the gas.  But what that energy is, is a complete and total mystery.  The astronomers who discovered the acceleration in 1998 were expecting, based on currently accepted theories, to measure how fast the well-known outward expansion of the universe was slowing down, not speeding up.  In the words of Alex Filippenko, one of those astronomers, it was as if “we were doing a multiple-choice exam and the right answer was not one of the choices.”  In the twenty ensuing years, little progress has been made in solving the mystery, in spite of the many references to dark energy as if it were a familiar thing.  A calculation was made of how much energy must be involved to make the universal expansion accelerate like it does, and that energy is so enormous that it must account for 68% of everything in the universe, including all the stars, planets, and galaxies.1 That’s where the percentage in the pie chart comes from.  We don’t know anything more about it than that.  It defies any explanation. The best guess of what it might be comes from high-energy physics, in which a universal energy field known as a scalar field might behave as the “dark energy” does.  The Higgs is such a scalar field.  But there’s no field in the standard model that explains the accelerating universe. There are other big holes in the standard model.  Like gravity.  No explanation at all for it, or how all those particles in the standard model that make up mass as we know it are affected by or affect gravity.  Or why neutrinos have mass, also discovered in 19982, and which is unexpected according to the standard model.  Dark matter is a different matter entirely, being something that is known to be affected by gravity and affects how galaxies spin and move around in clusters but is otherwise not detectable, making it something unlike any other kind of matter.  Calculations based on how much it affects galaxy movements indicate its total mass must be 27% of all the matter in the universe, far more than the ordinary matter we and our earth and our sun are made of, which is less than 5%.  Whatever dark matter and dark energy are, they don’t seem to be in the standard model.  

Some of the biggest mysteries of the elementary particles and forces in the standard model are associated with their quantum nature.  Personally, the big mysteries of dark energy and dark matter leave me a bit stunned, but the mysteries of quantum mechanics make me say “Wow, that’s amazing!” Quantum mechanics originated in the discovery that the smallest amounts of energy must come in well-defined chunks, even for things that behave precisely like waves, like light and infrared radiation. This discovery was made by Max Planck at the end of the 19th century to explain why light with really short frequencies, in the ultra-violet range, is radiated by hot things at lower intensities than other light in the spectrum: it is limited by being broken up into little chunks.  This defines the spectrum of light that we see from stars, including our sun, which is a spectrum that is really important to us.  Sunlight would be very different and the ultraviolet would kill us all if it weren’t for the exact size of these light chunks and the way they determine the intensity of the different colors in the rainbow.  And it also determines the way that electrons arrange themselves in atoms, which in turn determines everything about chemistry.  

Experiments at the very small quantum level reveal some really mysterious behavior, which is still mysterious after nearly a century of experiments, theorizing, and debating. This bizarre behavior and the history of thinking about it is elucidated in a couple of excellent books published in 2018.  In Adam Becker’s What is Real? The Unfinished Quest for the Meaning of Quantum Physics, the emphasis is very strongly on the word meaning in his title.  The major theme is the great divergence between practical application of the mathematical theory of quantum mechanics and our understanding of what it all means.  This divergence hasn’t narrowed since the math of quantum mechanics was formulated almost a century ago.  Unlike Newton’s theories of gravity, mass, and other forces, which can be explained intelligibly in words and picture concepts, quantum mechanics simply cannot.  “Nobody understands quantum mechanics,” said Richard Feynman3, who greatly advanced its science.  In discussing why a young physicist’s career disintegrated, Steven Weinberg, one of the great contributors to the standard model, quoted a colleague as saying, sadly “He tried to understand quantum mechanics.”4  Some of the most fundamental equations of quantum mechanics were formulated by Werner Heisenberg, who arrived at them by “careful guessing” based on experimental results.  Heisenberg’s resulting “matrix mechanics” and Schrödinger’s wave function, which is used today, only describe the probabilities of what will happen during interactions of fundamental particles.  Many of the debates among physicists in the early days of quantum mechanics argued that the mathematical theory gave correct predictions but wasn’t satisfactory because it was unintelligible.5  There’s no “mental model,” only equations that describe probabilities.  This bothered Einstein so much he disavowed quantum mechanics, in spite of his early contributions to it.  

Becker traces the history of efforts to understand the foundations and meaning behind the equations, which continue while the “shut up and calculate” consensus has proceeded to use the mathematical theory to produce results used in many practical applications including nuclear reactors, micro-electronics, particle accelerators, and, unfortunately, weapons.   What stands out is how research and debate on the fundamentals is always relegated to the backwaters of physics, dismissed and even disparaged by the mainstream pursuing practical results.  Yet the biggest mysteries in quantum mechanics are in its fundamentals.  Some of the most outstanding are:

  •  How can something be in two places at the same time, which quantum experiments have proved true?  (This is known as the non-locality problem, to give it the proper jargon.)
  • How can physical processes be random, governed by probabilities rather than deterministic cause and effect? (Known as the indeterminism problem.)
  • How can objects at the quantum level be in two mutually exclusive conditions at the same time? (Known as superposition. This is the famous “Schrodinger’s cat” problem in which an experiment that would kill the cat in one quantum condition but not in the other are in superposition, but before the experiment is performed the cat can be either, or neither, or perhaps both dead and alive.)
  • What is the role of the “observer” in events at the quantum level?  (Known as the measurement problem.) As per the problem with Schrodinger’s cat, the quantum superposition of mutually exclusive conditions collapses whenever a measurement is made.  What makes this transition from the micro, quantum world to the macro world occur?  Some have seriously suggested it is an effect of human consciousness. 

Anil Ananthaswamy’s Through Two Doors at Once – The Elegant Experiment That Captures the Enigma of Our Quantum Reality, uses a famous quantum experiment, the “double-slit” experiment, to illustrate a number of the fundamental features of quantum mechanics.  It’s got some of the best plain-language explanations of quantum phenomena I’ve seen.  The double-slit experiment displays the wave-particle duality of quantum chunks of light, which we know as photons.  Light shining through two vertical slits in an otherwise opaque barrier displays evidence of being a wave.  Just like circular water waves generated by dropping two stones at the same time on a pond surface, the waves of light going through two narrow slits produce circular waves that pile up on each other downstream at some locations wherever two wave crests coincide and cancel each other wherever a wave bottom from one circle and a crest from the other coincide.  With light, this shows up as a pattern of light and dark vertical bands on a photographic plate catching the light on the far side of the slits from the light source.  But when the light source is reduced to almost nothing, the light comes through in those little chunks, and individual photons appear on the photo as small dots, one at a time in sequence over time.  You would think there could be no light and dark bands because each photon, which is an irreducible quantum chunk, must go through only one slit.  And indeed, each photon dot on the photo shows up in only one location.  But over time, amazingly, the photon dots build up a pattern of vertical bands, just as if they were waves!  How could this be possible?  No one knows. This is an example of the non-locality problem.  Each irreducible chunk must be present in some weird way in both of the two pathways through the two slits to the photo film.  If there’s only one slit there’s no light and dark bands.
The book traces the history of double-slit experiment results and more elaborate experiments with mirrors and beam splitters that also demonstrate photon non-locality.  These latter share with the true double-slit experiment the key ingredient: they provide two simultaneous potential pathways for the photons, which then cause photons to show up as if they are interfering with themselves. Also described in Ananthaswamy’s book are experiments which show how beams of electrons, that is, matter instead of light, also display the same wave-particle duality.  This is really important, since we don’t normally think of matter as being composed of waves, do we?  Yet the papers reporting experiments proving this behavior with electrons using early electron microscopes in the 1950s sat untranslated from German in an obscure publication for years, unknown even to famous physicists who speculated in the 1960s that it might be demonstrated some day.  The demonstration just wasn’t important to the practical probability calculations that physicists were most concerned with. 

The slow progress in the foundations of quantum physics only deepens the mysteries.  This is wonderful for people who like to speculate.  But much of the speculation about quantum mysteries today in science fiction is based on misunderstandings.  For example, the potential for human consciousness to mysteriously affect quantum phenomena.  As described by the careful history related in Becker’s book, there is no basis for this particular weird idea, which some physicists have postulated; there are more likely explanations for the collapse of quantum superpositions when measurements are made.  On the other hand, the locality problem – one thing spanning a large space across which random changes are instantaneously correlated, has been irrefutably proven by experiments proving something called Bell’s theorem.
Some of the most interesting areas for valid speculation appear to be:

  • Indeterminism: What are the implications of the randomness in nature that appears to be fundamental according to quantum mechanics?  Can it be the basis for a concept of free will?

  •  Non-locality: How can things be in two places at once, and can there be instantaneously correlated random changes in two objects separated by a large distance, violating the speed-of-light limitation of Einstein’s relativity?  What does this mean for our concepts of space and time?

  • Consciousness:  Can quantum superpositions and quantum randomness somehow be important in understanding how our brains produce consciousness?  (This speculation would be how quantum mechanics affects consciousness, not the other way around.)

But the biggest thing to wonder about is whether the seemingly bizarre behavior of quantum phenomena might be giving us a peek at some underlying reality that explains them.  Informed speculation on the fundamentals of quantum reality might just provide a breakthrough that shutting up and focusing on refining the calculations could never arrive at. 

There’s plenty of mystery in the universe for us to wonder about.

[1] The mass of stars, planets, galaxies and all other matter are converted to energy for this calculation using Einstein’s famous equation E = mc2, energy is equal to mass times the constant speed of light squared.
[3] Richard P. Feynman, The Messenger Lectures, 1964, MIT
[4] Weinberg. S., Dreams of a Final Theory, 1992, p. 84.
[5] The German word Anschaulichkeit was used in the debate, which means picturable, intelligible, intuitive, or clear. This was a major theme of the great summit of early quantum physicists known as the Fifth Solvay conference in 1927, described in detail in Bacciagaluppi and Valentini, Quantum Theory at the Crossroads, 2009: