Most people would not turn to mathematics for a message of spiritual hope, but there it is.
* * *
As this darkened universe expands and cools, lower-energy quanta (or, equivalently, radiation at longer and longer wavelengths) can store or transmit information. Just as an infinite series can have a finite sum (for instance, 1 + 1/2 + 1/4 + ........ = 2), there is perhaps, in principle, no limit to the amount of information processing that could be achieved with a finite expenditure of energy. Any conceivable form of life would have to keep ever-cooler, think slowly, and hibernate for ever-longer periods.
But there would be time to think every thought, Dyson believed, even in the face of the heat death. As Woody Allen once said, "Eternity is very long, especially toward the end."
Life that keeps its temperature fixed will not make it, though. It will eventually exhaust its energy store. The secret of survival will be to cool down as the universe cools. Being frugal means you could dole out in ever-smaller amounts the energy necessary to live and think.
Silicon or even dust could form the physical basis of such enduring life, at least until the protons decay. After that, there is no fundamental reason that information cannot be lodged in electron-positron plasmas, or even atoms made from them. "Positronium" is an "atom" of a positron, an anti-electron, orbiting with an electron, much like a hydrogen atom. In September, 2002, a European group succeeded in producing tens of thousands of them in a magnetic bottle, so they could conceivably be used to build solid structures of a wholly new sort.
No matter what the basis of life is, the crucial distinction for far-future thinkers is their method of storing information. In our computer-saturated world, using information defines life—active flow, not mere passive storage.
Life tends to be defined in terms of the reigning paradigm of the time, so in our computer age we make a crucial distinction. There are two choices: analog or digital.
Old fashioned LPs are analog; CDs are digital. Cosmologist Fred Hoyle's ominous Black Cloud, imagined in a novel in the 1950s, was analog, storing its memories in magnetic fields and dust particles. A human mind uploaded into a computer would be digital life.
Are our brains analog or digital? We do not know, as yet. But this point became the battleground between Dyson and a bevy of physicists, including Larry Krauss of Case Western University. In The Physics of Star Trek Krauss tried to make sense of the mangled science in Trek. Many of his colleagues suspected his motives were less that of informing the masses than making money, and his challenge to Dyson had the quality of a young buck butting heads with an aging bull. The debate got rarefied right away, including lengthy calculations on the thermodynamics of ultracold, with quantum mechanics for dessert.
Our genetic information carried in DNA is clearly digital, coded in a four-letter alphabet. But the active information in our brains remains mysterious. Memories live in the strengths of synaptic connections between billions of neurons, but we do not fathom how these strengths are laid down or varied. Perhaps memory is partly digital and partly analog; there is no reason the methods cannot blend.
If we are partly analog, then perhaps the hope of the brain-downloading method will be only partly fulfilled, and some of our more fine-grade thoughts and feelings will not make it into a digital representation.
Actually, the analog/digital divide may not be the whole story. Some theorists think the brain may be a quantum computer, keeping information in quantized states of atoms. But since we know little about quantum computers beyond their mere possibility, the argument over in-principle methods has fastened upon analog vs. digital.
Interestingly, the long-term prospects of digital intelligences are not the same as analog forms. Krauss leaned heavily on a digital determinism, which shaded quickly into pessimism. Dyson stood his analog ground.
That there is any contest at all may surprise some, since we are so used to analog tools like slide rules giving way to digital ones like hand calculators. The essential difference is that analog methods deal with continuous variables while digital ones use discrete counting.
Surprisingly, analog wins, digital loses. It turns out that the laws of physics allow a thrifty, energy-hoarding information machine (life) to persist, but not a digital one.
The reasons are fairly arcane, involving the quantum theory of information storage. Still, one can think of a digital system as having rachets that, once kicked forward, cannot go back. As the universe cools, you eventually can't kick the rachet far enough forward. But a smooth system can inch up as much as you like, storing memories in smaller and smaller increments of energy.
Life can use hibernation to extend its analog form indefinitely. Like bears, it can adapt to falling temperatures by sleeping for progressively longer cosmic naps. Awake, it spends its energy reserves at unsustainable levels. Asleep, it accumulates.
It turns out further that such life can communicate with other minds over the great distances between galaxies, too. Energy reserves can dwindle, but so does the noise background in the universe, as expansion cools the night sky.
Communication depends not on signal strength (energy) but on the ratio of signal to noise. A cold, expanding universe is friendly to the growth of intergalactic networks. Life will have ample time to wait for an answer from, say, the Andromeda galaxy, without worrying about being able to hear the reply.
But not all is well for analog life if the universe continues to accelerate forever. At some distance, the repulsive force that causes this acceleration must win out over gravity's attraction. So galaxies further away than this critical distance will accelerate beyond view, setting the limit on the size of structures that life can build. This ultimately dooms it.
So to persist forever, life needs to be analog and the universe must not be accelerating forever. The first is an engineering requirement, and presumably savvy life forms will heed it. The second we can do nothing about, unless somehow life can alter the very cosmological nature of our universe—surely a tall order.
We do not yet know (and may not for quite a while) whether the acceleration will slow, because we do not know its cause. This is the biggest riddle in cosmology, and many are pursuing it. The Dyson-Krauss dispute rages still in the hallowed pages of Physical Review. Dyson's own vaguely optimistic theology clashes with Krauss's apparent atheism. They are reprising an ancient difference in tastes over the deepest issue: is there any discernible purpose to the universe? And does human action mean anything on this vast stage?
* * *
These long-range projections over zillions of years involve fascinating physics, most of which is quite well understood... but not all of it.
First, we can't be absolutely sure that the regions beyond our present horizon are like the parts of the universe we see. Just as on the ocean, there could be something amazing just over the horizon.
Physicists John Barrow and Frank Tipler have pointed out that a new source of energy—so-called "shear-energy"—would become available if the universe expanded at different rates in different directions. This shearing of space-time itself could power the diaphanous electron-positron plasmas forever, if the imbalance in directions persists. To harness it, life (whatever its form) would have to build "engines" that worked on the expansion of the universe itself.
Such ideas imply huge structures the size of galaxies, yet thin and able to stretch, as the space-time they are immersed in swells faster along one axis than another. This motor would work like a set of elastic bands that stretch and release, as the universal expansion proceeds. Only very ambitious life that has mastered immense scales could thrive. They would seem like Gods to us.
As well, our universe could eventually be crushed by denser material not yet in view. Or the smoothing out of mass on large scales may not continue indefinitely. There could be a new range of structures, on scales far larger than the part of the universe that we have so far seen.
Physics can tell us nothing of these, as yet. These ideas will probably loom l
arger as we learn more about the destiny of all visible Creation.
Or... Even more fundamentally, maybe time itself is a hominid illusion, not fundamental at all. It might rather be an emergent property of some deeper structure to be revealed. Our human temporal anxiety would then be a passing fashion, not a feature of the universal destiny. This idea may be more sobering than even the cold comfort awaiting us "way up ahead."
Finally, what can one infer from physics about theology?
It is tempting to suppose that a God who made such a universe might, as narrative-addicted humans do, think that the end of a story tells its meaning. If all order is to be leached away by eternal cold, what did the building of such structure by intelligence amount to? Put differently, what is the meaning of human action?
Perhaps nothing, if the fate of all order is mere ruin. If it is not, and Dyson proves right, we might turn to another Dyson idea: that the universe has been designed to be the most interesting possible. This means that variations arise and abound, then evolve and finally aspire to greater heights.
So in the end our choice of endings implies a choice of the Designer behind it all.
One wonders if, once the theoretical physics is settled, the outcome will provoke fresh theological thinking. If intelligence can persist forever in principle, will this result be used in a new form of the Argument from Design?
Conversely, if life cannot survive, will atheists make this into an argument for no God, or for a God with a perverse (to us) purpose?
Either way, the debate will be made more interesting by the injection of a new set of physical facts. Science fiction's role is to explore the human implications. Hot topics like the possibility of other dimensions in which different universes dwell ("branes" for membranes; not a great scientific shorthand) will be experimentally checkable within perhaps five to ten years.
Such exotic notions will provoke much fiction—already has, in my Beyond Infinity. The accelerating expansion might itself accelerate, leading to the "big rip" which shreds atoms, erasing all information—truly a horrifying prospect, if you think Shakespeare's works should live forever. Surely this is a grand, Wagnerian struggle worthy of life in the far future.
So I end by quoting James Gunn: "Fiction, I think, is humanity's way of seeking justice in an uncaring universe."
* * *
The Perpetual Electron
Written by Stephen Euin Cobb
Many of the articles this humble author writes must be considered speculative. The goal of speculation is to generate new ideas, new visions and new interpretations of what is and what might be. Occasionally the intellectual envelope becomes so stretched, however, that it's wise to seek a second opinion from someone sufficiently grounded that they can keep the speculations at least partly within the realm we like to call reality. Fearing the speculations in this article had indeed gone too far, I emailed a wise and brilliant friend and asked him to take a look.
Doctor Travis S. Taylor is a scientist and engineer and the author of the hard science fiction novel Warp Speed and its sequel The Quantum Connection. Doc Travis, as he is known to fans of his hard SF novels, has discovered two exoplanets and has a doctorate in optical science and engineering, a bachelor's in electrical engineering, and no less than three master's degrees: one in astronomy, one in physics and one in aerospace engineering. (Did you think I was kidding when I used the words wise and brilliant? Never doubt my eagerness for accuracy. You can learn more about him at his website, or at the end of this article.)
Hoping for a few supportive quotes, I emailed Travis the original version of this article, which you will find in its unaltered entirety just a few paragraphs below here. While I can not say that he was supportive of the specific speculations, I can say that he was patient and not at all condescending in his explanations of exactly why he disagreed. And that alone is sufficient encouragement for one who loves science and ideas as much as yours truly.
So, in the spirit of intellectual exploration, here for your speculative enjoyment is the article in its original form, followed by Doctor Taylor's disagreements. As you read the article, see if you can spot the points he found problematic.
* * *
THE PERPETUAL ELECTRON
by Stephen Euin Cobb
Let's play a little game: what Einstein liked to call a "Thought Experiment."
Imagine a hypothetical device that spins, requires no energy input, and that no matter what you do to it you can not make it stop. You can squeeze it, rub it, beat it, throw it against a hard surface, abuse it any way you like, but it will continue spinning. Minutes, hours, days, years; it will spin forever so long as it continues to exist, and nothing that it can experience from you or anyone else will make it stop.
Would this be a perpetual motion device? Yes, I would think so. It not only fits the definition it sounds like a remarkably robust perpetual motion device. Which is particularly interesting since this device is not hypothetical. This device exists in our universe and is quite common. You have probably heard of it. It's called an electron.
All electrons are perpetual motion devices; as are protons and neutrons. In point of fact, on the subatomic scale, there is no object that does not fit the description of a perpetual motion machine. They require no energy input yet they spin endlessly.
"But Steve," I can hear you say, "the spin of a subatomic particle is not a real spin. Physicists just called it spin because we had no word on the macro-scale for what the subatomic particles were doing. And the physicists had to call it something that didn't sound stupid."
Nice argument, but it won't hold water. Here is the opening paragraph of a news release from a Dutch University which was issued in 2006:
"Researchers of the Kavli Institute of Nanoscience at Delft University of Technology and the Foundation for Fundamental Research on Matter (FOM) have succeeded for the first time in the world in controlling the spin of a single electron in a nanostructure. They are able to rotate the spin to every possible direction and to record it accordingly. This achievement makes it possible to use the electron's spin as a 'quantum bit', the basis of a (still theoretical) future quantum computer. The researchers have published this scientific breakthrough in a Nature article on 17 August 2006. An electron does not only have an electrical charge, but it also behaves like an ultra small magnet. This is caused by the spinning of the electron around its axis, also called 'spin'."
(You can read the entire Dutch University news release here.)
http://www.tudelft.nl/live/pagina.jsp?id=4b3e55d0-1a34-4388-b3ca-acbe48c87696&lang=en
Not one to give up easily, I now hear you say, "But, Steve, an electron's spin is surely built into its wave function."
That may be true, but it doesn't matter what drives an electron's perpetual spin, it only matters that it drives it perpetually and without an external energy source.
"But Steve," I hear you say one last time, "These objects probably exist in a frictionless environment."
My response to this is simple but requires on your part a familiarity with college physics: the permittivity and permeability of free space are greater than zero. This is just a fancy way of saying that space itself gently resists any and all changes to electric and magnetic fields.
Since electric and magnetic fields are an extension of the subatomic particles which possess them, this resistance to change subjects every subatomic particle's spin to a small but non-zero amount of friction.
That they overcome this friction, as well as all the other chaotic events that would slow their spin, is what causes subatomic particles to fit the definition of perpetual motion machines.
This may be a small part of why human beings have had so much trouble making sense of the subatomic world. We live in a macroscopic world in which perpetual motion is impossible, while in the subatomic world the situation is reversed. There, perpetual motion is obligatory.
Between our macroscopic world where perpetual motion is impossible, and the subatomic where it is mand
atory, there is another world. An intermediate world with one foot in the bigger world and one foot in the smaller. A world where perpetual motion may be neither impossible, nor mandatory. A world where it may be optional. And while this world is relatively new to our technological manipulations, it is a world in which we are learning to build more and more things. We call this the nano-world or the nano scale, and our manipulations within it we call nanotechnology.
And while it may be half a century before we can tap into the energy available from the naturally occurring perpetual motion machines on the subatomic scale, the engineering of artificial ones on the nanoscale may almost now be within our reach.
-- End of the Original Article --
* * *
Did you spot any assertions the Doctor might have found questionable? Here's a clue.
My love of astronomy and classical physics has never translated into a similar love of quantum physics. Oh, sure my curiosity on the subject is powerful and has led me to read a dozen or more books on the subject, my favorite being QED by Doctor Richard Feynman, which I read twice. But I've read the Bible from cover to cover and I'm still an atheist. Reading and understanding something verses completely buying into it are two different actions. It's not that I doubt the results of quantum physics; I admire few things more than results, and quantum physics has generated far more than its fair share. It's that I doubt the explanations of the results. Telling me, as too many of those books did, that a thing is true because "it just is," or worse, because "it's elegant," is the same as slapping me in the face. And believe me, my face is very sensitive.
Jim Baen's Universe-Vol 2 Num 2 Page 32