Far futures, p.2
Far Futures, page 2
To ponder futures beyond that era, we must discuss the universe as a whole.
Modem cosmology is quite different from the physics of the Newtonian worldview, which dreamed uneasily of a universe that extended forever but was always threatened by collapse. Nothing countered the drawing-in of gravity except infinity itself. Though angular momentum will keep a galaxy going for a great while, collisions can cancel that. Objects hit each other and mutually plunge toward the gravitating center. Physicists of the Newtonian era thought that maybe there simply had not been enough time to bring about the final implosion. Newton, troubled by this, avoided cosmological issues.
Given enough time, matter will seek its own land, stars smacking into each other, making greater and greater stars. This will go on even after the stars gutter out.
When a body meets a body, coming through the sky . . . Stars will inevitably collide, meet, merge. All the wisdom and order of planets and suns will finally compress into the marriage of many stars, plunging down the pit of gravity to become black holes. For the final fate of nearly all matter shall be the dark pyre of collapse.
Galaxies are as mortal as stars. In the sluggish slide of time, the spirals that had once gleamed with fresh brilliance will be devoured by ever-growing black holes. Inky masses will blot out whole spiral arms of dim red. The already massive holes at galactic centers will swell from their billion-stellar-mass sizes at present, to chew outward, gnawing without end.
From the corpses of stars, collisions will form either neutron stars or black holes, within about a thousand billion years (in exponential notation, 1012 years). Even the later and longest-lived stars cannot last beyond 1014 years. Collisions between stars will strip away all planets in 1015 years.
Blunt thermodynamics will still command, always seeking maximum disorder. In 1017 years, the last white dwarf stars will have cooled to be utterly black dwarfs, temperatures about 5 degrees Kelvin (Absolute). In time, even hell would freeze over.
Against an utterly black sky, shadowy cinders of stars will glide. Planets, their atmospheres frozen out into waveless lakes of oxygen, will glide in meaningless orbits, warmed by no ruby star glow. The universal clock would run down to the last tick of time.
But the universe is no static lattice of stars. It grows. The Big Bang would be better termed the Enormous Emergence, space-time snapping into existence intact and whole, of a piece. Then it grew, the fabric of space lengthening as time increased.
With the birth of space-time came its warping by matter, each wedded to the other until time eternal. An expanding universe cools, just as a gas does. The far future will freeze, even if somehow life manages to find fresh sources of power.
Could the expansion ever reverse? This is the crucial unanswered riddle in cosmology. If there is enough matter in our universe, eventually gravitation will win out over the expansion. The “dark matter” thought to infest the relatively rare, luminous stars we see could be dense enough to stop the universe’s stretching of its own space-time. This density is related to how old the universe is.
We believe the universe is somewhere between eight and sixteen billion years old. The observed rate of expansion (the Hubble constant) gives eight billion, in a simple, plausible model. The measured age of the oldest stars gives sixteen billion.
This difference, I believe, arises from our crude knowledge of how to fit our mathematics to our cosmological data; I don’t think it’s a serious problem. Personally I favor the higher end of the range, perhaps twelve to fourteen billion. We also have rough measures of the deceleration rate of the universal expansion. These can give (depending on cosmological, mathematical models) estimates of how long a dense universe would take to expand, reverse, and collapse back to a point. At the extremes, this gives between twenty-seven billion and at least a hundred billion years before the Big Crunch. If we do indeed live in a universe that will collapse, then we are bounded by two singularities, at beginning and end. No structure will survive that future singularity. Freeman Dyson found this a pessimistic scenario and so refused to consider it.
A closed universe seems the ultimate doom. In all cosmological models, if the mass density of the universe exceeds the critical value, gravity inevitably wins. This is called a “closed” universe, because it has finite spatial volume, but no boundary. It is like a three-dimensional analogue of a sphere’s surface. A bug on a ball can circumnavigate it, exploring all its surface and coming back to home, having crossed no barrier. So a starship could cruise around the universe and come home, having found no edge.
A closed universe starts with a big bang (an initial singularity) and expands. Separation between galaxies grows linearly with time. Eventually the universal expansion of space-time will slow to a halt. Then a contraction will begin, accelerating as it goes, pressing galaxies closer together. The photons rattling around in this universe will increase in frequency, the opposite of the redshift we see now. Their blueshift means that the sky will get brighter in time. Contraction of space-time shortens wavelengths, which increases light energy.
Though stars will still age and die as the closed universe contracts, the background light will blueshift. No matter if life burrows into deep caverns, in time the heat of this light will fry it. Freeman Dyson remarked that the closed universe gave him “a feeling of claustrophobia, to imagine our whole existence confined within a box.” He asked, “Is it conceivable that by intelligent intervention, converting matter into radiation to flow purposefully on a cosmic scale, we could break open a closed universe and change the topology of spacetime so that only a part of it would collapse and another would expand forever? I do not know the answer to this question.”
The answer seems to be that once collapse begins, a deterministic universe allows no escape for pockets of space-time. Life cannot stop the squeezing.
Some have embraced this searing death, when all implodes toward a point of infinite temperature. Frank Tipler of Tulane University sees it as a great opportunity. In those last seconds, collapse will not occur at the same rate in all directions. Chaos in the system will produce “gravitational shear,” which drives temperature differences. Drawing between these temperature differences, life can harness power for its own use.
Of course, such life will have to change its form to use such potentials; it will need hardier stuff than blood and bone. Ceramic-based forms could endure, or vibrant, self-contained plasma clouds—any tougher structure might work, as long as it can code information.
This most basic definition of life, the ability to retain and manipulate information, means that the substrate supporting this does not matter, in the end. Of course, the style of thought of a silicon web feasting on the slopes of a volcano won’t be that of a shrewd primate fresh from the veldt, but certain common patterns can transfer.
Such life-forms might be able to harness the compressive, final energies. Charles Sheffield’s story in this volume revolves around the allure of that distant end, the Omega Point. Frank Tipler’s The Physics of Immortality makes a case that a universal intelligence at the Omega Point will then confer a sort of immortality, by carrying out the computer simulation of all possible past intelligences. All possible earlier “people” will be resurrected, he thinks. This bizarre notion shows how cosmology blends into eschatology, the study of the ultimate fate of things, particularly of souls.
I, too, find this scenario of final catastrophe daunting. Suppose, then, the universe is not so dense that it will ever reverse its expansion. Then we can foresee a long, toiling twilight.
Life based on solid matter will struggle to survive. To find energy, it will have to ride herd on and merge black holes themselves, force them to emit bursts of gravitational waves. In principle these waves can be harnessed, though of course we don’t know how as yet. Only such fusions could yield fresh energy in a slumbering universe.
High civilizations will rise, no doubt, mounted on the carcass of matter itself—the ever-spreading legions of black holes. Entire galaxies will turn from reddening lanes of stars into swarms of utterly dark gravitational singularities, the holes. Only by moving such masses, by extracting power through magnetic forces and the slow gyre of dissipating orbits, could life rule the dwindling resources of the ever-enlarging universe. Staying warm shall become the one great Law.
Dyson has argued that, in principle, the perceived time available to living forms can be made infinite. In this sense, immortality of a kind could mark the cold, stretching stages of the universal death.
This assumes that we know all the significant physics, of course. Almost certainly, we do not. Greg Bears story occurs at an end point of time itself, when the universe is closing down all prospects, for physical reasons that the viewpoint human cannot fathom. The universe appears to be still expanding and cooling, but duration itself is ending as a category. Bizarre events unfold.
This is a useful fictional reminder that our chimpanzee worldview may simply be unable to comprehend events on such vast time scales. Equally, though, chimpanzees will try, and keep trying.
Since Dyson’s pioneering work on these issues, yet more physics has emerged, which we must take into account. About his vision of a swelling universe, its life force spent, hangs a great melancholy.
For matter itself is doomed, as well. Even the fraction that escapes the holes, and learns to use them, if mortal. Its basic building block, the proton, decays. This takes unimaginably long—current measurements suggest a proton lifetime of more than 1033 years. But decay seems inevitable, the executioner’s sword descending with languid grace.
Even so, something still survives. Not all matter dies, though with the proton gone everything we hold dear will disintegrate, atoms and animals alike. After the grand operas of mass and energy have played out their plots, the universal stage will clear to reveal the very smallest.
The tiniest of particles—the electron and its antiparticle, the positron—shall live on, current theory suggests. No process of decay can find purchase on their infinitesimal scales, lever them apart into smaller fragments. The electron shall dance with its anti-twin in swarms: the lightest of all possible plasmas.
By the time these are the sole players, the stage will have grown enormously. Each particle will find its nearest neighbor to be a full light-year away. They will have to bind together, sharing cooperatively, storing data in infinitesimally thin currents and charges. A single entity would have to be the size of a spiral arm, of a whole galaxy. Vaster than empires, and more slow.
Plasmas held together by magnetic and electric fields are incredibly difficult to manage, rather like building a cage for Jell-O out of rubber bands. But in principle, physics allows such magnetic loops and flowing spheres. We can see them in the short-lived phenomena of ball lightning. More spectacularly, they occur on the sun, in glowing magnetic arches that can endure for weeks, a thousand kilometers high.
Intelligence could conceivably dwell in such wispy magnetic consorts. Communication will take centuries . . . but to the slow thumping of the universal heart, that will be nothing.
If life born to brute matter can find a way to incorporate itself into the electron-positron plasma, then it can last forever. This would be the last step in a migration from the very early forms, like us: rickety assemblies of water in tiny compartment cells, hung on a lattice of moving calcium rods.
Life and intelligence will have to alter, remaking basic structures from organic molecules to, say, animated crystalline sheets. Something like this may have happened before; some theorists believe Earthly life began in wet clay beds, and moved to organic molecules in a soupy sea only later.
While the customary view of evolution does not speak of progress, there has been generally an increase of information transmitted forward to the next generation. Complexity increases in a given genus, order, class, etc. Once intelligence appears, or invades a wholly different medium, such “cognitive creatures” can direct their own evolution. Patterns will persist, even thrive, independent of the substrate.
So perhaps this is the final answer to the significance of it all. In principle, life and structure, hopes and dreams and Shakespeare’s Hamlet, can persist forever—if life chooses to, and struggles. In that far future, dark beyond measure, plasma entities of immense size and torpid pace may drift through a supremely strange era, sure and serene, free at last of ancient enemies.
Neither the thermodynamic dread of heat death nor gravity’s gullet could then swallow them. Cosmology would have done its work.
As the universe swells, energy lessens, and the plasma life need only slow its pace to match. Mathematically, there are difficulties involved in arguing, as Dyson does, that the perceived span of order can be made infinite. The issue hinges on how information and energy scale with time. Assuming that Dyson’s scaling is right, there is hope.
By adjusting itself exactly to its ever-cooling environment, life—of a sort—can persist and dream fresh dreams. The Second Law of Thermodynamics says that disorder increases in every energy transaction. But the Second Law need not be the Final Law.
Such eerie descendants will have much to think about. They will be able to remember and relive in sharp detail the glory of the brief Early Time—that distant, legendary era when matter brewed energy from crushing suns together. When all space was furiously hot, overflowing with boundless energy. When life dwelled in solid states, breathed in chilly atoms, and mere paltry planets formed a stage.
Freeman Dyson once remarked to me, about these issues, that he felt the best possible universe was one of constant challenge. He preferred a future that made survival possible but not easy. We chimps, if coddled, get lazy and then stupid.
The true far future is shrouded and mysterious. Still, I expect that he shall get his wish, and we shall not be bored.
Science fiction must assume the centrality of humans, for narrative interest at least. But the universe, as far as we can tell, cares naught for us. To some extent, we rage against the infinite stretches of space and time because that stage seems to dwarf us. But mere mute mass is less complex than the wonder of our own minds.
Only we can understand that vast stage. In the end, we may shape it as well. Our fiction says this, over and over, in intricate ways.
GREGORY BENFORD
February 1995
Greg Bear began writing full-time in 1975 after a career as an artist. His range is broad, encompassing fantasy and SF, with his principal asset being the ability to incorporate hard sciences and intricate plots into narratives that bristle with character complexities and vivid settings. Novels such as Blood Music, Eon, Eternity, and The Forge of God brought him to the forefront of U.S. SF. He lives in Washington State.
In the final moments of a universe governed by physics we can barely fathom, “Judgment Engine” foresees the timeless struggle of life for meaning. For us, meaning derives from memory, for humans in their mortality are finally about continuity. Such perspectives are indeed Stapledonian, confronting fundamental questions against the largest possible landscapes.
JUDGMENT ENGINE
Greg Bear
We
SEVEN TRIBUTARIES DISENGAGE from their social=mind and Library and travel by transponder to the School World. There they are loaded into a temporary soma, an older physical model with eight long, flexible red legs. Here the seven become We.
We have received routine orders from the Teacher Annex. We are to investigate student labor on the Great Plain of History, the largest physical feature on the School World. The students have been set to searching all past historical records, donated by the nine remaining Libraries. Student social=minds are sad; they will not mature before Endtime. They are the last new generation and their behavior is often aberrant. There may be room for error.
The soma sits in an enclosure. We become active and advance from the enclosure’s shadow into a light shower of data condensing from the absorbing clouds high above. We see radiation from the donating Libraries, still falling on School World from around the three remaining systems; we hear the lambda whine of storage in the many rows of black hemispheres perched on the plain; we feel a patter of drops on our black carapace.
We stand at the edge of the plain, near a range of bare brown and black hills left over from planetary re-formation. The air is thick and cold. It smells sharply of rich data moisture, wasted on us; We do not have readers on our surface. The moisture dews up on the dark, hard ground under our feet, evaporates and is reclaimed by translucent soppers. The soppers flit through the air, a tenth our size and delicate.
The hemispheres are maintained by single-tributary somas. They are tiny, marching along the rows by the hundreds of thousands.
The sun rises in the west, across the plain. It is brilliant violet surrounded by streamers of intense blue. The streamers curl like flowing hair. Sun and streamers cast multiple shadows from each black hemisphere. The sun attracts our attention. It is beautiful, not part of a Library simscape; this scape is real. It reminds us of approaching Endtime; the changes made to conserve and concentrate the last available energy have rendered the scape beautifully novel, unfamiliar to the natural birth algorithms of our tributaries.
The three systems are unlike anything that has ever been. They contain all remaining order and available energy. Drawn close together, surrounded by the permutation of local space and time, the three systems deceive the dead outer universe, already well into the dull inaction of the long Between. We are proud of the three systems. They took a hundred million years to construct, and a tenth of all remaining available energy. They were a gamble. Nine of thirty-seven major Libraries agreed to the gamble. The others spread themselves into the greater magnitudes of the Between, and died.
The gamble worked.
Our soma is efficient and pleasant to work with. All of our tributaries agree, older models of such equipment are better. We have an appointment with the representative of the School World students, student tributaries lodged in a newer model soma called a Berkus, after a social=mind on Second World, which designed it. A Berkus soma is not favored. It is noisy; perhaps more efficient, but brasher and less elegant. We agree it will be ugly.
