Hyperspace (51 page)

In this distant future, black holes may become “life preservers” because they slowly evaporate energy. Intelligent life would necessarily congregate next to these black holes and extract energy from them to keep their machines functioning. Intelligent civilizations, like shivering homeless people huddled next to a fading fire, would be reduced to pathetic outposts of misery clinging to a black hole.
⁴

But what, we may ask, happens after 10
¹⁰⁰
years, when the evaporating black holes will have exhausted most of their own energy? Astronomers John D. Barrow of the University of Sussex and Joseph Silk of the University of California at Berkeley caution that this question may ultimately have no answer with present-day knowledge. On that time scale, quantum theory, for example, leaves open the possibility that our universe may “tunnel” into another universe.

The probabilities for these kinds of events are exceedingly small; one would have to wait a time interval larger than the lifetime of our present universe, so we need not worry that reality will suddenly collapse in our lifetime, bringing with it a new set of physical laws. However, on the scale of 10
¹⁰⁰
years, these kinds of rare cosmic quantum events can no longer be ruled out.

Barrow and Silk add, “Where there is quantum theory there is hope. We can never be completely sure this cosmic heat death will occur because we can never predict the future of a quantum mechanical universe with complete certainty; for in an infinite quantum future anything that can happen, eventually will.”
⁵

The Cosmic Whimper is indeed a dismal fate awaiting us if the average density of the universe is too low. Now assume that the average density is larger than the critical value. This means that the expansion process will contract within tens of billions of years, and the universe will end in fire, not ice.

In this scenario, there is enough matter and hence a strong enough gravitational pull in the universe to halt the expansion, and then the universe will begin to slowly recollapse, bringing the distant galaxies together again. Starlight will become “blue shifted,” instead of red
shifted, indicating that the stars are rapidly approaching one another. The temperatures once again will rise to astronomical limits. Eventually, the heat will become sufficiently great to vaporize all matter into a gas.

Intelligent beings will find that their planets’ oceans have boiled away and that their atmospheres have turned into a searing furnace. As their planets begin to disintegrate, they will be forced to flee into outer space in giant rockets.

Even the sanctuary of outer space may prove to be inhospitable, however. Temperatures will eventually rise past the point where atoms are stable, and electrons will be ripped off their nuclei, creating a plasma (like that found in our sun). At this point, intelligent life may have to build gigantic shields around their ships and use their entire energy output to keep their shields from disintegrating from the intense heat.

As temperatures continue to rise, the protons and neutrons in the nucleus will be ripped apart. Eventually, the protons and neutrons themselves will be torn apart into quarks. As in a black hole, the Big Crunch devours everything. Nothing survives it. Thus it seems impossible that ordinary matter, let alone intelligent life, can survive the violent disruption.

However, there is one possible escape. If all of space-time is collapsing into a fiery cataclysm, then the only way to escape the Big Crunch is to leave space and time—escape via hyperspace. This may not be as farfetched as it sounds. Computer calculations performed with Kaluza-Klein and superstring theories have shown that moments after Creation, the four-dimensional universe expanded at the expense of the six-dimensional universe. Thus the ultimate fate of the four- and the six-dimensional universes are linked.

Assuming that this basic picture is correct, our six-dimensional twin universe may gradually expand, as our own four-dimensional universe collapses. Moments before our universe shrinks to nothing, intelligent life may realize that the six-dimensional universe is opening up, and find a means to exploit that fact.

Interdimensional travel is impossible today because our sister universe has shrunk down to the Planck scale. However, in the final stages of a collapse, the sister universe may open up, making dimensional travel possible once again. If the sister universe expands enough, then matter and energy may escape into it, making an escape hatch possible for any intelligent beings smart enough to calculate the dynamics of space-time.

The late Columbia University physicist Gerald Feinberg speculated on this long shot of escaping the ultimate compression of the universe through extra dimensions:

At present, this is no more than a science fiction plot. However, if there are more dimensions than those we know, or four-dimensional spacetimes in addition to the one we inhabit, then I think it very likely that there are physical phenomena that provide connections between them. It seems plausible that if intelligence persists in the universe, it will, in much less time than the many billions of years before the Big Crunch, find out whether there is anything to this speculation, and if so how to take advantage of it.
⁶

Almost all scientists who have investigated the death of the universe, from Bertrand Russell to current cosmologists, have assumed that intelligent life will be almost helpless in the face of the inevitable, final death throes of the universe. Even the theory that intelligent beings can tunnel through hyperspace and avoid the Big Crunch assumes that these beings are passive victims until the final moments of the collapse.

However, physicists John D. Barrow of the University of Sussex and Frank J. Tipler of Tulane University, in their book
The Anthropic Cosmological Principle
, have departed from conventional wisdom and concluded just the opposite: that intelligent life, over billions of years of evolution, will play an active role in the final moments of our universe. They take the rather unorthodox view that technology will continue to rise exponentially over billions of years, constantly accelerating in proportion to existing technology. The more star systems that intelligent beings have colonized, the more star systems they can colonize. Barrow and Tipler argue that over several billion years, intelligent beings will have completely colonized vast portions of the visible universe. But they are conservative; they do not assume that intelligent life will have mastered the art of hyperspace travel. They assume only that their rockets will travel at near-light velocities.

This scenario should be taken seriously for several reasons. First, rockets traveling at near-light velocities (propelled, say, by photon engines using the power of large laser beams) may take hundreds of years to reach distant star systems. But Barrow and Tipler believe that intelligent beings will thrive for billions of years, which is sufficient time to colonize their own and neighboring galaxies even with sub-light-speed rockets.

Without assuming hyperspace travel, Barrow and Tipler argue that intelligent beings will send millions of small “von Neumann probes”
into the galaxy at near-light speeds to find suitable star systems for colonization. John von Neumann, the mathematical genius who developed the first electronic computer at Princeton University during World War II, proved rigorously that robots or automatons could be built with the ability to program themselves, repair themselves, and even create carbon copies of themselves. Thus Barrow and Tipler suggest that the von Neumann probes will function largely independently of their creators. These small probes will be vastly different from the current generation of
Viking
and
Pioneer
probes, which are little more than passive, preprogrammed machines obeying orders from their human masters. The von Neumann probes will be similar to Dyson’s Astrochicken, except vastly more powerful and intelligent. They will enter new star systems, land on planets, and mine the rock for suitable chemicals and metals. They will then create a small industrial complex capable of manufacturing numerous robotic copies of themselves. From these bases, more von Neumann probes will be launched to explore even more star systems.

Being self-programming automatons, these probes will not need instructions from their mother planet; they will explore millions of star systems entirely on their own, pausing only to periodically radio back their findings. With millions of these von Neumann probes scattered throughout the galaxy, creating millions of copies of themselves as they “eat” and “digest” the chemicals on each planet, an intelligent civilization will be able to cut down the time wasted exploring uninteresting star systems. (Barrow and Tipler even consider the possibility that von Neumann probes from distant civilizations have already entered our own solar system. Perhaps the monolith featured so mysteriously in
2001: A Space Odyssey
was a von Neumann probe.)

In the “Star Trek” series, for example, the exploration of other star systems by the Federation is rather primitive. The exploration process depends totally on the skills of humans aboard a small number of starships. Although this scenario may make for intriguing human-interest dramas, it is a highly inefficient method of stellar exploration, given the large number of planetary systems that are probably unsuitable for life. Von Neumann probes, although they may not have the interesting adventures of Captain Kirk or Captain Picard and their crews, would be more suitable for galactic exploration.

Barrow and Tipler make a second assumption that is crucial to their argument: The expansion of the universe will eventually slow down and reverse itself over tens of billions of years. During the contraction phase of the universe, the distance between galaxies will decrease, making it vastly easier for intelligent beings to continue the colonization of the
galaxies. As the contraction of the universe accelerates, the rate of colonization of neighboring galaxies will also accelerate, until the entire universe is eventually colonized.

Even though Barrow and Tipler assume that intelligent life will populate the entire universe, they are still at a loss to explain how any life form will be able to withstand the unbelievably large temperatures and pressures created by the final collapse of the universe. They concede that the heat created by the contraction phase will be great enough to vaporize any living being, but perhaps the robots that they have created will be sufficiently heat resistant to withstand the final moments of the collapse.

Along these lines, Isaac Asimov has conjectured how intelligent beings might react to the final death of the universe. In “The Last Question,” Asimov asks the ancient question of whether the universe must inevitably die, and what will happen to all intelligent life when we reach Doomsday. Asimov, however, assumes that the universe will die in ice, rather than in fire, as the stars cease to burn hydrogen and temperatures plummet to absolute zero.

The story begins in the year 2061, when a colossal computer has solved the earth’s energy problems by designing a massive solar satellite in space that can beam the sun’s energy back to earth. The AC (analog computer) is so large and advanced that its technicians have only the vaguest idea of how it operates. On a $5 bet, two drunken technicians ask the computer whether the sun’s eventual death can be avoided or, for that matter, whether the universe must inevitably die. After quietly mulling over this question, the AC responds:
INSUFFICIENT DATA FOR A MEANINGFUL ANSWER.

Centuries into the future, the AC has solved the problem of hyperspace travel, and humans begin colonizing thousands of star systems. The AC is so large that it occupies several hundred square miles on each planet and so complex that it maintains and services itself. A young family is rocketing through hyperspace, unerringly guided by the AC, in search of a new star system to colonize. When the father casually mentions that the stars must eventually die, the children become hysterical. “Don’t let the stars die,” plead the children. To calm the children, he asks the AC if entropy can be reversed. “See,” reassures the father, reading the AC’s response, the AC can solve everything. He comforts them
by saying, “It will take care of everything when the time comes, so don’t worry.” He never tells the children that the AC actually prints out:
INSUFFICIENT DATA FOR A MEANINGFUL ANSWER
.

Thousands of years into the future, the Galaxy itself has been colonized. The AC has solved the problem of immortality and harnesses the energy of the Galaxy, but must find new galaxies for colonization. The AC is so complex that it is long past the point where anyone understands how it works. It continually redesigns and improves its own circuits. Two members of the Galactic Council, each hundreds of years old, debate the urgent question of finding new galactic energy sources, and wonder if the universe itself is running down. Can entropy be reversed? they ask. The AC responds:
INSUFFICIENT DATA FOR A MEANINGFUL ANSWER
.

Millions of years into the future, humanity has spread across the uncountable galaxies of the universe. The AC has solved the problem of releasing the mind from the body, and human minds are free to explore the vastness of millions of galaxies, with their bodies safely stored on some long forgotten planet. Two minds accidentally meet each other in outer space, and casually wonder where among the uncountable galaxies humans originated. The AC, which is now so large that most of it has to be housed in hyperspace, responds by instantly transporting them to an obscure galaxy. They are disappointed. The galaxy is so ordinary, like millions of other galaxies, and the original star has long since died. The two minds become anxious because billions of stars in the heavens are slowly meeting the same fate. The two minds ask, can the death of the universe itself be avoided? From hyperspace, the AC responds:
INSUFFICIENT DATA FOR A MEANINGFUL ANSWER
.