In 1935 Einstein and physicist Nathan Rosen formulated “Einstein-Rosen” bridges as a way of describing electrons and other particles in terms of tiny space-time tunnels.83 In 1955 physicist John Wheeler described these tunnels as “wormholes,” introducing the term for the first time.84 His analysis of wormholes showed them to be fully consistent with the theory of general relativity, which describes space as essentially curved in another dimension.
In 1988 California Institute of Technology physicists Michael Morris, Kip Thorne, and Uri Yurtsever explained in some detail how such wormholes could be engineered.85 Responding to a question from Carl Sagan they described the energy requirements to keep wormholes of varying sizes open. They also pointed out that based on quantum fluctuation, so-called empty space is continually generating tiny wormholes the size of subatomic particles. By adding energy and following other requirements of both quantum physics and general relativity (two fields that have been notoriously difficult to unify), these wormholes could be expanded to allow objects larger than subatomic particles to travel through them. Sending humans through them would not be impossible but extremely difficult. However, as I pointed out above, we really only need to send nanobots plus information, which could pass through wormholes measured in microns rather than meters.
Thorne and his Ph.D. students Morris and Yurtsever also described a method consistent with general relativity and quantum mechanics that could establish wormholes between the Earth and faraway locations. Their proposed technique involves expanding a spontaneously generated, subatomic-size wormhole to a larger size by adding energy, then stabilizing it using superconducting spheres in the two connected “wormhole mouths.” After the wormhole is expanded and stabilized, one of its mouths (entrances) is transported to another location, while keeping its connection to the other entrance, which remains on Earth.
Thorne offered the example of moving the remote entrance via a small rocket ship to the star Vega, which is twenty-five light-years away. By traveling at very close to the speed of light, the journey, as measured by clocks on the ship, would be relatively brief. For example, if the ship traveled at 99.995 percent of the speed of light, the clocks on the ship would move ahead by only three months. Although the time for the voyage, as measured on Earth, would be around twenty-five years, the stretched wormhole would maintain the direct link between the locations as well as the points in time of the two locations. Thus, even as experienced on Earth, it would take only three months to establish the link between Earth and Vega, because the two ends of the wormhole would maintain their time relationship. Suitable engineering improvements could allow such links to be established anywhere in the universe. By traveling arbitrarily close to the speed of light, the time required to establish a link—for both communications and transportation—to other locations in the universe, even those millions of billions of light years away, could be relatively brief.
Matt Visser of Washington University in St. Louis has suggested refinements to the Morris-Thorne-Yurtsever concept that provide a more stable environment, which might even allow humans to travel through wormholes.86 In my view, however, this is unnecessary. By the time engineering projects of this scale might be feasible, human intelligence will long since have been dominated by its nonbiological component. Sending molecular-scale self-replicating devices along with software will be sufficient and much easier. Anders Sandberg estimates that a one-nanometer wormhole could transmit a formidable 1069 bits per second.87
Physicist David Hochberg and Vanderbilt University’s Thomas Kephart point out that shortly after the Big Bang, gravity was strong enough to have provided the energy required to spontaneously create massive numbers of self-stabilizing wormholes.88 A significant portion of these wormholes is likely to still be around and may be pervasive, providing a vast network of corridors that reach far and wide throughout the universe. It might be easier to discover and use these natural wormholes than to create new ones.
Changing the Speed of Light. The second conjecture is to change the speed of light itself. In chapter 3, I mentioned the finding that appears to indicate that the speed of light has differed by 4.5 parts out of 108 over the past two billion years.
In 2001 astronomer John Webb discovered that the so-called fine-structure constant varied when he examined light from sixty-eight quasars (very bright young galaxies).89 The speed of light is one of four constants that the fine-structure constant comprises, so the result is another suggestion that varying conditions in the universe may cause the speed of light to change. Cambridge University physicist John Barrow and his colleagues are in the process of running a two-year tabletop experiment that will test the ability to engineer a small change in the speed of light.90
Suggestions that the speed of light can vary are consistent with recent theories that it was significantly higher during the inflationary period of the universe (an early phase in its history, when it underwent very rapid expansion). These experiments showing possible variation in the speed of light clearly need corroboration and are showing only small changes. But if confirmed, the findings would be profound, because it is the role of engineering to take a subtle effect and greatly amplify it. Again, the mental experiment we should perform now is not whether contemporary human scientists, such as we are, can perform these engineering feats but whether or not a human civilization that has expanded its intelligence by trillions of trillions will be able to do so.
For now we can say that ultrahigh levels of intelligence will expand outward at the speed of light, while recognizing that our contemporary understanding of physics suggests that this may not be the actual limit of the speed of expansion or, even if the speed of light proves to be immutable, that this limit may not restrict reaching other locations quickly through wormholes.
The Fermi Paradox Revisited. Recall that biological evolution is measured in millions and billions of years. So if there are other civilizations out there, they would be spread out in terms of development by huge spans of time. The SETI assumption implies that there should be billions of ETIs (among all the galaxies), so there should be billions that lie far ahead of us in their technological progress. Yet it takes only a few centuries at most from the advent of computation for such civilizations to expand outward at at least light speed. Given this, how can it be that we have not noticed them?
The conclusion I reach is that it is likely (although not certain) that there are no such other civilizations. In other words, we are in the lead. That’s right, our humble civilization with its pickup trucks, fast food, and persistent conflicts (and computation!) is in the lead in terms of the creation of complexity and order in the universe.
Now how can that be? Isn’t this extremely unlikely, given the sheer number of likely inhabited planets? Indeed it is very unlikely. But equally unlikely is the existence of our universe, with its set of laws of physics and related physical constants, so exquisitely, precisely what is needed for the evolution of life to be possible. But by the anthropic principle, if the universe didn’t allow the evolution of life we wouldn’t be here to notice it. Yet here we are. So by a similar anthropic principle, we’re here in the lead in the universe. Again, if we weren’t here, we would not be noticing it.
Let’s consider some arguments against this perspective.
Perhaps there are extremely advanced technological civilizations out there, but we are outside their light sphere of intelligence. That is, they haven’t gotten here yet. Okay, in this case, SETI will still fail to find ETIs because we won’t be able to see (or hear) them, at least not unless and until we find a way to break out of our light sphere (or the ETI does so) by manipulating the speed of light or finding shortcuts, as I discussed above.
Perhaps they are among us, but have decided to remain invisible to us. If they have made that decision, they are likely to succeed in avoiding being noticed. Again, it is hard to believe that every single ETI has made the same decision.
John Smart has suggested in what he calls the “transcension”
scenario that once civilizations saturate their local region of space with their intelligence, they create a new universe (one that will allow continued exponential growth of complexity and intelligence) and essentially leave this universe.91 Smart suggests that this option may be so attractive that it is the consistent and inevitable outcome of an ETI’s having reached an advanced stage of its development, and it thereby explains the Fermi Paradox.
Incidentally, I have always considered the science-fiction notion of large spaceships piloted by huge, squishy creatures similar to us to be very unlikely. Seth Shostak comments that “the reasonable probability is that any extraterrestrial intelligence we will detect will be machine intelligence, not biological intelligence like us.” In my view this is not simply a matter of biological beings sending out machines (as we do today) but rather that any civilization sophisticated enough to make the trip here would have long since passed the point of merging with its technology and would not need to send physically bulky organisms and equipment.
If they exist, why would they come here? One mission would be for observation—to gather knowledge (just as we observe other species on Earth today). Another would be to seek matter and energy to provide additional substrate for its expanding intelligence. The intelligence and equipment needed for such exploration and expansion (by an ETI, or by us when we get to that stage of development) would be extremely small, basically nanobots and information transmissions.
It appears that our solar system has not yet been turned into someone else’s computer. And if this other civilization is only observing us for knowledge’s sake and has decided to remain silent, SETI will fail to find it, because if an advanced civilization does not want us to notice it, it would succeed in that desire. Keep in mind that such a civilization would be vastly more intelligent than we are today. Perhaps it will reveal itself to us when we achieve the next level of our evolution, specifically merging our biological brains with our technology, which is to say, after the Singularity. However, given that the SETI assumption implies that there are billions of such highly developed civilizations, it seems unlikely that all of them have made the same decision to stay out of our way.
The Anthropic Principle Revisited. We are struck with two possible applications of an anthropic principle, one for the remarkable biofriendly laws of our universe, and one for the actual biology of our planet.
Let’s first consider the anthropic principle as applied to the universe in more detail. The question concerning the universe arises because we notice that the constants in nature are precisely what are required for the universe to have grown in complexity. If the cosmological constant, the Planck constant, and the many other constants of physics were set to just slightly different values, atoms, molecules, stars, planets, organisms, and humans would have been impossible. The universe appears to have exactly the right rules and constants. (The situation is reminiscent of Steven Wolfram’s observation that certain cellular-automata rules [see the sidebar on p. 85] allow for the creation of remarkably complex and unpredictable patterns, whereas other rules lead to very uninteresting patterns, such as alternating lines or simple triangles in a repeating or random configuration.)
How do we account for the remarkable design of the laws and constants of matter and energy in our universe that have allowed for the increasing complexity we see in biological and technology evolution? Freeman Dyson once commented that “the universe in some sense knew we were coming.” Complexity theorist James Gardner describes the question in this way:
Physicists feel that the task of physics is to predict what happens in the lab, and they are convinced that string theory, or M theory can do this. . . .But they have no idea why the universe should . . . have the standard model, with the values of its 40+ parameters that we observe. How can anyone believe that something so messy is the unique prediction of string theory? It amazes me that people can have such blinkered vision, that they can concentrate just on the final state of the universe, and not ask how and why it got there.92
The perplexity of how it is that the universe is so “friendly” to biology has led to various formulations of the anthropic principle. The “weak” version of the anthropic principle points out simply that if it were not the case, we wouldn’t be here to wonder about it. So only in a universe that allowed for increasing complexity could the question even be asked. Stronger versions of the anthropic principle state that there must be more to it; advocates of these versions are not satisfied with a mere lucky coincidence. This has opened the door for advocates of intelligent design to claim that this is the proof of God’s existence that scientists have been asking for.
The Multiverse. Recently a more Darwinian approach to the strong anthropic principle has been proposed. Consider that it is possible for mathematical equations to have multiple solutions. For example, if we solve for x in the equation x2 = 4, x may be 2 or −2. Some equations allow for an infinite number of solutions. In the equation (a−b) × x = 0, x can take on any one of an infinite number of values if a = b (since any number multiplied by zero equals zero). It turns out that the equations for recent string theories allow in principle for an infinite number of solutions. To be more precise, since the spatial and temporal resolution of the universe is limited to the very small Planck constant, the number of solutions is not literally infinite but merely vast. String theory implies, therefore, that many different sets of natural constants are possible.
This has led to the idea of the multiverse: that there exist a vast number of universes, of which our humble universe is only one. Consistent with string theory, each of these universes can have a different set of physical constants.
Evolving Universes. Leonard Susskind, the discoverer of string theory, and Lee Smolin, a theoretical physicist and expert on quantum gravity, have suggested that universes give rise to other universes in a natural, evolutionary process that gradually refines the natural constants. In other words it is not by accident that the rules and constants of our universe are ideal for evolving intelligent life but rather that they themselves evolved to be that way.
In Smolin’s theory the mechanism that gives rise to new universes is the creation of black holes, so those universes best able to produce black holes are the ones that are most likely to reproduce. According to Smolin a universe best able to create increasing complexity—that is, biological life—is also most likely to create new universe-generating black holes. As he explains, “Reproduction through black holes leads to a multiverse in which the conditions for life are common—essentially because some of the conditions life requires, such as plentiful carbon, also boost the formation of stars massive enough to become black holes.”93 Susskind’s proposal differs in detail from Smolin’s but is also based on black holes, as well as the nature of “inflation,” the force that caused the very early universe to expand rapidly.
Intelligence as the Destiny of the Universe. In The Age of Spiritual Machines, I introduced a related idea—namely, that intelligence would ultimately permeate the universe and would decide the destiny of the cosmos:
How relevant is intelligence to the universe? . . . The common wisdom is not very. Stars are born and die; galaxies go through their cycles of creation and destruction; the universe itself was born in a big bang and will end with a crunch or a whimper, we’re not yet sure which. But intelligence has little to do with it. Intelligence is just a bit of froth, an ebullition of little creatures darting in and out of inexorable universal forces. The mindless mechanism of the universe is winding up or down to a distant future, and there’s nothing intelligence can do about it.
That’s the common wisdom. But I don’t agree with it. My conjecture is that intelligence will ultimately prove more powerful than these big impersonal forces. . . .
So will the universe end in a big crunch, or in an infinite expansion of dead stars, or in some other manner? In my view, the primary issue is not the mass of the universe, or the possible existence of antigravity, or of Einstein’s so-called cosmologica
l constant. Rather, the fate of the universe is a decision yet to be made, one which we will intelligently consider when the time is right.94
Complexity theorist James Gardner combined my suggestion on the evolution of intelligence throughout the universe with Smolin’s and Susskind’s concepts of evolving universes. Gardner conjectures that it is specifically the evolution of intelligent life that enables offspring universes.95 Gardner builds on British astronomer Martin Rees’s observation that “what we call the fundamental constants—the numbers that matter to physicists—may be secondary consequences of the final theory, rather than direct manifestations of its deepest and most fundamental level.” To Smolin it is merely coincidence that black holes and biological life both need similar conditions (such as large amounts of carbon), so in his conception there is no explicit role for intelligence, other than that it happens to be the by-product of certain biofriendly circumstances. In Gardner’s conception it is intelligent life that creates its successors.
Gardner writes that “we and other living creatures throughout the cosmos are part of a vast, still undiscovered transterrestrial community of lives and intelligences spread across billions of galaxies and countless parsecs who are collectively engaged in a portentous mission of truly cosmic importance. Under the Biocosm vision, we share a common fate with that community—to help shape the future of the universe and transform it from a collection of lifeless atoms into a vast, transcendent mind.” To Gardner the laws of nature, and the precisely balanced constants, “function as the cosmic counterpart of DNA: they furnish the ‘recipe’ by which the evolving cosmos acquires the capacity to generate life and ever more capable intelligence.”