Full name: Scott Jackson
Location: Irvine, California
Question: In "Seeing the Unseen" (December) E. L. Doctorow discusses the wall between science and the unfathomable. Later, in "How to Survive the End of the Universe" Michio Kaku discusses the theory of infinite parallel universes. The question is: Is the concept of infinity belong in the realm of science or in the realm of the unfathomable? That is to say, on which side of the wall does it lie?
Kaku responds: You raise some difficult theological and epistemological questions! In my personal point of view, everything is, in principle, knowable. We cannot know all the truths about the universe, but we can, with enough time, come arbitrarily close. For example, some infinities we see in physics are actually an illusion, created by our faulty mathematics and physics. The quantum theory of the relativistic electron, for example, was once thought to be hopelessly riddled with infinities, but Feynman, Schwinger, and Tomonaga won the Nobel Prize for showing how to banish the infinities of quantum-field theories. Similarly, the singularities we find in general relativity, such as black holes and big bangs, are actually due to the failure of Einstein's theory at these extreme points, signaling the necessity of a higher theory, such as string theory. Other infinities, such as the infinite number of universes in a multiverse, are perhaps real and physical and cannot be banished using clever mathematics. Of course, we can never know everything about the infinite number of these universes (it's hard enough knowing the truths about just our universe!), but personally I feel that if the theory is correct and we have enough time, we may come close to knowing about them as well. To sum up: I think, with enough time and patience, we will come arbitrarily close to knowing everything physical about the so-called unfathomable.
Full name: Robert J. Rorden
Location: Los Altos, California
Question: In your December 2004 issue Michio Kaku advocates sending a probe through a black hole. Here are some comments on this project. I believe that the nearest known black hole is near the center of our galaxy, about 50,000 light-years from here. If we build a probe that can accelerate to 70 percent of light speed (very expensive), it could make the trip in about 71,000 years. A signal could get back after another 50,000 to 121,000 years after launch. Can we build a machine that will work after 71,000 years in space, including millennia of intense ionizing radiation? Would anyone be listening? Will the human race even exist, considering its tendency to collective insanity (war)?
Kaku responds: Stellar black holes have been found in our vicinity, so we need not journey 25,000 light-years or so to the galactic center (where there is a monstrous black hole weighing about 3 million solar masses). But you correctly conclude that communicating with a probe sent to a black hole (by a Type 0 civilization like ours) would be impractical. My point is that a Type III civilization, perhaps 100,000 to a million years more advanced than ours, would have already mapped out most of the galaxy. Given these vast timescales, they would have enough time to send trillions of self-replicating robotic probes throughout the galaxy (exponentially growing like a swarm of viruses), to locate all the neighboring black holes, even traveling at sublight speed. Moreover, a Type III civilization may, by definition, have the ability to manipulate the Planck energy (10 to the 19 billion electron volts), so it is conceivable that they may be able to create wormholes to visit distant parts of the galaxy. In conclusion, what is impossible for a Type 0 civilization like ours may seem like child's play to a Type III civilization.
Full name: Jonathan Eziquiel-Shriro
Location: St. Augustine, Florida
Question: I read the December article on escaping an ending universe, and one small detail caught me for its omission. Actually it wasn't truly omitted, just possibly overlooked for importance. The seventh option for escaping the universe—using nanobots—talked about re-creating everything on another side, basically sending information through the wormhole via machine. Perhaps it is naive of me to assume, but isn't information all that our and any Type III civilization need to escape? The big concern, it seems, is the unknown of whether information can survive a wormhole trip. If somehow it can, perhaps one of those methods described would be enough; for example, just send raw data through and allow it to recombine at the other end. Perhaps a Type III would not need machines or devices to facilitate information dissemination. Perhaps the true power of the Type III civilization is to make all of history and time a singularity in itself that it could send where it wanted.
The other notion that occurred to me is that a Type III might not experience time as we do and could possibly experience all time as a moment. Wouldn't the ultimate harnessing of power allow a civilization to advance its understanding of dimensions and possibly transcend far beyond our current abilities? I tend to believe that the nature of a Type III civilization and its power-generating capabilities create possibilities way beyond the scope of our existence. Even a Type 1 civilization will have powers unimaginable to us today. This tends to lead me to the currently unimaginable conclusion that the members of a Type III civilization may become extracorporeal, no longer needing physical bodies to define them.
If that becomes the case, doesn't that radically change the need to escape our universe? Perhaps being as powerful as to exist on a higher plane beyond the constraints of our physical universe would mean such a civilization already regularly "jumps" from universe to universe at will—they are no longer bound by any sort of rules that we are. "Escape" might be a term that's only useful for us and our comparatively limited abilities of perception.
Nevertheless, we are only at the dawn of the first iteration of a Type I civilization. A lot of it seems to rest in the potential of chips, computing and entry-level quantum mechanics. Tasty stuff, but a meal so large we will be lucky to see the second course.
Kaku responds: You are correct that the important point is that information be sent through a wormhole to a neighboring parallel universe. However, information must come in a practical, sturdy, self-replicating form. For example, simply sending computer tape or digital code through the wormhole will not succeed. What is necessary is to send a probe that is self-replicating, which can create trillions of copies of itself, containing enough information to reclone their entire civilization. In other words, we need the hardware in addition to the software.
Full name: Keith Salvas
Location: Simi Valley, California
Question: I thoroughly enjoyed your article on "How to Survive the End of the Universe." However, I recently attended a lecture on supermassive black holes and I've found what appears to be a contradiction in one theory that makes traveling through such a place impossible. As the theory goes, if I could enter into the event horizon, then measure the circumference of space at a fixed point, by dividing by 2pi I should get the radius to the singularity. If I then move closer and make a similar measurement, I should get a radius that, when added to the distance I traveled from the first point, should equal the first radius. But the theory states that the sum of the two measurements would be greater than geometrically possible because the black hole stretches space. So here's the contradiction: If the singularity, which by definition is mass without volume, stretches space, then the closer I get to it the more space is stretched. So a geometric inch could be a mile, and the next inch inward could be 10 miles, and so on. This means that the closer I get to the black hole, the more space is stretched, to the effect that the closer I get to it the further away it becomes. The conclusion is that I could never reach the black hole itself because space becomes stretched infinitely at the singularity. This also makes the black hole a mini universe or a place where the universe is turned inside out. Do you have any comments on this apparent problem?
Kaku responds: Yes, as you approach a black hole, severe distortions of space and time take place, but they are visible mainly to someone far away observing you fall into the black hole. If you are unfortunate to fall into a stellar black hole, you will pass the event horizon and probably crash into the black hole itself in a blink of an eye. From your vantage point, death is mercifully swift. However, to an observer watching the event, he will see something quite different. Because light is stretched and redshifted as it reaches the observer, it appears as if you are slowing down in time. It appears as if you are moving in slow motion as you are being ripped apart. It seems to take thousands of years before you inevitably reach the vicinity of the event horizon.
