Theoretical physicist and string theorist Michio Kaku shares his thoughts on time travel, matter-fabricators and 2001: A Space Odyssey.
Also, be sure to check out Professor Kaku's latest book, Physics of the Impossible, available from Doubleday.
1. If time machines exist, can we ever hope to meet our older, or younger, selves?
A. That is a big "if." But assuming they exist, then there is hope that we might meet our older or younger selves, but they won't be exactly "us." The river of time, I believe, may fork into two rivers if we travel in time.
Hence, if we jump from one time line to another time line, we may meet ourselves in the past, but these people won't really be "us." They will be genetically identical to us, but will be a younger or older version of ourself in a parallel universe. Hence, we won't have any time paradoxes. So if we change the past, we change someone else's past, who is genetically identical to us, but is not really "us." Of course, we won't know for sure until we finally build a time machine. (In fact, I give a blueprint for a time machine in my book, Physics of the Impossible, which is consistent with all known physics.)
2. Since we haven't ever met any time travelers from the future, does that mean they will never be invented?
A. No. Perhaps we are not interesting to them. We think we are so great that they will want to visit us, but maybe we are too primitive for them. After all, if we see an anthill, do we go down to the ants and say "I bring you beads. I bring you trinkets. Take me to your leader"? Some of us may even have the urge to step on them.
But the technological distance between an ant and us may be small compared to the technological chasm between us and a time-faring civilization. They may be thousands to millions of years ahead of us in technology, and hence have no interest in visiting us. But one day, if someone knocks on your door and says she is your great-great-great-granddaughter, do not slam the door. Perhaps in the far future our descendants will develop time machines, and want to visit their illustrious ancestors.
3. Are fears of robots taking over the world, Terminator-style, ever founded in reality?
A. Yes, robots may eventually take over the world. But we will have plenty of warning. Right now, robots have the intelligence of a cockroach. A retarded, stupid cockroach. Our most advanced robots take about six hours just to walk around a strange room. It may be years to decades before they are as smart as a mouse, then a rabbit, then a dog or cat, and finally a monkey. By the time they have the intelligence of a monkey, they can be dangerous, since they will have agendas of their own. But we will have plenty of warning. By the time they are as smart as a monkey, I think we should put a chip in their brains to turn them off when they have murderous thoughts. The key is that we will have plenty of time before these robot creations become truly sentient and conscious, with their own goals and desires.
4. Would you have your brain "downloaded" into a computer? Could it mean eternal life? Or would it be like being one of the heads in bell jars in Futurama?
A. Living in a bell jar is not my idea of "living." However, in the far future, merging with our robot creations may be a better alternative. In this case, we could have superhuman powers, live forever and explore the universe in near-invulnerable bodies. There is no law of physics preventing this. In fact, if we ever make contact with an advanced civilization in space, we should not be surprised if they have already altered their genetics and biological organs. In fact, I would be surprised if a civilization a million years more advanced than us has not modified their bodies genetically and mechanically. Just to live on distant worlds and harsh environments, they may have to alter their bodies in this way. And also remember that we must leave the Earth in the far future, due to ice ages (perhaps 10,000 years in the future), meteor impacts (perhaps 10 million years in the future) and the death of the sun itself (5 billion years from now). And when we do, it will be absolutely essential that we modify ourselves, or perish. There is no other choice.
5. What is the first thing you would make if you had your own matter-fabricator?
A. Some people may ask for diamonds, gold bullions or truckloads of cash. However, I have never desired to be wealthy. Money does not interest me. I've always wanted something that a replicator can never create: ideas. Wealth is something that corrupts and dies with you. But ideas can live forever and change the world.
6. Are there any TV series or films that you feel got it right in terms of portraying the future, or time travel?
A. The movie 2001 was off in terms of a timetable by perhaps a century, but it was the most realistic portrayal of an encounter with an extraterrestrial civilization. An advanced civilization is not going to send Capt. Kirk in a huge, expensive star ship. This is inefficient. More likely, they will send robot probes, which land on distant moons. (Moons are stable over billions of years.) They will then create a robot factory capable of reproducing themselves by the millions. Then they will shoot off to distant moons, and create even more robot factories. Starting with just one robot, eventually there is a sphere of trillions of these robots, expanding at near the speed of light, exploring the galaxy. This may sound fantastic, but it is happening in your body.
This probe can be a virus, which can colonize trillions of your cells in a matter of two weeks, giving you a cold. In the same way, these robot probes can explore the entire galaxy in just 100,000 years. Then they will wait until an intelligent species rises from the primeval swamp. This is the basic plot line behind 2001, the most realistic encounter with ET.
In fact, Kubrick originally interviewed scientists for the beginning of his movie, explaining all of this. But then he cut these interviews from his film at the last minute.
7. What was your homemade atom-crasher made from?
A. When I was 16, I went to Westinghouse, got 22 miles of copper wire and 400 pounds of transformer steel, and built a 2.3 million-electron-volt atom smasher in my mom's garage. The magnets produced 10,000 gauss of magnetism (which is enough to pull the fillings out of your teeth if you get too close). When I plugged it in, it consumed 6,000 watts of power, so I blew out all the circuit breakers in the house. My mom would ask herself, "why couldn't I have a kid who plays basketball? or baseball?" But I never regretted building an atom smasher, because it helped me to get a scholarship to Harvard, where I could fulfill my dreams.
8. Can you summarize The Theory of Everything?
A. All physical knowledge today can be summarized in two theories: the quantum theory (which describes electricity and magnetism and the nuclear forces) and relativity (which describes gravity). The quantum theory describes the world of the very small inside the atom, while relativity describes the world of the very large (e.g. expanding universes and black holes).
The Theory of Everything should unite these two theories into a single, coherent theory. Einstein spent 30 years of his life chasing after this theory, which would allow him to "read the Mind of God," but he failed. Today, our best (and only) candidate is called string theory, which is what I do for a living.
And this summer, the Large Hadron Collider (the largest atom smasher in the world) will be turned on, and we hope to test the periphery of this theory. If proven correct, it will be the crowning achievement of 2,000 years of science, ever since the Greeks asked the question, what is the world made of?
9. Do you feel the knowledge that you've gathered through the years has allowed you to see the world differently from when you were, say, a college student?
A. Yes. When I was a kid, I used to read a lot of science fiction. I used to wonder about time travel, parallel universes, anti-matter, the fourth dimension, etc. But eventually, I realized that I would wind up as a crackpot, always babbling about pseudo-scientific theories, unless I got serious and "paid my dues," i.e., unless I learned the most advanced mathematics and physics. Today, after years of doing research on the most advanced physics in the world, I know the precise boundary where advanced physics ends and science fiction ends. That's one reason I wrote the book, Physics of the Impossible, so that I could tell young people whether certain technologies were possible in the future or not.
10. How does the rest of the world view the U.S.'s take on science?
A. Let's put politics aside and just talk about science. I do a lot of lecturing around the world, and wherever I go, I am surprised that people admire and envy the science created in the U.S. It's surprising to me, since the U.S. has the worst educational system known to science. U.S. kids score near the very bottom in almost every math and physics exam. So why doesn't the U.S. collapse as a technological nation? The U.S. does a miserable job in educating the average student, but the U.S. has two secret weapons that other nations don't have. The first is the H1B visa (the genius visa), which puts high-tech immigrants on the fast track right to a green card and Silicon Valley, where they go on to create entirely new industries. Fifty percent of Silicon Valley is actually foreign born. This is the brain drain. The second is that our education system selects out the exceptional student. In the East, there is the expression, "The nail that sticks out gets hammered down." In the U.S., we have the expression, "The squeaky wheel gets the grease." The U.S. educational system does nurture exceptional, creative talent, which is the weak spot in many Asian societies.
