Michio Kaku Interview — Physics, String Theory & Future

We are happy to present this archived interview with Dr. Michio Kaku, conducted in 2004. Michio Kaku is an American theoretical physicist, futurist, and popularizer of science. He is a professor of theoretical physics at the City College of New York and the CUNY Graduate Center. Kaku has written several books about physics and related topics, makes frequent radio and television appearances, and writes online blogs and articles. — Wikipedia

What do you think about the Hubble Space Telescope — salvage or let it burn?

Dr. Michio Kaku:
I think we should salvage it. There have been many breakthroughs in land-based telescopes that make some aspects of the Hubble less revolutionary, but one shuttle mission would be sufficient to salvage it. A robotic mission might not work, but humans can certainly repair it. It would be a shame to lose a billion-dollar workhorse. Advances in laser-assisted systems and the new giant ground-based telescopes complement Hubble, but they do not replace the value of a serviced space telescope.

How did particles form after the Big Bang, and why are they so small?

Dr. Michio Kaku:
No — the Big Bang produced a large flux of particles, and these particles continually interact rather than “getting smaller.” For example, matter/antimatter annihilation at the Big Bang created a huge flux of gamma rays; the particles we see today, including us, are a tiny remnant of that explosion.

Do you think string theory will ever be testable? If so, when?

Dr. Michio Kaku:
Yes. Contrary to some critics, string theory can be tested. For example, LISA (Laser Interferometer Space Antenna)—planned for orbit—will consist of three satellites connected by laser beams across millions of kilometers; gravity waves that hit LISA will produce detectable interference. LISA should be able to confirm or disprove inflationary and some string-inspired cosmologies. Also, the LHC may detect new particles or supersymmetric partners, which are effectively higher excitations of strings. Dark matter detection experiments may also provide indirect evidence. Many groups are searching for signs of higher dimensions experimentally, though as of 2004 there was no definitive proof.

In your book Visions you were optimistic about the future — are you still optimistic?

Dr. Michio Kaku:
In my book Visions I made several predictions, many of which are being realized. The predictions extend to 2020 and some to 2050, so while some may eventually fail, the ones so far are holding up. For the book I interviewed about 150 top scientists who are inventing the future, so many predictions came from people directly building those technologies.

What do you think of the state of technology in 2004?

Dr. Michio Kaku:
It’s hard to judge progress year by year. In the book I made predictions in roughly five-year increments. Breakthroughs sometimes appear subtle in a single year. For example, recently doctors in Germany used a seven-year-old girl’s stem cells to grow about 19 square inches of bone—enough to reconstruct a large hole in her skull. Human stem-cell regeneration like that is a real breakthrough in medicine.

When might the next big breakthrough in string theory arrive?

Dr. Michio Kaku:
Big breakthroughs in string theory tend to come roughly every decade. The theory originated in 1968, was shown to be consistent in 1984, and in 1994 the existence of an 11-dimensional theory called M-theory was proposed. After another ten years, we might expect further advances. The theory is mathematically deep and rich; we are still exploring where its miracles originate. Shallow or incorrect theories tend to be sterile, while string theory remains remarkably fertile.

Is it impossible for us to visualize four or more dimensions?

Dr. Michio Kaku:
We cannot easily visualize higher-dimensional objects because our brains evolved in three spatial dimensions. Computers, however, can handle higher-dimensional calculations and visualizations. As a child I tried to “leap into hyperspace” and always failed; this convinced me our brains are not adapted for manipulating higher dimensions. When I write papers in 10 or 11 dimensions, I keep diagrams to a minimum and rely on equations because visual aids become cumbersome.

What’s the difference between hyperspace and the multiverse?

Dr. Michio Kaku:
They are different concepts. Hyperspace refers to dimensions beyond our four-dimensional spacetime. The multiverse denotes parallel universes. A multiverse can be embedded within hyperspace—for instance, 4D “bubbles” floating in an 11D space. Currently there is no experimental proof for either concept.

What advice do you have for aspiring mathematicians and physicists?

Dr. Michio Kaku:
The most important piece of advice is to keep your sense of wonder alive. You need a lot of math to become a physicist, but math is a tool to visualize the physical picture. Physics is driven by a handful of physical principles—relativity and quantum mechanics, for example—and math is bookkeeping that helps describe those principles. Don’t get bogged down in algebra at the expense of the physical picture. I read a lot of science fiction as a child, but I realized I needed to learn the math to avoid becoming a crackpot. The language of nature is math: share the wonder, then learn the language.

Which particles would you hope to see at the LHC?

Dr. Michio Kaku:
I hope we find dark matter particles. Dark matter, which makes up a large fraction of the universe’s mass-energy, may consist of neutral supersymmetric particles such as photinos (higher excitations of the photon in some models). Ordinary baryonic elements compose only a small fraction of the universe. I also hoped the LHC would find the Higgs boson—the last missing piece of the Standard Model—and potentially other new particles. Neutral particles are hard to detect directly because they leave no tracks; we find them via collisions with charged particles.

Why was 2005 designated the World Year of Physics?

Dr. Michio Kaku:
Because 2005 marked the centennial of Einstein’s miracle year, 1905, when he published several landmark papers: introducing the photon concept, establishing special relativity, deriving E = mc^2, and providing strong evidence for atoms—all while working at the Bern patent office.

How can a student stay interested in physics when the teacher is boring?

Dr. Michio Kaku:
Many physicists had uninspiring teachers yet remained fascinated by physics. Often, an external spark—visiting a planetarium, using a telescope, playing with a compass or gyroscope, or working with a mentor—triggers lifelong interest. Don’t be discouraged if your teacher is uninspired; use other resources, devices, or mentors to keep your curiosity alive. It’s a test of a budding physicist to love physics even without enthusiastic classroom instruction.

What do you think of the Super-Kamiokande neutrino results? Are theorists catching up?

Dr. Michio Kaku:
The neutrino-mass results were not a surprise to many theorists. For decades physicists extended the Standard Model to include tiny neutrino masses and different symmetry-breaking schemes. The Standard Model is extremely successful, so extensions often focus on subtle deviations; neutrino mass was an obvious candidate and is well understood in many theoretical frameworks.

Are you working on any new books?

Dr. Michio Kaku:
I had just finished writing a new book titled Parallel Worlds, published by Doubleday. It covers the latest in cosmology, the multiverse and parallel universes, and ends with a speculative idea: according to current data the universe may die in a Big Freeze, which would force advanced civilizations to consider leaving the universe. I discuss how sufficiently advanced civilizations might manipulate Planck-scale energies to open wormholes or create baby universes, effectively escaping to other, warmer universes. The book tour schedule was to be posted at my website www.mkaku.org.

How should a student properly learn calculus? Which textbooks do you recommend?

Dr. Michio Kaku:
For beginners, use a practical “cookbook” style text that provides many worked problems and recipes rather than a purely elegant, abstract presentation. Elegant books like Feynman’s freshman physics are beautiful but can be difficult for beginners. Start with clear problem-solving resources, then move to more sophisticated and elegant texts as your understanding matures.

How can one gain a deeper understanding of quantum physics?

Dr. Michio Kaku:
Don’t be discouraged — even professors debate quantum foundations. As Niels Bohr said, anyone not shocked by quantum theory does not understand it. Mathematically, quantum mechanics can be presented as differential equations, but the interpretation remains debated: many-worlds, decoherence, Wigner’s friend, and more. In Parallel Worlds I discuss various interpretations; decoherence and many-worlds are among the leading ideas today. The conceptual questions remain active topics of research and philosophy.

That wraps up our event for tonight. We’d like to thank Dr. Kaku for stopping by. Read part 2 here.

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