I'm a physicist and my primary vocation is doing theoretical physics, on paper, by hand. I also have a passion for explaining science, so I've written a number of popular science books-about hyperspace, the physics of the impossible, the future of the mind, and more. My latest (out now in paperback) is about The Future of Humanity: on Earth, across space, throughout time, all the way to our destiny among the stars. Read more about The Future of Humanity here: https://www.penguinrandomhouse.com/books/555722/the-future-of-humanity-by-michio-kaku/9780525434542/ Proof: https://twitter.com/michiokaku/status/1120404221369696256 Fire away! I'm ready for your best!

I'll be signing off now. If you have more questions or I wasn't able to get to yours, I'll be doing a Facebook Live on Tuesday, April 30th. Hope to see some of you there. Thanks for your comments and curiosities!

Comments: 2580 • Responses: 36  • Date: 

Sosa951165 karma

What do you think is the most important thing the average person should know about the universe?

michiokakuauthor2985 karma

One thing that people should know about science in general is that science is the engine of prosperity. All the wealth we see around us is the byproduct of scientific discovery. Concerning the universe, the average person should appreciate the fact that the universe is knowable, i.e. with enough time and effort, we can explain the great mysteries of the universes, without resorting to magic.

Astronaut100261 karma

Great answer. Unfortunately, America seems to be going backwards rather than forwards with regards to scientific temper. Ridiculous ideas like not believing in climate change, being afraid of vaccines, and believing that the Earth is flat are going mainstream. How do you react to that?

michiokakuauthor715 karma

We will always have superstition and magic with us, because I believe there is a gene for it. This superstition gene was moderately helpful when we lived in the forest. But now that we have nuclear weapons, biotech, computers, etc., this superstition gene can pose problems. I think there is a gene for wonderment and curiosity, but no gene for the scientific method. Hence, centuries from now, we will still have flat earthers who confuse appearance and reality.

duhitsryan189 karma

I don’t think that America is going backwards, but rather the dominance of social media serves as a constant reminder of the scientifically illiterate.

Are more people becoming anti-science or does it just feel this way because the internet provides a forum for those individuals to speak out?

michiokakuauthor429 karma

The internet doesnot change human behavior so much as it magnifies it. We will always have cranks, petty criminals, rumor mongers, etc. Normally, their influence was limited. However, the internet magnifies human behavior, so that even silly ideas get promoted. This is sad, but overall the internet has been a great gift for all of civilization. The internet promotes education, science, democracy, and free discussion, which are all great, but as an aside it also provides a platform for cranks. That is the price we pay for the internet. But eventually, most people will tire of the novelty of hearing from cranks and shrill self-promoting prophets, and ignore them.

FrogKidFrankReynolds916 karma

With the first picture of a black hole being revealed, what do you think is the logical next step to learn more about them?

michiokakuauthor2016 karma

The next step is to release the data from the black hole at the center of the Milky Way galaxy, which weighs about 2-4 million times more than the sun. Personally, I would be interested in studying spinning blackholes, since (mathematically speaking) they might have a spinning ring in the center, which might (possibly) be a gateway to another universe.

Destructopoo639 karma

Hey I just wanna say thanks for making me fall in love with something I don't really understand. I read one of your books in high school and it set me on a really great path of curiosity. The fact that you made these groundbreaking topics like string theory somewhat available for a teenager to get a feel for is really great and I appreciate it.

michiokakuauthor2071 karma

Thank you. We are all born scientists. We are born wondering where we came from, why the sun shines, why the stars twinkle, etc. But eventually we hit one of the greatest destroyers of science known to science, high school. In high school, science is made boring and irrelevant to people's lives. In my books, I try to make young people cherish science once again.

insaneWJS53 karma

A gateway to another universe through a spinning blackhole? WICKED COOOOOOOL!!! I wonder the spinning effect has to do with its stability to the connection for another universe.

michiokakuauthor237 karma

This is hard to grasp, but Einstein's theory for a spinning black hole does not describe a stationary singularity. Einstein's theory says a spinning black hole collapses into a spinning ring, and if you fall through the ring, you (mathematically speaking) wind up in a parallel universe. This is a wormhole, which Einstein himself introduced in 1935. What divides physicists is whether the wormhole is stable (quantum mechanically) when you pass through it, as in Alice's Wonderland.

brazasian52 karma

So, if blackholes can be gateway to another universe how come we do not see matter emerging on our universe from other universes?

michiokakuauthor220 karma

There is a theory which says that there is a white hole on the other side of a black hole, so the matter which enters the black hole is thrust out the other side. In fact, some physicists have proposed that the Big Bang is actually a white hole. Unfortunately, this theory cannot be proven with present day instruments.

theMDinsideme607 karma

What is your opinion on the simulation hypothesis?

michiokakuauthor1239 karma

I do not think we live in a computer simulation. No digital computer can compute all the motions of molecules in a simple object, e.g. the weather. The smallest object which can simulate the weather is the weather itself. When you add quantum corrections, then no digital computer on earth can simulate the quantum effects in the weather. So no digital computer can possibly simulate reality as we know it.

thndrchld232 karma

Why does it have to be digital? If a species is cable of building a simulation that can model... well... everything, I doubt they're doing it on anything we would recognize.

michiokakuauthor408 karma

I mentioned that a digital computer cannot simulate even a simple reality, since there are too many molecules to keep track of, far greater than the capabilities of any digital computer. We need a quantum computer to simulate quantum reality, and hence, once again, the weather is the smallest object that can simulate the weather. Therefore, I don't think we live in a simulation, unless the simulation is the universe itself.

LolaLiggett363 karma

Thank you for your AMA! What do you think is the most fascinating thing we might be able to see in our lifetime? Anything you really want to see happen in your lifetime?

michiokakuauthor990 karma

I think in this century (not necessarily in our lifetime) we will have the first star ship sent to the stars (e.g. perhaps a computer chip), the "theory of everything" will be proven, the genes controlling the aging process will be found, brain-net will be established, and we will detect the signals from an extraterrestrial civilization.

Exodus111314 karma

What's your preferred Fermi-Paradox explanation?

michiokakuauthor887 karma

Personally, I think alien civilizations exist in outer space. But distances between stars are so great, they would probably have to be Type 2 or 3. This means there are perhaps several thousand years to a million years ahead of us. To them, we might appear to be like forest animals, like deers. At first, they might want to talk to the deers, but eventually, since the deers do not talk back, and lose interest, and leave the deers alone. Hence ETs in space realize that we have nothing to offer them. But they will not want to plunder us for resources, because there are plenty of uninhabited planets out there to plunder without worrying about the restive natives on them.

franknwh288 karma

What do you think about Elon Musk’s Neurolink technology that will connect humans to computer technology, and where does that potential put us on the long term Type 0, Type 1, Type 2 advanced species spectrum?

michiokakuauthor621 karma

Maybe its a bit premature to invest in brain/computer technology, but the field is rapidly moving ahead. Telepathy, forms of telekinesis, photographing thoughts, etc. were all once considered impossible, yet we can do them now, via physics. Eventually, we will have brain-net, with the ability to send emotions, memories, feelings, etc. on the internet. This could rapidly reduce boundaries between people, and correct misconceptions between nations, as well as open up entirely new areas of entertainment. The movies and TV will seem so old when we have brain-net.

_Robbie235 karma

The big question (two parts, if you don't mind!):

1) Do you think that there is a way/we will discover a way to theoretically "cheat" the speed of light ("warp drives", stable wormholes, etc.) to allow for practical travel of vast distances across the universe?

2) Do you think that, even if we discover a way that it was possible, that we as a species (perhaps in the far-flung future) could ever develop some kind of technology to allow it to actually happen?

Interstellar travel has captured all of our imaginations, but it's hard to imagine how it might be made a reality.

Thanks for the AMA! I've been a big fan of yours for a long time. :)

michiokakuauthor394 karma

Wormholes that can break the light barrier are allowed within Einstein's theory, since they were introduced by Einstein himself in 1935. But going through them is problematic. First, you need to have the energy of a black hole to open the gateway to another universe. So don't think that an inventor will create a wormhole in his or her basement. Second, you need negative energy or matter to stabilize the wormhole so it doesn't collapse. Negative mattter has never been seen in nature, but negative energy has been created in the laboratory, but only in small quantities. The energy necessary for all of this is the Planck Energy, or 10 to the 19 billion electron volts, the energy at which space-time becomes unstable. Perhaps only a Type 3 civilization can manipulate the Planck Energy.

Deadmeat55352 karma


michiokakuauthor119 karma

Positive energy on a scale of a black hole is necessary to rip space time and create a wormhole, but negative energy is required to stabilize it so it doesnot collapse. Negative energy has been found in the lab (in the form of the Casimir effect) but is extremely tiny in magnitude. In fact, in nanotechnology, negative energy is actually a nuisance, since it interferes when trying to manipulate individual atoms. So negative energy is a quantum reality, but is extremely tiny. It would take perhaps a type 3 civilization to then use this negative energy, concentrate it, and then use it to stabilize it. As an aside: the movie Interstellar had Nobel prize caliber scientists consulting for it. At the end of the movie, our astronaut winds up in hyperspace, i.e. the arena of string theory, and is found floating in the 5th dimension.

B_K_23_03186 karma

I'm here about asking some personal opinion from you.. I wanna become a theoretical physicist, but I'm facing constant failure to crack the entrance exams to get into high quality universities. In order to be successful, Should I do UG on normal colleges Or should I only try to focus on getting into those universities, Dr. Kaku?

michiokakuauthor397 karma

To become a theoretical physicist, it certainly helps to go to a top notch Ivy League school. (I went to Harvard). But it is not absolutely essential. Most of the advanced material necessary to become a physicist is found in graduate school, not undergraduate school. In a Ph.D. program, that is where your true talent as a mathematical physicist begins to shine. So it certainly helps to get into a good school, but only as a Ph.D. student in grad school do you begin to flourish as a research scientist.

rpprdud170 karma

Can you help me understand how black holes can radiate away their mass through Hawking radiation? How is the mass/ energy leaving the gravity well of a black hole.

It is said that Hawking radiation is a result of quantum field interactions near the event horizon, but this doesn’t translate for me intuitively.

michiokakuauthor295 karma

Many textbooks say that lack holes are black since not even light can escape. Nothing can escape a black hole. However, this violates the Uncertainty Principle. Pure blackness violates Uncertainty, since pure blackness is the absence of all matter and energy, but the position and velocity of particles is always uncertain. Hence, black holes must be gray. That is what Hawking found. Surrounding the black hole, there is an event horizon, a sphere. If you are outside the event horizon, then you do not necessarily fall in. Hence, Hawking radiation can escape the black hole. (However, it is very small. That is probably why Hawking never won the Nobel Prize, since the Prize is usually given for physical discoveries that can be measured.)

superd76127 karma

Do you think a solar flare could wipe out humanity?

michiokakuauthor264 karma

A giant solar flare can wipe out modern civilization, but not humanity itself. We now know that the earth suffered two giant solar flares, in the year 775 and 1849. People back then felt nothing, since electronics as we know it did not exist back then. But another Carrington Event of 1859 could set back world civilization 200 years. Power stations would short circuit. Satellites would be fried. Black outs would be planetary. The internet and all telecommunication would be destroyed. We physicists have estimated that property damage would be 2 trillion dollars.

thardoc28 karma

I'm pretty sure he mentioned this specifically in one of his books talking about stages of civilization. The Kardashev scale would be a good thing to look at.

michiokakuauthor91 karma

Briefly, we physicists like to quantify things we study, using several metrics, e.g. energy and information. So Kardashev ranked civilizations in space by their energy consumption. A Type 1 civilization uses up all the energy that falls on their planet from the sun, i.e. they are planetary and can control the weather and planetary forces. Type 2 controls the energy of an entire star. Type 3 is galactic and roams the galaxy. Star Trek would a typical Type 2 civilization, and Type 3 would be described by Star War. We, by contrast, are Type 0 and get our energy from oil and coal, but we are about 100 years from becoming Type 1. So we privileged to be alive to witness the greatest transition in human civilization, the transition from type 0 to type 1.

SherpaForCardinals112 karma

In your opinion, what are we losing as we invite more and more technology into our daily rhythms and habits?

michiokakuauthor286 karma

In every revolution, we gain and lose. As a student, we used to have slide rules on our hips. It was our symbol. Engineers considered it a badge of courage. Today, the only place to find a slide rule is in a museum. So we lost slide rules, but gained cell phones and pocket calculators. So technology continually shapes our daily life. Some people claim, however, that kids spend too much time on line. My attitude is that a new social norm is being created, so that kids should by all means engage in online social interactions. But they must also be socialized, so they can interact socially with their peers. As long as kids have healthy relationships and friends, I see no reason why they shouldn't be on line.

willyvanvee89 karma

Dr. Kaku, given the opportunity to merge your conciousness with a non biological interface, would you? Do you think a copy of ourselves is made if consciousness is transferred? Or will it be truly "us"?

michiokakuauthor131 karma

I think that in this century, robots will not attain human-level consciousness (see my book The Future of the Mind for a definition of consciousness). But eventually digital immortality becomes possible at the end of the century. Already, it is possible to digitize all your emails, credit card transactions, videos and pictures, to create a rough avatar of yourself. In the future, instead of reading of Winston Churchill, you will talk to him. A holographic image of Churchill will appear that has all his speeches, books, bios, etc. I personally would love to talk to Einstein. Eventually, we might be digitized and become "immortal." But is really "us" that becomes immortal?? If our soul is actually information, and this information is digitized (with all our memories), then this copy might be indistinguishable from us. By the end of the century, the Connectome Project may be finished to map all the neural pathways of the brain, so that we have an exact neural copy of our brain. So digital immortality might be possible. It becomes semantic whether the copy is a true copy, since the copy is indistinguishable from the real one.

aaronthenia74 karma

What progress in space travel do you foresee in the next 100 years?

michiokakuauthor244 karma

We are entering the 2nd Golden Age of space travel. The first golden age took us to the moon, but absorbed 5% of the entire US federal budget, so it was unsustainable, and eventually collapsed. But the 2nd Golden age of space travel a) is being partially funded by billionaires b) is benefiting from the reduced cost of space travel c) will be fired up with resuable rockets d) benefiting from the computer revolution. Hence, I think one day our grandchildren will be able to honeymoon on the moon. And a self-sustaining base will be on Mars. .Remember, the dinosaurs did not have a space program, and that is why there are no dinosaurs today.

sporophyte59 karma

Are there any ways that the existence of 5 or more dimensions could impact us that we don’t realize?

michiokakuauthor110 karma

If string theory is correct, then we have no direct contact with hyperspatial dimensions, since they are too tiny for atoms to enter. But consider this: our universe is a bubble of some sort, and it is expanding, and we live on the skin of this bubble. This is the Big Bang theory. But string theory says there is actually a multiverse of universes, like a bubble bath, with bubbles colliding and fissioning all the time. So Big Bangs are happening all the time somewhere in the multiverse. This multiverse is the hyperspace of 11 dimensions.

Mmg4558 karma

I remember reading Parallel Worlds and you spoke of how long it would take for space travel to advance to a suitable price per weight. Has it progressed faster than you imagined in recent years with private companies like Space X and Blue Origin? and do you think it is the beginning of a large step for mankind? (By the way, I would just like to say thank you for starting my love of physics)

michiokakuauthor97 karma

We are seeing a shift in thinking with the coming of Space X and Blue Origin. The SLS booster rocket, funded by NASA with federal funds, is behind schedule and over budget. Worse, it may cost $1 billion per mission and fly once a year. Meanwhile Space X with the Falcon Heavy claims to be able to send a rocket to the moon at a fraction of this cost and several times year. So we are seeing that private enterprise may kick start the space program.

ricctp653 karma

I just have to say that I am one of your biggest fans. I’m an archaeologist and writer, and you make theoretical physics something I can at least begin to understand (a bit). I was wondering if you could talk to us a bit about your writing process:

Do you have a routine?

Did you find that it easier to write popular novels than academic articles or vice versa?

What is the hardest part about making complicated science relatable and clear for a general audience?

michiokakuauthor75 karma

I am a research physicist. I spend most of my time thinking about equations and manipulating them. However, I am also a science junkie, and seek out science on my own. Being a professor, I also am interested in science education. Hence, it was natural that I try to engage the public with a fascination about science. Unfortunately, there is no gene for the scientific method and mathematics, but there is a gene for wonderment and curiosity. The hard thing is to channel that natural inclination towards curiosity and a sense of wonder without sacrificing scientific rigor. But since I have interviewed over 300 scientists while working for BBC, the Science Channel, etc, it gives an appreciation for all the fantastic developments in science as a whole.

fznmomin42 karma

Is string theory on its way out the door?

michiokakuauthor86 karma

The progress of science is largely independent of public popularity. Science is not done by popularity contests on game shows. It often takes decades for scientific theories to be vindicated, yet the public often wants immediate results. The public wants breakthroughs-for-the-moment, but science progresses at its own pace. Presently, string theory dominates much of theoretical physics, but lacks immediate experimental verification. The Large Hadron Collider found the Higgs boson, but failed to create Dark Matter, unfortunately. Many physicists believe that Dark Matter consists of the photino, a supersymmetric partner of the photon which is stable but invisible, and is predicted by string theory. We will have to wait until more results from the LHC come in. Also, the next generation of accelerators beyond the LHC are being discussed now, with proposals from Japan, China, and the European Union. Perhaps the next generation of accelerators (or perhaps results from spark chambers deep in the earth) will pick up evidence for Dark Matter, which would be tremendous boost for string theory if the theory matches the data. Meanwhile, scores of physicists around the world are still finding new and fascinating discoveries about the nature of string theory.

pramit5741 karma

Do you have any advice for young scientists who want to explain science to the public, in both written and oral forms? How can a scientist make a career out of it?

michiokakuauthor82 karma

I am a research physicist, spending most of my time working on the mathematics of string theory. However, I have the ultimate respect for professional science writers who based their careers on science education. For advice, I would say that a science writer first has to master as much science as possible Second, this science has to be explained in terms of physical pictures and concepts, rather than just memorization. E.g. learning about plants is fine, but simply listing the parts of a flower is boring. What is more interesting is how plants evolved, which explains their coloration, their shape, their live cycle. Once, the father of the young Richard Feynman would explain to him everything about the evolution of birds. But one day, a bully challenged him to name that bird they just saw. The young Feynman knew everything about that bird (the shape of its wings, beak, its habit) except it name. Then the bully said that Richard must be stupid because he couldn't name that bird. The young Feynman suddenly realized something profound: most people think science is giving names to things like birds. But that is not science at all.

bjorn17127 karma

Does space and time fabric have surface tension, as in the only thing strong enough to puncture it is a black hole?

michiokakuauthor48 karma

Space time has no surface tension as we know it. But we have something called frame dragging. When a black hole rotates, it drags space-time around it, like molasses. Stars and gas follow the frame dragging space-time. But at the very center, it might be possible that space-time itself begins to rip.

Mafeoqbag26 karma

Where do you see humanity in the next 100 years ?

michiokakuauthor66 karma

In the next 100 years, we will see the birth of a Type 1 civilization, a planetary civilization. The internet, for example, is the first type 1 technology to appear in this type 0 civilization. We see the beginning of a type 1 language, with English and Mandarin Chinese being the first and second language of the internet. We see the beginning of a type 1 economy, with the emergence of planetary agreements. We see the beginning type 1 music, fashion, sports.

stakatsu26 karma

I've been loving your book. Absolutely visionary. I appreciate your unashamed fusion of science and the imagination. Which brings me to a question that may seem spiritual - you mention the Star Maker in your book. Do you personally believe after studying the complexities of the universe and the multiverses, that there may very well be a Star Maker? Do you believe that technology can allow humans to transcend the physical form and exist at a higher dimensional state?

michiokakuauthor38 karma

In my book, the Future of Humanity, I mentioned the Star Maker, as celestial being who could manipulate entire universes, and witness the panorama of the multiverse. This was a stunning vision for the pre-war generation. I mentioned it because that is how we string theorists sometimes feel, as we manipulate solutions of string theory. Each solution of string theory represents an entire universe, with different laws of physics. To study string theory, we not only have to study our own universe (which is but one solution of string theory) but also universes that do not exist, at least in our neighborhood of the multiverse. Hence, we feel like the Star Maker. Instead of studying just our universe, we have to study unvierses that don't exist with different laws of physics (e.g. some universes may have protons which are unstable, so the universe dissolves into a mist of electrons and neutrinos. Or universes with a stronger nuclear force, so stars burn out quickly, and life cannot get started) However, this was only meant to be an analogy.

radiofiend26 karma

In two hundred years, IF humanity is still around, what do you think the history books will say about our current era?

michiokakuauthor73 karma

In this century, technology will give us AI which can usher in prosperity and growth. But by the end of the century, our machines may gradually become self-aware, and hence pose an existential risk to us. At that point, we should put a chip in their brain to shut them off if they become too rebellious. But 200 years from now, our machines will become so powerful they can remove all failsafe systems and pose a real threat. At that point, we might have to merge with them. So the 21st century may be the last century when we are purely biological.

s1gn1fy19 karma

Do you believe that ITER and other fusion technologies will solve energy problems and alleviate some of the factors causing climate change in time to make a difference in the overall health of the planet and improve the quality of life in under served parts of the world?

michiokakuauthor40 karma

Personally, I hope that the ITER fusion reactor in South France will be a success, so that one day even sea water can be source of hydrogen which drives our fusion reactors, producing minimal nuclear waste and posing no problems with meltdowns. However, the ITER has been delayed several times, and hence still has not proven that fusion can help solve our energy problem. So it is still a distant but promising hope. More immediate, is the falling cost of battery power. We forget that the problem with solar and wind power is storage, since the sun does shine at night and the winds don't blow all the time. There is no Moore's Law for batteries. But recently, there has been a dramatic fall in the cost of batteries, which might fulfill the dream of having solar and wind power fully competitive with fossil fuels.

BigBlackHungGuy19 karma

Hello Professor Kaku. Thanks for coming back.

With the advent of private spaceflight, do you feel that mankind is being held back by profit motivations of space travel?

Also from one vet to another, thank you for your service.

michiokakuauthor26 karma

I think that the profit motive, instead of holding back space travel, is accelerating it. It think that a partner ship between public and private funds is the way of the future. In old days, the 1st golden era of space travel ended because tax payers could not maintain this costly program. But with costs dropping dramatically, and private billionaires creating their own fleet of rockets, this has opened up a 2nd golden era. And yes, I served in the US military from 1968 to 1970.

NedRadnad19 karma

When are we getting flying cars and when can I expect HD displays inside my contact lens?

michiokakuauthor53 karma

Flying cars are finally coming. I spoke in Dubai last year, where they are actually in negotiations for introducing flying cars. The problem was never the technology; the problem was getting cost down and solving political issues. Internet contact lenses will take longer. Already is is possible to put chips into contact lenses (diabetics can use this to monitor their blood via these contact lenses). Putting chips into contact lenses can be done. One problem is heat generation. Heat must be dissipated so that it does not pose a problem. And the optics has to be perfected as well. This work is being pioneered at the University of Washington in Seattle.

Koronakesh5 karma

What are your thoughts on the political environment that is limiting progress towards our goal of becoming a multi-planetary species? What can be done, if anything, to solve this problem?

michiokakuauthor8 karma

No I don't think that the current political environment is limiting progress toward becoming a multiplanet species. It will take time, on the scale of decades to centuries, to lay the foundation for a multiplanet species, while political movements come and go in a matter of years and decades. We have to look at the long-term.

Tailtappin2 karma

Love everything you do and spend a lot of time watching your appearances in science docs.

As for the question, what can you tell us about propulsion ideas for interstellar travel? I know there's nothing truly practical on the horizon but is there anything plausible in the hypothesis stage?

Also, as an aside, how convinced are you that dark matter and dark energy are real things as opposed to misidentified or poorly gauged known phenomena?

michiokakuauthor3 karma

In this century, there is hope that the Breakthrough Starshot program will send the first computer chip to a near by star. It is a chip connected to a parachute, fired up with a blast of laser power on the earth. It might reach Proxima Centauri travling at 20% the speed of light for 20 years. After that, the hope is that fusion engines can power a star ship in the next century. A ram jet fusion engine might even run forever, scooping up interstellar H from outer space.