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Dr. Michio Kaku is the co-founder of string field theory, and is one of the most widely recognized scientists in the world today. He has written 4 New York Times[…]

Every Wednesday, Dr. Michio Kaku answers reader questions about physics and futuristic science. If you have a question for Dr. Kaku, just post it in the comments section below and check back on Wednesdays to see if he answers it.

Today, Dr. Kaku addresses this question: What is the most dangerous technology?

Michio Kaku: In my book, Physics of the Impossible, I mention the dazzling forms of technology that we may have in the future, but I'm also careful to point out that there are wildcards, that is, technologies that can really upset the whole applecart and, in fact, destroy the human race.  For example, let’s you say take the AIDS virus or Ebola virus and you weaponize it so that it’s airborne.  Think about that: you sneeze and it’s a death warrant.  The question is, is that possible?  Well, the answer is yes.  It’s unlikely, but it is possible because we know the genes that are responsible for being airborne.  And we also know that the AIDS virus is actually quite simple; it has less than ten genes.  Also we should realize that a government in the future may decide to weaponize a virus one day.   

And in the coming decades high school kids, high school kids will have the capability of, in some sense, manipulating life forms.   One danger is that we’ll have a typewriter, a typewriter where you simply type A-T-C-G, A-T-C-G and it creates DNA in the exact sequence, and so it’s conceivable that in the future high school kids for their high school science fare project will simply type letters on a keyboard and create different kinds of life forms.  That is something that is actually fairly close to becoming a real possibility.


And just remember also that the Spanish flu virus genome--the Spanish flu killed more people than all of World War I--its genome is published on the web.  You can download the genome of one of the greatest killers in the history of the human race, and, when people have typewriters by which they can type A-T-C-G and create practically any kind of DNA they want, then we begin to realize that this technology may become so cheap, so available, that perhaps by chance or by intention a super virus will be created that can wipe out most of humanity.

And then on the physics front there is another nightmare and that is laser enrichment of uranium.  When the United States first began to enrich uranium, we did it the hard way.  We created this gigantic plant in Tennessee and we had these huge hundreds of miles of pipes by which we took uranium hexafluoride, shot it through with a tremendous amount of electricity, and then slowly separate out heavy uranium hexafluoride from light uranium hexafluoride and that’s how we built the atomic bomb.  Today you can do it with ultra centrifuges simply by spinning.  By spinning uranium in liquid form, the heavier form, or uranium U238, goes to the bottom; the light U235 rises to the top.  And that’s how you can make atomic bombs using ultra centrifuges.  

Now, there is a third way.  The third way is with laser beams.  It turns out that the electron shells of U235 and U238 are almost identical but not exactly identical.  By the laws of quantum mechanics, the energy levels of U235 are slightly misaligned to the energy levels of U238.  You can create a laser beam, a laser beam with exactly the energy of the difference between these two so that you can activate one but not the other.  In other words, laser beams can be used to zap these atoms and separate out U235 from U238.   

Well, this means that in some sense somebody in their basement at some point in the future might be able to build a separation device to create U235.  That’s a nightmare that we don’t have yet, but it’s a nightmare that we will have in the coming years as the price of laser enrichment of uranium starts to go down.  

A third thing to worry about is global warming.  Now we can debate how much human activity drives global warming, but we do know the earth is heating up.  If you extrapolate that into the future Manhattan, parts of Manhattan may be underwater.  We may have to build dikes around certain cities like San Francisco, Boston and New York City.  New Orleans may, who knows, have to be simply taken off the list because it is—most of it is below sea level and may not be able to sustain a rising level of sea water around the world.

Also the United States Pentagon commissioned a report from the Global Business Network asking “What is the worst case political military scenario if global warming gets out of control?” and their conclusion was, it could spark a nuclear war.  Think of, for example, the border between Pakistan, India, Bangladesh.  That’s a hotspot because of the fact that Bangladesh could be flooded in the future by global warming, in which case hundreds of millions of refugees could go flooding into other countries, and nations that have nuclear weapons may actually use nuclear weapons to defend their disintegrating borders.  

So in my book Physics of the Future, I talk about the bright side, about fantastic technologies that we will have in the next 20, 50, 100 years.  But hey, let’s be blunt about this: there is also a dark side. 

Directed / Produced by

Jonathan Fowler & Elizabeth Rodd