Michio Kaku is a futurist, popularizer of science, and theoretical physicist, as well as a bestselling author and the host of two radio programs. He is the co-founder of string field theory (a branch of string theory), and continues Einstein’s search to unite the four fundamental forces of nature into one unified theory. He holds the Henry Semat Chair and Professorship in theoretical physics and a joint appointment at City College of New York and the Graduate Center of C.U.N.Y. He is also a visiting professor at the Institute for Advanced Study in Princeton and is a Fellow of the American Physical Society.
Kaku launched his Big Think blog, "Dr. Kaku's Universe," in March 2010.
Michio Kaku: We have found the Higgs boson. So then the next question is what's next? Well the Large Hadron Collider, this machine that is 27 miles in circumference, costing 10 billion dollars is big enough to create the next generation of particles. So the Higgs boson in some sense is the last hurrah for the old physics, the old physics of what is called the standard model, which gives us quarks and electrons. The new theory is going to take us into dark matter. Now we know dark matter exists. Dark matter is invisible, so if I held it in my hand you wouldn't see it. In fact, it would go right through my fingers, go right through the rock underneath my feet and go all the way to China. It would reverse direction and come back from China all the way here to New York City and go back and forth.
So dark matter has gravitational attraction, but it is invisible and we are clueless as to what dark matter really is. The leading candidate for dark matter today is called the sparticle. The sparticle is the next octave of the string. Now look around you. Everything around you, we think, is nothing but the lowest vibration of a vibrating string, the lowest octave in some sense, but a string of course has higher octaves, higher notes. We think that dark matter could in fact be nothing but a higher vibration of the string. So we think that 23% of the universe, which is the dark matter's contribution to the universe, comes from a higher octave of the string. Now the standard model which we have ample verification of only represents four percent of the universe. So the universe of atoms, protons, neutrons, neutrinos - that universe only represents four percent of what there is. 23% is dark matter, which we think is the next vibration up of the string and then 73% of the universe is dark energy.
Dark energy is the energy of nothing. It's the energy of the vacuum. Between two objects in outer space there is nothing, nothing except dark energy, dark energy, which is pushing the galaxies apart. So when people say if the universe is expanding they say two things, what's pushing the galaxies apart and what is the universe expanding into. Well what's pushing the galaxies apart is dark energy, the energy of nothing. Even vacuum has energy pushing the galaxies apart. And then what is the universe expanding into? Well if the universe is a sphere of some sort and we live on the skin of the sphere and the sphere is expanding what is the sphere expanding into? Well obviously a bubble, a balloon expands into the third dimension even though the people living on the balloon are two dimensional.
So when our universe expands what does it expand into? Hyperspace, a dimension beyond what you can see and touch. In fact, string theory predicts that there are 11 dimensions of hyperspace, so we're nothing but a soap bubble floating in a bubble bath of soap bubbles and so in some sense the multiverse can be likened to a bubble bath. Our universe is nothing but one bubble, but there are other bubbles. When two bubbles collide that could merge into a bigger bubble, which could be the big bang. In fact, that is what probably the big bang is or perhaps a bubble fissioned in half and split off into two bubbles. That could be the big bang. Or perhaps the universe popped into existence out of nothing. That is also a possibility.
And so the universe could essentially be nothingness, which was unstable and created a soap bubble Now you may say to yourself well that can't be right because that violates the conservation of matter and energy. How can you create a universe from nothing? Well if you calculate the total matter of the universe it is positive. If you calculate the total energy of the universe it is negative because of gravity. Gravity has negative energy. When you add the two together what do you get? Zero, so it takes no energy to create a universe. Universes are for free. A universe is a free lunch. And then you may say to yourself well that can't be right because positive and negative charges don't cancel out, therefore, how can the universe be made out of nothing. Well if you calculate the total amount of positive charge in the universe and calculate the total amount of negative charge in the universe and you add it up what do you get? Zero, the universe has zero charge. Well what about spin? Galaxies spin, right? But they spin in all directions. If you add up all the spins of the galaxies what do you get? Zero, so in other words, the universe has zero spin, zero charge and zero matter energy content. In other words, the universe is for free.