SPEAKER: With this knowledge, I want to describe how human beings view the universe. And we call this the cosmology and a new term that is being used today called the anthropic principle.
We ask a question. Did the universe have a purpose and destiny when it began 13.7 billion years ago? We are here today. We see all the stars, the Milky Way. We see all this evolution going on in the universe. We see all the galaxies out there.
Is there a purpose? Lots of questions. Why is the universe the way it is? Could things have been otherwise? Why is it the way it is? Or have all things been dictated by an ultimate force at the big bank?
These are big, huge philosophical questions. And as we shall see, some may have answers. Some may not. Professor Thomas Gold, a professor here at Cornell University who just passed away, unfortunately, a cosmologist, once said, "The universe is what it is because it was what it was."
This is the perfect causality principle. Everything has a cause, and the universe is today what it is because it was what it was. Otherwise, it could have not been different. So was the universe made for man also is the question, which is the anthropic principle.
And is it a coincidence that life evolved on Earth, or is it written-- or was it written in the laws of the Big Bang? And what does coincidence mean, by the way? Now, we have to remember that you cannot change the laws of nature.
The laws of nature seem to have started at the Big Bang, and they have not changed. Omar Khayyam, one of the Persian philosopher scientists once said, "With Earth's first clay, they did-- the last man's need, and then of the last harvest sowed the seed. Ye, the first morning of creation wrote what the last dawn of reckoning shall read."
This is very deterministic. It says the universe follows laws-- gravity, nuclear forces, and so on that I will just show you in a minute. And you cannot do anything about it. You can't change any of that.
Now, this anthropic principle that says perhaps the universe was made for man is a modern idea by Brandon Carter, who, in 1973, during a meeting of the International Astronomical Union, actually honoring Nicolaus Copernicus, explained it. Many books have been written ever since. An important book is the one by Barrow and Tipler in 1986 called The Anthropic Cosmological Principle.
But we also found later that Bernard le Bovier de Fontanella, a few centuries ago, in a book called Conversation on the Plurality of the Worlds, had actually touched on this subject. He's trying to explain why the orbits of comets lie mostly out of the plane of the ecliptic. The ecliptic is the plane of the planets going around the sun, all more or less in one plane.
The comets don't follow the same path. Rather, the comments go round perpendicular to this plane and in many other angles. Now, the book says the reason is extremely evident why the comets have orbits outside the ecliptic, for had this not been the case, it would have been impossible for the Earth to be out of the way of the comet tails.
Now, what does that mean? Well, comets at the time, comet tails at the time were presumed to be harmful to life. Comet tails were presumably made of poisons. And if the Earth had to go through the comet tails, and everybody would be poisoned, nobody would be here to talk about it.
So comet tails are presumed to be harmful to life. So we must observe inclined orbits for, otherwise, no one will be around to wonder about the matter. Therefore, the orbits of comets were designed as such so that we can exist. This is part of an explanation or an observation of the anthropic principle.
But what is the scientific paradigm of today? Well, the universe behaves according to fixed laws of nature. We have come to understand that from our physics. And there is a belief that perhaps there is a theory of everything that we call a toe, a T-O-E, presumably, in principle to be able to explain the universe completely.
Where are we in this knowledge of physics? We know there are four main forces that govern everything, and the known forces are the nuclear force that actually is the force that keeps the protons and the neutrons together in the nuclei of atoms, like a strong super glue. The electromagnetic force that has to do with the electrons that surround the nuclei of atoms, that the dance of these electrons, the interaction of these electrons with the neighboring atom electrons that combine together to form molecules and bigger particles and so on.
The electromagnetic force, and the weak force, which has to do with the radioactivity of the breaking up, disintegrating of some nuclei. And the fourth force is gravitation, objects attracting one another, or like Einstein explained to us, the curvature of space and the falling objects in a curved space.
Now, the nuclear force, the electromagnetic force, and the weak force, today we understand in the theory we call quantum mechanics, and gravitation with the theory of Einstein's general theory of relativity. If we can combine all these forces, then we will have a theory of everything.
This is a diagram that shows what I'm talking about. Here on the left, you see the strong force, the nuclear force governing the stability and the existence of the nuclei of atoms without disintegrating them, permitting, of course, for us to be here. Then you have the weak force in the electromagnetic force that control radioactivity, light, magnetism, chemistry, electricity.
All the complex things are governed by this electromagnetic force and the weak force. That part of the diagram, the electroweak force and the strong force, is what we call the theory of quantum mechanics that for the last 100 years has never failed us. Everything else that moves, for example-- falling bodies, celestial motions, planets going around stars, stars moving, galaxies moving, are controlled with the force of gravity, Einstein's theory of relativity.
If we are ever able to combine the general theory of relativity with quantum mechanics, we will have the ultimate force or a theory of everything. We're not quite there yet, but we are very close. Some brave young men and women today have developed a new theory called string theory that are trying to see if they can solve this problem of a theory of everything.
These forces, these laws of the universe that we can do nothing about dictate how the universe evolved in the past. And this photograph is all the universe that we know in all of time so that the axis on one side, all the way down, is zero time. And the very center of the horizontal scale is zero space.
The universe began 13.7 billion years ago with an explosion that we don't understand why. Call it super gravity or supersymmetry or quantum gravity and began to expand immediately from the quarks and the electrons I mentioned.
And these quickly formed the protons and the neutrons. Light nucleosynthesis took place of the light elements. And immediately, the universe began to cool, coalesce into clusters of material to form the galaxies that we see today.
For example, if you ask the history of the atoms, well, they started from the Big Bang, where you had mostly hydrogen and helium. Some of the material ran into stars. The stars evolve. They formed heavy elements. The stars died and exploded. And as a result, the heavy elements populated the interstellar space.
These interstellar clouds, together with primordial hydrogen clouds and helium, coalesce to form second-generation and third-generation stars. The solar system, the sun is a second- or third-generation star. And as a result, remnants of the formation of second- and third-generation stars formed-- in the case of the sun, formed planets and the asteroids and the satellites that we now examine in the solar system. The Earth, you and me, are really stardust.
Now, the basic structure of the universe is, in principle, determined by a few constants. And these include the masses of the elementary particles and the strengths of the forces that we now know quite well. We exist here and now because of the exact relationships between the basic forces and these particles.
And this raises a question to some people. If any of these forces were even slightly different, we would not have emerged to talk to you right now. Complexities would not have formed unless conditions were just right. For example, gravity in stars has to be strong enough to cause high temperatures so that particles can move very fast and collide and with energies to exceed the electrical repulsion of the protons so that to allow the nuclear force to dominate to actually form heavy elements.
And without heavy elements, you cannot form you and me. For example, the size of stars, planets, and people are the inevitable result of the relative strengths of the basic forces and constants of nature. The fact that we exist shows that carbon, for example, which is one of the dominant atoms that we have in life, carbon in other such elements had to be made somewhere and then dispersed into space in order to re-coalesce to form other stars and planets and complexities like you and me.
And the only place that could happen, this could happen to form the heavy elements is, indeed, in the core of hot stars. And in the 1950s, where all this was started to unravel, there was a big problem. And the big problem that scientists of the time could not really explain is how to form carbon.
Carbon was essential. If you cannot form carbon, you cannot form life. The problem we call the beryllium problem. First in the stars, you form helium from hydrogen. And then if you take 2 helium atoms and then combine them, you form beryllium. And beryllium 8 isotope is very unstable, however.
And the moment you make it, it actually disintegrates. Beryllium 9 isotope is the stable one that we need. Enter Edwin Salpeter. Professor Salpeter, a retired professor of astronomy and physics at Cornell University at the time thought, all right, you can actually have a collision of 3 helium atoms together called the triple alpha reaction. And that can actually make carbon in the core of the stars.
And that was a new idea. And you can make carbon, but it was also shown that it's not a very efficient process. You will not make enough carbon to explain all the carbon that we see.
Enter Fred Hoyle, the famous British, late British astronomer who predicted that the energy levels of helium, beryllium, and carbon, he said, must just have the right energy to make the Salpeter process go very fast.
And that is called the resonance. Fred Hoyle predicted that carbon should have yet unknown energy level that resonates with the combined energy of helium and helium to make carbon. Enter Willy Fowler, professor at Caltech. Immediately took Fred Hoyle's idea.
He was an experimental nuclear physicist. He went in the lab to find out if carbon, indeed, had that kind of an energy level, which was unknown before. And yes, it did. Carbon had that level, that energy level.
Now, suppose that carbon had an energy level slightly off from what it is. Then no sufficient carbon would form, and no life would exist. Since life exists, carbon must have that resonance energy level.
This is a kind of a prediction of the anthropic principle. And the question is, is the universe just tailor-made for men? Carbon had to have that particular exact energy level in order to be able to form the heavy elements so that you and I be here.
People think that there is this kind of cosmological fine tuning. Here is another example-- the strength of gravity. If it were a bit stronger, the universe would collapse into a big crunch long before you form any stars or planets. We would not be here.
On the other hand, if gravity were a bit weaker, matter would not collect to form stars and galaxies by gravity, so we would not be here either. So there is this fine tuning that says that the conditions had to be just right to form complexities and life.
Supernovae, when the start explodes, where neutrinos, atomic, subatomic particles might have just the right energy to aid the shock to explore the star. Otherwise, stars would not explode, and heavy elements would not populate space, and we would not be here.
So how can you answer this anthropic principle? Is this a special universe just made for men? Maybe it's special, but not so special. It is possible now, physicists think, that at the Big Bang, you form not just one Big Bang, but rather millions and trillions of Big Bangs.
Many universes may have started, each one with different laws and constants, a completely new idea. If so, life exists in the universe with laws and constants that permit life. Now, there could be other Big Bangs that have started that also permit life or different other complexities.
It looks like this. You are facing execution by 100-man firing squad. They fire, and all miss the target, you. Had they not done so, you would not be here to ponder the matter. Being alive, you are perplexed, and you wonder why. How come?
You are here. According to these laws, there could have been no other way. Otherwise, you would not have been here. Famous scientists have commented on these issues. Freeman Dyson-- physicist, astronomer, astrophysicist at Advanced Institute in Princeton-- said the universe knew we were coming.
It could not have been otherwise. And of course, Fred Hoyle, what would you expect? He said, we exist only because the energy levels of carbon were correctly spaced.
Here is another analogy. How bizarre it looks. Now, suppose one walks into a clothing shop and buys a suit that fits perfectly. How would you explain that? There are two possibilities.
One is that the suit was tailor-made for that person. Therefore, it fits beautifully. That's the anthropic principle example. The universe was made for men. On the other hand, the shop may have had a vast number of suits, and one of them just fits you.
And that is the multiverse idea. The Big Bangs-- multi Big Bangs took place. One of them had the right constants and forces for us to be here. So accept the multiverse model in order to avoid the anthropic principle. The multiverse model sometimes is also called multiverse.
The unfortunate issue is that from the physics we know, if this model is correct, there will be no way for us to check or test the multi-universe model. The physics we have forbids us in communicating or experimenting or seeing another Big Bang.
So we will actually-- experimentally, we will never know if this model is correct, not a very happy situation. Here is what David Spergel at Princeton University says about the anthropic principle. He says, "I view the anthropic principle as intellectual surrender. It says the values of the cosmological parameters will never be understood."
Remember, at the beginning, I did say that we made a lot of progress in understanding the universe and how it works, and we haven't stopped yet. I hope that we will learn much more. And David Gross, Nobel laureate in physics in Santa Barbara said, "Anthropic reasoning is both defeatist and dangerous. It suggests that a more scientific explanation can never be found, and it plays into the hands of intelligent design supporters. And it smells of religion."
So this subject has taken new dimensions. On the other hand, there is an alternative, what I would call and still call the theory of everything. It may be possible that there is a theory of everything that would be able to explain why we have these laws and forces in the universe.
It would be the theoretical basis of all the fundamental laws and constants of the universe with no need of a multiverse. That's also a possible explanation. Now, in this connection, there is something what I would call the weak anthropic principle. The laws and constants of the universe have created not just and me, complexities in life, but also everything else in the universe-- all the other stars, all the other planets that exist around other stars, most probably all the complexities that exist on other planets around other stars, not just in the Milky Way galaxy, but throughout all the other galaxies, the immensity of the universe that I showed you.
So why do we think, then, that the universe was created just for us here on Earth? Some think we are the most complex entities in the universe. But as I said, it is likely that other, more complex entities have evolved on other planets.
Therefore, the universe was not uniquely created just for us, but actually for everything that we see and experience in the universe. Stay tuned. The mysteries of the universe continue to unfold. This is certainly not the last word in cosmology. It's in its golden age. Thank you very much.
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Join Yervant Terzian in a discussion of "why is there a universe? Why is there something rather than nothing?" and examine how humans think about their place in it.
This video is part 3 of 3 in the Cosmology and the Anthropic Principle series.