|The amazing thing is that every atom in your body came from a star that exploded. |
[…]So, forget Jesus. The stars died so that you could be here today.’
As we gather in the DRT, Monty Python’s ‘The Galaxy Song’ plays in the background, and I can already tell that this talk is going to be a little different from other physics lectures I have attended.
‘Why is there something rather than nothing?’ Professor Krauss asks to start us off. Before beginning to answer the question Prof Krauss points out that it is a bad one. Why imply purpose he states, it is much better to ask ‘How is there something rather than nothing?’ Well this is the question, which over the next hour, Prof Krauss answers for us. Here, I shall attempt to give, to the best of my ability, an overview of how there is something rather than nothing. Of course, this will not be nearly as clear or comprehensive as Prof Krauss’s explanation, and my descriptions are going to be fairly general, for which I am sorry. If I were to add more detail I would be required to add a lengthy explanation of basic astrophysics, or risk losing all but the most well-read of my audience. If you really want a full understanding you probably should have gone to the lecture yourself, or you could buy Prof Krauss’s book ‘A Universe from Nothing’. But anyway, here we go.
Prof Krauss talks about three grades of nothing:
· Nothing 1: No matter or energy
· Nothing 2: The absence of space and time
· Nothing 3: The absence of physical laws
Nothing 1 is probably what you would understand nothing to be, but Krauss goes further, and we need a new understanding of nothing to appreciate how the universe began.
Nothing 1 is quite straightforward to explain. It is simply empty space. So how can matter and energy appear? The answer is that it happens all the time. In empty space stuff can just pop in and out of existence. Quantum mechanics allows for this, and we know that particle and antiparticle pairs appear, meet each other again, and are annihilated. Here the total energy of the particles and their antiparticles are zero. We can show that the total energy of the universe is zero, so scientists believe that the universe could have begun in a similar way.
Nothing 2 gets a bit more complex. We know that quantum mechanics gives a good description of much of physics, but we still need to find a quantum mechanical description of gravity. However, we know that once we are able to combine quantum mechanics and gravity, space and time will become quantum mechanical objects, which allows them to pop into existence, just like before. Again, if this is true, we need the total energy to be zero, which is only true if the universe is closed (which is to do with the way our dimensions are warped). This has a significant impact. If the universe is closed, for it to get to be how it is today, the universe must have gone through a period of rapid expansion just after the big bang. This is known as something called inflation and is driven by dark energy. During inflation the universe would have increased to 1078 times its original volume in less than 10-32 of a second.
Nothing 3 is the complete absence of physical laws, which is definitely difficult to get your head around. However, borrowing some ideas from string theory we can explain this one too. One of the consequences of string theory is that our universe exists in 11 dimensions. We observe four, three of space and one of time. The other 7 dimensions are in a way curled up so tightly that we cannot observe them. The ways in which these dimensions are curled determine the physical laws and constants of the universe. This means that as our space and time dimensions pop into existence, so do the other 7, bringing the physical laws with them.
I will admit, this probably all seems very odd. These suggestions are very theoretical, but the theories make predictions which can be tested in a laboratory, and so they hold well as scientific theories. I imagine many of you are thinking, very well, I can just about manage this, but it seems very unlikely that a universe could appear out of nothing and produce us. It is indeed true that the universe is set up very well for our existence, with finely balanced physical constants, and here we turn to something called the anthropic principal. The universe is perfect for us, because we are here asking why it is perfect for us. If the universe was inhospitable to life we wouldn’t be here to ask the questions. Going back to Nothing 3, there are infinitely many ways the extra dimensions can be folded up in string theory, and there are about 10520 ways in which the physical laws are similar to our universe. So when you think, it seems likely that at least one universe would be created which could support life, and we are in the one that does, because we couldn’t be in any other one.
During his lecture Professor Krauss explained to us how there is something rather than nothing, and why this it is likely that something would come from nothing. Krauss also points out how insignificant we are, but insists this is something we should celebrate. Be thrilled, he tells us, and he is right, because the truth of our existence is truly remarkable.
I could not write this article without mentioning the incredibly entertaining questions and answers session which followed. After a couple of straightforward questions regarding the material in the talk somebody asked a question about religion. It turns out Krauss is quite opinionated on this subject. Excellent. ‘Should we be worried about the political influence of creationism?’ he is asked. Prof Krauss is quick to make it clear that as far as he is concerned people can think what they like, ‘they can delude themselves’. But now he goes on, if people believe in myths and fairy tales, he says, they are likely to make irrational decisions, and if these people have influence over another group of people then that is when we should be worried. He takes the example of parents who are strong believers in creationism who do not wish their children to be taught evolution for religious reasons. Since much of modern biology is based on the theory of evolution, these children are missing out in their education. Krauss is on a roll, and he points out that this is just one example, and that there are many other situations in which people impose restrictive rules over others due to their beliefs. As soon as he is finished the audience erupts in applause; it is clear that many in the theatre share his views.
After some more questions Krauss reveals to us his views on the existence of a god. He can understand that people are confused about how the universe began, and how there can be such absolute nothingness. However the leap from this confusion to the belief in a loving and caring god, who created the earth, and listens to prayers, is something he finds irrational. Why, Krauss asks, would God create the universe, wait for billions of years and then form a planet, wait some more, and then create life, wait for evolution to run its course, and once humans have formed, wait a bit longer, before revealing himself to us? Again, Krauss’s response is met with applause.
Professor Krauss’s talk was as fascinating as it was entertaining, the physics which we were carefully guided through was indeed complex, and the idea of nothing was truly mind bending. I greatly appreciated Prof Krauss’s question and answer session, and I’m sure from their reaction that much of the audience did too. I would like to end with a quote by Prof Krauss, I find that it sums up the beauty of physics, and why we should celebrate it.