Dr. Bijan Nemati Talks about the Big Bang
- Considering perfect order of the universe, there must have been extremely sensitive values in motion during the expansion of the Big Bang. Can you tell us about the order that began with the Big Bang? Such as the cosmological constant and others and how precise these numbers are?
- About a hundred years ago, right now it's 2018, so hundred and three years ago was 1915. In 1915, Albert Einstein published his work on general relativity, the theory of relativity. One of the predictions of his own theory was that the universe’s state is dynamic and the solution to Einstein’s equation is that the universe is dynamic and that means the universe could be expanding, or it could be contracting. This wasn't immediately obvious when Einstein came up with it. It was Alexander Friedmann, who was I believe a Russian, young Russian mathematician, who first solved Einstein’s equations because they were very difficult to solve. And he sent a letter to Einstein and said, "Dr. Einstein, I have made an attempt under certain conditions to solve your equations and what I find is a dynamic universe". Einstein didn't like that answer. Einstein actually didn't even answer Friedmann. He didn't like the answer because Einstein, like many of his colleagues at the time, believed in a universe that was static. They believed that the universe has eternally been here and if it has eternally been here, then there is no need to talk about a Creator, the universe is the only thing there is. You know, Carl Sagan famously used to start his TV show called the Cosmos, he would say "the cosmos is all there is, and all there was, and all there will ever be". And that totally reflects the attitude of the scientists of that time relative to the origin of the universe. The reason I mentioned this story is that the very fact that the universe is dynamic was already something totally unexpected. It was one of those situations where science forsake progresses and the scientist always has a bias. But sometimes his finding doesn't match his bias. So in this case, what they found was that the universe was dynamic and one of the first implications of that was that the universe must have had a beginning. The fact that the universe had a beginning in a finite amount of time was actually a very surprising result for them, very unpleasant. By the way, Einstein’s theory was demonstrated to be true in a solar eclipse in 1919, led by an experiment led by Arthur Eddington. Eddington was Einstein’s friend, and he actually was a very big advocate of general relativity. He would go around giving lectures on Einstein’s relativity theory. And then he came up with a brilliant experiment in which he was measuring how much does the angle at which the star appears change if the star comes near the sun. That is very difficult to look for a star near a sun because the sun is so bright. The moon is so fantastically matched to the sun in the sky, something very surprising, most people don't know to appreciate this. The moon on the sky is the same size as the sun on the sky. The moon is 400 times smaller and it's 400 times closer. It’s a very strange coincidence. What the moon being that size allows us to do is to do an experiment in which we can test general relativity. Because the moon completely makes a perfect eclipse that allows me to see the star, and now I can see that the star looks like it’s coming from a bigger angle due to the Einstein relativity theory. That experiment was done in 1919, and that was the experiment that made Einstein famous. And the whole world became excited about relativity. But a consequence of relativity was that the universe is expanding. And Eddington, the man who actually made the discovery, so disliked the answer that he said that he found the idea of a beginning to the universe as philosophically repugnant. It’s very interesting; you think of the picture of a scientist as they are very logic-driven, they don't have any bias, they just follow the evidence where it leads. Well, most don't. And Eddington was very frank about it. He found it philosophically repugnant that universe would have a beginning. I think they had an atheistic bias. They didn't want a beginning to the universe because the beginning would point to a Creator. So this is all the story of a beginning to the universe and that now we associate with the Big Bang. By the way, the word "Big Bang" itself is a derogatory term, it was a way of mocking this theory by people who didn't want there to be a beginning to the universe. And it was Fred Hoyle who came up with this in a radio program. At any rate, not only now we recognize that beginning as we call it the Big Bang, but now we see that the properties of the Big Bang are very fine-tuned. For example, the universe appears to have a level of orderliness in the distribution of matter in space. That is very hard to explain. It seems like the level of orderliness or the entropy is a very improbable level. Roger Penrose, who is a very famous physicist, computed that probability as being of the order of 1 over 10 to the 123rd power. Very, exceedingly, unbelievably small number. So, there are some very special things going on in the way the universe is set up just in terms of matter and energy and its condition. For example, in a universe that’s dynamic you can have a situation where there is so much matter and so little energy that the matter basically, at first there is this expansion and then there is this collapse. Or you could have that there is so much energy that there is expansion and there is no collapse ever, it goes forever farther away. Where we find ourselves is we are exactly at the boundary, very close to the boundary where at infinity there is zero energy or zero motion. Except now, since 1998 there is a possibility that we are just a tiny bit more energetic than that, this is this thing that they call dark energy. And it’s completely not understood. All of this points to the fact that first of all, there is a lot more to learn and the other is that the universe is far from being something that could fit in a standard simple static self-existent narrative. It’s very contingent on a Creator.