A look at physicist, humanist and author Alan Lightman’s talks. Sudhamahi Regunathan

Alan Lightman is a scientist (physicist) and a humanist, not to mention author of The Accidental Universe. This column brings glimpses of two of his talks. There are many more to listen to.

Speaking deliberately and yet with a flow, Lightman says, “…everything in nature is passing away…some ants and bees live only a few weeks, coastlines are eroding, our sun is using up its nuclear fuel and in 5 billion years it will be just cold cinder. That will be true of all the stars floating around. So the question is why do we long for immortality, pray to something eternal? Every culture has its elixir of youth… what interests me is this mismatch between the desire for permanence and the counter message we get from the Universe. There are two possibilities. Nature is hiding something. The second is that we are delusional. Of the two, I favour the second. It is very hard for me to believe that if there was something eternal it would not be apparent in nature.

For centuries the great goal of science has been to discover a necessary set of fundamental principles from which everything would be a natural consequence. There is a hope that the universe is like a crossword puzzle with only one solution...about ten years ago we came to realize that the crossword puzzle appears to have many solutions. That is starting from such principles as the conservation of energy you can get a universe with three dimension such as ours, you can get a universe with seventeen or sixteen dimensions, you can get a universe that is expanding rapidly and you can get a universe that is not expanding at all, you can get a universe that allows stars and planets to form and you can get a universe that is just empty space. You can get a universe with life and one where life is not allowed to form. This is deeply upsetting to a physicists…like finding a size, 9,11 and 3 shoe, all fit you perfectly!

The rationale why we believe there are many universes is that some of our modern theories like the inflationary universe theory predict other universes. The key element of this theory is that when the universe was just a few second old it went through rapid expansion that lasted for a sliver of a second and then it assumed the more relaxed expansion model.

Twenty or thirty years ago scientists began to appreciate the fact that the parameters of our universe lie within a very narrow range and life can exist only within it. For example, if the nuclear force were a little bigger then all elements would be fused together for we would not have had hydrogen and therefore no water. If the nuclear force were a few percent weaker, you could not make complex atoms required for biology and chemistry.” Lightman gives examples of dark energy also being just the right amount for life to exist. Why is our universe so finely tuned?

There are two explanations: the theological explanation…there is a divine creator who adjusted the parameters. The other possible explanation is the multi force...the possibility that there are lots and lots of universes out there…where parameters would be different for each and in most of them conditions would not be right. We are living in the universe where conditions are right.

If we were closer to the sun there would be no water. In Neptune, all would be ice. We are not a unique planet. There are many other solar systems…there is no way that we can prove that all the other universe exists. By definition they are separate and we conjecture that they exist but cannot prove it. We need faith to accept this just as theology demands.”

Lightman brings theology and science so beautifully close as he says, “I believe in the power of the unknown. I believe that a sense of the unknown propels us in all of our creative activities, from science to art. When I was a child, I had so many questions. How far away were those tiny points of light? Did space go on forever and ever, or was there some end to space, some giant edge…? And if so, what lay beyond the edge? Another of my childhood questions: Did time go on forever? Scientists are happy, of course, when they find answers to questions. But scientists are also happy when they become stuck, when they discover interesting questions that they cannot answer. Because that is when their imaginations and creativity are set on fire. That is when the greatest progress occurs.”

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