Monday, 12 March 2012

A Universe From Nothing

A Universe from Nothing: Why There is Something Rather than Nothing, by Lawrence M. Krauss.

Financial Times, 10-11 March 2012

Why is there something rather than nothing? “While this is usually framed as a philosophical or religious question,” writes Lawrence Krauss in A Universe from Nothing, “it is first and foremost a question about the natural world, and so the appropriate place to try and resolve it, first and foremost, is with science.”

A leading physicist at Arizona State University, Krauss begins his entertaining and engaging introduction to cosmology by pointing out that when scientists ask “why?” they usually mean “how?” So for “Why is the Earth 93m miles from the Sun?” read “How is the Earth 93m miles from the Sun?” What we need to understand are the physical processes that led to the Earth ending up in its present position.

“Nothing expands the mind like the expanding universe,” says Richard Dawkins in an afterword to this book. It was the American astronomer Edwin Hubble who, in the 1920s, discovered the first evidence that we lived in an expanding universe. As Krauss makes clear, the weight of the accumulated observational data since points to a Big Bang some 13.75bn years ago.

There have been a number of fine cosmology books published recently, but few have gone so far, and none so eloquently, in exploring why it is unnecessary to invoke God to light the blue touchpaper and set the universe in motion.

An instant after the Big Bang, the cosmos was smaller than an atom. It is here that the best theory physicists have for understanding the science at this atomic level comes into play: quantum mechanics. Often counter-intuitively, this describes an atomic reality where “virtual” particles can pop in and out of existence in a time so short they cannot be seen but only inferred from circumstantial evidence.

Lawrence Krauss
“At the heart of quantum mechanics is a rule that sometimes governs politicians or CEOs – as long as no one is watching, anything goes,” explains Krauss. Given the size of the baby universe after the Big Bang, quantum mechanics suggests it is possible that space and time, like virtual particles, just pop out of nothing because “nothing” is an unstable state. This is a concept of “nothing” far removed from the ordinary usage of the word: in quantum physics it is full of potential and possibilities, always poised on the verge of something.

So why does the universe exist? “Ultimately,” Krauss admits, “this question may be no more significant or profound than asking why some flowers are red and some are blue.” Nevertheless, I am glad that there are scientists like him who will tackle it all the same.