Is there something about our universe that makes it conducive to life?The UK Astronomer Royal, Sir Martin Rees discusses the possibilities with Dick Ahlstrom.
The fact that plants and animals including humans exist on planet Earth proves that the universe in which we live supports life. But is there something about the universe that makes life inevitable? And if so, can we assume that we are not alone?
The potential for a "biophilic universe" was one of many issues raised during the visit this week of the UK's Astronomer Royal, Prof Sir Martin Rees. His round of engagements included a visit to the President, Mrs McAleese and two lectures at the Royal Irish Academy and Trinity College Dublin.
His new book, Our Cosmic Habitat, discusses life in our quiet corner of the universe, but when he was in Dublin he told The Irish Times that we need to think bigger. "We need to think of ourselves as part of a wider cosmic environment," he says. "To understand things on the Earth, we have to expand our horizons."
Clearly he has earned the right to delve into such deep territory given his credentials. Astronomer Royal and Royal Society research professor at Cambridge University, he is one of the foremost cosmologists of today.
He has broken new ground in his studies of the physical processes near black holes, cosmic background radiation, quasars, gamma ray bursts and galaxy formation.
He was the 2001 recipient of the Cosmology Prize of the Peter Gruber Foundation and was president of the Royal Astronomical Society.
He was at the RIA on Monday to deliver the inaugural McCrea Lecture, a new series of talks that celebrate the achievements of William McCrea (1904-1999), a Dublin-born astrophysicist and one of Ireland's greatest scientists of the last century. Sir Martin's involvement was particularly apt given that the two worked together while at the University of Sussex.
Sir Martin's book espouses challenging new ideas on how we might interpret our place in the universe, which he suggests, might just be a part of an ensemble of universes making up a "multiverse". The laws of nature that govern our specific member of the ensemble in that case would be no more than local bylaws that could be different for any other part of the multiverse.
He quickly points out that we have no evidence yet for such a concept, but this may emerge in time. His belief that evidence for a multiverse or a biophilic universe might be found relates to the extreme complexity of the universe. And it is "not necessarily presumptuous" that humans might aspire to understand such complexity.
The universe is between 12 and 13 billion years old, he says, and cosmologists are struggling with how the laws that govern the universe have allowed it to develop such a high degree of complexity. Obviously there are many stars and presumably many planets like Earth orbiting them, so why not many universes? "Perhaps our Big Bang wasn't the only one," he postulates.
HE likened the potential for extra spatial dimensions that we cannot perceive to bugs living on the two sides of a sheet of paper. The bugs on one side have no way of knowing about the ones living so close by on the other, but they are there just the same. Understanding this "might also remove the element of surprise that our universe is also biophilic," Sir Martin adds.
He subscribes to the idea that our universe is biophilic, mainly because we are here to consider such a concept, but we still don't know whether life might exist elsewhere. Within 20 years or so however, astronomers should be able to pinpoint distant planets that carry a chemical signature like Earth's, raising the possibility of finding life out there.
"We have no idea whether life exists \", but he believes it is important to try to find out.
He has only cold comfort for those hoping that a biophilic universe might be kind to us in its old age. Recent research has shown that the universe's 95 per cent dark matter and 5 per cent visible matter have insufficient gravitational pull to prevent unending expansion. With no "Big Crunch" on the cards, stars will get further apart and eventually their nuclear powered lights will wink out with no hope of regeneration.