Rees, Lord (Martin)

Martin is Professor of Cosmology and Astrophysics; Master of Trinity College at the University of Cambridge; President of the Royal Society; and the UK Astronomer Royal. He was previously Plumian Professor of Astronomy and Experimental Philosophy at Cambridge, having been elected to this chair at the age of thirty, succeeding Fred Hoyle. He has originated many key cosmological ideas: for example, he was the first to suggest that the fantastically energetic cores of quasars may be powered by giant black holes. For the last twenty years, he has directed a wide-ranging research program at Cambridge's Institute of Astronomy. He is the author of about 500 research papers, in which he has made important contributions in the origin of cosmic microwave background radiation as well as galaxy clustering and formation. His studies of the distribution of quasars proved a strong argument against the steady state theory; he was one of the first to propose that enormous black holes power the quasars; and he was an early supporter of the multiverse, the theory that there may be many more universes, perhaps infinitely more, than our own. Martin has written several important popular books including, Before the Beginning; Just Six Numbers: The Deep Forces that Shape the Universe; Our Cosmic Habitat; and Our Final Hour. His primary current research areas are: (i) High energy astrophysics -- especially gamma ray bursts, galactic nuclei, black hole formation and radiative processes (including gravitational waves); and (ii) Cosmic structure formation -- especially the early generation of stars and galaxies that formed at high redshifts at the end of the cosmic ”dark age.” Following are Martin’s reflects on Edge: “…I've been puzzled for a long time about why the laws of nature are set up in such a way that they allow complexity. That's an enigma because we can easily imagine laws of nature which weren't all that different from the ones we observe, but which would have led to a rather boring universe—laws which led to a universe containing dark matter and no atoms; laws where you perhaps had hydrogen atoms but nothing more complicated, and therefore no chemistry; laws where there was no gravity, or a universe where gravity was so strong that it crushed everything; or the lifetime was so short that there was no time for evolution. It always seemed to me a mystery why the universe was, as it were, 'biophilic'—why it had laws that allowed this amount of complexity… For about 20 years I've suspected that the answer to this question is that perhaps our universe isn't unique. Perhaps, even, the laws are not unique. Perhaps there were many Big Bangs which expanded in different ways, governed by different laws, and we are just in the one that has the right conditions. This thought in some respect parallels the way our concept of planets and planetary systems has changed. People used to wonder: why is the earth in this rather special orbit around this rather special star, which allows water to exist or allows life to evolve? It looks somehow fine-tuned. We now perceive nothing remarkable in this, because we know that there are millions of stars with retinues of planets around them: among that huge number there are bound to be some that have the conditions right for life. We just happen to live on one of that small subset. So there's no mystery about the fine-tuned nature of the earth's orbit; it's just that life evolved on one of millions of planets where things were right. It now seems an attractive idea that our Big Bang is just one of many: just as our earth is a planet that happens to have the right conditions for life, among the many many planets that exist, so our universe, and our Big Bang, is the one out of many which happens to allow life to emerge, to allow complexity. This was originally just a conjecture, motivated by a wish to explain the apparent fine-tuning in our universe—and incidentally a way to undercut the so-called theological design argument, which said that there was something special about these laws.