JIM PEEBLES is widely known as the architect of modern cosmology – and its nice-guy-in-chief. Awarding his half-share of the 2019 Nobel prize for physics, the committee said he “took on the cosmos”, helping to create a framework now considered “the foundation of our modern understanding of the universe’s history”, known as the standard model of cosmology. Others have described him as “an extraordinary physicist”, and “uncommonly thoughtful, gracious and kind”.
Now the Albert Einstein Professor of Science, emeritus, at Princeton University, Peebles’s career began there in the 1960s, focusing on Einstein’s general relativity, which casts gravity as the result of mass warping space-time. He later worked out the characteristics of cosmic microwave background (CMB) radiation, the “echo” of the big bang, whose discovery made cosmology an experimental science. He also showed that dark matter haloes around galaxies would create a mass distribution that matched astronomers’ observations, and persuaded the field that our description of the cosmos needed to reinstate Einstein’s much-derided cosmological constant. This was originally stuck into the equations of general relativity as an awkward fudge, but we now think of it as dark energy, the repulsive force driving the universe’s accelerating expansion.
Despite the success of the standard cosmological model, Peebles has always sought to undermine it. In the past few years, he has been musing on astronomical anomalies – observations of weird galaxies and other curious phenomena – that might expose flaws in our thinking.
He tells New Scientist about his vision for cosmology, why it is important to stray from the mainstream…