Research Fellows Directory
Professor James Dunlop PhD, F Inst Phys, FRSE
University of Edinburgh
The aim of my research is to build a complete picture of how the universe of galaxies we see around us today evolved from the tiny fluctuations left in the wake of the Big Bang, 14 billion years ago. While the exact origin of these fluctuations is still a matter of controversy, observational evidence that they were present, at the tiny 0.00001% level, ~ 300,000 years after the big bang, is provided by images of the micro-wave background. The micro-wave background has now been studied in exquisite detail by a series of satellites. It represents the "echo" of the big bang - the radiation that was emitted as the universe cooled, and the first atoms formed as a result of electrons finally settling down to bond with protons. Originally emitted at a temperature comparable to the surface of our Sun (~ 5000 degrees Kelvin), this radiation has since cooled to the incredibly low-temperature of only 3 Kelvin as a result of the expansion of the universe. This radiation comes towards us from all around, and is incredibly, but not perfectly, smooth. The tiny fluctuations seen in this "fingerprint" of the young universe, show that small over- dense regions of matter existed, which provided the seeds for the first objects to form in the universe.
My research is now largely focused on when and how these first objects formed, and what they looked like. At some stage the irresistable pull of gravity created sufficiently dense objects that nuclear fusion commenced and the first stars and galaxies formed, producing "first light" and ending the so called "dark ages". We are fortunate in astronomy that, due to the finite speed of light, we can actually look back in time by looking at ever more distant objects. Now, due to advances in technology, we are close to being able to observe the first galaxies in the process of formation. We have recently discovered the earliest known galaxies, shining when the universe was less than
500 million years old.