Physics Colloquium on Planck's view of the origin of cosmic structure

Start: Jan 22, 2014 04:00 PM
End: Jan 22, 2014 06:00 PM

Dr Hiranya Peiris

Department of Physics and Astronomy, UCL

Date: Wednesday 22 Jan 2014, 16:00 to 17:00

Location: Harrie Massey Lecture Theatre, 25 Gordon Street, London, WC1H 0AY

Wine reception to follow afterwards in room E7.


Dr Hiranya Peiris

The cosmic microwave background (CMB) is the left-over heat from the Big Bang. This radiation provides a picture of the universe when it was only 400,000 years old. Now, 14 billion years later, it has cooled to microwave frequencies and is nearly uniform. The slight variations of 1 part in 100,000 in its temperature reflect initial inhomogeneities in the matter and radiation that later collapsed to form clusters and galaxies. These fluctuations carry information about the origin, composition and evolution of the universe, and theories of the origin of the universe make detailed predictions about their statistical properties. The CMB is therefore our best hope of uncovering fingerprints of the physics operating at very high-energy scales, inaccessible to Earth-bound particle accelerators. Current cosmological data are, for the first time, precise enough to allow detailed tests of models of the very early universe. The Planck satellite has then dramatically sharpened our view of the early universe, and provided a window into the origin of cosmic structure. I will describe how the Planck data progress our understanding of the extreme physics of the very early universe, and what we have yet to learn.


Hiranya Peiris obtained her undergraduate degree in physics from the University of Cambridge, and her Ph.D. in astrophysics from Princeton University. She is currently a Reader in Cosmology at UCL. Previously, she was a Halliday Fellow at the Institute of Astronomy at the University of Cambridge, having been a Hubble Postdoctoral Fellow at the University of Chicago prior to that. Her main research interests are in cosmology, the study of the basic characteristics of the universe (its contents, history, evolution, and eventual fate), and she spends much of her time studying the properties of the oldest light we can see in the universe to understand why and how the Big Bang occurred. She is also interested in how galaxies form and evolve, and in determining the structure and properties of our Galaxy, the Milky Way.