Cosmology: What we know, what we don’t know and what we don’t know we don’t know

Image of galaxies in space
September 13, 2022
Monday, September 19, 2022 at 4:15 p.m.
Location: Physics North Lecture Hall #1
Speaker: Michael Turner, University of Chicago

Abstract: For most of the last century cosmology was the province of astronomers (mostly in California) and concerned itself with galaxies in an expanding universe.  Beginning around 1980, ideas from particle physics began to enter cosmology, focussed on events that took place during the first microsecond.  Circa 2000, with the discovery of cosmic acceleration/dark energy and precision measurements of CMB anisotropy the current paradigm — LambdaCDM emerged, revealing deep  onnections between particle physics and cosmology.  According to LCDM, the gravity of particle dark matter holds all structures together, the repulsive gravity of dark energy is speeding up the expansion and the quantum seeds for galaxies arose during a very early burst of accelerated expansion (inflation).  Cosmology solved?  Not exactly, we have no direct evidence for the dark matter particle; we don’t understand dark energy; and have no standard model for inflation (or evidence to support it).  And our aspirations are even higher.  Great time to be a cosmologist.

Research Area: Astrophysics