Bethe Colloquium

Approaches to understanding dark energy

by Ed Copeland (Nottingham University)


Dark Energy is the name given to the illusive substance that appears to be driving the acceleration of the expansion of our Universe. It's name has come to reflect our uncertainty as to the what the substance is: a cosmological constant, an evolving scalar field, the impact of a modification of General Relativity on large scales, or maybe just the inhomogeneity of our own universe? We will go through a number of the current options, discuss how we may test for them, from galactic down to atomic scales, and we will ask whether the current Hubble tension is driving us to the possibility that new physics kicked in around the time of radiation-matter equality (or earlier !) in the form of early dark energy.