Speaker: GSU Astrophysics Lecturer Dr. Justin Robinson
The Cosmic Conundrum: We Can’t Seem to Agree on How Fast the Universe is Expanding
Summary: The rate at which the Universe is expanding is one of the most important and fundamental properties of our Universe, and we’ve been chasing after the best measurement of it ever since Edwin Hubble’s observations. Fortunately, or so we thought, we have two independent ways of finding the expansion rate (the Hubble Constant H0): 1) applying the Big Bang Theory to observations of the first light ever produced in the Universe (the Cosmic Microwave Background radiation), and 2) measuring how fast galaxies are moving away from us at farther and farther distances. Premier space telescopes (Planck, Hubble, and James Webb) have provided the highest quality observations for both these avenues of measuring H0. However, the two measurements of H0 do not agree, and over time, the discrepancy has only gotten worse. This disagreement has garnered the name ‘The Hubble Tension’, and remains one of the largest conundrums in modern day astrophysics and cosmology. Is the Big Bang Theory wrong, are our distance measurement techniques wrong, or have we fundamentally misunderstood the physics that govern the Universe?
No tickets required. Just show up, grab a beer, and learn about cool stuff.
