Event Details

In 1998, two essentially independent research teams made a shocking announcement: the expansion of the Universe is accelerating rather than decelerating. The evidence for this Nobel-worthy conclusion was that the measured brightness of Type Ia supernovae (SN Ia, thermonuclear explosions of carbon-oxygen white dwarf stars) at a given redshift were fainter than expected. Since then, the evidence for cosmic acceleration, probably propelled by “dark energy” having a negative pressure, has grown ever stronger. We review the history of both the original SN Ia research and subsequent studies. The most recent surprise is that our measured current expansion rate of the Universe (Hubble’s constant) using SN Ia is 5s higher than that predicted from observations of the cosmic microwave background radiation together with the standard LCDM cosmological model. Other, completely independent techniques support this tension, implying the possibility of exciting new physics.

Video Recording