High-Z Supernova Search Team

The High-Z Supernova Search Team was an astronomical collaboration that used distant Type Ia supernovae to measure the universe’s expansion history and helped establish that cosmic expansion is accelerating.

Type Ia supernova: A stellar explosion whose nearly uniform peak luminosity makes it a useful distance indicator. The team used these explosions as calibrated markers for measuring distances across the universe.
Brian Schmidt: An Australian-American astronomer who led the High-Z Supernova Search Team. Schmidt organized the collaboration and led its analysis of distant supernovae.
Accelerating expansion of the universe: The observed increase over time in the rate at which the universe expands. The team’s 1998 supernova results provided one of the first strong lines of evidence for acceleration.
Dark energy equation of state: A parameter describing how dark energy’s pressure relates to its energy density. Future supernova measurements test whether the acceleration matches a constant cosmological term.
Standard candle: An astronomical object with known or inferable luminosity, used to estimate distance from its observed brightness. The team converted supernova brightness into distance using standard-candle methods.
Nicholas B. Suntzeff: An American astronomer who co-founded and helped lead the High-Z Supernova Search Team. Suntzeff helped establish the team’s observational program and its supernova expertise.
Dark energy: The name for the unknown cause of the universe’s observed accelerated expansion. The team’s discovery prompted renewed efforts to explain what drives cosmic acceleration.
Hubble tension: The discrepancy between some measurements of the present expansion rate of the universe. The team’s distance-based approach belongs to the broader observational tradition behind this unresolved disagreement.
Redshift: An increase in the wavelength of light caused by motion, gravity, or the expansion of space. Comparing supernova distances with their redshifts traced the expansion history.
Supernova Cosmology Project: An independent collaboration that measured distant Type Ia supernovae to study cosmic expansion. This rival team reached the same conclusion about accelerating expansion in 1998.

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Adam RiessBroader topic: Riess led this team, which reported evidence for acceleration in 1998.