What is the significance of Type Ia supernovae in cosmology?

Type Ia supernovae are significant in cosmology as they are used as standard candles to measure distances in the universe.

Type Ia supernovae occur when a white dwarf star in a binary system accumulates enough mass from its companion star to exceed the Chandrasekhar limit, causing a runaway fusion reaction that completely destroys the star. These explosions release a tremendous amount of energy and can briefly outshine entire galaxies.

The significance of Type Ia supernovae lies in their uniform brightness, making them useful as standard candles for measuring distances in the universe. By comparing the observed brightness of a Type Ia supernova to its expected brightness, astronomers can determine the distance to the supernova and the expansion rate of the universe.

In 1998, observations of Type Ia supernovae led to the discovery of the accelerating expansion of the universe, which was attributed to the presence of dark energy. This discovery revolutionized our understanding of the universe and earned the Nobel Prize in Physics in 2011.

Overall, Type Ia supernovae play a crucial role in cosmology by providing a standard candle for measuring distances and contributing to our understanding of the expansion and evolution of the universe.