Standard candles: How astronomers measure distance in space

Unlocking secrets of cosmic expansion with improved parameters


New research has made significant advancements in improving the accuracy of the parameters that govern the expansion of the Universe. These refined parameters will greatly assist astronomers in their quest to understand how the Universe has evolved from its early stages to its current state, as well as provide insights into its future evolution.

Cosmic expansion

The expansion of the universe, a fundamental concept in cosmology, has long fascinated scientists and astronomers alike. It describes how the space between galaxies and other celestial objects is continuously expanding over time, providing invaluable insights into the origins and fate of our universe.

This expansion was first proposed by Belgian astronomer Georges Lemaître and is supported by various pieces of observational evidence, such as the redshift of light from distant galaxies.

Through meticulous measurements of distances to distant celestial objects, researchers are unlocking the secrets of cosmic expansion and venturing deeper into the mysteries of our vast cosmos.

Standard candles

As researchers continue to refine the accuracy of these distance-measuring techniques, we inch closer to solving one of the universe's most profound mysteries: Will it continue expanding indefinitely, or might it one day retract upon itself? The journey to answer this question, driven by the illumination of standard candles, promises to unveil more of the universe's well-guarded secrets.

Standard candles play a critical role in the cosmic distance ladder, a sequence of methods astronomers use to measure distances to objects in the Universe. By calibrating each step of the ladder with objects of known distance, we can extend our distance measurements to ever more distant galaxies and gain a better understanding of the large-scale structure and evolution of the Universe.

Cepheid variables: Cepheid variables are a type of standard candle. These are pulsating stars, meaning they rhythmically expand and contract, which causes their brightness to vary in a predictable way. The period of their brightness variation is directly related to their intrinsic luminosity. By measuring the time it takes for a Cepheid variable to complete a cycle of brightness changes, astronomers can determine their true brightness. By comparing this true brightness to their observed brightness, they can calculate their distance from Earth. Henrietta Swan Leavitt made a groundbreaking discovery related to Cepheid variables in the early 20th century.

Type Ia supernovae: Another important type of standard candle is the Type Ia supernova. These are exploding white dwarf stars that release an almost uniform amount of energy when they explode. Since their intrinsic brightness is known, observing a Type Ia supernova allows astronomers to calculate its distance. This is how we've discovered that the Universe's expansion is accelerating, thanks to the work of teams like the one led by Saul Perlmutter and Brian Schmidt.

The advancements in measuring cosmic expansion using refined parameters and standard candles bring us closer to unravelling the mysteries of the Universe's evolution and its future trajectory.