Standard Candles

Standard candles are astronomical objects with known intrinsic brightness, or luminosity, allowing astronomers to determine their distance from Earth. By comparing how bright they appear from our perspective versus their true brightness, scientists can calculate how far away they are. Common examples include certain types of supernovae and variable stars like Cepheids. This method is fundamental in measuring cosmic scales, helping us understand the size and expansion of the universe. Essentially, standard candles serve as "brightness benchmarks" that enable us to map the universe more accurately.