Why are Cepheids considered reliable 'standard candles' in astronomy?
Answer
Their absolute magnitude can be derived from their pulsation period
Cepheids function as reliable standard candles because their absolute luminosity is predictable based on their observed pulsation period, a direct result of Henrietta Leavitt's work. If an object's true brightness (absolute magnitude) is known, comparing it to how bright it appears from Earth (apparent magnitude) allows for the application of the inverse-square law of light, which yields the distance to that object with surprising accuracy, overcoming the limitation of parallax for very remote objects.
Related Questions
What was the central conflict in the Great Debate regarding spiral nebulae?Which specific telescope did Edwin Hubble use atop Mount Wilson?What specific class of star was crucial for Edwin Hubble's distance proof for Andromeda?What relationship did Henrietta Swan Leavitt establish concerning Cepheid variables?Why are Cepheids considered reliable 'standard candles' in astronomy?What was the approximate estimated diameter of the Milky Way before Hubble's 1924 findings?Around what time did Hubble present his initial findings confirming Andromeda's distance?Which step immediately follows determining the Period of a Cepheid variable for distance measurement?What is the specific designation given to the object known as the Andromeda Nebula?Which hypothesis, championed by astronomers like Heber Curtis, was immediately validated by Andromeda being an island universe?What conceptual hurdle did the realization of Andromeda's distance force upon established scientists before the mid-1920s?