Did Cepheid Variables Help Discover the Expansion of the Universe?

💡 The Answer

• Edwin Hubble used Cepheid distances to show galaxies recede faster the farther they are.
• His 1929 paper relied on Cepheid calibrations by Henrietta Leavitt and others.
• This discovery led directly to the Big Bang theory and modern cosmology.
• Cepheids remain essential for measuring the universe's expansion rate today.