Cepheid Variables: Cosmic Distance Markers

Cepheid variables are pulsating stars whose brightness changes in a regular rhythm.
The longer a Cepheid’s pulsation period, the brighter its true luminosity.
Henrietta Swan Leavitt discovered this crucial period–luminosity relationship in 1912.
Cepheids act as “standard candles,” helping astronomers measure vast cosmic distances.
They allowed Edwin Hubble to prove the universe extends beyond the Milky Way.
Cepheids helped confirm that the universe is expanding, laying the groundwork for modern cosmology.
They are typically yellow supergiants, much larger and brighter than the Sun.
Cepheids can shine tens of thousands of times brighter than our Sun.
Space telescopes like Hubble and Gaia use Cepheids to calibrate the cosmic distance scale.
Without Cepheids, our map of the universe would be far dimmer and less certain.