Henrietta Leavitt's discovery of the period-luminosity relationship in Cepheid variable stars was crucial for measuring cosmic distances.

Edwin Hubble utilized Leavitt's findings to ascertain that Andromeda was a separate galaxy over two million light years away, not part of the Milky Way.

The revelation that the Milky Way was not the entirety of the universe fundamentally changed humanity's cosmic perspective.

Harlow Shapley's research further expanded our cosmic understanding by locating our solar system on the periphery of the Milky Way.

These astronomical discoveries underscore the significance of scientific exploration in comprehending the vastness of the universe and our place within it.