Who is Henrietta Swan Leavitt?

Henrietta Swan Leavitt was a scientist who helped us understand how big the universe is.

Henrietta worked in a place called a observatory, where people look at stars through special telescopes. She studied stars that were very far away, and she noticed something interesting: some of these stars got brighter and then dimmer in a regular pattern, like a heartbeat. This kind of star is called a Cepheid variable.

Imagine you're looking at a flashlight from across a dark room. If the flashlight is close, it looks bright. But if it's far away, it looks dim. Henrietta used this idea to figure out how far away stars were, and that helped scientists measure how big the universe is!

She was like a detective solving a mystery using clues from the sky. Her work made it possible for people to know how far apart galaxies are, even when they're billions of light-years away.

Henrietta's discovery was used by other scientists, including one named Edwin Hubble, who helped prove that our universe is much bigger than we thought, and that it’s still growing!