Copernicus

What if Earth isn't the center of everything? Meet Nicolaus Copernicus (1473–1543). He was a Polish scientist of the Renaissance who had a bold idea: the Sun, not Earth, is at the center of the planets' motions. This idea is called the heliocentric model — the single most important thing about him.

He lived in the late 1400s and early 1500s and worked in places like Kraków and Frombork. Copernicus studied math and astronomy and served as a church official. His claim to fame was saying Earth spins like a top and travels around the Sun — a very different picture than people believed before.

In 1543 he published De revolutionibus orbium coelestium, a book that showed his Sun-centered calculations. He explained odd planet moves (called retrograde motion) more simply. He used careful math and observations but no telescope — later scientists like Kepler and Galileo improved and proved his ideas.

Copernicus' idea started a huge change called the Copernican Revolution. It moved us toward modern science and helped people realize Earth is one planet among many. Today, when we send spacecraft and study stars, we build on the path he began. Look up tonight — the sky you see owes a lot to his courage to ask questions.