Today’s Wonder of the Day was inspired by Daniel. Daniel Wonders, “Who was Galileo Galilei?” Thanks for WONDERing with us, Daniel!

Have you ever used a telescope? Do you know about the many moons of Jupiter? Maybe you’ve learned that the Earth revolves around the sun. If so, then you’ve been influenced by the topic of today’s Wonder of the Day. Who are we talking about? Galileo, of course!

Galileo Galilei was born in Pisa, Italy, in 1564. His family moved to Florence, and Galileo was educated in a nearby monastery. He later returned to Pisa to attend the city’s university.

What did Galileo study in school? He planned to learn about medicine. Soon though, he became more interested in mathematics and physics. He also studied philosophy. However, Galileo never completed his degree. He left the university in 1585.

Still, Galileo continued to learn for the rest of his life. He studied the world around him. He also carried out many experiments to satisfy his curiosity. Later in his life, this quest for knowledge would bring Galileo a lot of trouble. 

Many people looked up to Galileo. He was known as a great teacher and scientist. Still, others thought Galileo’s ideas were dangerous. His strongest critics were leaders of the Catholic Church. 

What caused the Church to see Galileo’s ideas as dangerous? Their greatest clashes came when Galileo began building telescopes in 1609. Galileo didn’t invent the telescope, but he did make major improvements to the device. His telescopes were much stronger than others made during his lifetime.

Galileo was also the first person known to use a telescope to look into space. He learned that the moon had craters and mountains. He observed Saturn and was the first to see its rings. He also discovered sunspots. But one of his findings in particular put him at odds with the Catholic Church. Galileo found evidence to suggest that Earth was not the center of the universe.

That may not seem like a ground-shaking idea to you. But during Galileo’s lifetime, most people believed that everything in the sky—the sun, moon, planets, and stars—revolved around our planet. The Church taught that God had built the universe with Earth at the center. 

What evidence did Galileo have that the Church’s ideas about the solar system were wrong? First, he learned that Venus revolved around the sun instead of the Earth. Further, Galileo discovered the first four moons that circle Jupiter. Findings like these led him to believe that the sun was the real center of our solar system

Eventually, his disagreements with the Catholic Church caught up with Galileo. In 1632, he was called before the Inquisition. This was a body of the Church that worked to root out heresy. After a long trial, Galileo was convicted. He was under house arrest until he passed away on January 8, 1642. 

It was many more years before the Catholic Church fully accepted his findings. Today, Galileo is celebrated as one of history’s greatest minds. He made great contributions to the fields of mathematics, physics, and astronomy. 

Which of Galileo’s discoveries do you think is most impressive? Have you ever spotted anything interesting through the lens of a telescope?  

Standards: NGSS.ESS1.A, NGSS.ESS1.B, CCRA.L.1, CCRA.L.2, CCRA.L.3, CCRA.L.6, CCRA.R.1, CCRA.R.2, CCRA.R.4, CCRA.R.10, CCRA.W.2, CCRA.W.7, CCRA.W.9, CCRA.SL.1

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