“All truths are easy to understand once we discover them,” Italian astronomer Galileo Galilei once said. “The point is to discover them.” Galileo sought to understand the night sky and the motions of the heavens. In the process, he ushered in the modern study of astronomy and unveiled to the world the wonders that lay throughout the solar system. He learned much about the Moon and the planets of the Solar System through his observations. Through this work, he also learned much about Earth and sought to teach humanity. Galileo’s discoveries led to many legal problems as he learned that many long-held ideas about the universe, ideas closely protected by the church at the time, were in error. In spite of his persecution, he continued to work to advance the frontiers of knowledge.

Zone in on these basic facts on Galileo and his discoveries:

1. Galileo Galilei (1564-1642) has been called, by such figures as Albert Einstein, the father of modern science.

2. Galileo is the first known scientist to use the telescope for observing the night sky, now an indispensible tool for astronomers.

3. In the 1580s, he invented one of the first known thermometers.

4. In 1610, he discovered four of Jupiter’s largest moons (Io, Ganymede, Callisto, and Europa) through his telescope, the four of which are now often referred to as the “Galilean moons.”

5. Also in 1610, he discovered the rings around Saturn.

6. Through his observations, he also determined that the Moon was covered in tall mountains and deep craters and not a perfectly smooth sphere as many had long believed the Moon to be.

7. Galileo also determined that the Milky Way was not a cloud but a collection of millions of individual stars.

8. His theory of the Sun-centered solar system, long since accepted by scientists, led him to be charged before a church court on charges of heresy.

9. He recanted his findings about the Sun-centered solar system under threat of torture and was placed under house arrest from 1634 until his death, but the observations and conclusions of other scientists continued to support his findings.

— Dr. Bridges is a professor of history and geography living in Arkansas. He can be contacted at drkenbridges@gmail.com.