Galileo is one of the most famous astronomers in history. He helped advance telescope technology, observed sunspots, and established the heliocentric view of the universe. Even if that isn’t exactly correct, it was a big step forward at the time.

While he definitely suffered for his findings and the way he presented them, there is a lot of exaggeration and missing details in how his story of standing up to the Church is told these days.

Of course, the story of Galileo vs the Catholic Church is very compelling and interesting, which often overshadows the actual work of Galileo and how he figured out that the Earth (and the other planets) actually orbit the Sun.

So, for those interested in understanding what Galileo really did when coming up with the heliocentric view of the Universe, here it is.

In January of 1610, Galileo had already created a new and improved telescope that allowed him to look further and with more detail than would have otherwise been possible. With this impressive bit of modern (for the time) technology, he took the time to look at anything he could see.

Naturally, one of the first things he wanted to look at was Jupiter. As he was studying the giant planet, he saw some points of light next to the planet. Naturally, he assumed they were stars at first, but he kept monitoring them.

Eventually, a fourth point of light was spotted, and he saw that the spots of light were moving with Jupiter, not that Jupiter was passing them by.

He correctly theorized that these must be moons orbiting Jupiter just like our moon orbits Earth. These four moons are now known as the Galilean moons.

This might not seem like a big deal, but in the geocentric view of the Universe, which was the common belief at the time, everything orbited around the Earth. If Jupiter has moons, then clearly not EVERYTHING has the Earth as the center point.

That wasn’t enough to upend the common belief of the scientific and religious communities in the known world. So, he kept observing things and soon pointed his telescope at Venus.

Over the course of time, he documented that Venus passed through a range of phases just like the Moon. This wouldn’t happen if it were orbiting the Earth.

This, he proposed, proved that Venus was orbiting the Sun, not the Earth, and heliocentrism was born.

Unfortunately for him, some of his theories were incorrect, even if his overall concept of heliocentrism was a big step in the right direction. In addition, he wasn’t exactly nice to the Pope when presenting his ideas, which isn’t a smart move in teh 1600s.

So, he ran into a lot of trouble and ended up in house arrest (though, to be clear, it was a very comfortable house where he was encouraged to continue studying astronomy and had assistants to help).

That conflict with the Pope makes for a much better story than the years of patient observation that allowed Galileo to come up with his heliocentric view of the universe, which was a major advancement at the time.

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