What Everyone Knew Was True (Until It Wasn't)

How Galileo's Absurd Theory Became Reality

I want to talk about what a leap into the void, a leap into apparent madness Galileo Galilei’s (1564–1642) helio-centric theory was at the time. It contradicted everything that people knew. I mean, really, why would anyone believe it at the time? Here’s the story.

When the whole Galileo controversy began, almost everyone in the West believed that the Earth was the center of the universe, and that all planets and stars revolved around the Earth.

It only makes sense, as humanity of course, was the center of creation. God created the universe and made humans the preeminent life form. Of course, the Earth was the center of the universe.

This geo-centric theory is also obvious to any observer of basic physics. Objects in the sky appear to revolve around the Earth. The Earth is not moving. If it did, we would have noticed that. Here is the logic.

We see objects in the sky revolve around the Earth,

Therefore, celestial objects revolve around the Earth.

and

We do not feel the Earth move.

Therefore, the Earth does not move.

You have to admit that these are good arguments.

Because celestial objects revolve around the Earth, and

Because the Earth does not move,

The Earth is the center of the universe.

Aristotle and the Church both taught us that the Earth was at the center, and that objects revolved around the Earth. This was the Ptolemaic Model of the universe, and it held sway from around 150 CE until maybe the 16^th or 17^th century, with Copernicus and Galileo.

The only problem with the Ptolemaic Model is that the math was a bit complicated to account for the irregularities like retrograde motion (when planets appear to move backwards in the sky). Don’t worry, I am not going into that.

Still, the Ptolemaic model seemed to work just fine for understanding and forecasting the planets’ behavior, as far as most people were concerned.

So the Ptolemaic theory confirms what we can all see and feel, and its math works. What fool would question this?

Copernicus did, in the 16^th century, when he published his On the Revolutions in the Heavenly Spheres in 1543, the year of his death.

In terms of math, the heliocentric theory was simpler to use. It was more elegant.

Galileo continued this apparent madness, using his telescopic observations. If Jupiter’s moons orbit around Jupiter, then not everything orbits the Earth. In 1632 he published his Dialogue Concerning the Two Chief World Systems, where he defended heliocentrism against the prevailing geocentric view.

The big problem with this heliocentric theory was that Galileo said that the Earth moved around the Sun. Nobody had witnessed the Earth move, but all had seen the Sun and planets “move.” So why would anyone want to believe Galileo’s theory? Any person with common sense could see it was utter rubbish. This new idea flew in the face of everything people had observed and believed throughout history. Galileo’s theory required people to abandon what was obviously true in favor of an abstract and absurd theory.

In 1633 Galileo was summoned to Rome to face trial for heresy. He was found guilty. They sentenced him to prison, and they forced him to publicly recant his views on his knees. A day later, due to his age, and connections, he was instead placed under house arrest for the rest of his life.

The Church asked Galileo to state that his theory was not the truth, per se, but rather a useful characterization that allows for easier prediction of the motions of the planets. If he said that, they would have left him alone; but Galileo refused to accept this view of his theory.

And yet, within seventy years, scientists converged on heliocentrism as real. It was no longer disputed. Why? Better telescopes revealed more moons, and more patterns that only made sense if the Earth moved. Newton’s Laws of Motion and Gravitation, published in 1687, provided the mathematical framework and explained why we don’t feel the Earth move. . .because we move with it.

So, yeah, what seems a completely crazy theory that defied everything that nearly everyone knew, turned out to be true. Galileo’s madness became the foundation of modern astronomy.

This is a paradigm shift. I wonder what paradigm shifts are coming? What is it that we all take for granted, what accepted science, what common sense that everyone shares today will be abandoned in the future?