Galileo Galilei, history’s most famous astronomer, was born on this day 452 years ago. Though he may not have been the most consequential, the man who’s known just by his first name managed to play a pivotal role in advancing Copernicus’ then-heretical ideas about heliocentrism. In the age of rapper-slash-flat-Earthers and climate change deniers, we could all learn a thing or two from Galileo’s feats of intellectual bravery in the face of institutional idiocy.

In case you remember nothing from grade school, let’s recap: Galileo was born on February 15, 1564 in Pisa, Italy. A very gifted student of science with a strong proclivity for mathematics, Galileo would pursue physics to its furthest distances. He’s credited as being the first person to study the night sky with a telescope, soon learning to build and sell them to merchants in Venice who wanted to break into the “futures” market.

Astronomer #Galileo Galilei was born in Pisa today in 1564

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Later on, Galileo would discover Jupiter’s four largest moons — the first moons to be found orbiting a planet that wasn’t named “Earth.” These moons — Io, Europa, Ganymede, and Callisto — are collectively called the Galilean Satellites in his honor. He would also find out that Venus has phases just like the moon, observing them and documenting the evidence over time. He was the first to stumble on evidence of Saturn’s rings, though he had little idea about what they were made of or even how they worked. He saw mountains and geological shapes on the moon, proving it was not a smooth, sphere-like pearl in the sky.

Some of these biggest contributions had to do with the physics of the Earth and how things worked down here on the surface. Galileo is often credited with having established that all objects of the same density will fall to the ground at the exact same rate, regardless of mass. Furthermore, he demonstrated that this force that pulled things to the Earth was gravitational acceleration, compounding the speed at which a fallen object was going as time passed. (The legend goes that he demonstrated all of this on the Leaning Tower of Pisa, dropping cannon balls from on high.)

There’s more, of course, but Galileo’s most famous — or infamous — exploits have to do with heliocentrism, and the hot water that crept up soon enough. In 1543, Copernicus published his paper arguing that the universe — which, as we understood it back then, was pretty much just the solar system — consisted of planets, including Earth, that revolved around the Sun.

Naturally, there was a lot of pushback. This theory threatened to push man out of his place at the center of the universe — a notion the Catholic Church could not, despite its relative lenience, acquiesce to. At this point in Europe, the Church wasn’t totally against science and was actually kind of tolerant about scientists discovering things that went against Church doctrine. It just wasn’t OK to say that stuff very loudly.

Galileo wasn’t having it. He published papers declaring support for a heliocentric solar system for two decades. Finally, in 1633, he was summoned to Rome to answer charges that his latest book, Dialogue Concerning the Two Chief World Systems, was heretical.

As The New Yorker put it in a 2013 article, the book “use[s] every device of Renaissance humanism: irony, drama, comedy, sarcasm, pointed conflict, and a special kind of fantastic poetry.”

“There are passages that are still funny, 400 years later. At one point, the dispute takes up the high-minded Aristotelian view that ‘corrupt’ elements must have trajectories different from pure ones, and Sagredo points out that an Aristotelian author ‘must believe that if a dead cat falls out of a window, a live one cannot possibly fall, too, since it is not a proper thing for a corpse to share in qualities suitable for the living.’ The dialogue is also philosophically sophisticated. Though Galileo/Salviati wants to convince Simplicio and Sagredo of the importance of looking for yourself, he also wants to convince them of the importance of not looking for yourself. The Copernican system is counterintuitive, he admits — the earth certainly doesn’t seem to move. It takes intellectual courage to grasp the argument that it does.”

We could all use a dose of Galileo’s “intellectual courage.” Science has never before been so accessible to the general public as it is right now. It no longer exists in a metaphorical ivory tower but can be grasped by those willing to make the most of the resources on hand (most notably, the internet).

Despite this, our society is still inundated with skeptics who choose instead to promote bogus, unfounded theories that reject scientific evidence in favor of conspiracy-fueled biases. That’s why we have climate deniers, people spouting fears about A.I., GMO rejectionists, and even people who believe the earth is flat. In all of these instances, there is overwhelming evidence to prove what is right and what is wrong, yet people still choose to entertain their ignorant whims for whatever reason they find comforting. It’s maddening.

#HappyBirthday #Galileo 🎁🎉 #Heliocentric #Telescope #Inventor #Science #Math #LastWords #AndYetItMoves

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That’s intellectual courage, and that’s what’s lacking among the contrarians we have who choose instead to reject science in favor of crackpot explanations.

These people often claim that they are doing the work of Galileo — promoting real truths in the face of institutional falsities. But these people are wrong. Galileo’s stand was in defense of science. He didn’t thrust himself into his work with an agenda he wanted to prove. He simply did the research, collected the facts, and made conclusions based on where that evidence lied.

Galileo, unfortunately, paid a big price for speaking out, and was sentenced to house arrest until his death in 1642. Before he died, he said:

“I do not feel obliged to believe that the same God who has endowed us with sense, reason, and intellect has intended us to avoid their use.”

We’d all do well to remember these words. If we want to honor Galileo the right way, we ought to remember the facts trumps everything else, and it’s critical to our future that when we choose to defend an idea, we verify that we have real evidence to support us.

Photos via Justus Sustermans