Skip to main content

Rediscovering Galileo

In this episode, Rediscovering Galileo . . .

Today, we’re turning our telescopes back in time to explore Galileo Galilei's work and how amateur astronomers today can experience his groundbreaking discoveries for themselves.

If you listened to last week's podcast, Planetary Pursuit, you might have heard me say that Jupiter is “my favorite planet." Here’s why–

Galileo’s Dialogue Concerning the Two Chief World Systems, published in 1632, challenged the geocentric model of the universe—the belief that everything orbits around Earth. Instead, he advocated for the Copernican model, which places the Sun at the center of our solar system. This book was not just a scientific treatise but also a revolutionary act that put Galileo in conflict with the Catholic Church.

Galileo presented his arguments as a dialogue between three characters: Salviati, who supported the heliocentric model; Simplicio, who defended the traditional geocentric view; and Sagredo, an open-minded observer. It’s easy to see who emerged looking a bit foolish. Simplicio, perceived as representing Church doctrine, was portrayed as less informed, leading to accusations that Galileo mocked the Church's authority.

In 1633, Galileo was tried by the Inquisition, forced to recant his support for heliocentrism, and placed under house arrest. The Catholic Church had declared heliocentrism heretical in 1616, leading to his confinement. The Inquisition found him "vehemently suspect of heresy" for supporting the Copernican system and pressured him to retract his views publicly, which he refused. Galileo spent the remainder of his life under house arrest, where he continued his scientific work.

Despite the controversy, Galileo’s observations were difficult to refute. Let’s begin with one of his most famous: Jupiter and its moons. In 1610, Galileo discovered four moons orbiting Jupiter using his enhanced (20X) telescope. Today, we call them the Galilean moons: Io, Europa, Ganymede, and Callisto.

By tracking their movements night after night, Galileo demonstrated that these moons orbited Jupiter, not Earth. This was significant because it proved that not everything in the cosmos revolves around us. It was akin to discovering a mini solar system, providing strong evidence for the Copernican model.

It wasn’t until 1992 that Pope John Paul II formally pardoned Galileo, acknowledging the Church’s error in condemning his findings and praising his scientific contributions.

And here’s the fun part: You can repeat Galileo’s observations using a simple telescope. Just point it at Jupiter on a clear night. Over several evenings, you’ll notice the positions of its moons shift—evidence that they’re orbiting the gas giant. Here are a few hand-drawn diagrams and notes from my version of his experiment.

Galileo didn’t stop with Jupiter. He observed the phases of Venus, which change similarly to the Moon’s phases. This wouldn’t be possible if Venus orbited Earth. Instead, it only makes sense if Venus orbits the Sun, reinforcing the heliocentric model.

With a telescope, you can observe the phases of Venus yourself. It’s an incredible way to connect with the scientific revolution that Galileo helped ignite. And don’t forget his work with the Moon! Galileo’s sketches of craters and mountains shattered the belief that celestial bodies were perfect spheres. Grab some binoculars or a small telescope and look at the Moon during its crescent phase for stunning shadows and details.

So, whether it’s Jupiter’s moons, Venus’s phases, or the rugged surface of the Moon, Galileo’s discoveries are accessible to anyone with curiosity and a telescope. Why not step into his shoes and see the universe as he did. An amateur astronomer's way to step back in time.

I’m Patrick Ball. Thanks for listening, and I’ll see you in the next episode.

Labels:

Comments

Post a Comment

Most Popular of All Time

Paris – the End of Silence

✈️  In this special episode: Paris – the End of Silence Sometimes, connection arrives in the most unexpected form—not through grand gestures, but through a quiet voice carried by technology. In a Paris apartment, I finally understood my family’s words . . . and felt my mother’s presence in every sentence. Since I was a little boy, France has been both a beautiful and frustrating paradox in my life. Every six to nine years, my mother, Mauricette, would take my brothers and me back to La Rochelle to visit our French family. The moment we arrived, the air would fill with a sound I loved but couldn’t share in—the rapid-fire, musical rhythm of French. My aunts, uncles, and cousins would warmly sweep me into hugs and kisses, their words flowing like a lovely melody I couldn’t quite catch. I’d smile brightly, trying to communicate with my eyes and hands. But as soon as we stepped off the plane, my mother and her sister-in-law, Joséan, started talking animatedly. They were gone, chatting h...
2 comments
Read more

Pushing the Pause Button

In this episode, Pushing the Pause Button: Stepping Off the Treadmill Hello, friends — If you're reading this, I'm already off the grid. Today begins a much-needed vacation, and for the next few weeks, On the Fly is taking a break right along with me. For a long time, my inner voice has said, 'Keep every commitment, no matter what.' That's meant early mornings, long days, and a calendar packed with posts, podcasts, and projects I couldn't seem to say no to. I've been trying to be the tireless workhorse—but that kind of grind doesn't end well. Lately, I've noticed I'm not quite myself—shorter fuse, louder sighs, and a few too many grumbles (Lori deserves a medal). That's when you know it's time to hit pause before the spark burns out. So, I'm stepping back to rest, recharge, and remember what it feels like to not live by the next deadline: no tech, no to-do lists, just some space to breathe. Thank you, truly, for all your support and ...
2 comments
Read more

Noirmoutier: An Ocean Between Us, Gone in a Moment

In this episode, Noirmoutier: An Ocean Between Us, Gone in a Moment. Sometimes love waits half a century for its moment — and when it finally arrives, time doesn’t stand still; it disappears. The moment I stepped off the train in Nantes, it felt like time froze. There she was — my cousin Michèle — waiting on the platform, arms waving desperately. When we finally embraced, the fifty years that had passed between us disappeared in an instant. The melody in her voice was the same, but softer than I remembered. We both shed tears of joy that only come from love long overdue. “I’m so happy you are here,” she whispered, her voice trembling.   Thank goodness for the translation app on my phone, because the conversation began immediately — fast, fluid, and unstoppable. The Frenzy of Catching Up As we drove for about an hour to the tiny town of L’Épine on the Island of Noirmoutier, the words kept tumbling out. Michèle and her husband, Alain, are the most gracious hosts — but my new challe...
1 comment
Read more

Our Journey to Avignon

🇫🇷 Lost in Transition: Our Journey to Avignon (Part 1) When everything that can go wrong—does—sometimes grace still finds you. Our Monday morning trip began on the quiet island of Noirmoutier , where salt marshes and sea breezes whisper of simpler days. From there, our early morning drive was uneventful; we arrived at the Nantes station with plenty of time to spare. From Nantes to Paris Montparnasse, everything went smoothly—so we thought, until it didn't. That's when things started to unravel. If you've never traveled the Paris Metro , imagine a vast underground maze pulsing beneath the city—corridors twisting into one another, trains roaring in and out of the dark, staircases that rise and fall like riddles. It's efficient, yes—but only if you know where you're going. We had over an hour and a half to make our next train to Avignon —plenty of time. Or so we believed. We needed to reach the Gare de Lyon station, where our TGV (high-speed train) was headed south...
Post a Comment
Read more