The most intriguing places in our solar system might not be planets at all. This week we turn our attention to some of the most fascinating and unusual worlds in our solar system: its moons.

For most of human history, we assumed moons were quiet, lifeless companions like our own. But as spacecraft ventured deeper into the outer solar system, a very different picture emerged.

Some moons erupt with volcanoes. Some hide vast oceans beneath miles of ice. Some have weather, rivers, and lakes, made not of water, but methane. And a few of them may have the ingredients necessary for life.

We’ll explore these strange worlds, from Io and Europa to Titan and Enceladus, and take a closer look at what makes them so dynamic. Along the way, we’ll revisit Pluto and its surprisingly complex family of moons, and consider why the outer solar system is teeming with these objects while the inner planets remain mostly bare.

Finally, we’ll step outside for a guided tour of the night sky for the week of March 22–28, including a waxing crescent Moon, brilliant Venus in the evening sky, Jupiter and its Galilean moons, and the arrival of spring’s galaxy season. We'll also check in on our book discussion with a look at Chapters 8 and 9 in Nightwatch.

Connect with us on Bluesky @startrails.bsky.social or YouTube @TheStarTrailsPodcast.

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In 2006, a group of astronomers gathered in Prague and made a decision that shocked the world: Pluto was no longer a planet.

But the story of Pluto is far more complicated—and far more fascinating—than that single vote.

In this episode of Star Trails, we reopen the case. From Percival Lowell’s search for the mysterious “Planet X” to Clyde Tombaugh’s painstaking discovery using a blink comparator, we trace the strange history of the ninth planet. We’ll examine the discoveries that led to Pluto’s controversial demotion, meet the astronomers who helped redefine what a planet is, and follow NASA’s New Horizons spacecraft as it revealed Pluto to be a dynamic and surprisingly complex world.

Along the way we explore Pluto’s bizarre orbit, its giant moon Charon, its icy surface and hidden mysteries—and the poetic moment when the ashes of its discoverer finally returned to the distant world he found.

And later in the show, we step outside for a look at the night sky for the week of March 15–21, including dark skies near the new moon, the arrival of the vernal equinox, brilliant Jupiter in Gemini, and a few deep-sky treasures worth tracking down with your telescope.

Connect with us on Bluesky @startrails.bsky.social or YouTube @TheStarTrailsPodcast.

If you’re enjoying the show, consider sharing it with a friend! Want to help? Buy us a coffee! Also, check out music made for Star Trails on our Bandcamp page!

Podcasting is better with RSS.com! If you’re planning to start your own podcast, use our RSS.com affiliate link for a discount, and to help support Star Trails.

This week we leave the rocky inner planets behind and journey into the deep cold of the outer solar system. From the storm-wracked atmosphere of Jupiter to the ringed elegance of Saturn and the mysterious ice giants Uranus and Neptune, these distant worlds reveal how strange and varied our planetary neighborhood truly is.

Along the way we explore how the solar system formed, why the inner planets are rocky while the outer planets became giants of gas and ice, and why the distant ice giants remain some of the least explored worlds we know.

Later in the episode we share a personal observing report after attempting to spot a SpaceX rocket launch from hundreds of miles away, offer up tips on how you might see one yourself, and we'll walk through what’s visible in the night sky for the week of March 8–14.

We’ll also continue our NightWatch book club with Chapters 6 and 7, exploring the realities of visual astronomy and how patient observation reveals the subtle beauty of the deep sky.

Mentioned in this episode:

• Spaceflight Now website

Connect with us on Bluesky @startrails.bsky.social or YouTube @TheStarTrailsPodcast.

If you’re enjoying the show, consider sharing it with a friend! Want to help? Buy us a coffee! Also, check out music made for Star Trails on our Bandcamp page!

Podcasting is better with RSS.com! If you’re planning to start your own podcast, use our RSS.com affiliate link for a discount, and to help support Star Trails.