This week we continue our month-long journey through the world of galaxies, but this time, we venture into one of astronomy’s darkest frontiers. Beyond the glowing spirals and brilliant star clouds lies a universe filled with hidden structures, invisible matter, and mysteries that continue to challenge modern science.

We venture into the Zone of Avoidance, a cosmic blind spot created by the dust and stars of our own Milky Way, and ask whether entire galaxies may still be hiding just beyond our view. From ghostly ultra-diffuse galaxies like Dragonfly 44, to the invisible gravitational scaffolding of dark matter, we’ll follow the clues that reveal a universe far stranger than it first appears.

Along the way, we’ll look at the mind-bending beauty of gravitational lensing, the mysterious pull of the Great Attractor, and the breathtaking scale of the cosmic web, an immense network of filaments, nodes, and voids that connects galaxies across billions of light-years.

Later in the show, we step back outside for your weekly night sky report, featuring dark skies after the new moon, evening views of Venus and Jupiter, pre-dawn glimpses of Saturn and Mars, early Milky Way core season, and a few lesser-known galaxy targets hiding in Canes Venatici.

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This week we continue our month-long journey through the world of galaxies, but this time, we move beyond what galaxies are and explore what galaxies actually do. It turns out these vast islands of stars are anything but static. They collide, merge, exchange gas and dust, fling stars into deep space, and sometimes grow by consuming smaller neighbors in a process astronomers call galactic cannibalism.

We begin close to home with the Sagittarius Dwarf Spheroidal Galaxy, a hidden companion galaxy currently being torn apart by the gravity of our own Milky Way. From there, we travel some 70 million light-years away to the spectacular Antennae Galaxies, where two spiral galaxies are locked in a slow-motion collision that is both destructive, and strangely creative.

Along the way, we recall my recent conversation with astrophysicist Enrique López Rodríguez to explore the possibility of magnetic bridges and “superhighways” carrying gas, dust, and charged particles between galaxies, raising the astonishing possibility that the raw ingredients of future planets may sometimes originate far beyond their home galaxy.

And finally, we return to the question we teased last week: What about us? Is the long-predicted collision between the Milky Way and the Andromeda Galaxy still inevitable? New observations from Hubble Space Telescope and Gaia suggest the answer may be far less certain than we once believed.

We'll also check in with this week's night sky, and wrap up our discussion of NightWatch.

Connect with us on Bluesky @startrails.bsky.social

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 begin a new month-long journey into one of the most awe-inspiring subjects in astronomy: Galaxies.

We start close to home by exploring our own galaxy, the Milky Way, and asking a deceptively simple question: where does a galaxy actually end? Along the way, we’ll explore spiral arms, dark matter, supermassive black holes, the hidden structure of our galactic halo, and the faint ghostly glow of Integrated Flux Nebula, dust clouds illuminated by the combined light of billions of stars.

We’ll also discover why our solar system doesn’t align with the Milky Way the way you might expect, how astronomers mapped our galaxy from the inside using radio waves, and what the night sky might look like if the Milky Way simply vanished.

Later in the episode: I report on a backyard observation of Amazon’s recent Leo satellite launch, plus, this week’s night sky highlights, the Eta Aquariid meteor shower, Jupiter and Saturn, and a trio of deep-sky galaxies perfect for spring observing.

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.