Star Trails: From Backyard Astronomy to Cosmic Wonder

Saturn has a moon with a hidden ocean, and that ocean is spraying samples of itself into space. Enceladus is only about 310 miles wide, but beneath its brilliant shell of ice lies a global saltwater ocean warmed by the pull of Saturn. Along its south pole, enormous fractures release water vapor and tiny frozen grains. NASA's Cassini spacecraft flew through that spray and found salts, organic compounds, molecular hydrogen, silica and phosphorus: an intriguing collection of water, chemistry and energy. Now two new studies make the story even more compelling. One suggests that Enceladus naturally separates and concentrates its ocean chemistry into individual ice grains, potentially making signs of life easier for a future spacecraft to detect. The other shows that a methane-producing microorganism from Earth can survive under a laboratory recreation of Enceladus-like conditions. This week on Star Trails, we'll visit the little moon that may be preparing its own samples for us. Then, after the break, we'll discover why the average color of the universe is called Cosmic Latte before heading outside for Mars in the Beehive Cluster, a young Moon beside Antares, Vesta at opposition and a perfectly timed fade of the Demon Star. 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.

A black hole in our galaxy appears to be aiming a relativistic jet almost directly toward Earth. That sounds like a reasonably good opening line for October. The object, IRAS 18293−0941, is a binary system about 12,000 light-years away. A stellar-mass black hole is feeding on material from a massive companion star and launching jets at no less than roughly two-thirds the speed of light. Because one jet is directed close to our line of sight, astronomers believe they may have found the Milky Way's first convincing microblazar—a miniature version of the blazars powered by supermassive black holes in distant galaxies. This week on Star Trails, we'll look down the barrel of that cosmic engine, learn why the jet is far more interesting than frightening, and follow the other jet as it crashes into a molecular cloud and may accelerate particles to extraordinary energies. Then in the Night Sky Report for October 4 through the 10th, Saturn reaches opposition, the waning Moon visits Mars and the Beehive Cluster, and much of North America gets to watch the Moon make Jupiter disappear. We'll also look for a dragon's handful of meteors under nearly moonless skies before the new Moon arrives on Saturday. 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.

What if Venus once had a moon, and then destroyed it? A new study suggests that under plausible conditions, an ancient Venusian moon could have slowly migrated inward, crossed the Roche limit and ultimately been torn apart or swallowed by the planet. And Venus may not be the only hungry object in our cosmic neighborhood: another recent study explores whether the young Sun could have consumed a super-Earth, leaving subtle chemical and structural fingerprints behind billions of years later. This week on Star Trails, we're following a cosmic version of the old nursery rhyme "There Was an Old Lady Who Swallowed a Fly." Planets can swallow moons. Stars can swallow planets. Galaxies devour other galaxies. Along the way, we'll explore why orbits aren't permanent, why Earth's Moon is slowly escaping us while Mars's Phobos is falling inward, and how gravity can transform apparently stable systems over astronomical timescales. Then in the Night Sky Report for September 27 through October 3, autumn has officially arrived. We'll look for Saturn near opposition, a Moon-and-Pleiades pairing, Jupiter and its Galilean moons, and the changing fall sky. We'll also visit a newly discovered crater on the Moon and check in on the fast-moving mystery of Webb's strange Little Red Dots. 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.

What if the first evidence of an advanced alien civilization isn’t a message, but a star whose energy books don’t quite balance? This week, we explore the strange history and surprisingly real science of Dyson spheres, from Olaf Stapledon and Freeman Dyson to the unforgettable Star Trek: The Next Generation episode “Relics.” We’ll learn why a vast swarm of orbiting collectors makes more sense than a solid shell, and how astronomers search for the missing starlight and excess infrared heat such a civilization might produce. We also examine Project Hephaistos and its search through millions of nearby stars, the James Webb observations that unmasked two promising candidates, and a recent proposal suggesting that hyper-efficient alien computers could create a much colder, and harder to find, form of waste heat. Then, in the night sky report, the Moon visits brilliant Venus, Antares and the Teapot of Sagittarius. Venus reaches peak brightness, Saturn rules the evening sky, and International Observe the Moon Night gives everyone a reason to spend Saturday evening looking up. 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.

Galaxies carry the evidence of their past. When the Milky Way captures a dwarf galaxy or tears apart a globular cluster, it leaves behind long, ghostly ribbons of stars called stellar streams. These streams preserve the history of ancient collisions, and their shapes may trace the invisible dark matter surrounding a galaxy. This week, we follow the stellar wreckage left behind by galactic cannibalism, from the enormous Sagittarius stream wrapped around the Milky Way to Oyashio, the first suspected globular-cluster stream discovered beyond our galaxy. We’ll explore how astronomers use these delicate structures as cosmic windsocks and seismographs, and why gaps or kinks in a stream might reveal an encounter with something made almost entirely of dark matter. We’ll also look at how the newly launched Nancy Grace Roman Space Telescope could transform this work by finding stellar streams around hundreds of other galaxies. Then, in this week’s night sky report, the Moon visits Mars and Jupiter, the September Epsilon Perseids arrive under nearly moonless skies, and Saturn returns as a prime telescopic target. 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.