Star Trails: From Backyard Astronomy to Cosmic Wonder

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.socialIf 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.socialIf 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.

The James Webb Space Telescope has uncovered hundreds of tiny red points in the early universe. They are extraordinarily compact, unexpectedly bright and strangely quiet in the X-ray and radio wavelengths where an active black hole should reveal itself.Astronomers call them “little red dots,” but that modest nickname conceals one of the most intriguing mysteries of the Webb era.In this episode, we follow the clues hidden in their light. Some may contain young black holes buried inside enormous cocoons of hydrogen, objects researchers have nicknamed “black hole stars.” Others may be powered by supermassive stars, furious bursts of star formation or combinations of several different cosmic engines.We’ll examine new evidence from several unusual objects, visit the nearby Saguaro galaxy and the curious galaxies known as Green Peas, and ask whether the young Milky Way might once have appeared as a little red dot of its own.Then, in the Night Sky Report for August 30 through September 6, we’ll look for the Moon beside Saturn, Venus near Spica, Mars and Jupiter before dawn, and some of the quieter constellations hiding around the Summer Triangle.Connect with us on Bluesky @startrails.bsky.socialIf 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.

The Milky Way looks permanent from our place inside it, a great band of stars stretching across the night sky. But new research suggests our galaxy may once have been oriented in a completely different direction, perhaps reorienting by more than 90 degrees during its violent youth.This episode explores the evidence for the Milky Way's possible ancient flip and, even more remarkably, how astronomers could possibly reconstruct something that happened around ten billion years ago. Using stellar motions measured by Gaia, the debris of the ancient Gaia-Enceladus merger, cosmological simulations, and even the inferred shape of the Milky Way's invisible dark-matter halo, astronomers are learning to read our galaxy's history from the fossils it left behind.We also follow up on the August 5 rocket-body impact on the Moon, and discover why an event involving four tons of hardware traveling thousands of miles per hour was still almost impossibly tiny from Earth.Then we head outside for the August 16–29 night sky. Venus meets the crescent Moon, Saturn continues its return to the evening sky, Mars and Jupiter appear before dawn, and the first autumn constellations begin climbing into view. We'll use Pegasus and Cassiopeia to find the Andromeda Galaxy and watch for lingering Perseids and Kappa Cygnid fireballs.And circle August 27–28 on the calendar: the Full Sturgeon Moon will pass almost completely into Earth's shadow during a deep partial lunar eclipse, with roughly 96 percent of the lunar disk immersed in the umbra at maximum.Connect with us on Bluesky @startrails.bsky.socialIf 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 happens when a black hole spins? According to general relativity, it doesn't simply rotate in space, it actually drags spacetime around with it.This episode explores the strange phenomenon known as frame dragging, from its first predictions more than a century ago to new observations that may let astronomers watch it at work around supermassive black holes. We'll visit a distant black hole where the remains of a shredded star appear to be wobbling through twisted spacetime, then return to the center of our own Milky Way to meet S301, a star racing around Sagittarius A* at more than eight percent of the speed of light. Its extreme orbit may eventually help astronomers measure the spin of our galaxy's central black hole.And there's plenty happening closer to home. A spent Falcon 9 rocket stage is expected to crash into the Moon on August 5, Comet 10P/Tempel is making a favorable pass through the inner Solar System, and the Perseid meteor shower arrives under nearly perfect dark-sky conditions thanks to the New Moon.We'll also look at Mercury, Venus, Mars, Saturn and Jupiter in the August sky, plus the total solar eclipse of August 12.Finally, we look back fifty years to Viking 1 and the extraordinary moment when Mars stopped being merely a world seen from afar and became a place with rocks, dirt, sky, and a horizon.It's a packed couple of weeks beneath the stars.Connect with us on Bluesky @startrails.bsky.socialIf 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.