The silence of the stars might be hiding more than an absence of life — it might conceal ancient machines, monuments, and traps from civilizations long vanished. Today, we explore these eerie cosmic echoes and the risks of unearthing them.

The silence of the stars might be hiding more than an absence of life — it might conceal ancient machines, monuments, and traps from civilizations long vanished. Today, we explore these eerie cosmic echoes and the risks of unearthing them.

Rogue planets wander the cosmos without stars, but could we still call them home? This episode dives into how humanity might transform these frozen giants into thriving outposts of civilization.

Rogue planets wander the cosmos without stars, but could we still call them home? This episode dives into how humanity might transform these frozen giants into thriving outposts of civilization.

What do snake oil, N-rays, and cold fusion have in common? They’re all cautionary tales reminding us why skepticism is essential to science—and to our future.

What do snake oil, N-rays, and cold fusion have in common? They’re all cautionary tales reminding us why skepticism is essential to science—and to our future.

Are we alone, or just looking for the wrong kind of aliens? Discover how the path to hive minds and distributed consciousness might answer the Fermi Paradox — and pose new dilemmas of their own.

Are we alone, or just looking for the wrong kind of aliens? Discover how the path to hive minds and distributed consciousness might answer the Fermi Paradox — and pose new dilemmas of their own.

Imagine engineering projects so vast they mold galaxies into new shapes. We’ll explore the staggering feats of Kardashev-3 and beyond civilizations, crafting CARD galaxies, Birch Planets, and even rearranging superclusters.

Imagine engineering projects so vast they mold galaxies into new shapes. We’ll explore the staggering feats of Kardashev-3 and beyond civilizations, crafting CARD galaxies, Birch Planets, and even rearranging superclusters.

Explore the entire life story of the cosmos, from quantum flickers at the Big Bang to the distant eras of black holes and dark energy, and discover what kinds of civilizations might endure across these unimaginable spans of time.

Explore the entire life story of the cosmos, from quantum flickers at the Big Bang to the distant eras of black holes and dark energy, and discover what kinds of civilizations might endure across these unimaginable spans of time. Watch my exclusive video Mass Drivers on the Moon: https://nebula.tv/videos/isaacarthur-mass-drivers-on-the-moon-enabling-a-lunar-economy Get Nebula using my link for 40% off an annual subscription: https://go.nebula.tv/isaacarthur Get a Lifetime Membership to Nebula for only $300: https://go.nebula.tv/lifetime?ref=isaacarthur Use the link https://gift.nebula.tv/isaacarthur to give a year of Nebula to a friend for just $36. Visit our Website: http://www.isaacarthur.net Join Nebula: https://go.nebula.tv/isaacarthur Support us on Patreon: https://www.patreon.com/IsaacArthur Support us on Subscribestar: https://www.subscribestar.com/isaac-arthur Facebook Group: https://www.facebook.com/groups/1583992725237264/ Reddit: https://www.reddit.com/r/IsaacArthur/ Twitter: https://twitter.com/Isaac_A_Arthur on Twitter and RT our future content. SFIA Discord Server: https://discord.gg/53GAShE Credits: Spaceport Innovations - Designing the Next Generation of Launch Sites July 31, 2025; Episode 744 Written, Produced & Narrated by: Isaac Arthur Epochs of the Universe - The Cosmic Clock & Civilization (July 31, 2025) Recorded: June 2025 Written by: Isaac Arthur Editor: Lukas Konecny Select imagery/video supplied by Getty Images Music Courtesy of Epidemic Sound http://epidemicsound.com/creator See Privacy Policy at https://art19.com/privacy and California Privacy Notice at https://art19.com/privacy#do-not-sell-my-info.

Aliens don’t always attack with lasers—sometimes, the smartest invasions begin with a gift, a whisper, or a smile. Join us as we count down ten invasion strategies that actually make sense.

Aliens don’t always attack with lasers—sometimes, the smartest invasions begin with a gift, a whisper, or a smile. Join us as we count down ten invasion strategies that actually make sense.

From metal scrolls buried under alien skies to frozen vaults holding minds or monarchs for millennia, we examine how advanced civilizations might safeguard their legacy against the slow grinding of eternity.

From metal scrolls buried under alien skies to frozen vaults holding minds or monarchs for millennia, we examine how advanced civilizations might safeguard their legacy against the slow grinding of eternity.

From carbon nanotubes to multi-layered graphene, we explore the revolutionary materials that could turn space elevators from sci-fi dreams into real-world infrastructure. Discover how these supermaterials might let us weave ribbons to the stars.

From carbon nanotubes to multi-layered graphene, we explore the revolutionary materials that could turn space elevators from sci-fi dreams into real-world infrastructure. Discover how these supermaterials might let us weave ribbons to the stars.

Join us as we journey beyond the birth of the universe to unravel the mysteries of what might have preceded the Big Bang—and whether time itself had a beginning.

Join us as we journey beyond the birth of the universe to unravel the mysteries of what might have preceded the Big Bang—and whether time itself had a beginning.