Amid the swirling vastness of galaxies, each a cosmic city of stars and planets, the silence raises a compelling question: could the very nature of galaxies themselves hold the key to why intelligent life remains unseen?

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Credits:
The Fermi Paradox: Galactic Great Filters
Episode 484; January 30, 2025
Written, Produced & Narrated by: Isaac Arthur
Select imagery/video supplied by Getty Images 
Music Courtesy of Epidemic Sound http://epidemicsound.com/creator
Phase Shift, "Forest Night"
Chris Zabriskie, "Unfoldment, Revealment"
Stellardrone, "Billions and Billions"

The Fermi Paradox: Galactic Great Filters (Narration Only)

Imagine a scale that ranks civilizations not by their borders or technology, but by the sheer energy they command— some spanning entire galaxies. Join us as we explore the Kardashev Scale, the ultimate measure of cosmic power.


Watch my exclusive video Big Alien Theory https://nebula.tv/videos/isaacarthur-big-alien-theory
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Credits:
The Kardashev Scale & Population
Episode 486; February 13, 2025
Written, Produced & Narrated by: Isaac Arthur
Editors: Ludwig Luska
Graphics: Fishy Tree, Jeremy Jozwik, Ken York YD Visual
Select imagery/video supplied by Getty Images 
Music Courtesy of Epidemic Sound http://epidemicsound.com/creator
Phase Shift, "Forest Night"
Chris Zabriskie, "Unfoldment, Revealment", "A New Day in a New Sector", "Oxygen Garden"
Stellardrone, "Red Giant", "Billions and Billions"

The Kardashev Scale & Population (Narration Only)

What if the "magic" of tomorrow is just science we don’t yet understand? In this episode, we explore the wildest speculative technologies—faster-than-light travel, Dyson Spheres, teleportation, wormholes, and more. Could these breakthroughs redefine our future or explain the Fermi Paradox? Find out as we dive into the impossible!

Watch my exclusive video Big Alien Theory https://nebula.tv/videos/isaacarthur-big-alien-theory
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Credits:
Impossible Technologies: The Clarketech Compendium 
Episode 486a; February 16, 2025
Written, Produced & Narrated by: Isaac Arthur
Editors: Ludwig Luska, Thomas Owen, Lukas Konecny
Graphics: Jeremy Jozwik, Ken York YD Visual, Mihail Yordanov, Sergio Botero
Select imagery/video supplied by Getty Images 
Music Courtesy of Epidemic Sound http://epidemicsound.com/creator
Phase Shift, "Forest Night"
Chris Zabriskie, "Unfoldment, Revealment", "A New Day in a New Sector", "Oxygen Garden"
Stellardrone, "Red Giant", "Billions and Billions"
Lombus, "Hydrogen Sonata", "Cosmic Soup"

Impossible Technologies: The Clarketech Compendium

Imagine a world stretched along a single, endless river inside a colossal space megastructure. Explore the fascinating concept of the Topopolis, a futuristic habitat billions of miles long, where humanity might thrive in a sprawling civilization bound by physics, engineering, and imagination.

Watch my exclusive video Big Alien Theory https://nebula.tv/videos/isaacarthur-big-alien-theory
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Get a Lifetime Membership to Nebula for only $300: https://go.nebula.tv/lifetime?ref=isaacarthur
Use the link gift.nebula.tv/isaacarthur to give a year of Nebula to a friend for just $30.
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Credits:
Topopolis: The Eternal River 
Episode 487a; February 23, 2025
Written, Produced & Narrated by: Isaac Arthur
Graphics: Apogii.uk, Ken York YD Visual, Steve Bowers, Udo Scroeter
Select imagery/video supplied by Getty Images 
Music Courtesy of Epidemic Sound http://epidemicsound.com/creator

Topopolis: The Eternal River Space Habitat (Narration Only)

Topopolis: The Eternal River Space Habitat

Gravity Tech: The Power To  Reshape Our Civilization... And The Cosmos Themselves

Gravity Tech: The Power To  Reshape Our Civilization... And The Cosmos Themselves (Narration Only)

Are we alone in the universe—or just early to the party? We’ll explore the math, models, and megastructures that might answer how many alien civilizations are out there, and why the night sky remains so quiet.

Watch my exclusive video Fishbowl Starships - Water As Shielding - https://nebula.tv/videos/isaacarthur-fishbowl-starships-water-as-shielding

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Use the link gift.nebula.tv/isaacarthur to give a year of Nebula to a friend for just $30.


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Join Nebula: https://go.nebula.tv/isaacarthur

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SFIA Discord Server: https://discord.gg/53GAShE



Credits:

How Many Alien Civilizations Are There?

Episode 723; June 8, 2025 

Written, Produced & Narrated by: Isaac Arthur

Editor: Ludwig Luska

Graphics: Ken York YD Visual

Select imagery/video supplied by Getty Images

Music Courtesy of Epidemic Sound http://epidemicsound.com/creator

Phase Shift, "Forest Night"

 Chris Zabriskie, "Unfoldment, Revealment" & "A New Day in a New Sector" 

Koalips, "Kvazar"

 Stellardrone, "Red Giant" & "Billions and Billions"

How Many Alien Civilizations Are There? (Narration Only)

In order to succeed in space, we must be able to produce as much as possible on-site, or ‘in situ’, but what are the most critical resources to harvest and how do we do it?

Watch my exclusive video Fishbowl Starships - Water As Shielding - https://nebula.tv/videos/isaacarthur-fishbowl-starships-water-as-shielding
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Get a Lifetime Membership to Nebula for only $300: https://go.nebula.tv/lifetime?ref=isaacarthur
Use the link gift.nebula.tv/isaacarthur to give a year of Nebula to a friend for just $30.


Visit our Website: http://www.isaacarthur.net
Join Nebula: https://go.nebula.tv/isaacarthur
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Support us on Subscribestar: https://www.subscribestar.com/isaac-arthur
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SFIA Discord Server: https://discord.gg/53GAShE
Credits:
I.S.R.U. In-Situ Resource Utilization
Written, Narrated & Produced by: Isaac Arthur
Graphics:
Fishy Tree
Jeremy Jozwik
Ken York / YD Visual
Sergio Botero
Udo Schroeter
Music Courtesy of
Epidemic Sound Epidemic Sound http://epidemicsound.com/creator


ISRU: In-Situ Resource Utilization (Narration Only)

This episode explores how spaceports will evolve in design, technology, and purpose—shifting from fuel-thirsty towers to seamless transport hubs for Earth, Moon, Mars, and beyond.
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
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Use the link  https://gift.nebula.tv/isaacarthur to give a year of Nebula to a friend for just $36.
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SFIA Discord Server: https://discord.gg/53GAShE
Credits:
Spaceport Innovations - Designing the Next Generation of Launch Sites
July 10, 2025; Episode 731
Written, Produced & Narrated by: Isaac Arthur
Graphics:
Anthrofuturism
Atlantis Project
Jarred Eagley
Katie Byrne
Fishy Tree
Phil Swan
Select imagery/video supplied by Getty Images 
Music Courtesy of Epidemic Sound http://epidemicsound.com/creator
Stellardrone, "Red Giant", "Billions and Billions"

Spaceport Innovations: Designing the Next Generation of Launch Sites (Narration Only)

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.

Watch my exclusive video Mass Drivers on the Moon: https://nebula.tv/videos/isaacarthur-mass-drivers-on-the-moon-enabling-a-lunar-economy
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Credits:
Before the Big Bang - What Came Before Time?
Episode 738; July 20, 2025
Written, Produced & Narrated by: Isaac Arthur
Select imagery/video supplied by Getty Images 
Music Courtesy of Epidemic Sound http://epidemicsound.com/creator
0:00 Intro Asking the Impossible
2:08 The Limits of Time and Spacetime
7:45 Beyond the Big Bang: Alternate Beginnings
14:38 Other Realities: Higher Dimensions and Shadow Universes
18:28 Emergent Time
22:38 Bubble Collisions and Multiverse Scars
24:44 Conclusion: What Came Before Time?

Gravity Tech: The Power To Reshape Our Civilization... And The Cosmos Themselves

Isaac Arthur

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