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.

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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?

Interstellar travel may one day take us to the stars, but surviving the journey could be the greatest challenge humanity has ever faced. In this episode, we explore the physical, psychological, and societal trials of a voyage that could span centuries—or forever.

Watch my exclusive video Fishbowl Starships - Water As Shielding - https://nebula.tv/videos/isaacarthur-fishbowl-starships-water-as-shielding
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Credits:
Interstellar Travel: Can We Survive The Long Journey?
Episode 724; June 12, 2025
Written, Produced & Narrated by: Isaac Arthur
Graphics:
Bryan Versteeg
Jarred Eagley
Jeremy Jozwik
Melanvois
Udo Schroeter
Select imagery/video supplied by Getty Images 
Music Courtesy of Epidemic Sound http://epidemicsound.com/creator
Chris Zabriskie, "Unfoldment, Revealment", "A New Day in a New Sector", "Oxygen Garden", "Wonder Cycle"
Stellardrone, "Red Giant", "Billions and Billions"

Interstellar Travel: Can We Survive the Long Journey?

Could we sculpt dead planets into living worlds? From artificial crusts and orbital mirrors to taming tectonics and engineering biospheres, this is your definitive guide to turning alien rocks into second Earths.

Watch my exclusive video Fishbowl Starships - Water As Shielding - https://nebula.tv/videos/isaacarthur-fishbowl-starships-water-as-shielding
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Credits:
Interstellar Travel: Can We Survive The Long Journey?
Episode 725; June 15, 2025
Written, Produced & Narrated by: Isaac Arthur
Graphics:
Jarred Eagley
Jeremy Jozwik
Ken York YD Visual
Mafic Studios
Sergio Botero
Select imagery/video supplied by Getty Images 
Music Courtesy of Epidemic Sound http://epidemicsound.com/creator
Chris Zabriskie, "Unfoldment, Revealment", "A New Day in a New Sector", "Oxygen Garden", "Wonder Cycle"
Kai Engel, "Endless Story About Sun and Moon"
Taras Harkavyi, "Alpha and..."
Dark Future, "Staring Through" pt1
Miguel Johnson. "The Commanders", "Far From Home"
Lombus, "Hydrogen Sonata", "Cosmic Soup"
Aerium, "Deijocht"
Stellardrone, "Red Giant", "Solar Eclipse", "Billions and Billions"

The Terraforming Compendium - From Barren Rocks to Living Worlds (Narration Only)

Space is big—but could life out there be even bigger? Join us as we ask just how enormous alien life can get—and what it might look like.



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Credits:

Cosmic Megafauna - Could Giant Alien Life Forms Exist?

Episode 727; June 22, 2025

Written, Produced & Narrated by: Isaac Arthur

Select imagery/video supplied by Getty Images 

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

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

Cosmic Megafauna - Could Giant Alien Life Forms Exist? (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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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)

Explore the real economics of building and operating a space elevator—from ship-launched ribbons to megaton climbers—and how this infrastructure could change the world.

Watch my exclusive video Fishbowl Starships - Water As Shielding - https://nebula.tv/videos/isaacarthur-fishbowl-starships-water-as-shielding
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Credits:
Space Elevator Economics: Building And Operating A Superhighway To Space 
Episode 726; June 19, 2025
Written, Produced & Narrated by: Isaac Arthur
Edited by:
Adrian Nixon
Ludwig Luska
Peter Swan
Graphics:
Anthrofuturism
Atlantis Project
Katie Byrne
Phil Swan
Sergio Botero
Udo Schroeter
Select imagery/video supplied by Getty Images 
Music Courtesy of Epidemic Sound http://epidemicsound.com/creator
Chris Zabriskie, "Unfoldment, Revealment", "A New Day in a New Sector"
Aerium, "Deijocht"
Stellardrone, "Red Giant", "Billions and Billions"
Lombus, "Hydrogen Sonata", "Cosmic Soup"

Space Elevator Economics - Building And Operating A Superhighway To Space (Narration Only)

Space Elevator Economics - Building And Operating A Superhighway To Space

Space colonization isn't about abandoning Earth—it's about transforming it. Discover how expanding into space can drive innovation, sustainability, and prosperity right here on the ground.

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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Credits:
How Colonizing Space Benefits Earth: The Ground-Level Gains of a Galactic Future
Episode 726.1; June 22, 2025
Written, Produced & Narrated by: Isaac Arthur
Graphics: Bryan Versteeg, Jeremy Jozwik, Sergio Botero
Select imagery/video supplied by Getty Images 
Music Courtesy of Epidemic Sound http://epidemicsound.com/creator

How Colonizing Space Benefits Earth - The Ground-Level Gains of a Galactic Future (Narration Only)

How Colonizing Space Benefits Earth - The Ground-Level Gains of a Galactic Future

From quantum tunneling to cosmic inflation, we journey through the theories behind the Big Bang and beyond — and ask the big question: could another Big Bang be in our cosmic future?

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Credits:
Could We See a Second Big Bang?
Episode 724.1; June 10, 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
1:59 Why Did the Big Bang Happen?
3:01 Quantum Fluctuations
5:20 Inflation and False Vacuum Decay
7:56 Cyclic Models and the Ekpyrotic Universe
9:43 Big Bounce Cosmology 
12:35 Tunneling from Nothing 
14:04 Beginnings, Endings, and Echoes

Could We See a Second Big Bang?

Everyone talks about terraforming Mars, but Venus might be the real prize. Discover the surprising ways we could cool, reshape, and colonize this hostile world.

Any comments, corrections, or thoughts on the video? email Isaac.Arthur.Utube@gmail.com
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Credits:
How Hard Would It Be to Terraform Venus?
June 17, 2025; Episode 725.1
Written, Produced & Narrated by: Isaac Arthur
Graphics:
Ken York
Mafic Studios
Sergio Botero
Select imagery/video supplied by Getty Images 
Music Courtesy of Epidemic Sound http://epidemicsound.com/creator

How Hard WouldIt Be to Terraform Venus?

Isaac Arthur