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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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)

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
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
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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.



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

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Any comments, corrections, or thoughts on the video? email Isaac.Arthur.Utube@gmail.com

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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)

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

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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)

In-situ resource utilization (ISRU) is the key to building lasting colonies in space—by turning local materials into shelter, fuel, and even food. Explore how humanity might thrive beyond Earth by living off the land on other worlds.

Watch my exclusive video Fishbowl Starships - Water As Shielding - https://nebula.tv/videos/isaacarthur-fishbowl-starships-water-as-shielding
Get Nebula using my link for 40% off an annual subscription: https://go.nebula.tv/isaacarthur
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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

Chapters:
0:00 Intro
3:20 Shelter
11:06 Extraction of Volatiles
13:45 Regolith Processing
16:55 Energy Production
18:19 Manufacturing and Construction
20:24 Agriculture
23:40 Propellant Production
26:25 Starlifting

ISRU: In-Situ Resource Utilization - From Regolith to Rocket Fuel (Narration Only)

From Martians undone by germs to predators who insist on sporting duels, we explore the most ridiculous alien invasion tactics in fiction, and what they reveal about strategy, science, and human resilience.

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.
Visit our Website: http://www.isaacarthur.net
Join Nebula: https://go.nebula.tv/isaacarthur
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SFIA Discord Server: https://discord.gg/53GAShE
Credits:
The 10 Worst Alien Invasion Strategies
Episode 733; July 1, 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
0:48 10. The “Park and Wait” Strategy
2:02 9. Invading a Planet That Can Kill You
3:46 8. Single Point of Failure: The Hive or Control Ship
5:22 7. Telegraphing Your Arrival
6:50 6. Overly Convoluted Takeovers
8:30 5. Broadcasting Your Weakness
9:55 4. Playing Fair & Ritual Combat
11:54 3. Overconfidence & Underestimating the Locals
13:07 2. Hive Minds That Collapse Instantly
15:03 1. Ignoring the Home Field Advantage
16:06 Outro

The 10 Worst Alien Invasion Strategies (Narration Only)

If everything is free, what’s still worth striving for? From replicators to reputation, we examine the surprising economics of a post-scarcity world.
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Credits:
The Economics of a Post-Scarcity Universe - What Happens When Everything Is Free?
Episode 730; July 3, 2025
Written, Produced & Narrated by: Isaac Arthur
Select imagery/video supplied by Getty Images 
Music Courtesy of Epidemic Sound http://epidemicsound.com/creator
Chapters
0:00 Intro
2:02 What Post-Scarcity Means Economically
5:10 Incentives Without Scarcity
8:17 Distribution, Duty, and Designed Idleness
14:27 Ownership and Property in a Post-Scarcity Economy
20:03 The Star Trek Economy & the Myth of a Moneyless Society
22:58 Wealth, Inheritance & Intergenerational Power
27:57 Upward Mobility and Inequality
29:02 Economic Failure Modes in Post-Scarcity
30:35 Where Economics Still Matters
33:02 The Infinite Price of a Meaningful Life

The Economics of a Post-Scarcity Universe - What Happens When Everything Is Free? (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
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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
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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)

Transhumanism promises a better humanity—or perhaps something no longer human at all. Join us as we explore the moral dilemmas and future paths of human augmentation.

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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SFIA Discord Server: https://discord.gg/53GAShE
Credits:
How Would Aliens Behave?
July 13, 2025; Episode 732
Written, Produced & Narrated by: Isaac Arthur
Editor: Donagh Broderick
Select imagery/video supplied by Getty Images 
Music Courtesy of Epidemic Sound http://epidemicsound.com/creator
Stellardrone, "Red Giant", "Billions and Billions"
Taras Harkavyi, "Alpha and..."

The Ethics of Transhumanism (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
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
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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?