The Megastructure Compendium

In the future humanity may build enormous structures, feats of mega-engineering that may rival planets or even be of greater scope. This episode catalogs roughly 100 major types of Megastructure, from those that are cities in space to those that rival galaxies.
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▬ Megastructure Index ▬▬▬▬▬▬▬▬▬▬
0:00 - Intro
03:23 - Active Support
04:30 - Alderson Disc
08:30 - Arcology Megatower
09:48 - Arkship
10:49 - Artificial Sun
11:49 - Asteroid Colonies
13:02 - Atlas Pillars
14:19 - Banks Orbital
16:29 - Bernal Sphere
17:34 - Birch Planet
20:48 - Bishop Ring
22:55 - Black Hole Gravity Generator
23:54 - Black Hole Power Generator
25:40 - Bubble Hab
26:36 - Buckyhabs
28:12 - BWC Megastructures
29:08 - Caplan Thruster
29:46 - Carbon Nanotubes
30:31 - Chainworlds
31:07 - Chandelier Cities
31:45 - Clarketech
32:30 - Cube Worlds
33:24 - Cylinder Habitat
36:09 - Dark Sky Station
36:37 - Disc Worlds & Flat Earths
38:01 - Dyson Spheres
40:04 - Dyson Spike
40:45 - Dyson Swarm
42:14 - Ecumenopolis
42:44 - Edersphere/Ederworld
43:52 - Fusion Candle
44:29 - Graphene
44:49 - Grav Plating
45:20 - Hammer Hab
45:48 - Helios Drive
46:43 - Hoop World or Donut World
47:27 - Hydroshell
48:13 - Interstellar Black Hole Highway
48:48 - Interstellar Laser Highway
50:06 - Jenkins Swarm
50:27 - Kalpana 1
51:28 - Kipping Terrascope
52:08 - Lagite
52:57 - Lofstrom Loop
53:52 - Magmatter
54:50 - Matrioshka Brain
56:45 - Matrioshka Shellworld
57:53 - McKendree Cylinder
58:36 - Megatelescope Arrays
59:25 - Mini Earth
1:00:30 - Mushroom Habitat
1:01:26 - Neptunian Chainsaw
1:01:55 - Nicoll-Dyson Beam
1:02:52 - Nova Drive
1:03:16 - O'Neill Cylinder
1:03:57 - Orbital Plates
1:04:42 - Orbital Ring
1:07:22 - Paperclip Maximizer & Grey Goo
1:08:26 - Parabolic Habitat
1:10:08 - Planet Brain / Jupiter Brain
1:10:35 - Planet Ships
1:11:25 - Planet Swarm
1:12:21 - Planetary Cycler/Aldrin Cycler
1:13:10 - Power Beamers
1:13:55 - Quasar drive
1:15:25 - Quasite
1:16:00 - Red Globular Cluster
1:17:14 - Relativistic Kill Missile
1:17:55 - Ribbon Worlds
1:19:12 - Ring Habitat
1:20:06 - Ringworld
1:21:36 - Rotacity or Bowl Hab
1:22:19 - Rungworld
1:23:25 - Shell World
1:24:53 - Shkadov Thrusters
1:25:37 - Sky Cities & Cloud Cities
1:26:38 - Skyhooks
1:27:24 - Smoke Ring
1:28:26 - Solar Mirrors
1:29:21 - Solar Shades
1:30:29 - Sombrero Planet
1:30:51 - Space Elevetors
1:32:18 - Space Farms
1:33:27 - Spin Gravity
1:34:05 - Space Towers
1:34:50 - Stanford Torus
1:35:45 - Starlifting
1:36:55 - Statite
1:38:31 - Stellar Pinwheel
1:39:00 - Stellaser
1:40:34 - Suntower
1:41:51 - Supramundane Worlds
1:42:57 - Terran Ring
1:43:58 - Topopolis
1:45:07 - Unobtainium
1:45:35 - Valley House
1:45:55 - World House
1:46:26 - Wormhole
1:53:00 - Credits
Credits:
The Megastructure Compendium
Science & Futurism with Isaac Arthur
Episode 346, June 9, 2022
Written & Produced by Isaac Arthur
Narrated by Isaac Arthur & Sarah Fowler Arthur
Editors:
David McFarlane
Graeme Kilshaw
Sarah Fowler Arthur
Sig’unnr’s Deluge
Cover Art:
Jakub Grygier www.artstation.com/jakub_grygier
Graphics:
Bryan Versteeg
Fishy Tree
Jarred Eagley
Jeremy Jozwik www.artstation.com/zeuxis_of_losdiajana
Justin Dixon
Katie Byrne
Ken York Ken York of YD Visual YDVisual/
Mafic Studios
Mike Munt (Apogii)
Rapid Thrash
Sergio Botero www.artstation.com/sboterod?fref=gcJarred Eagley
Stephen Huck
Steve Bowers
Udo Schroeter
Music Courtesy of Epidemic Sound epidemicsound.com/creator

[@isaacarthurSFIA]

▬ Megastructure Index for this Episode ▬▬▬▬▬▬▬▬▬▬ 0:00 - Intro 03:23 - Active Support 04:30 - Alderson Disc 08:30 - Arcology Megatower 09:48 - Arkship 10:49 - Artificial Sun 11:49 - Asteroid Colonies 13:02 - Atlas Pillars 14:19 - Banks Orbital 16:29 - Bernal Sphere 17:34 - Birch Planet 20:48 - Bishop Ring 22:55 - Black Hole Gravity Generator 23:54 - Black Hole Power Generator 25:40 - Bubble Hab 26:36 - Buckyhabs 28:12 - BWC Megastructures 29:08 - Caplan Thruster 29:46 - Carbon Nanotubes 30:31 - Chainworlds 31:07 - Chandelier Cities 31:45 - Clarketech 32:30 - Cube Worlds 33:24 - Cylinder Habitat 36:09 - Dark Sky Station 36:37 - Disc Worlds & Flat Earths 38:01 - Dyson Spheres 40:04 - Dyson Spike 40:45 - Dyson Swarm 42:14 - Ecumenopolis 42:44 - Edersphere/Ederworld 43:52 - Fusion Candle 44:29 - Graphene 44:49 - Grav Plating 45:20 - Hammer Hab 45:48 - Helios Drive 46:43 - Hoop World or Donut World 47:27 - Hydroshell 48:13 - Interstellar Black Hole Highway 48:48 - Interstellar Laser Highway 50:06 - Jenkins Swarm 50:27 - Kalpana 1 51:28 - Kipping Terrascope 52:08 - Lagite 52:57 - Lofstrom Loop 53:52 - Magmatter 54:50 - Matrioshka Brain 56:45 - Matrioshka Shellworld 57:53 - McKendree Cylinder 58:36 - Megatelescope Arrays 59:25 - Mini Earth 1:00:30 - Mushroom Habitat 1:01:26 - Neptunian Chainsaw 1:01:55 - Nicoll-Dyson Beam 1:02:52 - Nova Drive 1:03:16 - O'Neill Cylinder 1:03:57 - Orbital Plates 1:04:42 - Orbital Ring 1:07:22 - Paperclip Maximizer & Grey Goo 1:08:26 - Parabolic Habitat 1:10:08 - Planet Brain / Jupiter Brain 1:10:35 - Planet Ships 1:11:25 - Planet Swarm 1:12:21 - Planetary Cycler/Aldrin Cycler 1:13:10 - Power Beamers 1:13:55 - Quasar drive 1:15:25 - Quasite 1:16:00 - Red Globular Cluster 1:17:14 - Relativistic Kill Missile 1:17:55 - Ribbon Worlds 1:19:12 - Ring Habitat 1:20:06 - Ringworld 1:21:36 - Rotacity or Bowl Hab 1:22:19 - Rungworld 1:23:25 - Shell World 1:24:53 - Shkadov Thrusters 1:25:37 - Sky Cities & Cloud Cities 1:26:38 - Skyhooks 1:27:24 - Smoke Ring 1:28:26 - Solar Mirrors 1:29:21 - Solar Shades 1:30:29 - Sombrero Planet 1:30:51 - Space Elevetors 1:32:18 - Space Farms 1:33:27 - Spin Gravity 1:34:05 - Space Towers 1:34:50 - Stanford Torus 1:35:45 - Starlifting 1:36:55 - Statite 1:38:31 - Stellar Pinwheel 1:39:00 - Stellaser 1:40:34 - Suntower 1:41:51 - Supramundane Worlds 1:42:57 - Terran Ring 1:43:58 - Topopolis 1:45:07 - Unobtainium 1:45:35 - Valley House 1:45:55 - World House 1:46:26 - Wormhole 1:53:00 - Credits

[@adamcaillouette7375]

Do you think that sun should seem relatively the same in regards to size and brightness by the year 10,000 AD? I just really want so definite confirmation so that humanity still has plenty of time to advance into space, while also spending time on Earth. Of course, I'm sure that'll all start not long after my lifetime is up, which will be 2100 AD or sooner.

[@achtsekundenfurz7876]

@@adamcaillouette7375 According to current science, the sun will slowly increase in brightness, which will affect temperatures on the planets in the far future, but the rate of change is very slow. Current estimates claim that Earth will become too hot for life in a little less than a billion years, and unsuitable for big lifeforms like humans in a few hundred million years. Taking these data, we can say that there should be significant change within 10 million years, but that's still 1000 times the time scale you're looking at. That doesn't take human technology into account either. Someone claimed that at the rates we've been launching satellites during the last 60 years, these alone should be enough to shadow Earth partially and offset the effect completely, assuming that the # of launches keeps increasing linearly. If we start doing it on purpose, we can do _much_ better (but not enough to offset greenhouse effect, which is increasing more rapidly. xkcd.com/1732/ ).

[@adamcaillouette7375]

@@achtsekundenfurz7876 Well, at least we know that humanity has time to advance into space. I mean, have you read about current space-related projects lately? Such as the warp drive that only requires solving the mysteries of dark matter left to complete?

[@adamcaillouette7375]

@@achtsekundenfurz7876 Also, we both know that the world is trying to work on projects that will counter climate change.

[@adamcaillouette7375]

@@achtsekundenfurz7876 At least it's nice to know that we'll still have winters with snow for at least thousands of more years. Hey, maybe when space colonies become more frequent beyond my lifetime, they'll be able to simulate frigid cold winters.

[@barryon8706]

Something very like an Alderson disk might be more easily accomplished by supporting it on the backs of several rather large elephants, with the elephants in turn atop a turtle of unusual size.

[@isaacarthurSFIA]

I miss Pratchett :)

[@darkpixel1128]

Ah, but is the turtle male or female? These are the important questions

[@charlesrockafellor4200]

Yes, but should there be four elephants - or _five_ ?

[@UnitSe7en]

...It's a better explanation for The Big Bang.

[@BurnDoubt]

Can we stack a few Turtles on top of each other, just for the sake of it being Turtles All The Way Down

[@dudebromcfrattington6488]

My favorite things that Isaac believes: -Planets are just giant cosmic Lego blocks -A positive outlook of humanity’s future -Humans are physically incapable of going an hour without eating or drinking

[@jaimebibelot4398]

That last one is a bit suspicious

[@MySpottyGirlfriend]

gotta be positive, otherwise what's the point?

[@Embassy_of_Jupiter]

@@jaimebibelot4398 Isn't that just diabetes?

[@jamieisausername]

@@MySpottyGirlfriend "Nothing great was ever achieved without enthusiasm" - Ralph Waldo Emerson

[@carl8703]

I've said it before, but I wouldn't mind seeing a "Shit Isaac Arthur Says" compendium, either.

[@DicePunk]

This compilation is exactly what I need to binge now I'm writing lore.

[@twenty-fifth420]

I think I am personally done with that step and just ready to write overall, but I also use Isaac as ASMR to keep me calm writing in general. It is poetically soothing lol.

[@HandlesAreStupid11]

@@twenty-fifth420 I listen to these videos while i write code lol, it’s so relaxing

[@Inertia888]

I was in the middle of pulling my hair out, with a project that I am hitting a wall with. And then I find this video, and I am calm as can be. Ready to get back to work without losing my mind. This channel is the best!

[@sciencerscientifico310]

True

[@thaneoflions975]

Learn how commas work👎🏽

[@Embassy_of_Jupiter]

I've taken it for granted recently, that I can make almost any wild and wacky world/universe or scifi/fantasy concept work within the known laws of physics, having completely forgotten that I entirely learned it from you. So thank you for that! It's like being handed fire from the gods

[@spencervance8484]

You do remember what the gods did to individuals who stole fire from the gods to give to humans. Isaac needs protection

[@sponge1234ify]

@@spencervance8484 Hence the Nebula partnership and CuriousityStream bundle. Goddess KZbin won't harm our precious Issac

[@spencervance8484]

@@sponge1234ify interesting

[@nutyyyy]

Same. There's so much info and ideas I've absorbed over the years from this channel and a few others.

[@Pyxis10]

@@nutyyyy A few others?

[@orionspur]

Compared to the largest megastructures, the smaller ones are little more than a torus attraction.

[@sciencerscientifico310]

Haha!

[@Moridorable]

Oh, you.

[@sebastianszejna8119]

bruh💀

[@SAVikingSA]

@@Moridorable Oh, Neill

[@endeyfire]

i see what u did there :)

[@leeroyjames7463]

When you've waited in anticipation, and it arrives. Sir - I have no doubt that this will be glorious.

[@leeroyjames7463]

Sarah's voice so well compliments yours. I love this format.

[@rexmann1984]

Omg two hours 😍🤩

[@stevesmith1810]

absolutely phenomenal, everyone involved should be incredibly proud of this one. This will go down as one of the best sci-fi world-building resources on youtube. Thank you so much for doing this!

[@isaacarthurSFIA]

You're very welcome :) It was a lot of work but fun to do too

[@upandready4u]

I whole heartedly agree just finished my second time through

[@dmsteiner1991]

​@@isaacarthurSFIA e

[@thahbiaasad7]

It’s very exciting. Cool to say the least.

[@thedoruk6324]

An entire complication ! Sir Arthur spoils us! Hopefully gigastructural engineering could take opinions for another batch from this awesome list

[@A_Spec]

Thank you for rekindling my love for Megastructures Isaac. I've been watching for many years and it's been a pleasure to be on this journey with you.

[@CheeseWheelEnthusiast]

Now only if someone made an updated Gigastructures mod with every one of these megastructures included. That would be quite the project.

[@coffeenator3219]

Now time to play some stellaris 😂

[@isaacarthurSFIA]

Arthur's Note: This is our first video doing a chapter index but since there's around 100 entries I intentionally didn't do them all, not really wanting to spend the time for something I was worried it might make the index too crowded if they were all there. If anyone wants to do a full index I would paste it in. Here's the current one, that's all the formatting required, time stamp and Title (hh:mm:ss - EntryName) ▬ Megastructure Index (Not all entries included) ▬▬▬▬▬▬▬▬▬▬ 0:00 - Intro 2:06 - 101 Alphabetically-Organized Megastructures 03:23 - Active Support 04:30 - Alderson Disc 08:30 - Arcology Megatower 13:02 - Atlas Pillars 17:34 - Birch Planet 20:48 - Bishop Ring 23:54 - Black Hole Power Generator 26:36 - Buckyhabs 30:31 - Chainworlds 31:07 - Chandelier Cities 32:30 - Cube Worlds 33:24 - Cylinder Habitat 36:37 - Disc Worlds & Flat Earths 40:45 - Dyson Swarm 45:20 - Hammer Hab 46:43 - Hoop World or Donut World 48:13 - Interstellar Black Hole Highway 48:48 - Interstellar Laser Highway 53:52 - Magmatter 54:50 - Matrioshka Brain 56:45 - Matrioshka Shellworld 1:01:26 - Neptunian Chainsaw 1:03:57 - Orbital Plates 1:10:08 - Planet Brain / Jupiter Brain 1:11:25 - Planet Swarm 1:13:55 - Quasar drive 1:17:14 - Relativistic Kill Missile 1:20:06 - Ringworld 1:22:19 - Rungworld 1:25:37 - Sky Cities & Cloud Cities 1:27:24 - Smoke Ring 1:32:18 - Space Farms 1:39:00 - Stellaser 1:43:58 - Topopolis 1:46:26 - Wormhole 1:53:00 - Credits

[@UbugUnman]

Alright I'll do it. Here's the list of entries that was not indexed (I think I got them all): 9:48 - Arkship 10:49 - Artificial Sun 11:49 - Asteriod Colonies 14:19 - Banks Orbital 16:29 - Bernal Sphere 22:55 - Black Hole Gravity Generetor 25:40 - Bubble Hab 28:12 - BWC Megastructures 29:08 - Caplan Thruster 29:46 - Carbon Nanotubes 31:45 - Clarketech 36:09 - Dark Sky Station 38:01 - Dyson Spheres 40:04 - Dyson Spike 42:14 - Ecumenopolis 42:44 - Edersphere/Ederworld 43:52 - Fusion Candle 44:29 - Graphene 44:49 - Grav Plating 45:48 - Helios Drive 47:27 - Hydroshell 50:06 - Jenkins Swarm 50:27 - Kalpana 1 52:08 - Lagite 52:57 - Lofstrom Loop 57:53 - McKendree Cylinder 58:36 - Megatelescope Arrays 59:25 - Mini Earth 1:00:30 - Mushroom Habitat 1:01:55 - Nicoll-Dyson Beam 1:02:52 - Nova Drive 1:03:16 - O'Neill Cylinder 1:04:42 - Orbital Ring 1:07:22 - Paperclip Maximizer & Grey Goo 1:08:26 - Parabolic Habitat 1:10:35 - Planet Ships 1:12:21 - Planetary Cycler/Aldrin Cycler 1:13:10 - Power Beamers 1:15:25 - Quasite 1:16:00 - Red Globular Cluster 1:17:55 - Ribbon Worlds 1:19:12 - Ring Habitat 1:21:36 - Rotacity or Bowl Hab 1:23:25 - Shell World 1:24:53 - Shkadov Thrusters 1:26:38 - Skyhooks 1:28:26 - Solar Mirrors 1:29:21 - Solar Shades 1:30:29 - Sombrero Planet 1:30:51 - Space Elevetors 1:33:27 - Spin Gravity 1:34:05 - Space Towers 1:34:50 - Stanford Torus 1:35:45 - Starlifting 1:36:55 - Statite 1:38:31 - Stellar Pinwheel 1:40:34 - Suntower 1:41:51 - Supramundane Worlds 1:42:57 - Terran Ring 1:45:07 - Unobtainium 1:45:35 - Valley House 1:45:55 - World House

[@bobsterclause342]

15:00-17:00 all I can hear os gregorian chant. Oh, the guitar rift is starting up now, oh yeah.

[@extropiantranshuman]

it actually was really helpful to not chapter all of them - as it makes flipping through all the chapters go by much faster via a remote control!

[@extropiantranshuman]

@@UbugUnman that's what peeps are for, thanks!

[@extropiantranshuman]

I think the issue isn't the lack of chapter indices - it's a lack of entries lol. There are just so many megastructures - to fit them into one video is crazy - and this one took 2 hours. Imagine if all of them were truly added in - like the whole alien, astronomical (like orbital), and time ones - big rip civilizations, space outposts, galactic disasters, virtual worlds, etc. not to mention all the episodes not done yet! For its length, it needs a part 2! If we think chapter indices are bad, it would get convoluted with a series! Still - I really can't wait for a part 2 - this one was awesome! I actually see (hypothetically speaking of course - as it doesn't have to be created) a part 2 just for digitization/virtualization/atomization/quantum-time allowances alone, part 3 being an alien one - like multi-species empires!

[@EddyA1337]

I've been here since that first episode, subbed back in 2017. You made me start thinking differently Isaac, about questions big and small. I'm happy to have your content and it's been very joyful seeing you get married and such. Thanks for letting us in to your lives.

[@Inertia888]

It has been quite a long and wonderful road...

[@captainhakob814]

I w had a lot of snacks

[@CockatooDude]

I have to agree, Isaac Arthur has completely changed the way I think about the world, the universe, and humanity's future.

[@tite93]

Can't even fathom how amazing it would be for humanity to one day discover something like this in our galaxy. Derelict or not

[@Zurround]

We won't. Structures like this would be so rare throughout the trillions of galaxies in our universe that finding one in OUR galaxy would be like winning the lottery.

[@MrNote-lz7lh]

@@Zurround Really? I'd imagine if you find one you'd find countless others in the nearby solar systems. But yes. I bet humans are the only intelligent species in our Galaxy.

[@jaydrianpieters7718]

@@MrNote-lz7lh *currently

[@Zurround]

@@MrNote-lz7lh It takes more than "intelligence" to build a megastructure like that. A species would have to be as far ahead of us in technology as we are ahead of the neanderthals. And I believe that intelligence of at least human level is very rare in the cosmos. Our world has only had it for a VERY VERY TINY percentage of its 4.5 billion years of life evolution. I believe that almost all planets with life have plants and animals but no life forms with the intelligence necessary to create technology and only a very tiny percentage of those worlds would ever get advanced enough to make a cosmic level megastructure like a Dyson's sphere.

[@kayakMike1000]

@@MrNote-lz7lh i'm not yet convinced humans are intelligent.

[@dustaone8521]

I remember listening back when you first suggested these ideas. I've followed since and watched you guys get married. Now youre presenting the show together and the animation and narration is insane. Thanks Sarah! (and Isaac I guess) :)

[@stevesmith1810]

I've been waiting for this for so long...Sarah, you did a fantastic job on this! Thank you both so much for redoing this incredible episode!

[@ryleyreishus1089]

I'm glad you did this. Your old megastructure series is my favorite thing on the channel

[@linz8291]

lol...looking forward to the newer megastructure series and habitable extroplanets 😁

[@therocinante3443]

Megastructures are what made me discover this channel. It's nice to see this compilation :)

[@MantraHerbInchSin]

Same here, and to this day it's the content I like the most. Gigant stuff in space trumps most other things!

[@ponyote]

Really nice to hear Sarah presenting for this. Yall make a good team.

[@defective6811]

My man, I've grown to love your voice and have enjoyed listening to it for years and years now. Here is to many more, and perhaps a conceptual gigastructure series sometime in the future

[@scottbruner9987]

Issac, I remember finding your channel about two years ago, on accident. The first thing I noticed was your speech. I loved it from the beginning. I've also been amazed at how much I learn here. I've even taken several recommendations of audio books from authors you mentioned. With you, looking to the stars, hoping we aren't alone.

[@ajakethompson]

26:58 I think you meant "carbon-60 molecule" or "60 carbon molecule" not atom. Allotrope works too. It's a small error but it did make me think twice about it so I thought I'd mention it. Love the channel!! It always puts me in a good mood about the future.

[@aarushpruthi7184]

Was looking forward to this week's episode after you announced it during the conference. Yay!

[@jaimebibelot4398]

These kinds of comps are really useful for me so I'm quite happy with this!

[@Everthus4]

Modern western sf: one ship, one captain, sometimes he finds two legged aliens that looks like human with some make up. Isaac Arthur: What if we move planets

[@sidpomy]

Sarah makes for an excellent narrator! Great voice for it. So glad to see this redone - I’m sure it was an enormous amount of work, and much appreciated.

[@orionspur]

I note large habitats are neatly classified by their intended population: * space station: 1 - 1,000 / various * kilo-structure: 1,000 - 1M / torus * mega-structure: 1M - 1B / cylinder * giga-structure: 1B - 1T / ring * tera-structure: 1T or more / swarm or shell I also note that other than as a "JBWC" novelty, bigger is not better. Walkable small towns of 100,000 people are very pleasant, manageable places to live. As long as transit between habitats is quick and easy, there is little reason to build any single habitat bigger than a 10km diameter torus. There's plenty of material in our local asteroids to build a swarm of billions of these, each specialized to whatever function makes the most sense, and with total habitable space over 1000 times the surface area of Earth and Mars. To expand into the galaxy, just shove flotillas of 1,000 habitats each on an intercept course with two nearby systems that have plenty of asteroids to mine. The trip will take a very long time, but it will at least be comfortable. Now repeat to populate the entire galaxy.

[@austin3600]

Been very excited for this episode. Also, your wife did a great job narrating

[@DAG_42]

This is an excellent resource for writers, designers, and creators of other sorts!! Not to mention it's educating me, a long time listener who needed some clarification on a few topics

[@joelmulder]

I’ve seen the original video many times, but I’m so happy to finally see the reboot of this classic! Long format is best format! Also, Sarah’s narration is really good!

[@patrickmchargue7122]

Definitely a snack-worthy episode. Thank you for the compendium, and nice use of tag-team narration.

[@LucasDimoveo]

This channel is a goldmine for sci-fi world building

[@spencervance8484]

Indeed

[@einbenutzenderbenutzer]

I love the positivity and optimism on this channel - its the same I try to convince everyone around me of All the time

[@shitrowersdo]

I just looked back, and the Eucemonopolis episode was the first one of your videos I watched(when it premiered!)! I can't believe how far the channel has come since I started watching and that it's been 5 years... This channel has changed and improved so much over the years, and your positive outlook of the future of humanity has definitely helped me suppress my inner skeptic. Keep doing what you do man, and I hope we see that clip of dino's eating imaginary leaves in the middle of the desert more often :P I only see it JMG's channel anymore! I only mention it because I made a comment about it once and felt so honored when you responded to me.

[@NathanTyph]

Been following this channel since its early years. I've been busy with college, so there have been stretches when I can't catch episodes, so it's always joy to return and be re-inspired by the amazing ideas here. Thank you Isaac and all for everything you do! ❤

[@jdiluigi]

Oh boy... This will replace quite a few videos in my end of day playlist. Thank you.

[@TheArtofFugue]

oh hell yes! almost 2 hours of SFIA this morning. what a great day!

[@meatsaucez1516]

Glad to see the return of clear structures in your videos.

[@npswm1314]

Issac Arthur: A couple hundred thousand years is a small amount of time for an advanced civilization. Also Issac Arthur: This is going to be a long time so get a drink and snack; Episode length: 38 minutes

[@spencervance8484]

There is a difference between civilization and the individual.

[@BierBart12]

I absolutely love flat planet megastructures like the Alderson Disc. A lot of funny conspiracy theories make for awesome science fiction concepts. The Concave Earth theory also spawned the Birch World gigastructure at 17:40. This is one of my favourites, as it's kind of the ultimate conclusion of what the Ringworld technology started. Besides what was mentioned in this vid, staying on the topic of conspiracy-inspired fiction, I also love the SCP wiki's take on the Mothman, where they are a species of reclusive extradimensional scavengers that can predict and feed off of natural disasters. They're very territorial and fight other Mothmen for territory(sometimes humans who are accidentally mistaken as threats). Also the 2 SCPs about the Ryugyong Hotel in North Korea(SCP-031 and SCP-1427), the latter is inspired by a real conspiracy theory that the hotel houses a mind-controlling radar array of sorts. The scp is a Beryllium Bronze block which transmits a long-range mental effect that makes people more submissive to authoritarian ideals, with some other, more dangerous effects that are dampened by the affected person already having an authoritarian mindset, so NK is the perfect place to contain it. The containment procedures for this one basically force the SCP foundation to prevent NK of ever stopping to be an authoritarian regime and opening up.

[@syndicatefive]

In this episode: we dream really really big and love Issac for delivering an amazing suspension of disbelief science fiction engineering lesson. 😊

[@yazaniragi6591]

glory to Isaac Arthur! the awaited one is here!

[@ramuk1933]

You should have mentioned Kurzgesagt's video on the Caplin Thruster when discussing it.

[@Imagine_Beyond]

Yes! Isaac Arthur barely talked about the caplan thruster in this episode and usually focuses on Shkadov thrusters instead

[@Andrew-zq3ip]

Hell yes. This is what I've been waiting for.

[@cascadia4105]

@Issac Arthur your megastructures episodes have always been my fav, this is a real treat. Thank you!!

[@Thoughtmage100]

This is such a treat to listen to while I go about my day. I love thinking about how humans might live generations from now, and the potential architecture and megastructures get my imagination going. Thank you both for this extra long video!

[@zey2bme]

I'm so excited for this!

[@InnocuousRemark]

Come on, guys. Let's build a Birch planet. We just need volunteers and some funding.

[@JohnBoen]

Wow. This represents a huge amount of work. I'm pretty confident that over the years I have seen them all. I have looked forward to Thursday mornings for years because of you. Great work.

[@Zieg777]

Thank you for this! I've been loving your channel for years and constantly refer people to your videos (whether they want me to or not)

[@justandrewthomas]

It's an incredible thing to get this for free... Thank you so very much, SFIA Team!

[@isaacarthurSFIA]

Our pleasure!

[@assemblyrequired7342]

As someone who has tried (and failed + put on the backburner) on trying to start a KZbin channel, I know full well that any help has it's weight of gold. Kudos to both you and Sarah. You two make a good team, and should consider future collabs if you haven't already done so!

[@CHmLgN]

Megastructures are my favorite avenue of theoretical science and watching this is just gonna be so so much fun. Big thanks to all involved for this one!

[@pegasusapollosson3747]

Jesus, this is a huge episode. Fitting subject!

[@spencervance8484]

A mega episode

[@charlesjmouse]

A two hour episode? Awesome! FWLIW: I've been watching this channel's videos since day one. While improved production values are nice it has always been the fantastic content that I am interested in and keep returning for. Also I can't say I have ever had trouble with comprehending your speech, Isaac. Keep up the good work.

[@Minotaur-ey2lg]

It took me a few videos to get used to the way you speak, but now I find it soothing. You, Luetin, and The Exploring series are often my lullabies.

[@AnimeSunglasses]

Gods, I love it here! 29:30 Where else could one hear phrases like "...a traditional Shakadov Thruster..."

[@kevinscott7292]

Great job, Sarah!! Y'all make one heck of a team!

[@VictorNiss]

I love that the wife is taking an interest and working on these with you!! Epic-tier relationship status! Sarah: Thank you for joining us! Your addition is awesome and welcomed. I've been watching Isaac Arthur since the beginning and love the growth and development. High quality content here. Thank you both!

[@extropiantranshuman]

has to be one of my favorite episodes. I really needed this video to get my head together - wrapping it around!

[@volcanoisland1895]

The thought and care that goes into these videos is incredible. They are my go-to if I need to get something done. They make it easy to be productive and that optimism and humour is contagious. Incredible video as always Isaac and crew.

[@christopherhughes2211]

YES! WooWho! Love me some megastructures! It’s so cool to hear the two of you. It’s really sweet and endearing 😊

[@boobah5643]

Larry Niven's "Larger Than Worlds" essay mentions one megastructure that's actually bigger than anything on this list. A Dyson shell around the galaxy. Most interesting is the low gravity and obscenely deep atmosphere if it's human habitable.

[@scientchahming5]

I'm assuming you're talking about a "birch world'', a Dyson sphere one or two light-years in diameter built around a supermassive black hole.

[@linz8291]

Dyson sphere is not advanced enough to explore space or as temporary interstellar stations. I mean Dyson sphere is belong to inter-solar civilization level, not galactic civilization level. We don't need too much this, but more advanced types.

[@chrisroberts1773]

Sara did an awesome job, and switching back and forth like that helped me keep focus.

[@DavidSmith-mt7tb]

Fantastic work as always, Isaac. Thanks for putting this together! The channel has come a long way. Looking forward to the future of SFIA.

[@red8884]

Thank you so much for this . Thank you for all the time and effort you put in your work. I enjoy every second of it.

[@exudeku]

Im literally playing Stellaris with the Gigastructures Engineering mod (Megastructures mod) and 3 of my construction ships are making Megastructures (a Nicol-Dyson Beam platform, a Yggdrasil Food Complex, and a S.U.C.C.), what a perfect coincidence!

[@Daltem]

Have you already got a Dyson and a star lifter?

[@exudeku]

@@Daltem yup, a Dyson in the Bernard Star for creds, and a Star Lifter is a random star for minerals. The Nicol Dyson is for "pacifying" the galactic community

[@connorsharp3570]

Great episode! Definitely going to listen to this again. Thank you both!

[@aarondyer.pianist]

What a fabulous compendium! I always come to this channel for quality content with no hype or agenda. I learned a lot of new things. First thing I watched of yours was space elevator, which has fascinated me since reading it in Arthur Clarke's 3001. Although I've heard so many reasons it might not be the best thing to try, it is still my favorite. P.S. Ecumenopolis is pronounced eh-kew-men-opolis, not yew-ka-men-opolis.

[@PhilosoFeed]

All this time I thought I was just getting used to your unique speech over the years. This is the first I'm realizing it has actually changed a lot.

[@byronnielsen8896]

Isaac produces such fantastic and binge-worthy content that I'm convinced economists will soon develop a drink and snack consumption model based on his release schedule.

[@Ratstail91]

I fell asleep listening to this, and dreamed I was sleeping over and my grandparent's house. Except their phone was playing the audio from this video. I couldn't figure out how to turn it off until I woke back up LOL

[@extropiantranshuman]

I love how you add where you get your inspiration from - so others can continue the intellectual journey - as videos are only just a blueprint and analysis of real world implications - it's up to us to actually decide what is right to build for our world and go do it :)

[@the_sage_of_dragons1881]

Notification gang!!

[@UnitSe7en]

Regarding cylinder worlds, one that is free-spinning in space will also be naturally unstable! It will flip end-over-end every so often. The free-floating concept is not a good idea.

[@blueredbrick]

Gives a new meaning to 'the flippening'

[@brian7android985]

That's a very flippant comment.

[@theOrionsarms]

This problem was addressed by O'Neil in his books, you pair two contrarotating cylinders and connect them with a tension tower at one end and a tensile cable at another, obviously you need to use some bearing to reduce friction. But one single cylinder spin stabilized also is possible if the mass distribution of the structure is chosed wise.

[@alketsadedinaj3011]

I open youtube and i see a THICK video. Thanks for the treat isaac. Good stuff as always

[@matthewdrum2961]

This is the best episode yet....I might be in love with megastructures. While I have never been bored with a SFIA episode, the Megastructures have always been among (but not my only) favorites.

[@MyJam]

Most of these violate known physics / material sciences. The rest would never be built due to politics, regulations, conflicts, little payoff or too long payoff, too much time / cost, or simply being incredibly impractical. None of these would happen but it's fun to think about at least.

[@gracefool]

Active structures make most of these physically possible. But yes to all the rest.

[@linz8291]

So you are suggest that we can go to the some extroplanets firstly to establish independent nations, and traveling as galactic members. Let them enjoy their own conflicts, we can developing our wonderful extroplanets and far away from chaos.

[@yamagishisan]

First!

[@jerrysstories711]

We told you to STOP using the time machine.

[@isaacarthurSFIA]

I'm gonna guess we'll have typos to fix anyway :)

[@del8359]

Nice 👍

[@BurnDoubt]

I can't believe you would cause another Mandela effect for a silly KZbin prank

[@luppo7189]

This video is amazing, and the channel itself is outstanding. Great work.

[@mugiwarated6319]

Just in time to go to bed! Well, one view to sleep to and one more tomorrow to go back and watch the entire thing.

[@marchernandezzz817]

I ended up staying up late because I have no work tomorrow and came across your channel again, it’s been awhile since I’ve watch anything and this long one is definitely a treat! It made me download my favorite civilization builder called “stellaris” where you choose your species and start the game with your first ship capable of FTL travel. You can work your way up the tech tree to become a at least a type 3 civilization and build huge mega/giga structures and work your way through tricky intergalactic politics or you can become a the emperor’s of the galaxy!!!!!!

[@kalinadog7176]

Wow I've always wanted a channel like yours to exist! I can't wait to dive into all your videos. Wow just wow thank you!!!

[@francoisjohnson6730]

You got to respect the ability to convey complex topics in such simplicity. Keep pushing boundaries @Issac Arthur!

[@krest5955]

Great episode! Grats to you, Sarah and the rest of the team for this!

[@Chrissweet1701]

I'm at a pool tournament right now, and listening to this. It's amazing how relaxing hearing you and your wife explaining this. I hope you have her voice on more. Keep up the amazing work.

[@prakadox]

Awesome episode!! Thanks a ton , Isaac and Sarah!

[@ericcloud1023]

I found your channel when you already had like a 150k subs, but even watching since the ball already started rolling I'm glad you're well on your way to a million subs! You definitely deserve it man, also it seems you have a wonderful family! Much love from Cali

[@AlecMuller]

Have you ever considered doing a survey episode on settlement-critical raw material abundance for the solar system's rocky bodies? For example, if a 1,000 person human settlement needs so many tons of C, H, N, Ca, P, K, for biology, buildings, and machinery, then what's the limiting element for potential settlements on the Lunar South Pole vs. Valles Marineris vs. Phobos vs. Ceres vs. Callisto vs. the clouds over Venus? Similarly, what useful elements will have an overabundance in each settlement site? (e.g. lunar magnesium, Venusian carbon).

[@isaacarthurSFIA]

It's come up but I get torn on the focus and format a bit

[@richardgreen7225]

Ran this a double speed to reduce it to ~ one hour. Audio is perfectly understandable at double speed. However, you might want to pause now and then to let a new concept sink in.

[@publicprofilename4273]

But, more importantly, I'm completely enthralled in your content! It's GREAT! The subjects you explore are right up my alley, and I'm very glad to have ran across this channel! Big time fan of everything I've watched thus far!

[@prestonirvin1209]

Seriously great job on the speech Therapy! You have come a long way! Keep it up because you are amazing at this!

[@Felenari]

Fantastic episode. Showed me some new designs I'd never heard of before. Thank you.

[@2creamy4you15]

Underrated video deserves millions of views for the work and effort put into this.

[@VeracityMedia]

I tear up everytime i watch one of your videos in on these topics. I took a break for a while and came back to this today and yet, time seems to be no measure of just how much your content still moves me. ~Cheers

[@BitcoinMeister]

Red Globular Cluster is an incredible concept that is simple enough for most anyone to understand! Brilliant on your part!

[@marktaylor6553]

Glad I discovered your channel (Subbed). I am developing an 'amalgam universe', combining a hundred or so different franchises together, and a lot of the 'tech stuff' I've been having to figure out on my own, but your channel is going to help a LOT moving forward. Thank you for making these videos. Cheers

[@liminal-ass]

Awesome work, this was wild!

[@specialfifteen4425]

You are definitely my favorite KZbinr and overall sci-fi/space guy mainly because of you positive outlook everytime I read a book or find a video it's mostly negative either megacorps, evil Ai, corrupt goverments but with I always come back around to being extremely hopeful for the future and unbelievably sad that I most likely won't be able to experience it

[@Maadhawk]

Haven't even started watching already giving this a like! I wish there were more compendiums on all kinds of things related to sci-fi and fantasy.

[@JepsDesign]

First time seen such incredible logically explained animations. This is an epic job you guys have done.🎉