If you have unobtanium, sure. The problem with unobtainum is that as soon as you get some, it becomes obtainedit.

The notion of a habitable world orbiting a gas giant was explored in depth by Robert Sawyer's 'Quintaglio' books. The fact that the main continent was always pointed away from the gas giant let to a major plot point of what happened when explorers traveled to the far side of the moon for the first time, and discovered this gigantic object in the sky, which became their god.

I lived in Alaska for 23 years, and one of the best auroras I've ever witnessed had green, blue, violet, red, and white in it. And it really danced (meaning it moved and jumped around quickly. Some auroras just slowly drift by.) We even caught this on camera. Absolutely breathtaking.

There isn't enough surface area on the top of the floating mountains to collect enough rain to feed the waterfalls.

If astronomers confirm that there is a gas giant orbiting Alpha Centauri, I hope they name it Polyphemus.

If Pandora had a very short orbital period around Polyphemus, then it would be deep in the radiation belt. Better if it's more like Callisto's distance from Jupiter. But what sci-fi maker can resist close-ups of a gas giant? Cameron deserves a medal for restraint in not giving Polyphemus unrealistic rings. I think of the floating mountains like the giant wave in Interstellar - a scientifically implausible liberty taken because it's awesome in a movie that otherwise tries to ground itself in the possible. Ditto the giant tree.

Cameron has already revealed the main antagonist of the next film will be a fire tribe of na'vi similar to how there were water tribes in the latest film. If Pandora is tidally locked I'm fascinated by a possibility that there could be a "twilight" tribe that lives in this eternal darkness. A cinematic challenge no doubt

In China, Avatar 2 was surpassed by a local Chinese sci-fi epic called The Wandering Earth 2. I find it quite curious that both films deal with Alpha Centauri as the main target for human survival, and reflect on the limits of today's technology.

I really love the point you brought up about tribes on one side not even knowing they orbit a gas giant.

I'm a sucker for speculative biology so Pandora's ecosystem with the lands and creatures is what hooked me in the first place.

Now that I've watched the whole video, I'm glad you touched on the aurora. That would be an indicator that Pandora has a magnetic field. Given that it is rich in superconducting minerals, this would only serve to enhance the magnetosphere of the planet. It makes sense that it would have one powerful enough to protect from the radiation belt.

I could watch hours of just fictional documentaries set on pandora. The human conflict is something i oersonally would cut in favor of telling Navi Stories.

I add to the floating mountains as a possibility that they AREN'T non-living chunks of rock in the air, but a living organism that has other tiny organisms controlling it entirely similar to coral, they create billions of air sacs that help keep the organism afloat, and the surface of the organism looks like rock because of it's peculiar armor that it uses for defense and camoflauge. I speculate these organisms are preyed on by flying creatures that favor the tiny organisms that create the air sacs, and to protect themselves, they'll sometimes lower themselves down to the surface so that they can blend in with the mountainous regions they hail from.

These avatar movies are different than just normal movies imo, they are more an experience and an escape from everything and i absolutely love them, especially at the cinema. Can't wait for the future avatar movies.

I would love a video about The Expanse. Imho it is a very possible future - at least the technology and the story of colonizing on mars and the belt.

Next tackle How Realistic Is the World of Three Body Problem by Liu Cixin

I love Avatar but had no idea it was based in the Alpha star system. Thats awesome

Based on the changing position of Polyhemus in the sky during both movies, Pandora is not tidaly locked. Sometimes we see it high in the sky, sometimes just touching the horizon, and a few times intersecting it.

One interesting issue regarding a tidally locked moon (which would be almost all moons in most star systems) would be that there would be a higher prevalence of the night and twilight compared to light day. This is not necessarily a bad thing, on the contrary: The gas giant would shelter and act as a shield, diminishing the amount of harmful radiation that could reach from the star. Also, as the star development during millions of years increases the amount of radiation and heat, the moon would be able to adapt much easily than a planet to such changing conditions, thus protecting life.

I've wondered about the factor of the Roche limit. A body of given size/density, if located within the Roche limit of the parent body it orbits, will be torn apart by tidal stress. This is the cause of Saturn's ring system. Visually it seems possible that Pandora might be too close to remain intact.

The dumbest part is unobtanium. Not the properties, but the name... Unobtanium? reallt Cameron was MacGuffin-ite already trademarked?

Very good vid. I have to point out though that oxygen is not why dinosaurs got as big as they did. A combination of hollow bones, efficient breathing and egg laying. During some periods oxygen was actually lower, yet dinosaurs still remained large. Although this is just a nitpick. Again great video

I'm just a major fan of anything bioluminescence, which made me fall in love with the world of Pandora very quickly . I just wonder how likely it is for planets dominated with bioluminescent life to exist out there.

I would like to see the science of a plant based neural link to animals and restoring consciousness via its connections too. Supposedly there was an intense battle scene he cut from the movie because of current world events and violence but I bet it was stellar, hope its in the extended cut.

As a Communications Engineering graduate, I found this video extremely interesting. The technology itself was astounding and the explanations were outstanding. Such videos would have been very helpful in my student life.

12:42 Not plausible either, if those mountains were filled with unobtanium, then there’s no reason they try to take down the large tree. They could’ve just mine the floating mountains

They went to all that effort for the world building and then made a plot that was pretty awful and badguys who were more two dimensional than cardboard cutouts...

The second movie didn’t make sense to me. Humans have apparently made earth unlivable so they’re moving to a planetoid that’s under extreme radiation, has an atmosphere with toxic gasses, and that has 16-18% CO2??? Like if they think they can terraform that how can they not terraform earth that is already pretty good or just build space cities where they can create the exact requirements for human life? They obviously have the advanced technology. Or we know it’s possible they can create alien biology through genetic manipulation, why not just engineer human bodies to better survive earth? First movie made more sense, they’re mining rare resources, however other planetoids in the star system should have the same resources right? We aren’t they mining them but the one that has life??? The only other known place in the universe that has life?

If humans are advanced enough to modify genes and interstellar travel, can't they just farm raw materials from asteroids or space dust and synthesize the substance they want on Pandora?

We can feel that James Cameron takes good care to polish every little detail in his movies ! that's what makes them so great ! There is only one thing that bother me with Avatar: All the fauna seems to have evolved to a 6 limbs creatures! the na'vi are the only exception to that! does that mean some catastrophy happened? or maybe even the na'vi are alien to this world? We can go very far and think that maybe they are the result of the human federation experiment to create a humanoid creature on this planet! hence the avatar program !

Floating mountains are probably unlikely as depicted in the film. Perhaps if there are some magnetic forces involved, maybe combined with gravitational effects of the gas giant the moon orbits (so floating mountains would only be on the side facing Polyphemus?), and toss in a thick enough atmosphere and make the mountains out of material that's relatively low mass to boost their buoyancy. Like Alex mentions in this video, I agree that the waterfalls just wouldn't happen - aside from where all that water is coming from, would whatever forces that allow the floating land allow for the water to fall instead of just float away?

Unfortunately the company adverised at the end of your video is a scam. You should vet your advetisers more thoroughly

I LOVE your videos!!! Not just narration, you provide opinions, and delve deep. Providing extra content like this just adds to the interest. THANK YOU!

I think unobtainable is the most interesting thing about this franchise. It’s a superconductor that has a magnetic field which is not what we observe in reality. Such a sci-fi metal would allow us to make extremely powerful and controlled magnetic fields. So yes the mountains do act as a sort of magnet probably being drawn to Polyphemus’ magnetic field until it gets to an altitude where gravity takes over so you get various mountains floating at various altitudes.

I'm offended by you saying I've been living under a rock sir, because I happen to be living on top of a rock. I demand an apology sir! 🌍

While I have never been infatuated with the Avatar movies I have really enjoyed your realistic exploration of them.

Never thought I'd see this video happen. I admire all your material... and I also really like Avatar, so this is a nice bonus for me.

Small correction: it is not widely accepted that during the Mesozoic era there were more oxygen than now. As far as I know, most experts do not think it's true, and there is no evidence of it. Other than that, it's a really nice video. I learned a lot, thank you!

The only problem with Pandora is that it would be in planet’s shadow for a substantial period of time. How this would impact its heat would be dependent on its GHGs, and the length of time in the planet’s shadow.

I would love to see more videos like this talking about fictional space settings.

James Cameron pours an incredible amount of research into his projects, so I'm not shocked that life imitates art. Conversely, as we see with the Halleluja Mountains, he's also able to suspend disbelief in order to give license to artistic creativity. Personally, after watching the second film I can honestly say that the Avatar franchise is probably right up there next to Alien & Predator as the best xenos-based series of all time.

What would the planet's gravity do to the moon? Thinking about about the inner moons of Jupiter are basically ripped apart by the intense gravity of Jupiter

The problem with gas giants is their enormous gravity which attracts metaorites. It drasticaly increase the chanche of an asteroid impact on its moon. Even if there are a habitable moon around a gas giant, such impact would surely happen and will surely make the moon uninhabitable

What about tides on Pandora??? Since, according to your video, Pandora is not tidally locked with its home planet, and since the home planet is MUCH larger (and presumably more massive) than Pandora itself, then the tidal effects of the home planet on Pandora's oceans would be ENORMOUS. On Earth, with a relatively small single moon, we experience tides that can often range from 10-20 feet, depending on the local geography. On Pandora, the tides would be immensely bigger. This would have major consequences for any areas near a Pandoran ocean.

I still don't understand how humans can jibe the time and date during interstellar travel with the time and date used on Earth

I think the mountains wouldn’t be possible under two teslas, as stated in the movie. Superconductor or not, that would require about 100000 Tesla to lift those mountains which is like magnetic field of neutron star. In that magnetic field, your blood will fly one way, while water will fly another.

Not going to lie... when I clicked I was thinking Pandora from Borderlands...

You can count on Astrum to change the thumbnail and title 5 times within a day for new videos 😂😂😂😂

Seeing this video talks about many speculative biology topics, Id recommend the channel Curious Archive. They have a series dedicated to these kind of works. Not just alien biology but fantasy biology and also how life on Earth would be like millions of years in the future. Etc.

13:14 thanks but no thanks. No one will ever persuade me to visit bloody dictator Winnie the Pooh.

Perhaps somewhere far away in another Galaxy or within our Galaxy there may be world like Pandora..... we will never meet them neither they will , they are busy in their own life and we too 💔💔💔

Good video, thank you. I wasn't hooked by the Avatar storyline but the film is beautiful. A similar video on the planets shown in Interstellar or Dune (Arrakis) would be good.

Unobtanium is not a metal, it's a compound as all other high-temperature superconductors are.

8:42 That would also mean that Na'vi on the Polyphemus-facing side of Pandora could use it as a point of reference for travelling, just as humans used stars, thus Na'vi on this side being much more connected (commercially, culturally...) than on the other side, or they could just have a much poorer knowledge of astronomy

Dan Simmons’ ‘Hyperion’ written in the 80s has floating islands that are explained to be fully alive with motility and sentience .. perhaps the inspiration?

What about the tides created by the gas giant’s gravity so close to Pandora? It would be full planet tides, I imagine.

Theres an old MMO that never had much popularity called Shores of Hazeron. Habitable moons orbiting gas giants were always my favourite places to colonize. Theyre so pretty!

I've never had an interest in these movies. So I am pleasantly shocked at how much they thought about the world building as far as the environment goes. I probably wouldn't notice it consciously while watching but subconsciously it would make the film reality vibe alive.

I've been becoming increasingly interested in realistic near future science fiction that doesn't break the laws of physics.

A strong enough magnetic field to levitate a mountain would cause the iron in a humans blood to boil.

There's a dearth of hard sci-fi these days. The Avatar films are colorful, candy corn autism bait. Where are the Hollywood writers who've had some science (or writing) courses, these days? 🤷‍♂️

It's not really oxygen that contributes to large flora and fauna. Plants feed on carbon dioxide. High atmospheric carbon dioxide is what allows for massive plant growth, and in turn massive animals which feed on those plants.

I wish aliens in movies would not look like us, with typical head, hand and legs. I wish the producers have little bit more imagination.

@10:21 , more oxygen in the atmosphere didn't allow dinosaurs to grow bigger. Blue whales are larger than dinosaurs so if that was the limiting factor, they couldn't have gotten that big. This is compounded by two facts: 1. Dinosaurs likely had the highly efficient unidirectional respiratory system characteristic of birds (which allows them to exert themselves at altitudes at which we'd asphyxiate at). 2. Blue whales are holding their breath the majority of the time and usually use ~85% of the oxygen that they inhale. So relatively low concentrations of oxygen in the atmosphere would have an even larger impact on a whale than it would a sauropod dinosaur.

You should discuss the concept of the planet being almost a supercomputer, considering how the root systems and all the life connect and act as almost a brain… really cool to think about

Never expected Avatar to hold up to scientific scrutiny.

I’m not sure, but we may have ruled out Polyphemus sized planets in that system?

Before I watch, is there spoilers from Avatar 2 in this video? I haven't watched it yet. Thanks.

Perhaps you should have bought and read _"The Science of Avatar"_ by Steven Baxter who is a sci fi author with a background in engineering and mathematics and sticks close to real science in his novels before making this episode. It's supposed to answer all the questions posed in this video.

Yooo! Didn’t think a video like this would come out!

Dinosaurs did not get larger because of more oxygen in the atmosphere, this is a myth that's shockingly resilient. For most of the Mesozoic the ratio of oxygen in the atmosphere was actually lower than it is now, it seems like it probably reached an absolute height of 19% as opposed to our current 21%, and could drop down to about 10%. Truth be told atmospheric oxygen availability just does not seem to be a significant limiting factor in Tetrapods, especially when they have lungs its so dependable and easily extracted from the air that its other factors like the food availability and the physical stresses on large bodies that cause issues. Its instructive that Baleen whales can get ridiculously large without even having to take breaths frequently, they can hold their breath for up to an hour despite their size and relatively intense metabolism based entirely off of atmospheric oxygen they may only suck up every 40 minutes on average, it shows how efficient their respiratory systems really are that they can do this. Additionally, we have no indication that whales, or any other large animals, are pushing the physical limits of what a body can support based on oxygen intake. And even then, it seems like dinosaurian lungs were more efficient than mammalian lungs with their use of air sacs rather than diaphragms. Birds have extremely efficient respiration, its something that allows animals that fly extremely high like Eagles and Geese to survive in the thin oxygen as you head up kilometres into the air, despite these being relatively large as far as birds go. Oxygen does seem to be more of a concern for creatures that live in water and can only extract dissolved oxygen in the water with gills, obviously this includes things like fish and crustaceans, oxygen availability in the water is a lot more restricted and prone to dangerous variation compared to atmospheric oxygen and its not unusual for oxygen starvation events to kill large amounts of animals on a large scale, it seems that anoxic events in the past have been responsible for a great many mass extinctions in the oceans. But atmospheric oxygen is far more stable, I don't think its ever been the case that oxygen in the atmosphere has ever dropped below 10% since the emergence of complex life more than half a billion years ago, there's probably never been a crisis stemming from lack of oxygen for land creatures. Oxygen in the atmosphere is such a sure bet that its one of the reasons why aquatic animals have repeatedly evolved lungs or similar lung-like organs, even if they aren't actually terrestrial it can be a lifesaver for a creature that usually lives in an aquatic habitat vulnerable to times of low oxygen stress, this especially applies to freshwater habitats with lots of still water that can accumulate decaying plant matter and where water levels change drastically based on seasonal rainfall, its how you end up with creatures like lungfish or Birchers.

I was a bit dismayed the space travel bit at the end got cut off. Are you planning to do a video about the interstellar spaceflight technology in the movies? That'd be cool.

Could a gas giant form within the habitable zone of a star? Or would the habitable zone for the moon be based on the moons distance from the gas giant (i.e. the gas giant itself is providing the habitable zone for the moon)? And if so (the gravity of the gas giant provides the energy via tectonics, etc) would that moon have enough light for plant photosynthesis?

my problem: only humanoids breath through their mouths & have 4 extremities. all other animals have breathing holes on the neck & 6 extremities. the humanoids had to have evolved from something reasonably physiologically similar, but there is no evidence of this presented.

The tremendous gravitational tidal forces of being in such close proximity to a gas giant might probably play havoc with the systemic stability required for a life rich ecosphere. 🤔

It has floating mountains, so I'd say that scientific accuracy wasn't a priority?

interesting prospect... if the earth was tidaly locked like pandora orbiting a gas giant and the center face would be the middle east jerusalem mekka lengh degree then basically the natives of the americas would never know they orbit a gas giant and probably the japanese, nz and a couple more

10:15 You're thinking of the insects of the Carboniferous, Dinosaurs did not grow this large because of higher oxygen concentration. Insects heavily benefit from this and are size limited by oxygen levels because their way of taking in oxygen involves the oxygen just passively diffusing into their skin. The larger any object gets, the interior volume grows at a faster rate than its surface, meaning that a larger insect has to be able to provide a larger body with relatively less skin to breathe with, limiting their size depending on the oxygen levels. But that’s not how lungs work, and Dinosaurs were not breathing these insanely high levels of oxygen as in the Carboniferous anyway In fact, the oxygen levels of the Mesozoic, the era of the Dinosaurs, was estimated (relative to modern levels) at 80% in the Triassic, 120% in the Jurassic, and 150% in the Cretaceous Period. This wouldn’t explain the Sauropods, the largest land animals of all time, existing since the Triassic

This is why I love avatar because of all the realism it has everything from the near future technology, the flora and fauna, and Pandora itself!

I would love to see you Alex to make review on movie interstellar and explain gravitational waves and gorgantua

The question is what radial distance does the moon need to NOT be tidally locked? Mercury is tidally locked to the sun. The images in the movie imply the moon is close to the gas giant so it would be tidally locked. That's the killer... if the moon was further out it might have its own rotation. This also helps the radiation problem. Cameron wanted a great visual but ruined the physics... not that most audiences would know that.

Are there gas giants but they are oxygen and terrestrial, ? Or is this a size thing where gravity or something else wont allow it?

Glad you did this one! It's a beautiful movie.

I don't know about the second movie but the first one certainly put some effort into trying to make it a bit more in the right direction than your generic scifi. Especially with who they had help them with designing the creatures

If magnetism was strong enough to make float heavy loads, any metal tools will be strongly affected by pull/pushed (weapons, choppers ... )

How about gravitational effect of the nearby planet on especially Pandora's oceans and seas? In the movie, it doesn't seems notable, but in reality you can only think of how much a small moon like earth's has on our oceans and seas activities.

I was thinking maybe the Floating Mountains might be possible if Pandora orbits just *barely* on the Roche limit. Close enough that a tiny little part of the planet is just a *liiiiiiittle* bit too close to the Gas Giant

The first Avatar movie was much more compelling in every way.

Videos like this are really fun. This movie really just struck me as Fern Gully again. Visually amazing but a fairly standard plot under that.

The *big* problem I have with the Avatar franchise is that we don't need Unobtainium to make the global vactrain system the Resources Development Corporation runs, it's more of a construction issue.

One thing that is ignored is the effect of xenon on sound wave frequencies.

Biggest problem I have with hallelujah mountains is where does all that water comes from?

About the “Unobtanium”, I think it can actually be metallic hydrogen, which is known to be a room temperature superconductor. That way it can stay suspended in the magnetic flux, thus creating the hallelujah maintains and everything else. According to some of the theories, immense pressure inside the big gas giants can create metallic hydrogen and this metallic hydrogen can keep its metallic state even after there is no pressure. My theory is that, in the past, two gas giants may have been collided and the metallic hydrogen got thrown out. After some time, just like our moon, pandora could be created from the debris cloud.

if Pandora is as close to it's parent planet as Io is to Jupiter, then theirs one issue, io experiences massive tidal forces cause by Jupiter's gravitational pull, and by it's sister moons too, which causes frequent volcano eruptions and quakes on it's surface, making it impossible for complex life to survive there, so I'm afraid to say that a earth like moon orbiting so close to a gas giant, may not be possible in real life.

Awesome content with great topics

Wouldn't a moon with a 60 hour orbit be too close? To be safe from the planet's radiation it would need to orbit further out but if it's far enough out it might not be tidally locked.

You left out one huge feature of Pandora, that it's biology is interconnected like synapses in a brain to form one world-brain

Astrum... Tank you, I am a huge avatar fan. Its nice to see some content that doesn't bash the universe.

Getting a jump on other science communicaters to a science of Avatar video is an excellent idea, liable to pay big dividends.

The most unrealistic thing in Avatar is that we didn't nuke the planet or use biological warfare against the Na'vi. To me it always looked like Cameron completely forgot about human history and how we generally deal with obstacles.