When the crew is entering Mann's planet's atmosphere, their ship hits a frozen cloud. How can a frozen cloud stay afloat even though the planet contains 80% of Earth's gravity?

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    Perhaps the planet’s atmosphere is denser than earth’s too. – Paul D. Waite Nov 25 '14 at 16:31
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    I had the impression they were connected to the ground in places, but perhaps I recall incorrectly. – BBlake Nov 25 '14 at 17:08
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    If I remember correctly, the entire sequence took place on frozen atmosphere. The whole reason Mann behaved as he did is because there was no actual surface to the planet. So, the higher clouds weren't afloat, they were just protrusions of the frozen atmosphere. – Liesmith Nov 25 '14 at 20:31
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    @Liesmith - Yes, the prequel comic written by Christopher Nolan indicated that Dr. Mann was looking for a solid surface under the ice clouds, but hadn't been able to find one. When Mann and his robot Kipp are retrieving a probe, there's this dialogue: Mann: "Do you think it found the surface?" Kipp: "We'll check the data." Mann: "But if it found some actual ground down there? Terra firma?!" – Hypnosifl Nov 26 '14 at 16:29
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    80% earth's gravity + denser atmosphere – Huangism Nov 26 '14 at 18:16

ScienceInsider interviewed Kip Thorne (who is a "renowned theoretical physicist at the California Institute of Technology in Pasadena and one of the world’s leading experts in the astrophysical predictions of general relativity", scientific consultant and executive producer of Interstellar, and author of The Science of Interstellar):

Q: Is there anywhere the moviemakers strayed outside your guidelines?

A: Not seriously. The one place where I am the least comfortable is on [a] planet where they have these ice clouds. These structures go beyond what I think the material strength of ice would be able to support. But I’d say if that’s the most egregious violation of physical law, they’ve done very, very well. There’s some artistic license there. Every time I watch the movie, that’s the one place where I cringe. I don’t think I’ve ever told anybody that.

(bold emphasis mine)

There’s also a lesson from Interstellar for Educators: Can Frozen Clouds Exist?

In this activity, students will experimentally determine the density of ice, then consider the air density and temperature required for a frozen cloud to remain suspended in the air.

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    In The Science of Interstellar Thorne says 'Motivated by a conversation with Paul Franklin, I imagine that these clouds are largely frozen carbon dioxide, "dry ice," and they are starting to be warmed as the planet is on its inward excursion toward the accretion disk...When warmed, dry ice sublimates--vaporizes--and so what appears to be clouds may be a mixture of dry ice and sublimating vapor; perhaps mostly vapor.' I wonder if there's any conceivable way clouds could form with icy shells around a mostly gaseous interior, since the external part seemed pretty solid when the ship bumped it. – Hypnosifl Nov 26 '14 at 16:04
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    And I just realized that the "surface" they were walking on was just more ice clouds, see my comment to Liesmith about the prequel comic above, so even if the clouds were more gaseous in their interior, the solid part of the clouds must have been fairly thick to support the weight of the ships landing on it. – Hypnosifl Nov 26 '14 at 16:33
  • Yeah, very cringe worthy. I could believe frozen clouds. I could believe frozen gasses able to support a landing. I can't believe both at the same time. Even with a denser atmosphere and using something super light weight (like aerogels) you just can't get both the strength and weight to do both. – Jim2B Jun 18 '15 at 2:38

I think gravity is not a factor because everything has mass it's really a matter of how much space that mass displaces, i.e., density. Like, ice cubes float in your milk even though gravity is pulling on the ice cubes. So I think the only factor that matters is that the solid clouds are less dense than the gaseous atmosphere.

In fact, stronger gravity contributes to greater atmospheric density by pulling the gases closer to the planet surface (e.g., air is thinner atop Mt. Everest). So, if planet Mann had an atmosphere made of the same molecules as Earth's atmosphere, that atmosphere would in fact be thinner on Mann than on Earth because Mann's 80% gravity is not pulling down as much atmosphere. Which would make floating a solid in such a thin atmosphere even harder--not easier. But, we know Mann's atmosphere is not the same as Earth's because Mann's atmosphere is not breathable.

Possibly the clouds and the atmosphere of Mann are not composed of the same elements/compounds as each other. The atmosphere could be chock full of dense gases. I see that sulfur hexaflouride has a density of 6.17 g/L. And the clouds are made of really not-dense solid. I see that NASA aerogel is only 3 g/L. So, maybe NASA made a sh*tload of aerogel, floated it out to Saturn where it [accidentally] got sucked through the wormhole and fell to planet Mann. Just maybe.

Or maybe the clouds and the atmosphere of Mann are made of the same elements/compounds as each other, and the temperature is just enough to have some of it freeze up, and the solid state is less dense than the gaseous state. Like imagine the planet is just a ball of water or whatever, where a lot of it has frozen into iceburgs but there's still some ocean left. I don't think this is likely though, as I don't know of any compounds whose solid state is less dense than its gaseous state.


The planet is a frozen Jupiter and probably it contains gas elements that freeze. I can also imagine that when the near star blows up a huge chunk of ice will burst trough the space where can hit a planets and can form a place like Earth. I had this feeling through the movie that all this planets are necessary to help forming later on planets like Earth. I also think that gasses act differently on different temperature and to create water in space is a long process that involves multiple cooling and heating up gasses.

What is life is still one of the biggest mysteries for me. If you imagine the Big Bang and all that energy spreading time and space, then stabilizing in hot gasses which eventually cool down and form stars and even planets due to the gravity (which is related to black holes). But then a microbe forms which is not moving, only affected by physical intefare rather it can make moves in every 3d direction by itself. We are missing something huge here and life itself is involved in the mystery of the universe.


Yes, frozen clouds can exist.

But only at unimaginable pressure. The pressure should be much more than at the bottom of the Earth's oceans, definitely not survivable by humans or spacecraft.

  • I agree that frozen clouds can exists, but the fact that "can they stay afloat" is the main question. Since frozen clouds are literally ice,they will be pull down by the gravitational force if they are heavier than air. – Khan May 18 '15 at 9:42
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    @Khan they can stay afloat but only at very huge pressures when the density of the gas becomes greater than the density of a solid. – Anixx May 18 '15 at 10:32
  • Citation needed. – Marvel Boy Apr 2 '18 at 13:59

I think clouds can float if they are frozen I know this is very farfetched but what if only the outer layer of the cloud was frozen and all the gases in it keep it afloat.

Even if this is right it wouldn't be able to support the weight of the ship and base as it does in the movie.

  • Scientifically this is complete nonsense. – Chenmunka Feb 9 '16 at 16:05

There's a reason why the frozen clouds can still float on the air.That's because the atmosphere is mixed with planets gravity and black hole's gravity pull so its like pulling the frozen cloud with two hands one from the sky and one from the ground.

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    That's not how gravity works. – Valorum Sep 2 '17 at 10:09

Mann's planet orbits Gargantua which is a black hole. I think because of the strong gravity that the Gargantua offers, holds the clouds in the air. Moreover it feels like the clouds are connected to some mountains giving them extra support.


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