I was watching Knights of Sidonia a while back, and one of the episodes in season 2 takes place on a gas giant. Throughout the episode, countless large boulders, each probably larger than a city block, were being pushed around by the intense winds within the cloud layer. Is this possible in real life?

I'm not looking for habitable conditions, as I don't expect people to be living on these rocks. This is just a question of curiosity.

  • $\begingroup$ No. Boyancy in a gas giant has been duscussed in several questions, including this which directly looks at the general principle. $\endgroup$
    – JDługosz
    Commented Jul 6, 2016 at 15:30

2 Answers 2


This is not quite a duplicate of this question but the answer is close enough.


At the interface with the metallic hydrogen core of (for instance) Jupiter, the density is only about that of water, which is about 40% of that needed to float most rock. And the temperature at that depth is about 5000 K, which is not remotely survivable.

Note, also, that Jupiter is the densest gas giant in the solar system, so it's probably a good standard.


There is a type of Gas Giant called Type-V, in the Sudarsky's classification, they are predicted to have clouds made of silicate and iron, these kind of Gas Giants probably are Hot Jupiters. But in a way, their density should be high enough to suspend some less denser rocks like meteoroids that get caught in his gravity.

The problem is, Hot Jupiter are incredibly hot, 1400 K or more, so anything floating in his atmosphere will probably melt in short time.


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