Idea for an invested planet. A planet that is not bound to a solar system and is covered in ice

[Sythrin]

I recently saw a video of the youtube channel "Kurzgesagt" about roaming planets.
Realy interesting video about how, if a planet is by accident thrown out of the gravitational field of a star, than it could roam the universe as a singular agent.
It would loose like 98% of its energy, as the proximity to a star would be missed, whihc would result in the freezing of a the surface to near to 0 Kelvin.
But around 2% of the worlds (ours at least) warmth and energy comes from the core of it.
Theoreticle, its possible that deep under a layer of ice, liquid water is found, that is heated from the core.
And from that life could be created as well. The technology of the life could be have problems, because they cannot use fire for smithing (unless there are other ways I am not sure of) and they would be trapped in there own little world under kilimotor deep ice, never knowing what is beyond their ceiling.

What if such a world existed in the cosmere. Perhaps with access to investiture. Maybe an aquatic based magic system, similar to water bending? Or something else?
Would such a planet have a perpendicularity? Or would they only be discovered by chance, as they come closer to another shardic world?

[KaladinsSenseOfHumourSpren He/Him]

I've seen this video, though it was years ago.

A very similar thing can happen to gas giant moons like Europa, which could have cosmere equivalents, while still being in a solar system.

But yeah I'd love to see rogue planets in the cosmere. As for what Investiture and stuff they'd have, it could be anything. I'm thinking something that can keep the planet's core warm so it doesn't freeze.

[Returned he/him]

If ever there was a planet thematically suited to Autonomy...

A rogue planet would probably fit into the Cosmere pretty well since physical location is much less relevant to getting around and interacting with other people. And we know that a Shard can move a planet around, if it feels like doing that. Perhaps a certain, hidden Shard is working with exactly that!

As for magic and perpendicularities, I think that depends on which Shard (if any) has Invested itself there. A Shard almost guarantees a perpendicularity, and it seems like magic systems are what Shards want them to be (with at least some conceptual connection to their central concepts). So I don't think that the magic system would have to depend on the planet at all, in the same sense that Metallic Arts have nothing in particular to do with Scadrial's planetary features, though it would of course be used in ways that complement or respond to the planet.

I, personally, would want the magic system of such a planet to be really different from what we've seen elsewhere and so things like manipulating heat or producing food would fall flat for me. Stormlight Archive, with it's closeness to the cognitive realm and Soulcasting, has burned through a lot of the ground any "magic makes the technology go"-type approach could cover. And Mistborn's "it's too cold for us without magic" has covered a lot of environmental responses. I like the idea of something interacting with the planet's solitude, or maybe closeness to the galactic core, but I'm having trouble thinking of more details. Especially since hundreds of generations of inhabitants might not see any change in the planet's isolation relative to anything else.

How about: Isolatry. Investiture accumulates, naturally but slowly, in the habitable areas around the core of the planet, which includes both aquatic areas and air-filled pockets. Individual people can attune to that Investiture, and concentrate it within themselves over time. But that process is disrupted by others being nearby, with the result that any gathering of more than a few people in a square block or so are just barely able to use any magic at all. This results in a major social organization with cities of "ordinary" people who can't do or interact with magic at all, while others prefer isolated, hermit-like lives in which they develop their powers.

In times of great need the settlements can reach out to the hermits for aid and hope to get a favorable response, but any degree of interaction frustrates the magic-accumulation process and so contacting the hermits both interrupts their own plans and methods while also frittering away the powers they can command. Conversely, the hermits can't do a whole lot to control or even influence the communal folk for the same reason.

I can imagine some fun and interesting social structures that might develop to deal with these conditions, to allow contact and communication at varying levels while preserving as much capacity for magic as possible in specific people. What the magic can actually do and how it works... well, I guess that doesn't have to be as tightly thematic as the system itself. Maybe I'll think of something interesting-- it could happen!

Edited October 20, 2025 by Returned

[alder24]

Rogue planets are fun. There is a type of ocean planet with a very thick hydrogen atmosphere, which theoretically can sustain liquid surface even as a rogue planet (Hycean world), so we can have a fun sunless planet in Cosmere with people and technology on its surface, although breathing would be problematic as there is no oxygen, plus surface pressure would be insane. But hey, it's possible! Honesty, I would love to see more crazy worlds on Cosmere, just like Roshar, Era 1 Scadrial or Cantile. They are just so fun and a rogue planet would fit Cosmere perfectly. I'm confident we can easily have such a world in Cosmere because investiture can simply solve all our problems. 

A few years back we engaged in fun Cosmere world and magic crafting in one of the topics and I came up with the idea of magically sustained ecology with civilization on a surface of a rouge planet. If you're interested in reading about this world of mine (or other fun worlds created by others), you can find it here:

https://www.17thshard.com/forums/topic/133873-combined-shard-names/page/5/#findComment-1538987

Edited October 21, 2025 by alder24