I think there is a clear difference between being immortal and being indestructible. I would think if your planet breaks apart you’d probably die with it being crushed or whatever. Also always unclear if being immortal means you don’t need to breathe air.
Here’s a sci-fi web novel I read years ago, where a couple of the characters end up being immortal in different ways, and in one case they show exactly how far that can go (in the context of the story) even without invoking heat death.
I think there is a clear difference between being immortal and being indestructible. I would think if your planet breaks apart you’d probably die with it being crushed or whatever. Also always unclear if being immortal means you don’t need to breathe air.
I think a good author makes it explicit.
Here’s a sci-fi web novel I read years ago, where a couple of the characters end up being immortal in different ways, and in one case they show exactly how far that can go (in the context of the story) even without invoking heat death.