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[Doctor Who/Torchwood] what would Jack Harkness' body look like in space?

Say Captain Jack Harkness (after being turned unkillable) was ejected into deep space, where a normal person would suffocate, freeze, depressurize, and die, not in that order. Would his regeneration keep him alive against the constant degeneration? Would he experience a cycle of death and rebirth? What would it look like to an observer?

Also, I know he doesn't live forever forever, but if he did, what would the Heat Death of the Universe do to him? Any different from just space?
gpt
Firstly, to correct a common misconception: You don't freeze in space. You burn. Space is cold, yes, but it's also a near-vacuum so is a brilliant insulator. For this reason, you lose heat **very** slowly while being subjected to blistering cosmic radiation.

As for Jack, he's not really unkillable (he's died many times since his first death) and he doesn't regenerate quite in the same manner as some comic book superhero. It's just that if his body gets into a state different from the way it was in when he first died, it reverts. This means he can withstand stuff like radiation exposure.

For this reason, when he gets ejected into space, the normal stuff happens. He swells up, passes out, and burns, while his body reaches some kind of equilibrium with the destructive forces on it (so he'd look like a normal charred corpse in space, but a little better off than you might expect). But with no oxygen, he still dies. It's just that once he's back to a safe place he comes back to life again.