>>12581704>when the entire universe decays to iron, will it form a super magnet?That depends on its temperature, but it'll likely be less than the Curie temperature after sufficient time, so there will definitely be local magnetic domains. Globally, I'm not sure if there would be a strong magnetic field.
The problem is that matter isn't dense in the universe, there will never be a single cluster of iron in the end.
It also won't be the size of the universe. Remember, matter only makes up a few percent of everything, and that's not even accounting for empty space.
