That's because of our yellow sun.
When he goes to interstellar space...he needs a ship...the longer he's away from the yellow sun (combined with earth's gravity, etc...)...he becomes more human-like...meaning fragile.
Being near a red giant (like it was the case in Krypton)...Superman is just a regular Joe. Kryptonite would be harmless to him.
When he goes to interstellar space...he needs a ship...the longer he's away from the yellow sun (combined with earth's gravity, etc...)...he becomes more human-like...meaning fragile.
Being near a red giant (like it was the case in Krypton)...Superman is just a regular Joe. Kryptonite would be harmless to him.
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