"impossible" just doesnt work in comics and myths. Characters are doing impossible things all the time where the gravity laws and others dont apply. Drax was class 40 by the handbook at the time he was destroing stars and planets/asteroids while going against Thanos.
The reason the holding the " heavens " is cannon and the earth is not ( and both are greek and from Heracles myth ) its because exactly of that. He wasent a god so he couldnt be in space like that. He would have to be standing into something.