Superman is often seen floating or flying near Earth's orbit or in outer space.
What type of physiology would Superman or any humanoid life-form require to be able to withstand the vacuum of space?
There is no air in space so breathing (respiration) is not an option.
Could Superman be using an invisible atmospheric force field as part of his 'aura' (think Green Lantern) that could provide 'artificial atmosphere' for him to breathe in space?
Is there any canon explaining how Superman was able to survive in space?