In the recent movie Man of Steel, we can see Kal-El being weakened down by Kryptonian atmosphere.. there isn't any question about a red sun or Kryptonite.. he got weakened by the air breathing on his planet artificially created by the ship life support system.

I loved this movie but that specific point as been bothering me ever since !

How can the Man of Steel become so weakened by Kryptonian air when 20 minutes later he simply breaks the panel and breath easily in the vacuum of space ?

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    Myself and two fellow scientists went to see this movie together, and spent the whole time screaming at the screen because none of the science made any sense. And yes, I understand that you have to suspend your disbelief, but even then, it wasn't consistent and didn't make much sense according to internal logic. This is really a case where I'd just walk away from trying to explain why anything was the way it was.
    – Broklynite
    Commented Dec 25, 2014 at 4:45
  • thanks for this i am still hopping for a complete answer at this... maybe they will come up with something in Dawn of Justice
    – Rocket
    Commented Dec 25, 2014 at 19:16
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    The same way Earth's sun gives him super powers.
    – Robert
    Commented Dec 27, 2014 at 23:04
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    @Broklynite - compared to being able to fly because the sun emits visible light with a different dominant wavelength? Keep in mind, they aren't inventing this stuff from scratch, the entire concept they have to try and wedge stuff into was from an artist, not even a sci-fi author, from 1938. I think you should reference this website, and be grateful it's as logical as it is in the movies. :D superdickery.com Commented Sep 9, 2016 at 14:13
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    @AndrewMattson yes even then- as I said, it lacked even internally consistent logic, regardless of the ridiculous premise. And yes, I love me some superdickery.
    – Broklynite
    Commented Sep 9, 2016 at 18:37

5 Answers 5


The Man Of Steel Answer Insight Commentary (MOSAIC) Podcast Episode 6 covers this topic fairly thoroughly.

However, let me give you the answer then you can listen to see the work / proofs / logic.

MOS Kryptonian super powers are powered entirely by Earth's Yellow Sun (this includes sensory abilities). That is the only mandate on having their powers. Thus their powers can persist in a vacuum, underwater, in an oil rig fire (which isn't normal Earth atmosphere), or in all the environments in between Earth and space.

Jor-El describes this using the metaphor of "drinking" and like water, you aren't only hydrated while you are drinking the water. You can also store the drink in your body to keep you hydrated while not drinking. This means Superman can exhibit powers even when not in direct sunlight.

However, a more apt metaphor is of a laptop with a removable battery and a power plug. The laptop will run on either battery, or plug, or both... but not neither.

The Kryptonian Atmosphere acts to unplug (but not drain!) the battery. Additionally, space ships are shielded against radiation. Therefore, being exposed to Kryptonian Atmosphere disconnected his battery and being on the Black Zero unplugged his power cord. So Superman lost his strength. After the Kryptonian Atmosphere was replaced (either by Earth Atmospherics OR vacuum), Superman's battery was reconnected and thus his strength immediately returned. He was NOT empowered by Earth's Atmosphere (otherwise vacuum would have weakened him). As for what Zod and company were breathing on Earth, we can't be certain, but even if they were breathing Kryptonian Atmosphere, they would still have power in the form of direct sunlight or a power cord (irrespective of a disconnected battery).

This theory is fully consistent with the entire film and the Podcast reconciles every instance (including the helmets and sensory "weakness"; and Superman briefly losing flight while fighting the World Engine) except the Prequel comic, but also explains why that example can be excluded.

As for why, mechanically, Kryptonian Atmosphere weakens Superman, it's a combination of two general factors: 1) He has organs and they work; 2) It's a biochemical reaction.

We know Superman tends to follow biological rules for a number of reasons, not the least of all is how Zod is stopped. Additionally, there's a strong suggestion that even with all his powers, Clark still biochemically reacts with the world... he drinks beer while watching football, implying that it is reacting with his body so that he can taste it. It is unlikely that Kryptonian Atmosphere is radiological simply because of how much was spewed into the air and Lois's exposure to it.

Therefore, it is possible that in breathing in the Kryptonian atmosphere, it reacts biochemically with his lungs and some other organ or process which allows him to metabolize stored sunlight energy, and therefore he becomes cut-off from his stores of energy. Just as sour may cause you to pucker, bitter to gag, spicy to pant, Superman's reaction to "tasting" Kryptonian air was temporary weakness.

Under this theory, if Superman had held his breath the entire time he was on the Black Zero, he would have been fine... but he also wouldn't have been able to speak and he would have had no reason to think to do so. Additionally, it's likely he would have eventually adapted. He did, nominally, in the sense that he didn't remain passed out and coughing, but merely powerless.

These are gone into more depth in Episode 7.

Via YouTube: Man of Steel Myths: How the Atmospheric Weakness Works

  • Wow.. that covers it. Thanks a lot :D
    – Rocket
    Commented Jan 9, 2015 at 2:23
  • -1 This does not explain Zod & friends gaining x-ray vision, heat vision, and super-hearing when exposed to Earth's atmosphere.
    – user1027
    Commented Jan 9, 2015 at 2:30
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    That's beyond the scope of his question and is addressed extensively in the podcast. The short version is that the helmets act as an artificial source of "focus", the same way Martha guided Clark to reign in his sensory powers, the same way being in the ocean helps mute the din, and the same reason Clark covers his ears when under sensory overload as a child. We know this is what happens because Superman explicitly tells Zod, "Without your helmet you're getting everything." Meaning he's aware of what's happening. If it was atmosphere, Superman would have said, "Without your breather..." Commented Jan 9, 2015 at 2:33
  • Well my question was about the man of steel exclusively... Thanks a lot for this answer wich answer perfectly MY question wich was "How can Superman be so weakened by Kryptonian air" :)
    – Rocket
    Commented Jan 9, 2015 at 2:54
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    Well done! I haven't seen a thoughtfully considered answer like this, It also explain how most Environmental suits work.
    – Virusboy
    Commented Jan 9, 2015 at 5:58

Man of Steel added a new source of Superman's powers (which to my knowledge hasn't been used in previous canons) in that he gains some of his powers from Earth's atmosphere. Specifically, there's something more nourishing about Earth's atmosphere than Krypton's. Early in life Clark adapted to Earth's atmosphere, this was the flashback where he was in a closet at school. When exposed to the Krypton atmosphere aboard the ship, it sickened him and disoriented him, as he had never been exposed to a non-Earth atmosphere before.

On the ship, Jor-El (the computer program) alters the ship's atmosphere to make it Earth-like, this then restores Superman's powers. Once he then flees the ship, we see that apparently a lack of atmosphere isn't harmful to him nor does it drain his powers.

See also this answer.

  • Isnt it sio though that the trouble started when he bgan to breathe the kryptonian air (which is more dense and thus allows no xyray vision) while in space he didnt breathe in the vacuum?
    – Thomas
    Commented Dec 25, 2014 at 11:54
  • ok thanks i guess.. i also like the comment that Broklynite left on my question. I think this is simply a no answer question
    – Rocket
    Commented Dec 25, 2014 at 17:50
  • This answer appears to be wrong. Jor-El says, "Your cells have drunken its radiation strengthening your muscles, your skin, your senses." Thus the sensory powers are explicitly attributed to radiation and not atmosphere. Commented Jan 9, 2015 at 2:37

It has to be Kryptonite particles in the air. Kryptonite was all over his home planet. Superman never grew up in it like Zod and his race did. They need it to keep their bodies in check (Zod, etc). Breathing the "good" air of Earth puts them out of balance. Fine particles caused him to spit up blood and become weak.

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    – Skooba
    Commented Feb 24, 2016 at 15:28

I remember that the atmosphere of planet krypton has red sun radiation, all kryptonians run out of powers in these atfmosphere because the red sun is old. With the yellow sun of the earth , the cells of the kryptonian body charge regain strenght and the rest of powers. In these part is not kryptonite that damage superman in the zod ship. The atmosphere of Krypton has red sun radiation, in these conditions and witouth any type of protection , superman collapse, he feeling the radition for the red sun by first time, and loses his powers . The another are not afected by his armours. Since he takes the energy of the yellow sun , he reagins his powers.

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    So, the atmosphere of Krypton is radioactive?
    – Adamant
    Commented Sep 8, 2016 at 21:21

In the film's official novelisation, it's made abundantly clear that spending time in an Kryptonian atmosphere weakens Superman. No special explanation is given why

“His body is rejecting our ship’s atmospherics.” Zod gazed down at Superman, who felt sicker than he had ever felt before. “You spent a lifetime adapting to Earth’s ecology, Kal. But you never adapted to ours.”

Superman struggled to overcome this unexpected weakness. His head throbbed painfully. His limbs felt like rubber. His vision blurred. Sudden chills alternated with feverish hot flashes, while pressure built within his ears. He heard Lois calling out from what sounded like miles away.

When it's time to leave the ship, he breathes in the "Earth-like air" and lo, his strength is renewed:

“It’s called a backup plan. Your ship’s atmospherics just switched back to Earth levels, which means I’ve got my strength again.” Steely blue eyes, with a hint of solar red, fixed on Jax-Ur. “So if I were you, I’d start running.”
Superman tested his shackles again. Straining beyond his limits, he ripped one loose, freeing his right arm. Jax-Ur’s sunken eyes grew wide. Coughing painfully, he staggered out of the lab as quickly as he could manage. He clutched the stolen blood sample to his chest.
Superman let him go. He took a deep breath, pulling the Earth-like air into his lungs. He felt his strength rushing back.

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