As a scientist and a father, Jor El wouldn't send his son to a planet with an environment that could potentially kill him, so he had to test what the yellow Sun's rays would do to the Kryptonian body. Jor El states that the yellow Sun of Earth will make Kal El a god. This means he would have tested its effects on Kryptonians.

Why not make a "tanning bed" that emits the radiation needed to make a Kryptonian into a superman? Yes a red Sun drains Superman of his powers, but radiation can be blocked. It would be a medical cure-all at minimum and a race of supermen at best.

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    Not sure it would solve the problem of the imminent obliteration of Krypton. And even if it would, I'm not convinced it would have done so in time May 31, 2015 at 22:04
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    @user23298 - Please refrain from making offensive comments. Remember rule #1
    – Valorum
    May 31, 2015 at 23:25

3 Answers 3


We don't know that he tested anything, and it seems unlikely that he could do so if he tried. We also don't know how one would go about making a false sun, or how effective it would be.

Basing my answer solely on Man of Steel, we don't know how long the effects of the yellow sun last after exposure ends. Maybe a month, maybe a day. If a Kryptonian got out of your tanning bed, then walked out into the light of a red sun, the tanning bed's effect might wear off immediately.

And in the short term, the experiences of (young) Clark and Zod suggest that being exposed to a yellow sun for the first time is a horrible ordeal. The powers it gives you are excruciating and very difficult to control - people would be shooting heat vision everywhere and cutting everything in half. They would accidentally crush everything they touched. Every noise would be painful to their ears and their eyes would burn from the slightest hint of light. Even if it had some medicinal effect, it would be like chemotherapy - so unpleasant that it would always be the last possible alternative.

And even if Jor-El discovered how a yellow sun would affect Kryptonians, he might have discovered it a week before he sent Kal-El away, in which case he didn't have time to try to build anything - he was too preoccupied with the imminent explosion of his planet.

And considering the fact that in the film, Kryptonians aren't even allowed to have babies the natural way, what makes you think they'd be allowed to make their children into Supermen?

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    Actually, we know from the movie that even spending an entire lifetime in the yellow sun wouldn't save you from a few minutes in their atmosphere (as replicated in the Kryptonians' spaceship). Superman became Relatively Fit Untrained Guy.
    – user40790
    Jun 1, 2015 at 17:09

Actually, we know from the movie that even spending an entire lifetime in the yellow sun wouldn't save you from a few minutes in the Kryptonian atmosphere (as shown by Superman's stint in the atmosphere replicated in the Kryptonians' spaceship). Superman became Relatively Fit Untrained Guy. Even without a red sun, he was unable to maintain his powers relative to other Kryptonians.

Essentially, in the movie, we're shown (and outright told by Jor-El in the scout ship) that the Kryptonians were held down not just by their sun but specifically by their actions which harmed their own world.

Note that Zod, exposed to the sun and the fresh air, also became an unbermensch in a relatively short time. With just the sun, he was only given super strength, and this strength dissipated while in the ship. Strong people is something -- but not something which could save the whole planet. That would require several full on supermen.

  • I don't think so. Clark suffered from a change in the chemical makeup of the air, not from a clash between yellow sun and Kryptonian atmosphere.
    – Wad Cheber
    Jun 2, 2015 at 22:44
  • @WadCheber That's exactly why I'm saying they wouldn't be useful. Their air alone keeps their senses and abilities weak, compared to a fully realized superman.
    – user40790
    Jun 3, 2015 at 15:40
  • But was the issue the air itself, or the fact that Clark wasn't used to it?
    – Wad Cheber
    Jun 3, 2015 at 16:15
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    It was the air. The other Kryptonians didn't maintain their super powers once they returned to their ship.
    – user40790
    Jun 3, 2015 at 20:03

Culture, religion, philosophy, ethics, etc.

Even assuming they had the foreknowledge on the effects of a different sun and that knowledge was widespread and deemed reliable... that doesn't mean their society would adopt it. Consider the fact that we could engage in eugenics, sterilization, and designer babies today if we wanted to. We could outlaw people with genetic defects from reproducing, we could terminate any prospectively "defective" child before being born, we could modify all humans before being born to meet certain specifications... but that's an anathema to us. Just like there is a ton we could learn from human experimentation and testing, but we don't for moral reasons.

Similarly, we have the technology to pump you full of steroids from birth or to amputate your limps and replace them with artificial ones which could supply a specific mechanical advantage... again, we don't for reasons that go beyond the inability to do so.

Perfection and strength are in the eye-of-the-beholder.

What little insight into Kryptonian culture we have, we know that they deemed their sun, Rao, a god. Shielding one's self from his light and accepting the light from artificial sources may well amount to heresy.

There's support for the idea that Kryptonians would find a super-powered society an anathema. Remember that's Zod's entire mission. To replicate and recreate Krypton exactly as it existed before with the sole modification of himself as leader. So did his plans include dropping all his men onto Earth so that they could ALL have super-powers? Clearly not! Zod went through every effort to put as few Kryptonians on Earth as possible. He had every intention of creating a New Krypton where none of them would have powers. Why was he (and Faora and Nam-Ek) an exception? That's the role of a soldier! Killing is an anathema! However, the soldier is given limited authority and window to do so within the scope of war. Here, Zod gave himself permission to have super-powers... only to be discarded as soon as Krypton was rebuilt.

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