The Superman article on dc.wikia.com says that, according to Justice League of America (Volume 2) #30, Superman can move faster than light.

Given that he can move faster than light, shouldn't he be able to manipulate kryptonite and get rid of it before being affected by its radiation? Or does kryptonite have some special characteristic that forbids him to do this?

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    Alas, I was really hoping that comic was an old Silver Age book that could be assumed as non-canon, but no, it's from 2 years ago.
    – user1027
    Commented Apr 27, 2011 at 23:48
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    What's wrong with Silver Age comics?
    – Mr Lister
    Commented Nov 13, 2012 at 13:58
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    @MrLister: The history of the DC universe has been completely rewritten a time or two since then, so we no longer have to explain away the silliness they included (such as Jimmy getting a new super power every time someone sneezed).
    – Jeff
    Commented Jun 24, 2013 at 19:35
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    Yes, or Superman working together with Batman! Oh, wait...
    – Mr Lister
    Commented Jun 25, 2013 at 5:47

5 Answers 5


Kryptonite blocks all of Superman's super powers including "faster than light" ability. So, once he falls under the influence of kryptonite, Superman can't escape faster than light.
To use this "faster than light" ability against kryptonite, Superman needs to know about it before its radiations reaches him. As Superman doesn't have sixth sense like Spiderman, there's no time to use this ability. Even if Superman just sees it, he will be affected by kryptonite radiation. So, he can't escape from kryptonite flying faster than light.

But yes, if he successfully guesses about upcoming Kryptonite attack, he can escape. Imagine it: Lex Luthor is trying to search his pocket for kryptonite ~> Superman guesses it ~> Kryptonite comes out, but Superman is gone..

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    Good point. As Superman can't see things faster than light, I guess he can't tell it's there, until it's too late... Commented Apr 28, 2011 at 4:01
  • Of course, if he's out of the range of the radiation, he can see it and get away fast enough - he has telescopic sight sufficient to see individuals from Low Earth Orbit, after-all. So it's more a matter of him knowing to look for it in advance and having a clear line of sight (or at least no lead in the way)
    – Jeff
    Commented Apr 28, 2011 at 10:56
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    @ThaddeusHowze That's not true.. All radiations don't travel at speed of light or close to it.. For instance, check Alpha & Beta radiations.. Beta travels at about 90% of c & Alpha travels at only about 10% of c.
    – user931
    Commented Mar 3, 2012 at 0:42
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    Alpha and Beta particles are technically "radiation", but both are low energy radiation, barely a threat to human beings unless ingested. Since Superman can handle both x-rays and gamma radiation, both with energy levels far greater than either of those, it is safe to assume Kryptonite would be on the order of x-rays and gamma radiation or he wouldn't have to worry about either of them. Alpha particles can be stopped by a sheet of paper. Beta by any appreciable level of metal. I am confident Kryptonite is more energetic than either. So let's assume its as fast as x-rays and call it a day. Commented Mar 3, 2012 at 1:01
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    Good point. Now, I'm more confident with my answer.. Thanks!
    – user931
    Commented Mar 3, 2012 at 1:07

As far as DC canon goes, much of this is incorrect.

Superman's vision and sensory powers don't "turn on" when he wants to use them (except heat vision, which is a narrowly focused blast of yellow sun radiation).

His eyes work fundamentally like everyone else's. You don't choose what you see or don't see or what part of the spectrum you can or can't see, etc. You see what you see and you hear what you hear. But similar to how you are able to focus to on the voice of a person at a bar or a stadium over all the other noise, or focus on a specific person or color in a crowed room, Superman can (on a ridiculously high level) focus on what he sees/hears, etc.

This has been established in multiple recent Superman issues. For instance, following Infinite Crisis in an issue of Action Comics, Lois mentions how Clark can almost simultaneously observe quarks at the subatomic level and then look out to the edge of the galaxy. In All Star Superman he lets Lex's use of his powers catch up to him and Lex sees the Universe the way Superman sees it.

He can see kryptonite radiation from any location within his range of vision (which extends to the far reaches of a galaxy) from wherever he is. This is another reason that it must be encased in lead or he must be extraordinarily distracted or fighting an opponent such as a Doomsday/Darkseid/Zod class, where is simply unable to avoid the radiation to hit him with it.

Lex said it best when asked about using kryptonite in a plan: "Every prize fighter has a punch that can knock out the heavyweight champ. The problem is none know how to land it."

Also, the statement itself is contradictory. Light moves at the speed of light, therefore it reacts at the speed of light. Whatever speed Superman moves at is the speed at which he is able to cognitively observe.

That's kinda why he's Superman, lol.

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    But sight doesn't "reach out" and see what's happening at great distances as it happens - it's still limited by when the light waves reach the eyes. Unless Superman does have another little-known 6th sense-style power, that can "reach out"?
    – Izkata
    Commented Jun 24, 2013 at 22:52
  • One of the DCeased comics released in the past years contradict part of this answer. In the story, a virus is transmitted through both blood and computer virus. Looking at the screen of a connected device (even accidentally) is enough to catch the virus. To avoid that, Superman exclusively used his x-ray vision, preventing him from seeing the content of any screen at all.
    – Clockwork
    Commented Jan 17, 2022 at 23:01

It would work if the Kryptonite just came to existence. However, due to it being present even before Superman could spot it, it's radiation field is already there (imagine a kryptonitishly glowing sphere around the Kryptonite) and Superman would have to penetrate some safety perimeter to get to it and thus be affected, no matter how fast he were.

Of course that should not prevent him from homing in with just enough momentum to collide with the Kryptonite itself such that it gets catapulted away by a temporarily powerless yet very ballistic Superman...

  • ...let's just hope the Kryptonite is out of harm's way before Superman "softly" touches whatever the Kryptonite was resting upon
    – Zommuter
    Commented Oct 15, 2013 at 13:47

As Evil Angel points out, in order to know or sense Kryptonite in order to flee from it, the emanations would have to already reach him, making it impossible for him to flee.

Also, if he's on Earth, the destruction caused by traveling even close to light speed, let alone faster, would be astronomical. We get sonic boom at the speed of sound. Thinking about E=MCC (don't know the symbol for squared), if he was somehow to retain physical form instead of converting to pure energy, the friction, collisions and resistance generated from colliding with even the molecules in the surrounding air would unleash huge amounts of energy.

EDIT: Here's a fairly theoretical article about how accumulated high-energy particles during faster-than-light travel would all be unleashed upon arrival/returning to sub-light speeds, causing additional destruction, so even non-atmospheric warp speed travel could be problematic.

The downside of warp drives: Annihilating whole star systems when you arrive


A piece of Green-K that has been sitting anywhere -- but not encased in lead -- would be continually emitting waves that would be visible to Superman if indeed he is able to see its radiation.

However, if someone whips out a piece of K while he is nearby, the light from the green K reaches Supie's eyes at the same speed as the radiation from the green K reaches him. Thus he can be surprised. HOWEVER, if he can fly faster than light without flying blind (see below), then he would never be surprised by green K and could always escape it.

Flying Blind: If Supie flies at, say, ten times the speed of light, the light (from any object) that reaches his eyes is moving at the speed of light. Therefore, if the object is moving rapidly he would be unable to see it before passing it or slamming into it. At any rate he would not be able to pinpoint its location until he slows down. In particular, if there is any range at all to his ability to see then there is the potential (depending on his speed) that he does not see a "dark" object at all until he hits it.

Solution: This is resolved by allowing Superman to see things by observing not through light but through tachyonic particles moving far faster than light. There could be many of these traveling at different rates, so that even if Supie races across the galaxy at 3,628,800 times the speed of light, he might be observing the objects around him through particles that move at 4,000,000 times the speed of light -- so that he sees the objects where they are. However, if Superman is able to see via tachyonic particles, these would be of such high energy that they would likely be unimpaired by the earth's atmosphere -- or even the sphere of the earth itself. Thus, he would never be surprised by Kryptonite anywhere -- rendering it effectively useless against him unless it emits tachyons.

If truly he is unable to "turn off" his vision powers, then most objects not containing lead would appear to him as x-rays do to us. He would see "ghostly objects" everywhere, as though he saw everything threw an airport scanner. Being able to "focus" would not change this, unless we mean that he could "de-focus" on everything else. This would be effectively the same as shutting off his vision powers. In all the early comics, X-Ray vision was clearly a power that he had to activate.

  • 1
    Hi, welcome to the SciFi & Fantasy StackEchange! You can improve your answer by backing it up with in-universe evidence, or quotes from the authors, outside evidence, etc. For example, is there an in-universe example of Superman being able to perceive tachyonic particles?
    – DBPriGuy
    Commented Dec 1, 2016 at 16:25

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