Superman/WMG

Superman is a scion of Dream.
This explains why no powerful magicians have managed to disintegrate him by now. After all, Truth, Justice, and the American Way are quite powerful dreams. It explains why he showed up at as well.
 * Of course, theoretically, every single person in the world was at.

Son Goku is literally the Superman of his universe.
The world Dragonball takes place in is Earth-7 in the New Multiverse, if that number isn't taken yet. Mr. Mind's eating of the world's history lead to changes in nearly everything:
 * Kryptonians now get powers from the moon rather than the sun.
 * Green Martians now come from a planet called Namek that's not even close to Earth.
 * The various talking animals of New Earth are far more prevalent on Earth-7.
 * The God of Earth-7 is far less impressive than his New Earth counterpart, but is totally a happenin' dude. As damage control, sufficiently advanced martial artists have taken over God duties from him, becoming the Supreme Kais.
 * Krypton is now Vegeta, as is Dru-Zod.
 * Jor-El and Kal-El are now Bardock and Kakkarot respectively.
 * The Waynes were never rich in this world, and Bruce was orphaned at a young age under the name Yamcha. Without the deep-seated urge for vengeance and justice as a driving force, Yamcha merely loafs around the world being a bandit, a baseball player, whatever comes up.
 * Frieza is the Mongul.
 * Cell is either Bizarro or Hank Henshaw, the Cyborg Superman.
 * Buu is Doomsday.
 * Broly might be a better Broly
 * Baby matches the Doomsday role the best (if he existed) ;).
 * The Spectre never Fell, and so rather than punishment as God's Vengeance, he has the much more relaxing job of watering His earth-based employee's flowers as Mr. Popo.
 * Garrison Slate, founder of S.T.A.R. Labs is Dr. Briefs; he never married on New Earth and thus Bulma doesn't have a parallel
 * Lex Luthor was born several years earlier than usual, and is Dr. Gero.
 * Destruction of the Endless isn't retired, and is quite active, resulting in the massive casualties and planetbusting. He is, however, still a nice guy, which is why none of the massive damage is ever permanent.
 * Etrigan got attached to someone from another world, rather than Jason Blood, and never became a rhyming demon. He now goes by the name Dabura.
 * Turles is Bizarro.
 * With no Speed Force to point him in the heroic direction, Wally West bulked up and became an immensely popular action movie star and tournament fighter. Having redubbed himself "Hercule"/"Mr. Satan", West would not discover his selfless streak until the world turned to him, of all people, to destroy the monster Majin Buu/Doomsday. Though grossly outmatched, his charm and charisma twice proved useful in the ensuing war.
 * Alternatively the speedforce is replaced by the "instant transmission dimension".
 * The Deadzone is obviously the altered negative zone.
 * "Earth-7" is already taken. Dragonball could take place in the Earth-7 of the Old Multiverse. All we know is that's where Dark Angel came from.
 * ...So Kryptonians have tails?
 * That universe's Gorilla Grod was a monkey instead, and he went back in time and really screwed up a plan to turn everyone into monekys, and just made all the Kryptonians more monkey like. Also Mr Satan isn't the Flash, HE'S BATMAN, who without the whole traumatic parental death thing, grew up to be a rich idiot for real who only finds his inner hero when he really needs to.
 * Originally, Lois was bossy, competitive, and demanding, and in this universe, as Chi-Chi, she never grew out of that.
 * Jimmy Olsen is Krillin, the best pal who has random spurts of great power but never surpasses Goku/Superman.
 * And Vegeta must be Zod, a man from the hero's homeworld who is considered his rival yet is defeated time and time again. In this universe, he eventually mellows and joins the heroes.
 * After reading the Dragonball Frige page It occured to me Piccolo is Batman, After a traumatic incident he grew up and went around the world alone, he like Batman depending on the continuity is a loner and Team Dad, he started out as rivals but eventually became friends with Superman/Son Goku.
 * Piccolo not Yamcha is Batman.
 * Ok if we are gonna use DC logic
 * Goku: Superman
 * Vegeta: General Zod
 * Nappa: Non
 * Piccolo: Lex Luthor (Unlike the Saiyans or Cell He wanted to rule the world rather than destroy it.)
 * Gohan: Superboy/Connor Kent
 * Frieza: Darkseid
 * Cell: Brainiac
 * Bardock: Jor El
 * Lord Slug: Mongul
 * Bojack: Massacre
 * Princess Snake: A depowered Maxima or Encantadora
 * Hatchack: Brainiac
 * Bio-Brolli: Doomsday
 * Pilaf: The Golden Age Luthor or Pokolistan Zod
 * Mai: Mercy Graves
 * Shao: Either Otis or any one of Luthor's henchmen in Superman Returns
 * Dr. Gero or Dr. Kochin: Cyborg-Superman
 * Shula: Satanus

Martha Wayne and Martha Kent are the same person.
Thomas Wayne did die (so Batman's angst is valid), but Martha escaped and went into witness protection, moving out to Kansas and marrying Jonathan Kent. Martha doesn't know Batman's identity (as seen in Identity Crisis) and even Superman may not even realize it.
 * This does raise the question of why Martha Wayne-Kent wouldn't take her grieving, shell-shocked ten year old son with her, though.
 * Amnesia! It solves so many inconvenient plot problems in comic books.
 * On the other hand, Clark and Bruce are around the same age, and Clark had been living with the Kents for a decade or so when Bruce's parents were killed...
 * She was leading a double life as both Kent and Wayne, 'visiting' relatives. The the Waynes got shot and she had to cover her tracks. Even worse, she might not have been innocent in the shooting.
 * Does that means that Pa Kent is sterile? Since Martha Wayne gave birth to Bruse, that means that both she and Thomas weren't. Oh and how do you explain that she looks nothing like other Martha? Bruse have her portrait in his mansion, what a detective is he if he can't see it? XD

The ancient Greek heroes were Kryptonians.
Hercules narrowed the Straits of Gibraltar to keep sea monsters out. Other Greek heroes had other improbable feats unless they were Kryptonian or half-Kryptonian.
 * The Greek Gods are already real in the DCU, and explicitly supernatural in origin. But the Godwave that formed them (assuming it's still canon) could also have been responsible for giving the Kryptonians their powers.

Superman, in The Movie, is literally Jesus.
Ignore the symbolism and just focus on the text:
 * Jor-El says he will have been dead for thousands of years when Kal-El grows up.
 * Krypton blew the heck up. Therefore, the destruction of Krypton was bright enough to be visible on earth as the Star of Bethlehem, which signified the coming of the savior. Thus, Kal-El is either a second coming of Jesus, or else the first one was just a coincidence.
 * In the comics, though, he's Moses. Had Jewish creators, was found in the reeds as a baby, empowered by his heritage, etc...
 * "Kal-El" is Hebrew for "All That Is God".
 * Try Maggin's novel Last Son Of Krypton. Superman has a near-death experience where he sees the face of God, who looks exactly like Jor-El.

God works In Mysterious Ways.

Kryptonians are actually genetically modified humans.
The people of Krypton are depicted as physiologically no different from humans on Earth, barring the fact that they gain super-powers under a yellow sun; this suggests a common ancestry. If we assume that humans were brought there Stargate SG-1-style, they were likely altered to survive living under a red star. They were deliberately made weak to kryptonite as a precaution if someone managed to escape off-world. This appears to be reinforced in stories were Clark and Lois successfully have offspring, such as in Superman Returns.
 * This was actually semi-canon in the Silver Age, when Kryptonians were said to be the descendants of two stranded Human Alien space travelers named Kryp and Tonn. A classic Adam and Eve Plot. And all DC Universe humanoids, including Kryptonians and Earthlings, were once said to be the descendants of the Oans. In the Post-Crisis continuity, it's implied that the Kryptonians genetically modified themselves, which could concieveably include mingling the DNA of native solar-absorbing lifeforms with "alien" Earth-human genes to help them better adapt to their harsh new homeworld.
 * The origin story of Doomsday is also consistent with this theory, as it too involved alien lifeforms being adapted to Krypton by a scientist with advanced knowledge of genetics. And they never did say what world the genetic material used to make Doomsday came from, just that it wasn't from Krypton... could it be Earth? And could other partly-modified clones have escaped into the wilderness to breed, becoming the ancestors of Superman?
 * Supposedly, in an early draft, Jerry and Joe planned to have Kal-L come from the distant future, when the dying sun is about to engulf the Earth. Jor-L sent his progeny back in time millions of years, where he would thrive and live a full live among his distant ancestors.
 * Let's reverse the theory: The Fourth Kryptonian told us about the existance of a Kryptonian Empire sometime before the end of Krypton. Kryptonians colonized many planets and killed many species off. In One Year Later, Lex used a Kryptonian ship that belonged to admiral Dru-Zod, Zod's descendant. Said ship was buried on earth. Alura Zor-El calls humans "Proto-Kryptonians" during New Krypton. Logical conclusion: Humans are actually genetically modified kryptonians. Earth is a lost kryptonian colony that gradually lost their super-powers and technology. Said colony eventually sucumbed and changed. The Bible's "antedelluvians" are actually mutant kryptonians who were still quite strong until the dinosaurs died. This forced them to change into smaller, weaker forms. Some time after, they started to evolve until they assumed the form of their kryptonian heritage again. Meta-Human powers come from genetic remants of their former kryptonian abilities that eventually evoluted to not require the sun's power. Optionally, Kryptonians lost their fabled powers due to outside interferance of the Guardians of the Universe. There are records that they did this before with another race, when they turned a race of cosmic horrors called "The Burning" into the Martian race.
 * Also, all characters from all mythologies and religions that shows powers similiar to Kryptonian (like Hercules, Samson, Thor, Goliath) or very long live span (Adam) are descedants of the Kryptonians, that for some reason has an acess to part of power hidden in their DNA. Same thing with all characters from Earth with Superman-like powers.
 * Already Jossed, see "Greek Gods" WMG above.
 * Maybe it's the other way around-- humans are actually descended from Kryptonians. Krypton is, after all, said to be a much older planet-- maybe they terraformed kryptoformed Earth billions of years ago, and we're compatible because we come from their DNA. This is how the Wildstorm Universe's Kryptonian-equivalent Kherubim did it, and they are an Alternate Universe of the DCU...
 * Alternately, Kryptonians are not related to humans, but one of Superman's undiscovered powers is genetic recombination-- he unconsciously altered his own reproductive DNA to be human-compatible.
 * This might explain why sometimes Earth Gods get upset/nervous when Superman or Supergirl mention Rao...
 * This might explain why sometimes Earth Gods get upset/nervous when Superman or Supergirl mention Rao...

Bizarro World is the original planet, and Earth is the planet of imperfect duplicates.
Bizarro World is a Utopia. Contrast with Humanity. Our memories of Earth being the original planet and Bizarro World being the duplicate are just a mixed-up version of the truth, caused by a flaw in the duplication process. They're not the Bizarro Universe, we are.
 * Everyone has superpowers.
 * The supervillains only do good deeds, and the superheroes only punish the villains by taking them to amusement parks.
 * Bizarro Batman is always cheerful.
 * The whole planet has a childlike innocence.
 * Bizarro Ambush Bug is intelligent and erudite.
 * That is massively depressing...
 * On the upside (for us) the Bizarro Beetles SUCK, musically.
 * That's probably because they're literally beetles. The Bizarros built tiny instruments for them and everything.
 * That's adorable.
 * Also consider that in one story, the Bizarros tried to maximize the casualties from a meteor strike.
 * Wouldn't which one was the "Real" Universe be relative? As in, which ever one you're on, is the real one for you? Hence, to a person on Bizzaro!Earth, they'd be the real ones. Sure, maybe they might have been the ORIGINAL ones, but that's not the same as the "Real" one's right?

Superman's tendency towards dickishness is the result of a Stable Time Loop.
The most formative years of young Clark Kent's life were spent with The Legion of Super Heroes - and check out the picture on that page. That's where he gets his famous dickishness, folks: his adolescent peers. But the Legion were inspired by the legend of Superman, which means that they learned their dickishness from Kal-El! It's a temporal loop of dickery, my friends.
 * Oh god... That makes sense... But it doesn't explain why he lacks some of his dickishness in animated series.
 * He didn't spend time with them in S:TAS?

Daily Planet's reporter Clark Kent is Superman.
Think about it; he and Superman look suspiciously alike, have never seen together and a number of Superman's civilian friends are also friends of Clark Kent. Kent's nerdiness might be a case of Obfuscating Stupidity
 * Impossible. Clark Kent wears glasses. If Clark Kent took off his glasses, he couldn't see. Superman doesn't wear glasses. Superman can see. Therefore, Clark Kent is not Superman.
 * Maybe he wears contacts
 * Or maybe they just happen to look alike. Clark maybe a bumbling oaf, but he is an investigative journalist. Superman is an alien from a hyper-advanced world. Give Them some credit. The guies of WEARING GLASSES won't fool anyone, least of all these two.
 * If he wore contacts then he wouldn't be able to use his heat vision.
 * Unless he had some sort of heat-vision-proof glass/plastic. Maybe something leftover from Krypton?
 * Also, Superman never lies. If he was pretending to be a mild-mannered reporter, he would all but have to lie. The guy was brutally honest enough to tell a fully clothed Lois Lane that he was using his x-ray vision to look at her underwear!
 * How do you know he's not lying about never lying? For all we know everything could be an intricate web of lies created by this possibly dangerous alien trying to made us trust him, and then destroy the world, or something.
 * ... That you Lex?
 * WRONG! ...... no
 * Next you'll all be saying that Bruce Wayne is the Batman...
 * Now that you mention it...
 * No no no, see the Batman WMG page. Batman is everyone but Bruce Wayne.
 * Jossed. A few minutes ago, Stephen Colbert took off his glasses and gave himself a coif, and he looked exactly like Superman. (No, seriously, he does. It's uncanny. Seen at 1:45.)
 * This is insane. Why would Superman, who is nearly a god, spend 40 hours a week playing reporter when he could spend all that time catching bad guys, deposing evil dictators, etc.? The very idea that Superman has a secret identity is just ridiculous.
 * Superman and Clark Kent have too been seen in the same place at the same time. Now Clark Kent and Batman...
 * And Bruce Wayne is Superman. I mean, if you had Superman's powers, and were making a secret identity for yourself, wouldn't you make yourself rich and powerful and live in a mansion and date tons of beautiful women?

Clark Kent is Superman.

 * Jossed. I mean, look at those glasses! Superman doesn't wear glasses!
 * A mild-mannered reporter who keeps losing interviews to that Lane girl... is Superman? He doesn't even have a coiff! My money's on Stephen Colbert. I have heard that Clark's been seen sneaking out at night in blue and red pajamas, but there hasn't been any picture evidence, and it's only hearsay that he caught a steel girder once with his bare hands. With that evidence, he sounds a lot like Spider-Man. Maybe he and Stephen just switch off patrol areas to have an alibi.
 * Nope, Colbert is in the Marvel Universe. He's appeared in their comics and has Captain America's shield, for Cthulhu's sake!
 * What better way for them to maintain alibi than to patrol in each others' universes?

Superman can't actually fly under his own power.
Martians can fly no matter what planet they're on. Tamarans can fly no matter where they are. But on Krypton, Kryptonians cannot. There is no real reason why solar charged cells could make somebody fly.
 * There's no real reason it should make you bulletproof, either. Just go with it.
 * Maybe Kryptonians have the same mechanism that allows those other species to fly, but it's less efficient and requires more energy. Thus, on sun-deprived Krypton, their "flying cells" were just too weak, they get supercharged under a brighter sun...
 * Perhaps he pretends he can fly by jumping dramatically.
 * No, because he actually hovers, and accelerates.
 * He can stand on and jump on air.
 * Maybe he stole an antigravity belt from Luthor?
 * He's just always using his Legion of Super-Heroes Flight Ring.
 * Psionic power. Self-telekinesis. The comics are starting to hint at this. Hey, it worked for Connor Kent! (RIP)
 * If by "starting" you mean "for the last two decades". Longer, if you count Gladiator, a Superman Captain Ersatz from the Marvel Universe.
 * Since the Post-Crisis Superman can absorb virtually the entire EM spectrum (that's how his Super Senses work) and convert it to other forms of energy such as heat vision and strength, he may also be able to convert it directly into kinetic energy (motion).
 * Maybe his body is the biological version of one of these...
 * In most continuities, Krypton has extremely high gravity, sometimes even described as having a core of degenerate matter, yet the inhabitants are human-shaped bipeds, an extremely inefficient form for an extreme high-G world. Perhaps, just as they adapted to the lack of energy by absorbing sunlight, they also adapted to the gravity by developing a means of manipulating graviton particles, this allowing them partial resistance to the crushing G. Deprived of this environmental stress, the Earth-raised Clark was able to learn to use this quality in different ways, such as creating an imbalance in the local gravitational field that makes him "fall" in directions other than straight down.
 * He stays still, and moves the planet under him.
 * He has the invisible Martian Manhunter carry him everywhere, the lazy oaf...
 * Rocket farts.

Superman is immune to Kryptonite.
Think about it. Jails are filled with people who almost killed Superman with Kryptonite. He could very well be faking the whole thing just to get people to use harmless green rocks on him instead of actual weapons. As for Red Kryptonite, he probably paid off some sorceress to fake the effects in exchange for watering her lawn.
 * The implications this bears for pink kryptonite are... odd. And explain why exactly he's always palling around with Batman.
 * He's faking it with Lois, possibly because, being raised in a rural setting with possible memories of "perfect" Krypton, he's homophobic.
 * Or he's just Bi...
 * In fact, pink kryptonite was only shown in an alternate timeline, so we don't actually need to explain that at all. He's never been affected by it in continuity. Besides, it's always possible that he's only faking it with the green, and the other colors do really affect him.
 * This would explain how he could survive being shot at point blank range in the back with two kryptonite bullets and survive.
 * See "Repeated Exposure" WMG below.

Silver Age Superman is a rogue Q
Think about it. The only thing more infamous than the Earth-1 Superman's dickishness is his sheer overpoweredness, performing godlike feats ranging from moving planets out of orbit to blowing out stars to bending the very space-time continuum itself to his will. Combine that with his callous, mischievous personality (and ignoring the far-fetched "excuses" he makes up for his behavior), Superman clearly has more in common with Picard's Q, or even Trelane, the Squire of Gothos, than with any other version of the Man of Steel. The bizarre monsters and enemies fought by Superman were, of course, also the product of his warped imagination, and his "friends" never saw through his Paper-Thin Disguise simply because he didn't want them to.

Pre-Crisis Superman is Mr Mxyptlzk
He wasn't erased from history.Being utterly over-powered and having visited Earth-Prime,Supes was aware the events of Crisis on Infinite Earths would Ret-Gone him.Using his total overpoweredness,he punched through reality and fled.However the resulting continuity disturbances would cause him to become even more powerful,causing him to create the entire 5th Dimension by accident.Now an Unperson,Supes decided to pretend to be an inhabitant,later known as Mr Mxyptlzk,and mess around with other versions of himself.Bat-Mite was created based off Batman,who was just as powerful and created Larry and his dimension. Hence why he has Medium Awareness -- he's visited our universe.

Kryptonite isn't a weakness for Kryptonians, but rather a strength of humans.
The Green Blast was a way of keeping other species from using their big guns o' death to eradicate the surface of Krypton and move in. If anything bad happened (including a security system malfunction), the entire planet would be bathed in a form of radiation that most species in the galaxy were affected by. Humans are affected too, but it takes about thirty years of constant exposure, so other forms of radiation would be a lot quicker. The extraterrestrial species that have handled Kryptonite would be okay for a couple of days, but would otherwise have to keep it in a shielded container or suffer the same effects as Superman, albeit more slowly. The reason we don't see more species that are as weak to kryptonite as Kryptonians is that they all have a healthy fear of not dying in an easily avoided manner.

Repeated exposure to Kryptonite makes Kryptonians more powerful.
Kryptonite still hurts Kryptonians, overwhelming their metabolisms and disrupting their powers, and overexposure can be fatal -- but when a Kryptonian survives exposure to K, he or she becomes more powerful, even gaining entirely new powers.
 * When Superman first appeared in 1938, he was very strong, very durable, very fast, and had amazing sensory abilities, but couldn't fly or shoot Eye Beams. After the The K-Metal from Krypton was written but not published two years later, he gradually started becoming more powerful. Leaping tall buildings gave way to flight, keen senses became X-Ray vision, and his strength and durability slowly increased. After Kryptonite was officially introduced to the comics in 1949, his Power Creep accelerated. The more Kryptonite he encountered, the more powerful he became, eventually becoming able to fly faster than light, break the time barrier, and move planets around by brute force.
 * In 1970, a storyline eliminated all Kryptonite on Earth. Superman's powers were reduced roughly by half, ostensibly because of an animated doppleganger -- but really because the same explosion also purged much of the effects of K radiation from his cells. As Kryptonite continued to fall to Earth, his power levels recovered, and eventually surpassed their pre-'70 levels.
 * After the Re Boot caused by the Crisis on Infinite Earths, his power levels dropped again -- but slowly climbed again as he continued to encounter Kryptonite.
 * Both the 1959 and 2004 versions of Supergirl had considerable exposure to Kryptonite prior to arriving on Earth. Each arrived on Earth with her power level roughly commensurate with Kal-El's then-current abilities, despite not having had a lifetime of exposure to absorb "yellow sun radiation" like her cousin.
 * Variation: Kryptonians don't gain their powers from Earth's yellow sun. They gain it from Kryptonite. Baby Kal-El caught enough radiation when his spaceship rocketed away from the exploding planet to give him the comparatively modest abilities of his early career.
 * That actually could work. Perhaps the reason Kryptonite hurts them is because it's over charging them, to the point where their energy absorbtion abilities have to kick into over drive, causing the effects of 'Kryptonite poisoning'. Like a 60W lightbulb in a 250W socket.
 * This may actually be supported by the unpublished K Metal story by Jerry Siegel. Kryptonite is depicted as making humans temporarily stronger (reminiscent of the Green Rocks from Smallville), and Superman comments that he drew strength from the stuff until "the connection was broken" upon his leaving Krypton, and now it weakens him. Weird, but the argument could be made that K-Metal still strengthens expatriated Kryptonians, albeit after some sort of "allergic reaction" caused by prolonged lack of exposure.

Kryptonite posseses intelligence and is actively trying to murder Superman.
The Kryptonite meteor follows Superman to Earth. It always winds up in his enemies' hands. It multiplies and spawns new forms of itself. Kryptonite may be a nanotechnological agent designed to destroy Krypton, and when Kal-El escaped, it sent a piece of itself to hunt him down. And it absolutely will not stop, ever, until Superman is dead.

Pre Crisis Kryptonians could project any form of electromagnetic radiation from their eyes.
The Pre-Crisis descriptions of X-Ray Vision made it clear that actual X-Rays were being projected (in at least one comic, Superman uses this to decontaminate a germ-ridden artifact). And we know that Kryptonians can project infrared radiation (heat vision). But there are some hints that the power goes beyond this. One old Silver Age cover showed Superman, underwater, using his eyes as headlights. In other words, he was projecting light in the visible spectrum. This implies that old-school Kryptonians may be able to project any kind of electromagnetic radiation they want. Superman restricts himself to "X-ray vision" and "heat vision" because that's how he conceptualizes his powers. But his biology probably isn't actually limited to that.
 * And perhaps into other forms of energy such as kinetic. See the Flight WMG above.
 * The above explains his super breath; it's not physically possible to toss cars down the street with a mere two lungfulls of air no matter how forcefully exhaled. He's adding to the kinetic energy of the air to give it more "push". His super-cold breath works because he absorbs heat from the same air.

Superman's source of power is somehow related to the emotional spectrum.
The thing is, it doesn't really make sense that Superman gets powers from yellow sunlight. Why would a species that evolved under a red sun develop powers from a yellow one, and actually be weakened by their own sun? Makes no sense. But the thing is, these colours are connected. Kryptonians have no power under a red sun, some powers under an orange, are ludicrously powerful under a yellow, and gain even more powers under a blue one. This is obviously connected to the spectrum; given the emotional nature of the spectrum in the DC universe, it stands to reason this would all be connected somehow. Perhaps Superman draws power from emotions, the more pure the emotion the better. This would also explain how he is able to defeat things through the Power of Love so often.
 * It logically follows that if someone were to synthesize violet sunlight, and expose a Kryptonian, Argonian, or Daxamite to it, they would become more powerful than Dream, capable of bending reality with mere thought.
 * Incidentally, how do green suns fit in? Like red ones, they do not provide superpowers.
 * They give him the power of positive thinking.
 * The Post-Crisis Byrne reboot explanation was that red suns simply put out less energy than yellow ones-- the red sunlight by itself didn't weaken him at all, it just wasn't enough to strengthen Kryptonians to Superman-levels (in fact one storyline of that era had him time-travel to Krypton and still had his powers). The recent "red sunlight weakness" is a Silver Age element that has crept back in thanks to those Running the Asylum, and Silver Age stuff doesn't have to make sense. But, if sense you must have, maybe the presence of the specific frequencies of light that Kryptonian bodies are evolved for "resets" the metabolism, including the solar energy absorbtion/conversion, to its basline levels. The body becomes keyed to Kryptonian conditions so as to better absorb the exact same type of energy present in the environment that it's best adapted to. In other words, it fools his body into "thinking" it's back on Krypton. Or maybe...

Superman's weaknesses are psychosomatic.
He isn't really physically harmed by Kryptonite, Red Sun radiation, or even magic. But due to his humble upbringing, he feels like he doesn't deserve the vast power he's been given, and sabotages himself by creating weaknesses that allow him the potential to be defeated or even killed. Even though he never is. (One necessary corollary of this has to be that his powers are far greater than he admits to himself-- Red Kryptonite transformations mean he must have some degree of shapeshifting or illusion, splitting due to black/"tar" Kryptonite means he has self-duplication powers, etc.)

There is no Krypton.
Superman is from right here on Earth. He is an unconscious Reality Warper, and created all the "evidence" of his alien origin to explain away his other powers. One wonders just how much of the world he inhabits is of his own making...
 * That's actually a plot point in the recent Superman arc "Superman and the Legion of Superheroes". Legion rejects from Earth get pissed off, claimed the Legion lied about Superman and had the Federation hunt the Legion down. Supes has to go to the future to help out.

Superman's only real power is telekinesis
He just can't think generally enough to use it as such. When he wants to lift an airplane, he puts his hands against it as a psychological prop, but pushes on every atom of it equally with his subconscious. This explains why he never leaves hand-shaped holes in things he lifts or needs solid ground to stand on.
 * That's been canon at least twice, under the term "tactile telekinesis" (once as an explanation of Clark's powers and once as the only superpower of the 1990s Superboy, to differentiate him from Clark), and it never stuck.
 * If he can fly, he wouldn't need solid ground to stand on. Just increase his thrust to match the object's weight. And whether he leaves handprints or not varies greatly Depending on the Writer.

Superman's "x-ray vision" is really Kryptonite Ray Vision.
Since it's powered by Green Rocks, it can do stuff like see through brick walls but not clothing, and we know that lead is an effective block for kryptonite radiation. The reason he doesn't harm himself with it is that he is immune to the kryptonite radiation that he produces, like how the Summers brothers are immune to their own powerblasts, but not of others. (Prove me wrong. )
 * Um, he can see though clothing. And lead is also an effective block for X-Rays. Besides, one or two of the recent canons had him not actually emitting anything at all to see through things, it was just called "x-ray" vision as a verbal shorthand or nickname given by Jimmy Olsen. No actual rays of any kind were produced. The speculation from a pre-insane Emil Hamilton was that Supes was sensitive to the weak electromagnetic emissions of cosmic radiation particles (or neutrinos, I forget which) passing through normal matter, and his brain simply interpreted that input visually.
 * I meant why it could be precise enough to not go through clothing at the same time as looking through a brick wall, and I don't consider "speculation by other characters" (emphasis mine) to be canon unless it's confirmed by a reliable source. The "not actually emitted anything at all" bit, though, Josses this acceptably.
 * The fact that he can use it selectively argues against it being either Kryptonite or X-Rays. And yes, lab tests done by Dr. Hamilton did confirm the no-emissions thing, so it's not just speculation. (Of course that was several Cosmic Retcons ago and the writers might have changed his powers yet again).

New Krypton is screwed.
Because you can't have an entire planet of Krypton and Superman around at the same time since that ruins the entire point. So the question is: how will it be destroyed?
 * Explosion into a new batch of kryptonite, of course.
 * It's been done. Sucked into the Phantom Zone?
 * Plus, New Krypton is in the unstable L3 point, so maybe it'll just fall into the sun.
 * ...If Superman can survive inside our yellow Sun, why would the New Kryptonians give a rip about it?
 * You do realize that it is unstable on an astronomic timescale. Waiting for something to happen would take hundreds of thousands to millions of years.
 * Unless one of their or Superman's many, many enemies speeds up that timetable.
 * Or maybe The Rocky Horror Picture Show becomes popular there, they all take up doing the Time Warp, the whole population jump to the left at the same time with Kryptonian strength, the planet's mass shifts sideways, and...
 * Well we know that come May, there will be a war between New Krypton and Earth. Presumably, much of the drama of this event will be Superman having to choose between his adopted home or his own people. Eventually he will choose Earth and rather than kill the Kryptonians he will simply shrink them and send them back to Kandor.
 * Confirmed.

Superman: Birthright didn't go far enough with Superman's Secret Identity Identity.
He's got a third one, which is "Dealing with Kryptonians Kal-El". You can tell because he slips into being Superman from this persona more easily than he reverts to Smallville Clark. He actually has to act Kryptonian (albeit an extremely human-affected Kryptonian, like Spock). It doesn't show up very often, though, because of (fewer and fewer of) all Kryptonians having died except him.
 * This is hardly original with Birthright, it's an idea that's been explored since the early Bronze Age of comics (late 60s/early 70s at least)-- that "Clark" and "Superman" are both aspects of "Kal-El", the "real" identity.

Lex Luthor and Superman's rivalry is a direct creation of Batman.
Sure, they started it on their own, but it would have died off. Batman exacerbated it, and why? To set it so they can never follow their true desires. We've seen that Superman has a tendency to be a dick, and in at least one alternative universe (Red Son), Clark has shown a tendency to take over the world. Bruce is a prudent man, he can't keep his eye on Clark all the time. So he decides that Superman needs a "distraction." Enter Lex, who could easily take over the world, so Superman's interest and desire to remove Lex as a threat for his own control of the world means he's wrecking Lex's plans as a matter of self-interest. Lex and Clark counter each other in a twisted checks and balances system created by Bruce.

Lex Luthor is Superman.
At some point in Kal-El's childhood, he manifested a power he's still unaware of-- the ability to produce a non-powered avatar of his dark side, manifesting and expelling all his worst traits in bodily form. That's why Lex is so obsessed with Superman; he's unconsciously trying to get back home. Lex is literally Superman's evil.
 * This also provides a nicely cynical explanation for how he can stay such a boyscout despite the universe continually going to hell. All the frustration is shunted into Lex and makes him evil enough to keep up with the general crapsackification of the DCU. Bravo.

all of the DCU is a video game series on krypton and Kal-El plays them with godmode turned on.
The game is a sim and the actual goal is to blend in with earthlings but he has used cheat codes to make it more interesting, it certainly explains why everyone takes superhero related events in stride so easily.
 * This has to be the most awesome WMG I've ever heard.

Superman has no powers and is an ordinary human being.
One of The DCU's many Gods, godlike aliens, demons, wizards or five-dimensional imps actually causes the effects of all his "powers", and the "evidence" for his alien origin, as part of an elaborate practical joke for their own amusement.

Superman is the Emperor of Mankind.
It explains his vast powers, his charisma, and why the world turned GRIMDARK after he wasn't around anymore to be a bright symbol of hope.
 * Objection. The God-Emperor's powers are known to be mostly psionic in nature, while Superman's powers are of a physical kind. If anything, the God-Emperor is Superman's father, Jor-El, and Superman is one of the lost Primarchs who were sent through the Warp lost in time and space he landed on Terra in the distant past with powers and abilities above mankind. As for his brother Primarches the same thing happened, except they landed on planets in the present.
 * Objection overruled. The Emperor can actually control the aging rate of his own cells, which is as physical as it gets. Telekinesis is a psionic power, after all. The Primarchs were also created from the Emperor's own DNA, so their powers all come from him anyway.

Superman's presence is actually increasing mankind's progress rather than decreasing it.
Sure, he's had his detractors who claim his presence causes people to become complacent. But on the other hand, there is a positive side effect: people are more likely to do something daring with an extra line of defense. Superman's presence causes people to be just that little bit more likely to climb the Everest or attempt a potentially dangerous science experiment. The reason The DCU has so many more astronauts seems to be that they know that even if everything goes wrong and the control center is powerless to help them, Superman might still save them.
 * That makes perfect sense. Also, repeated, repeated (to the tune of dozens of times) evidence that actually, Superman can't be everywhere at once, no matter how many supervillains and alien overlords turn up in the solar system, would naturally spur people into having some defenses other than "let's wait for Superman". After all, the U.S. military has far more weapons than they would ever need to use — just in case. Also, this might be a radical idea, but — surprise! —  This is not the Marvel Universe.  Maybe the citizens of the DC earth might...*gasp*...feel obligated to help Superman out by discovering the means to take care of some of their problems by themselves?

People commit crimes simply so they can meet Superman.
Seriously, if there were a real Lawful Good uber-god on the loose, why would anyone in their right minds try to commit a crime? I mean, I know criminals are stupid, but given people will act crazy to try to get celebrities' attention, it makes sense that at least some people will rob and commit violence simply so they can meet the Man of Steel.
 * This actually is the motive for minor 1990s villains Obsession and Encantadora.
 * I am pretty sure that this genuinely happened to Green Arrow or someone at his level recently.

Pink Kryptonite does nothing.
It was Jimmy Olsen's smashing bow tie. When he added it to the rest of his outfit at coincidentally the exact same time Superman was exposed to pink kryptonite, it turned all male kryptonians in the galaxy temporarily gay. All further uses of pink kryptonite were the Pavlov effect.

Superman can be killed without kryptonite, but it would take an extreme amount of force
We've seen superman get hurt & even injured without the aid of kryptonite, so surely he can be killed without it.
 * Canon. See: Doomsday.
 * Did Doomsday actually kill him? I know he beat him quite close to it. I may be just misremembering, but how did he get into the regen-chamber they used to bring him back?
 * Wasn't his body stolen... a few times? It was stolen twice in animated movie. By Luthor and by Superman's robot.

The Science Council knew Krypton was doomed
It's been established that Jor-El knew. Brainiac knew, even if he lied to them about it. Why did the Science Council avoid doing anything? Because they knew what was going on, but couldn't take the guilt of having to choose who to save. That and they probably figured any efforts were doomed anyway, but what would happen is that much of the populace would take it as a chance to riot and otherwise ruin their last days. Why put them through that? Especially if the idea that Kryptonians die if they go offworld is in effect.

Mr. Mxyzptlk is Jesus.
In Whatever Happened to the Man of Tomorrow?, he says he spent 2,000 years doing nothing, 2,000 being a saint, and 2,000 being a prankster. That'd place the end of his "saintly" phase roughly around... yeah. And that would explain why miracles seem to be concentrated in the so-called "Biblical times" (~4,000 BC - ~30 AD).

During the Silver Age, Superman had a one night-stand with Optimus Prime.
We all know that the Silver Age was an age when anything could happen. This was an age where Super-ventriloquism could work in space. As such, one night, Superman got stupidly drunk and flew all the way to Cybertron where he hooked up with Optimus Prime for a one-night stand. They had kinky sex and then Superman flew back to Earth, waking up in the morning with a horrible headache and no memory of what happened. However, thanks to Superman's Super-Fertility, Optimus Prime became pregnant and gave birth to Superboy-Prime. The real reason Superboy-Prime is raging so much is all the missed alimony payments on Superman's behalf.

Superman can't be killed by Kryptonite unless it's used as a weapon, and not just a rock.
Think about it, how many times Superman was exposed to it? How many times he became weak, disoriented, depowered? But it didn't killed him. However, both Metallo, and Batman made a bullet out of it. Why? Because depowered Superman is a human, and humans can be killed by bullets - Duh. In Doomsday movie, Lex put a lead capsule (probably with explosives as well) with Kryptonite to blow it up if Supeman-two will rebel (overkill anyone?) because who know maybe his brain is also Invincible.

Reason for Superman's dickishness is lack of sex.
Build up of sexual energy, costume that constantly rubbing his body, X-ray vision, upskirts whenever Lois is in danger... That can cause a lot of problems.

Superman would've to have sex with his cousin/female counterpart should the original idea were accepted.
You know, the whole his sperm make women explode like a projectile flying thru on high speed?
 * What?

Cir-El really is Lois and Clark's time warped daughter.
And the reason she has a boys name is that she's a Mt F transsexual. This conveniently covers the plot hole of Brainiac being inexplicably unfamiliar with Kryptonian naming conventions.
 * Or, it could be that Krypton was quite sexist, with men getting their own names (Jor-El, Zor-El, Kal-El) and women getting the full name of their fathers (Kara Zor-El) and then later their husbands (Lara Jor-El). Superman's always been a bit of a forward thinker so maybe he thought that Cir-El should have her own name.

Superman is attracted to Lex Luthor.
I am basing this solely on the fact that most if not all of Superman's love interests have the initials L.L. Lois Lane, Lana Lang, uh, that mermaid. But what are Lex Luthor's initals? (I'll let you figure that one out yourself) I don't really want to entertain the idea but come on. There has to be some explaination. And aside from extraodinarilly creative lazyness on behalf of the writers the only one I can think of is that Superman and Lex Luthor are or at least have been more than 'just enemies'.
 * Ah, but you seem to be forgetting that "Lex" is short for "Alexander"! Thus making his initials AL and not LL!

Kryptonian superpowers are a gift from the Anthropomorphic Personification of Rao rather than something purely natural
Which is why they make no sense from a physics or biological standpoint; naturally, Kryptonians just have golden-age level strength from gravity differences and such, but Rao enhanced it. Why? Remember from the Sandman prequel that life formed on Krypton as part of a grand plan to have one Sole Survivor to suffer and mourn. However, Rao seemed like a pretty nice guy, all things considered. He must have realized at some point how incredibly cruel to that one survivor the plan was, and gave the Kryptonians enhanced superpowers triggered by sunlight other than his own so that the sole survivor would get something cool to compensate for the suffering.

The Loisbot was created by Brainiac
The Loisbot's creator has to be someone with access to alien robotics technology. Presumably her creator either wants revenge on Lex Luthor (such as for betraying him and destroying his skull-ship) or knowledge about the black spheres.

The Kryptonians were Celestial experiments
In the DCU, the Celestials carried out their experiments with much greater secrecy than in the MU. They created the Kryptonians, beings who had incredible power when under yellow sunlight. They also gave them weaknesses of red sunlight, kryptonite and magic to stop them from being completely unstoppable.

The souls of Peter Parker and Mary Jane Watson, along with all other ruined Official Couples, are currently residing in Clark Kent and Lois Lane.
Think about it. Almost every single long-running couple in comics has been completely ruined, either by death, Character Derailment, or other Deus Angst Machina plot developments...except for these two. Since the odds of so many OOC, illogical, or otherwise stupidly contrived coincidences is nil, it stands to reason that the breakup of so many couples is the result of an Evil Plan by extra-multiversal omniscient beings to suck the life out of both the main DC universe and Marvel's 616.

However, Plot Immunity is an actual physical force that is the only thing that can stymie said beings, so someone with access to both the main DC universe and the Marvel 616 universe (possibly all the myriad Reed Richardses of the alternate Marvel universes?) has sprung an emergency plan to store the souls of all at-risk happy couples in the bodies of the one happy couple armed with eternally impenetrable Plot Immunity, in order to keep them intact while still fooling the omniscient beings into thinking their plans have succeeded by showing how miserable the Soulless Shells of all the couples other than Clark and Lois now are.

Naturally, everything will go back to normal after the omniscient beings lose interest in these universes and move on to other exploits.
 * Taking this a little further: When the DCU relaunches in September, Clark and Lois will no longer be together, meaning all the couples will get another shot.

There will eventually be a storyline where Superman sues Lex Luthor for years of unpaid child support payments
Face it, Connor is as much Lex's kid as he is Superman's, and Superman and associates have borne the full costs of raising him without a dime from Lex. Sure, Clark makes a good salary now as a newspaper reporter, but the newspaper industry is going down the tubes fast, and in a few years living on a newspaper reporter's salary won't be plausible. When that happens, Clark/Superman will persue a source of income from a very wealthy man that has been just sitting there for years, and all Clark/Superman needs is DNA test records and a decent lawyer. Yes, this is incredibly implausible and out of character, but it is wild mass guessing, and is actually a lot more faithful to canon than a lot of the silver-age wackiness.

Superman is a giant chicken.
A giant CHICKEN, I tell ya!

Superman is an Eldritch Abomination.
Krypton was a planet of incredibly ancient, incredibly powerful beings who, seing their impending extinction, sent one of their offspring to our Insignificant Blue Planet not as its savior, but to colonize it, getting rid of any intervening species if need be. In self-defense, the young Kryptonian took the shape of the first species it encountered - humans - but after that the plan went a little sideways. Without another elder Kryptonian there to educate it about the Way of Things (with Kryptonians at the top and all other species wayyyyyyyy below), it was instead raised by humans, and given a human perspective of things and ahuman morality. He is still infinitely more powerful than humans and could easily obliterate Earth (see also Superboy Prime), but he identifies with them and has made it his goal to protect them.

Superman Returns did not retcon Superman III and Superman IV from continuity
Instead it only retconned one line--where Lana mentions Ma Kent's death in III. In reality, II and III take place possibly a day apart from each other, explaining why Lois still doesn't look pregnant. After the events of III, Superman goes on his five-year absense, and IV takes place after Returns. The reason why Lois is single in that movie is that her boyfriend left her and has custody of the kid during the events of the movie, and she has renewed her advances to Superman in earnest out of desperation.
 * Also, the Supergirl film takes place during Superman's five-year absense. The reason why the radio reports Superman as on a "peace mission" is because they needed to come up with a plausible reason for his disappearance for fear of the public reaction. It's just that this story falls apart quickly when the officials are pressed for specifics, and this leads to events that allow Lois to write her Pulitzer-winning article.

Lois Lane has prosopagnosia.
This explains why she is unable to realize that Superman is Clark Kent.

Superman is BLACK
Think about it. He runs really fast. He's been shot and still remains. He jumps really high. He kinda came here not of his own volition. And just as a goofy slightly racist one. He get's messed up around dat Kryptonite

For those who watch Transformers:Prime. Green Kryptonite is a variation of Dark Energon, therefore Unicron may be responsible for all human "copy-cat" alien life including Superman.
]] Think about it, Kryptonite looks almost exactly like Energon and Dark Energon (though more like the latter). Whose to say Krptonite and all its variations are a mutated form of Dark Energon? And it would make sense in the context of the latter part of the subject, Primus makes mechanical life and Unicron makes organic life.
 * They are both bad for humans to be exposed to, Kryptonite just takes longer.