[science of science fiction]

This question cannot be definitively answered because DC Comics has never definitively answered it.

And this is still one of the greatest shames of the DC Comics franchise. Without a clear quantification of Superman’s powers, it is truly impossible to answer some of the most important questions around the character, including Could Superman die of old age? Granted, given the powers of his enemies and the danger of his lifestyle, the possibility of him living to a ripe old age is probably slim to none but should he find himself growing older and want to consider whether he should sign up for a 401K, the question does need to be asked.

To address the question effectively we have to check a few things before we dive in. The first question is WHICH Superman are we talking about? Since the character has had multiple iterations and multiple continuities, each has possessed varying levels of longevity.

See: How many canon Supermen have existed since his first appearance in Action Comics in 1938?

The main versions of the character include the Golden Age version, the Silver Age version, the Post-Crisis version and the Modern DC New Earth version. We are going to skip the Post Crisis, John Byrne version because he no longer exists and we will skip over the DCnU version because he is still too new for DC to have revealed enough to know for certain. He has been returned to his youthful age of 25 to 30-something after their recent reboot of their universe.

We will talk about a couple of examples of Supermen who didn’t appear to age and a couple that did.

DC has published the DC One Million storylines where a Superman has retreated into the sun to live (yes, INSIDE the sun is where he places his Fortress of Solitude, and I can bet he gets NO visitors) and has gained powers far beyond any of the versions of the character that has existed to date. His powers were so fantastic, he was able to power his descendants giving them extraordinary abilities as well. Superman Prime (as he was called) appeared to be invulnerable, immortal and completely unaging. This was a Post-Crisis version of Superman.

DC has also shown signs of Superman aging. The original Golden Age Superman (Kal-L) whose origins on Earth-2 (Pre-Crisis) seemed to age as an ordinary human would. He married his universe’s Lois Lane and the two seemed to age at comparable rates. His powers also diminished as he aged, making him only a fraction as strong as the Earth-1 Superman of the same time period.

Another aging Superman was the Kingdom Come Superman (which counts as an alternative Earth storyline, but it was a very popular version of the character). He aged far slower than humans, and grew more powerful as he aged. He lost his vulnerability to Kryptonite but was still capable of being harmed by the chaotic energies of magic (he tests this by cutting his finger on Wonder Woman’s god-forged sword). In this iteration, his power were great (not as great as the Silver Age Superman or the Superman Prime character) but quite formidable and he hadn’t appeared to lose a step due to the aging process.

The Silver Age Superman (the second most powerful version of the character, and the version you probably grew up on before his reduction of powers after the Crisis on Infinite Earths, DC’s first universal reset) had vast powers under a yellow sun and did not appear to age at all. While he could be (theoretically) killed in battle, once he reached an adult age, there was no further sign of aging. This character existed Pre-Crisis as well. This character was so powerful in one of his stories he sneezes and destroys a solar system. I believe this is the real reason the Crisis on Infinite Earths had to happen…

So CAN Superman die of old age?

The question can’t be answered effectively because no one has ever written the definitive treatment on how Kryptonians acquire superpowers on Earth, (or for that matter how metahumans acquire powers in the DC Universe) and there is no ratified documents describing how the Kryptonians (Homo Sapiens Krypton), who resemble (Homo Sapiens Sapiens) in appearance, but vary so far from us in terms of biological processes.

Are the Kryptonians related to Humans and happen to have a convergent evolution? Are the Kryptonians genetically-modified humans, who use technology to create superhuman abilities when powered by particular wavelengths of energy? Are the powers of Kryptonians only viable in certain environments or under certain conditions but in all other ways they resemble humans? Are Kryptonians peak engineered humans whose physiology without powers is simply better, having reduced or eliminated the threat of disease, genetic dysfunction, and slowed or erased the aging process?

These are the questions which are never definitively answered so questions about Superman’s aging (with yellow sun or without) can be answered fully.

As a thought experiment, let’s look at the recent Man of Steel version of Superman to determine through inference if Superman can die of old age.

The Kryptonians had a population management program where members of the society were born through an in-vitro process of genetic recombination of traits. This may imply:

Kryptonians possess superior genetic recombination science. They were able to selectively mix and match genetic capabilities to ensure genetic dispositions for abilities were passed down. The Kryptonians had already cleared away genetic imperfections or diseases which shorten lifespans. This may be the reason they were utilizing population controls. A species with very long lifespans may need to keep populations under control lest they overrun and destroy their environment with near-immortals consuming everything. Since they were mining the core of their planet, this may imply they had already HAD an ecological over-population which precipitated their regulation of their population as a potential counter. Though we have no indications of how old anyone was, we do see examples of older Kryptonians on the Council, and Jor-El is a bit grey (approximating the age of a man in his mid-fifties) though he appeared hale and hearty enough to hold his own in an unfair fight.

We can assume aging takes place among the Kryptonians while they live in their native environment, though its rate in comparison to Humans is as yet unknown. We can compare Kal-El’s growth rate from child to adult as similar enough to our own, he was able to blend into Human society without incident regarding his physiological growth rate.

Once he was fully an adult does he stop aging?

This is the question that cannot be answered effectively unless we are able to understand how he is able to fly, resist incredible amounts of physical damage and project energy from his body.

If we assume physical capabilities which require a catalyst to activate (in this case, the yellow sun) these abilities would be in addition to his normal Kryptonian genome, perhaps genetic technologies woven into their genome as a survival strategy for conquering other planets or surviving hostile environments.

With such abilities, however, a single Kryptonian could conquer any planet with an environment like Earth’s. And it would make sense for Kryptonians to do so. Unfortunately, only about ten percent of the galaxy’s stars are similar to our sun, so on most planets they would have far less durability or capability.

So if these are genetic patents designed to be a support technology increasing durability, strength and resilience, they would only be most effective on a tiny range of planets overall.

Did the Kryptonians know this? Judging from the speed some of them learned and used their abilities, I can only surmise that indeed, some of them were aware of what they were capable of.

If their genetic technology did not completely stop their aging on Krypton, but were an integral part of their biological structure, it is safe to assume, even under a yellow sun, the Man of Steel Kryptonians require sustenance, water, air and other biological necessities, which can be temporarily reduced or ignored while living under a yellow sun. For Kryptonians to be able to live and utilize energy as a biological organism, even a perfect one, experiences some level of entropy and overall decay.

SUMMARY

My verdict would indicate the Man of Steel’s Kryptonians were masters of genetic and engineering technologies which give their underlying Humanoid physiology fantastic capabilities under a tiny window of conditions. Given the right solar energy levels, the right gravitational fields, they are prodigious engines of destruction but even they had limits. Note that Faora Ul (who was wiping up Smallville with Big Blue and the US Army) was taken down by a cruise missile which evidently delivered sufficient force to knock her down and out.

That means we still had technology strong enough to kill a Kryptonian, if you didn’t mind the collateral damage required to do the job.

Having 100,000 years of technological evolution to work with makes any Kryptonian advance technology appear as magic to us. They mastered space travel, dimension-crossing, wormhole generation, genetic engineering, recombinant DNA mastery, and energy manipulation abilities we don’t even have names for.

But their greatest limitation is their desire to maintain a human form.

Is it vanity? Or is there some other societal issue? Is it an inability to alter their physical capabilities further without a change in their psychology? Why did they give their bodies such capabilities and then limit them to a tiny subset of environments?

Something in this limitation makes me believe there is an underlying limitation in their genome we are not aware of.

It is this unknown limitation which makes me believe they have mastered their genome sufficiently enough to REDUCE aging but not completely STOP it.