Science Has Some Issues With Superman's Superpowers
Superman may be the most famous superhero of all time, but science has a few bones to pick with him. Students at the University of Leicester have published a paper asserting that Superman's flight abilities are in direct contradiction with the first law of thermodynamics.
The Man of Steel has often been criticized for being a somewhat "boring" superhero due to the sheer scope of his powers. It's much more interesting to root for a relative everyman like Batman, who may be rich and have lots of gadgets, but at least can be wounded and die, than to root for someone you know is going to win because he's invulnerable. Clark Kent, as the ubermensch, has every superpower under the sun: super strength, super vision, even super breath (not kidding). There are probably arguments to be made against all of these powers on the grounds of science, but these students have focused on his ability to fly, as it is the most easily quantifiable.
According to most of the DC comics, Superman's powers derive from his cells' ability to absorb energy from the Sun. In order to gauge whether his ability to fly is plausible, they calculated the amount of energy he would need for an eight-hour flight at an altitude of 30 km. They found that in order to maintain this altitude and overcome drag forces, he would need to use 207 billion joules of energy. Then, by calculating the area of his body that would be in contact with the Sun's radiation, they calculated approximately how much energy he would absorb: 1,096 joules/second. As a result, Superman's solar cell efficiency comes to a whopping 656,000%. In other words, during his flight he would use 6,560 times the amount of energy that he absorbed from the sun. The most efficient solar cell on Earth has an efficiency of 44.7%, but more importantly, any number above 100% violates the first law of thermodynamics, which states that energy is conserved, or that it cannot be created or destroyed within a closed system. Superman would need to be creating energy to maintain altitude for an eight-hour flight.
The students asserted in the paper: "It is also possible that instead of immediately using all energy he obtains, he stores the energy for future use. However even with a solar cell efficiency of 100% Superman would soon reach a depletion of energy, especially when the calculation in this paper only considers one of his many super-human abilities."
Student Jason Watson said: "To put it into context, a normal solar cell would need to be twice the size of a football pitch to acquire the amount of energy Superman would use during flight." Considering that the absorption of the amount of energy Superman needs is, in fact, possible, it likely wouldn't be difficult for the Superman writers to explain this away using some facet of Clark Kent's alien biology. For example, the paper uses the height and weight of an average male in order to calculate how much energy his cells would absorb from the Sun, but Kryptonians could potentially boast many more cells than a normal human. Although it may be tricky to make it seem plausible that he could absorb as much energy as an electrical device that's bigger than a football field, the "he's an alien" explanation is essentially a catch-all. One could argue that his biology is likely relatively similar to a human's, since Kryptonians supposedly didn't have any superhuman powers while they lived on Krypton, which didn't have a "yellow sun," their biology would need to be different enough to have evolved on a foreign planet and be able to absorb electromagnetic radiation.
The students don't really want to burst our bubble anyway, as Watson provided another viable alternative explanation: "There are other ways that he could be getting his energy. As well as electromagnetic radiation, the sun emits neutrino particles. Millions of these pass through our bodies all the time. Maybe he is somehow able to use energy from the neutrinos – but we don't know how he would do this."
He also commented on the real-world applications of Superman's energy efficiency: "As Superman is so efficient, it would be good if he could use one of his other powers – such as his ability to fire lasers from his eyes – to supply us with energy here on Earth." Hopefully the next comic will feature Superman saving the world from one of its most immediate nemeses: the energy crisis.