Reality check: The science of Superman

Superman is one of the best-known characters in comic book history, an icon that everybody is familiar with. An alien from the planet Krypton, there is no doubt that he is an impossible idea but, if we were to use our current understanding of science to think about him, how might he work?

It is commonly acknowledged that Superman’s abilities stem from living under a yellow sun (he takes in and metabolises solar energy in the same way humans do food), and he is able to store or overcharge himself if he sees fit. By contrast, red sunlight weakens him – the make-up of the yellow and red stars’ emissions is no different, but the red sun emits far lower amounts of heat and light. The red sunlight blocks the yellow, and Superman is eventually starved, if you will.

Is it a bird? Is it a plane? No, it’s re-purposing of solar energy. Image: Pixabay

A lot of his powers are spun around his re-purposing of solar energy – his ability to fly, for example. Originally, Superman could just jump farther and higher than man, giving the impression of flight as he leapt about. In Zack Snyder’s Man of Steel, Superman’s stock of energy affords to him a bioelectric aura, and he uses this to manipulate the gravitational fields around the Earth and keep himself aloft.

Some of the more improbable powers have quite simple scientific explanations. We can use the Joule-Thomson effect to explain Superman’s freeze breath, for example. This principle shows that when compressed air is speedily pushed through a restricted opening, it rapidly reduces the temperature – as Superman can forcefully exhale at high velocity and high pressure, the trickiest aspect is aiming his pursed lips.

It’s Superman’s super strength that leads us to more hypothetical science. We’ve seen him stop planes by holding the nose cone, but that wouldn’t work in itself – it would involve balancing the entire weight of a falling plane on a section of metal the size of a man’s hands (it’s akin to stopping someone falling by resting their chest on an upright knife – you see how that’s going to end). To better explain this, we turn to negative mass.

as Superman can forcefully exhale at high velocity and high pressure, the trickiest aspect is aiming his pursed lips

Negative mass is a so-far hypothetical state of matter in which all the properties of a particle are the same, except how they react to certain forces. If you pushed something with negative mass, it would move in the opposite direction to the way you pushed it. The idea here is that Superman can control and turn things into negative mass. In the plane example, he creates a web of negative mass throughout the vehicle – the force of the plane pushes on the web, causing it to resist and slow the descent without damaging the plane. It would also serve to explain why Superman’s strength seems to vary based on his enemy – negative mass can only resist force that is applied to it.

We’ve not had time to cover all his abilities but next time you find yourself enjoying the adventures of Superman, there may be ways you can really believe a man could fly.