Superheroes are special because they are more than human. Their bodies can do things that we could only dream of, and they have access to technology that is years or even centuries ahead of our own. But they were written by people with their feet planted firmly in reality, and if you look hard enough, some of their powers are not as impossible as they first seem.
The first DC comic was printed in 1935, and Marvel's debut offering followed soon after in 1939. At the time, the first programmable computer had only just been invented, we didn't know the structure of DNA, and the mobile phone was still decades away.
Since then, science and technology have started to catch up with the stories, but are all superpowers within our grasp? Join us as we explore the science of superheroes, and find out which laws of physics have to be broken to allow our favourite characters to perform their signature moves.
Could Batman's tech exist?
The protector of Gotham City is just a man, but are his skills and technologies within reach? Most of Batman's abilities are the result of an arsenal of gadgets, and many are within our grasp. Take his motorcycle, for example; it has a stealth mode that enables it to disappear from view, and incredibly, there is already technology that can do something similar.
BAE Systems is developing a camouflage material known as ADAPTIV. When viewed through an infrared camera, the special panels mask the normal heat signature of military vehicles like tanks, replacing it either with signals that match the background, or with heat patterns that match other objects, like small cars or even cows.
Batman's suit is also grounded in reality. In the Christopher Nolan trilogy, his armour was fashioned from Kevlar - a synthetic material widely used to protect military and law enforcement personnel. When a bullet hits the vest, it tries to force through the layers, but it cannot push the fibres apart because they are tightly woven. The fibres absorb the energy of the bullet by stretching a small amount.
The US Air Force has even developed what they're calling the 'Battlefield Air Targeting Man-Aided kNowledge', or Batman. This programme will test innovative wearable devices for Special Forces to take into combat.
Superman was born on Krypton, a planet more massive and denser than the Earth. As a result, his bones and muscles are genetically adapted to withstand a greater gravitational pull. But could this explain his superpowers?
When human astronauts visited the Moon, they found that they could lift heavy objects with little effort and leap several metres in one bound. The idea is that Superman's experience on Earth - a relatively low-gravity environment for him - should be much the same. However, space travel takes its toll on the human body. Astronauts often experience problems with blood flow because the circulatory system is adapted to pump blood against Earth's gravitational pull, and muscle and bones start to waste away due to being underused.
Even if Superman were able to maintain his strength, there are still several aspects of his powers that science cannot explain. He must have travelled faster than the speed of light to arrive on Earth from Krypton as an infant; he is able to balance large structures above his head without them crumbling at the edges; and bullets bounce off his chest.
The latest films allude to the idea that his real superpower is in fact gravity control. According to Einstein, gravity is actually the result of distortions in the fabric of space-time. In theory, if Superman could manipulate this fabric, he would be able to change direction in mid-air, deflect bullets, and travel through time.
Super speed - would The Flash survive if it were possible to run at the speed of light?
If he were to travel at the speed of light, The Flash could get to the Moon and back in under three seconds, but reaching the 299,792-kilometre-per-second speed limit of the universe would defy physics. Assuming, however, that he is able to come close to this maximum speed, could The Flash really survive such rapid travel?
The first challenge is drag; as The Flash moved through the atmosphere, he would collide with gas and dust particles. The faster he went, the more he would disturb the air, and the more drag he would experience. Moving at such high speeds would also compress the air in front of him, because it just wouldn't have time to get out of his path. Both the friction and air compression would generate heat, even when travelling at relatively low speeds. For example, the surface of a Soyuz capsule re-entering the Earth's atmosphere at about 230 metres per second (over 1.3 million times slower than the speed of light) can reach blistering temperatures of 1,650 degrees Celsius. The Flash would also struggle with reaction speeds. The fastest human nerves can send messages at speeds of around 100 metres per second, but for someone travelling close to the speed of light, thousands of kilometres would go by before there was time to perform even simple movements.
So how does he do it? The Flash is said to use the 'Speed Force' to accelerate, which confers many abilities on other superheroes, including boosts to endurance, perception, advanced healing and decelerated ageing. Perhaps, rather than super speed, The Flash actually has the ability to manipulate time.
Super small, super strong
Does the real-life Higgs Boson act like Ant-Man's Pym particles? The man behind Ant-Man's amazing abilities is Dr Henry 'Hank' Pym, a fictional scientist who discovers subatomic 'Pym particles', capable of altering the size and mass of any object. Impossible? Yes, but there are actually some parallels in real-world science.
In 2012, scientists at CERN in Switzerland announced that they had discovered the Higgs boson. It is an elementary particle, thought to be evidence of the existence of something known as the Higgs Field. The field is everywhere, and is responsible for giving other particles their mass.
We cannot manipulate the Higgs Field to change the mass of subatomic particles, and it does not affect their size, but the fictional Pym particles could work in a similar way. If Pym particles had an associated Pym Field that could make particles smaller, and Dr Pym managed to find a way to manipulate it, he might be able to shrink himself down to miniature size.