Radiation that gives you super-strength instead of disfiguring or killing you, spider bites that empower you to fight crime instead of threatening your life with a potentially fatal allergic reaction: when it comes to superheroes we need to suspend a decent amount of disbelief.
But what about Marvel's The Avengers, the United States' largest grossing film of the year, which was spun up on many a home DVD player this Christmas? Just how much does science fact surrender to science fiction when it comes to the team of Iron Man, the Hulk, Captain America, Thor and Black Widow? Would it be possible to utilise real-life, workable technology to transform yourself into one of these characters?
It’s a six-person team, but there are only four actual superheroes in The Avengers.
We can discount Thor from the outset. No matter how hard we study, none of us are going to be born in another dimension as super-powered Norse gods.
What about The Hulk? David/Bruce Banner was the victim of an experiment gone wrong. Banner was caught by a blast of gamma radiation which somehow translated into being able to transform into a green muscular monster while under periods of extreme stress.
Gamma rays are the most energetic form of light and are produced by the hottest regions of the universe, generated by exploding stars. On Earth they can kill living cells and are used in medicine to zap cancerous growths. They would not, therefore, turn you into a green muscular monster and back again.
With Captain America all you’d need is some exotic steroids and limitless time in the gym. Oh, and you’d need a shield that was as effective in attack as it was in defence – capable of absorbing all impacts up to and including the hammer of a Norse god. But Captain America’s shield in the Marvel Universe is made of vibranium, a metal that exists only in the pages of the comic books, so that rules out Captain A.
Of all the heroes, it seems that Iron Man is most based in reality. We already have exoskeletons, armour plating, and even propulsion systems such as jet packs.
The US Army has the Human Universal Load Carrier, developed by Lockheed Martin. It’s a hydraulic unit worn by a soldier and allows them to carry loads of up to 200lb (91kg), with the load transferred to the ground via the titanium exoskeleton’s shoes. There’s also the XOS originally developed by Sarcos, the Salt Lake City firm that has since been bought by US arms mammoth Raytheon. The firm says it is now is lighter, faster, stronger and more flexible than before - and uses 50 per cent less power.
But the kit that is currently available in 2013 is nothing like you’d see Marvel's billionaire engineer Tony Stark wearing: there’s no armour plating, flexibility isn’t exactly liquid and then there’s power - HULC runs on li-ion batteries that run flat after a few hours' use. Better take some spares, soldier.
Next, protection. The standard issue for troops, SWAT teams and general law enforcement today is Kevlar, chemically treated nylon specially woven into special patterns to make it more resistant to penetration. The tight weave makes for a cosy jacket but Kevlar is unlikely to withstand the kinds of aerodynamic pressures Stark puts his flying suit through and bullets certainly wouldn’t fly off it – it's more likely they’d just be embedded.
Then there is the armour option.
Stark's form-fitting armoured suit looks to be no more than 3mm thick, but with a density similar to iron (8g per cm3), James Kakalios estimates it would produce 26,200cm2 of coverage with a mass of around 67kg - and if you add in the weaponry and onboard computing, you'd have quite a hefty costume, something in the region of 76kg. Kakalios is a professor in the school of Physics and Astronomy at the University of Minnesota and a comic book book fan, and wrote Everything I needed To Know About Physics I Learned From Reading Comic Books and The Physics Of Superheroes.