I’m often asked, "which is the most realistic superhero?" The standard answer would be Batman. But of course, given the number of times that Batman has been knocked unconscious in his 70-year career of crime fighting, he should be permanently brain damaged at this point. And obviously he’s got some sort of hidden superpower and some sort of Homer Simpson-type padding in his skull that’s preventing cerebral hemorrhaging.
The characters who just are physically trained and then dress up in spandex don’t require a suspension of disbelief, but there’s a limit to what the human body can do and how much it can achieve.
The next level up would be technologically-assisted superheroes, such as Iron Man. And there you’re actually on pretty good ground. In Iron Man, we do have exoskeletons that could enhance strength, we do have body armor. We could have a jet pack, we could have boot thrusters. The main problem is energy. If you have an exoskeleton, that’s going to enhance your strength. That extra energy that you’re supplying, that extra force has to come from someplace. And it comes from an external power supply. If you’re going to use boot thrusters to fly and you want to spend more than just a few seconds off the ground, you need an awful lot of energy.
In the Iron Man movie, Tony Stark builds an arc reactor, which is the one miracle exemption from the laws of nature, a small device about the size of a hockey puck that puts out the power equivalent of three nuclear power plants. And if you had such a device, well the world would be profoundly different, that’s for sure. So that’s the one big suspension of disbelief.
Even so, there has to be some sort of device that cuts out inertia in his suit because he gets banged around pretty good in that first Iron Man movie. So presumably, there’s some sort of damping mechanism that’s keeping him from getting crushed and destroyed as he flies and gets hit by missiles and other iron-suited villains.
Watch Tony Stark get knocked around some more in this trailer for Iron Man 3: