Iron Man’s Inertia Immunity

Iron Man performing a 90-degree turn. By: Justin Aujla

How does Tony Stark, Iron Man, fly? Of course there are rockets and thrusters involved, but that’s not quite what I mean. What I am referring to is how Iron Man flies around without his body turning into jelly. How does Tony make what seem to be 90-degree turns at jet fighter speeds without somehow destroying himself?

Let’s begin by imagining what Tony’s body is experiencing during such a maneuver. But first, to do that, we have to go back to the birth of modern physics. Sir Isaac Newton’s first law of motion states that “An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.” This is often referred to as the law of inertia, and it states that if you were to throw an object upwards it would continue off into space at a constant velocity after I it was thrown—but it comes back down to earth because forces like air resistance and gravity. However, inertia is solely dependent on mass, which is to say that the more mass something has, the harder it is to get moving or to stop it from moving. This is where Tony’s Iron Man suit works its magic—er, physics. Why does a seatbelt pull so tight on you when a car comes to a screeching halt? Well it’s because you and your inertia want to keep moving forward, so the seatbelt must provide a force to slow you down. Now imagine Iron Man in his suit, altogether weighing 425 pounds, making what is actually a 90-degree turn at a dead stop at jet fighter speeds. The suit stops, but Tony and his insides need to be stopped by the suit like a seatbelt in a car. At the very least, Tony’s brain would keep moving as his skull stopped. His brain would soon smash into his skull and would be severely bruised—giving him an instant concussion. So why doesn’t this happen? The most likely explanation is sci-fi for now, and is commonly a physics staple of any sci-fi show with a spaceship—inertia dampers.

Damping is simply a fancy word for re-directing forces. Instead of Tony Stark getting a serious concussion every time he turns a corner, an energy field absorbs or dissipates the forces the suit would put directly on Tony. Think again to a car. When the brakes are engaged, they aren’t engineered to bring the car to an instant stop. Rather, the forces required to stop the car are dampened through the heat and the friction of the brakes; therefore, bring the car to a more gradual stop. Without some kind of inertia damping system in place, Tony wouldn’t be able to make all the incredible movements that he does. A 90-degree turn would have to be replaced with a longer, more gradual curve. So what could really be going on with the Iron Man suit? Well maybe it’s some revolutionary, incompressible fluid that lines the interior of his suit—similar to the cerebrospinal fluid that lines the interior of your skull. Or, maybe it’s something a little bit more space-age that provides some gravitational assistance like the inertia dampers do in Star Trek. Well, either way, if you let Iron Man get into your car he would never need to wear a seatbelt.


  1. Danté W. says:

    Very interesting blog topic. I didn’t give much thought to the physics of moving in an Ironman suit and I wonder if Richard Browning who just showed off his version of an Ironman suit at Vancouver’s Ted conference this week ( has thought about it. His demonstration was at very low speed.

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