I didn’t watch the whole trial by combat in the latest Game of Thrones episode. I couldn’t. I was fine up to the point where Gregor Clegane (the Mountain) started gauging Oberyn Martell’s eyes out with his fingers. But I had to stuff my face in a pillow when Cersei’s champion buried both hands into his opponent’s skull, exploded his brain out the top and flattened his cranium.
Fans who watched the whole way though may feel the need, as we do, to settle the science of skull crushing. Could the Mountain actually explode a human skull using just his hands?
There are two factors that need to be considered here; the strength of the Mountain and the force required to smash a human skull.
According to a NASA report an average male can exert around 90 kg (200 pounds) or 1000 Newtons of force in a static push. A boxer can deliver 5,000 newtons of force with a single punch but their hand travels really fast (and, if you recall, The Mountain was pressing down not punching).
Neither the Icelandic strongman, Hafþór Júlíus Björnsson, who plays the Mountain, nor George R.R. Martin’s fictional character are anything like the average white male. Björnsson is the second strongest man in the world. He is nearly 7 feet tall, weighs 190 kg (419 pounds) and can lift 419 kg (925 pounds). I haven’t read the books but Lily Rothman from TIME who clearly has reported that the Mountain is 8 feet tall, 190 kg (420 pounds) “with massive shoulders and arms thick as the trucks of small trees.” We have to assume that The Mountain is going to have a much better chance at popping a skull than your average male.
So onto the second question: how much force required to crush a human skull?
Human bone is incredibly sturdy. It is stronger than steel and concrete of the same mass. The human skull encases the most important organ of the human body, the brain, and has evolved to be as strong as possible to withstand trauma.
Lenny Bernstein from the Washington Post spoke to neurosurgeon Tobias Mattei and reported that a skull fracture requires 500 kg of force. It would be possible for a man who weighed 500 kg (remember The Mountain only weighs 190 kg) to fracture a skull by stepping on it but, according to Mattei, it would be “impossible [for a man] to break [a skull] with his hands even if 90 percent of the 235 kg were biceps muscles.” Moreover, “It would be almost impossible … to ‘blow up’ the head’s top from inside… No explosion would be seen. The eyes of the victim would be pushed backward some few inches. That’s it.”
Cynthia Bir, a biomedical engineer at the University of Southern California, confirmed this assessment writing that “ there is no way to get the head to ‘explode’ by applying pressure from the eyes. You would need to create pressure inside the cranium. Even if you could generate pressure by squeezing the outside of the head, once the cranium is breached at the orifice where the eye nerves enter, this pressure would be greatly diminished."
Kyle Hill at the Slate asked the question about a similar stunt in the Star Trek movie. Quoting a bike-helmet study published in the Journal of Neurosurgery: Pediatrics, he wrote that 235 kg (520 pounds) or 2,300 newtons of force would be needed to crush a human skull, almost twice as much force as human hands could possibly muster.
You may recall from high school physics that Force = Mass x Acceleration, so something quite heavy has to be travelling very fast to generate enough force to crack a human skull. The Mountain might be able to lift 235 kg (520 pounds) but he probably couldn't channel that strength into his fingertips and exert enough force to crush a human head.
I’m calling it. In real life the Mountain could not break skulls like he did on TV. I’ll give HBO points for making it look believable.
But could a chimpanzee do any better? Chimpanzees are about 4 times stronger than humans and have been known to tear people’s faces off. Recent research even suggests that the evolution of large brains in humans was a trade-off for muscle strength.
And to wrap up, here's a little something to distract you from the painful knowledge of Tyrion’s imminent death: