Scientists, engineers and physicians are chiming in to debunk a controversial and very graphic scene in the latest Game of Thrones episode that aired two days ago – for people who haven't watched it, this is your cue to leave this page now.
SPOILER ALERT! SPOILER ALERT! SPOILER ALERT!
In this week's episode, Prince Oberyn Martell serves as Tyrion Lannister's champion in a trial by combat against "The Mountain", Gregor Clegane, whom Oberyn seeks revenge against for raping and murdering his sister.
Unfortunately for the prince, the trial by combat ends with the Mountain crushing Oberyn's skull with his bare hands, leading to his brain exploding out the top of his skull due to the pressure and force used.
The science of skull crushing
While a memorable scene and certainly good for ratings, the question is, can a man really manage to crush a human skull with just his hands?
To solve this problem, we need to consider the force that is required to smash a skull, as well as the strength (i.e. force that can be generated) by the Mountain.
The current actor playing Gregor Clegane is Hafþór Júlíus Björnsson, the second strongest man in the world who weighs 190kg (419lb), stands almost 7 feet tall and is able to lift up to 419kg (924lb).
In the book Game of Thrones, author George R R Martin describes the Mountain as being almost eight feet tall, "with massive shoulders and arms thick as the trucks of small trees", and later in A Storm of Swords, Martin adds that Gregor weighs about 30 stone (191kg). So Björnsson is a good choice to play the mountain, at least.
But what about the force required?
To refresh you on physics, the calculation for force reads as:
force (newton, N) = mass (kilogram, kg) x acceleration (metre per second squared, m/s2)
According to research by Nasa into body strength and how the body's push forces are affected by zero gravity, an average adult male is capable of exerting about 90kg (200lb) or 1,000 Newtons of force in a static push, in standard gravity.
On the other hand, a boxer whose hands travel at a really fast speed, is able to exert 5,000 Newtons of force in a single punch.
A 2012 study into the protective effects of bicycle helmets during impact and crush tests on lab skull models confirmed that it would take 235kg (520lb) or 2,300 Newtons of force in order to crush a human skull, which is more than double what a human is capable of.
The Washington Post asked neurosurgeon Tobias Mattei how much force it would take to crush a human skull and was told that just to fracture a skull would require a human to exert a force equivalent to 500kg (1,100lb).
No brains popping out, either
According to Mattei, in theory, a 500kg man could step on a human skull to crush it, but "it would be impossible to break it with his hands even if 90% of the 235kg were biceps muscles".
It's also unlikely that crushing a human skull would result in the brain bursting out the top.
"I would say that it would be almost impossible ... to 'blow up' the head's top from inside (even if you connect a firefighter's water pump in it) because the skull base as well as the squamous portion of the temporal bone ... would blow out (sideways) first," said Mattei.