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It Takes 2.99 Gigajoules To Vaporize a Human Body
Have you ever wondered how much energy is needed to power a phaser set to kill? A trio of researchers at the University of Leicester did, so they ran some tests and found out it would take roughly 2.99 GJ to vaporize an average-sized adult human body. Quoting:
"First, consider the true vaporization – the complete separation of all atoms within a molecule – of water. With a simple molecular structure containing an oxygen atom bonded to two hydrogen atoms, it takes serious energy to break these bonds. In fact, it takes 460 kilojoules of energy to break just one mole of oxygen-hydrogen bonds — around the same energy that a 2,000-pound car going 70 miles per hour on the highway has in potential. And that's just 18 grams of water! So as you can see, it would take a gargantuan amount of energy to separate all the atoms in even a small glass of water — especially if that glass of water is your analog for a person. The human body is a bit more complicated than a glass of water, but it still vaporizes like one. And thanks to our spies spread across scientific organizations, we now have the energy required to turn a human into an atomic soup, to break all the atomic bonds in a body. According to the captured study, it takes around three gigajoules of death-ray to entirely vaporize a person — enough to completely melt 5,000 pounds of steel or simulate a lightning bolt."
It's gonna take a mighty big shark to carry around that kind of firepower . . .
I read TFA and all I got was this lousy cookie
Since when does "vaporization" involve breaking chemical bonds inside a molecule? When you boil water you're not turning it into hydrogen and oxygen, you're just overcoming the vanderWaals bonds keeping the liquid together and giving them enough energy to float away. Likewise if you "vaporize" someone. You need enough energy to turn them from a solid/colloid state to a gaseous state, not the energy required to reduce the person to elemental atoms.
Seven puppies were harmed during the making of this post.
Often on TV, killing is actually easier than dealing with the bodies. The network censors really hate bloody corpses, but have less objection to the process of making them. A common solution is to introduce either mooks that conveniently diappear when dead (See Buffy, Charmed - the prefered fantasy solution) or weapons which leave no body (See half the weapons in Doctor Who or STs phasors - the prefered sci-fi solution).
The vaporisation option usually ignores the difficulty of where approximately eighty kilograms of water vapor is going to end up - boiling a human in such a short time would result in a blast of high-pressure superheated steam and organic soup.
Hang on a moment... TFA isn't talking about vaporizing - turning water to steam. It's talking about ionizing, which is clearly going to require a much bigger quantity of energy.
For actual vaporization, making a very rough calculation - 60kg person, 2,270 kJ/kg latent heat of vaporization of water = 136 MJ,
Sure there's specific heat to add in there too, but the vaporization of water is the dominant term, so it's at least out by an order of magnitude.
Lesson learned - don't try and be 'all sciency' and use the wrong jargon!
Leicester is correctly pronounced "lay-ses-ter".
No it isn't. It's pronounced "les-ter".
Source: I've been there. Also, this.
"Inveniemus Viam Aut Faciemus" 'We will find a way... Or we will make one!' --Hannibal of Carthage