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It Takes 2.99 Gigajoules To Vaporize a Human Body

Soulskill posted about a year ago | from the just-so-you-know dept.

Sci-Fi 272

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."

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272 comments

well done (2, Funny)

Anonymous Coward | about a year ago | (#44844839)

Just in time now that Texas can't get Sodium Thiopental.

Re:well done (-1)

Anonymous Coward | about a year ago | (#44845375)

Leicester is correctly pronounced "lay-ses-ter".

In Soviet USA (0, Offtopic)

Anonymous Coward | about a year ago | (#44844841)

It only takes NSA to vaporize your freedom

Hmm (5, Funny)

Mitchell314 (1576581) | about a year ago | (#44844845)

It's gonna take a mighty big shark to carry around that kind of firepower . . .

Re:Hmm (1)

fahrbot-bot (874524) | about a year ago | (#44845197)

It's gonna take a mighty big shark to carry around that kind of firepower . . .

Don't give the Sci-Fi -- I mean SyFy (sigh) -- channel any ideas. Sharknado [wikipedia.org] was bad enough.

Re:Hmm (4, Funny)

Delarth799 (1839672) | about a year ago | (#44845319)

Sharkalance, Sharknado, Sharkquake, Sharkquake 2 The After Sharks.

Re:Hmm (1)

milkmage (795746) | about a year ago | (#44845503)

Topshark - 80's movie, about the American pilots who went up against those Russian Sharks.

Re:Hmm (4, Funny)

petteyg359 (1847514) | about a year ago | (#44845459)

SyFy (sigh)

Iy think you myght have meant (sy).

Re:Hmm (1)

allaunjsilverfox2 (882195) | about a year ago | (#44845619)

It's gonna take a mighty big shark to carry around that kind of firepower . . .

Don't give the Sci-Fi -- I mean SyFy (sigh) -- channel any ideas. Sharknado [wikipedia.org] was bad enough.

Here's another terrible idea: Antalanche >.>

Re:Hmm (1)

only_human (761334) | about a year ago | (#44845475)

Dr. Emmett Brown: No, no, no, no, no, this sucker's electrical, but I need a nuclear reaction to generate the 1.21 gigawatts of electricity I need.

Disintegration (4, Interesting)

BasilBrush (643681) | about a year ago | (#44844849)

Phasers don't vaporise a person. They disintegrate them.

Since we don't yet know the physics behind this phenomenon we can't say how much energy it needs.

Re:Disintegration (2)

QuasiSteve (2042606) | about a year ago | (#44844943)

The normal maximum setting on a hand phaser would vaporize a humanoid lifeform or a Human-size android with a single hit. (TOS: "What Are Little Girls Made Of?"; TNG: "The Vengeance Factor"; Star Trek: First Contact) This was also called disintegration. (ENT: "In a Mirror, Darkly, Part II")

- memory-alpha.org

Though I suspect the Star Trek phaser suffered from the same problems as the StarGate zat'n'ktel, in that the effect would be a wee bit too convenient for plot reasons - as I've rarely seen them use it (even when they definitely had little regard for the wellbeing of whatever they pointed them at) in this manner.

Re:Disintegration (1)

reeno49 (1558221) | about a year ago | (#44844963)

You rarely saw the zat gun used? Is that because you didn't watch too many episodes or just blinked often?

Re:Disintegration (0)

Anonymous Coward | about a year ago | (#44845113)

used on disintegrate. That "third shot disintegrates" was ignored most of the time because they shot those things all the time with lots of shots.

Re:Disintegration (1)

reeno49 (1558221) | about a year ago | (#44845159)

Of course it was ignored. Most of the time they didn't bother to shoot twice, nevermind three times. Ain't nobody got time for that. Not even Richard Dean Anderson.

Re:Disintegration (1)

yurtinus (1590157) | about a year ago | (#44845287)

Eh, I noticed they used zat when they didn't want to be lethal (capture somebody, not overly infuriate the natives, etc), and the p90 or mp5 the rest of the time (probably cheaper special effects...)

Re:Disintegration (1)

reeno49 (1558221) | about a year ago | (#44845323)

That's how I remember it with pretty much everyone but Jack, but IIRC it got to a point where he became almost whiney when he didn't have a zat and had to resort to his p90, to the point where it became comical.

Re:Disintegration (1)

QuasiSteve (2042606) | about a year ago | (#44845377)

You rarely saw the zat gun used?

Sorry, I used poor phrasing :)

What I meant was - I rarely saw the Star Trek phaser used in a 'disintegrate' setting when used on living things, even though it would have been rather useful (no body to discover, e.g.)

The zat was of course used pretty much every other episode. Which is a shame - I'm partial to the staff weapon ;)

Re:Disintegration (5, Insightful)

SuricouRaven (1897204) | about a year ago | (#44845105)

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.

Re:Disintegration (1)

Em Adespoton (792954) | about a year ago | (#44845261)

I always figured that phasers had some sort of reclamation tech -- where the energy deployed in the first phase was then reclaimed, thus solving the issue of a bunch of superheated water vapor -- leaving it instead as ambient temperature water vapor, and the phaser as reusable. That was my own way of reasoning it away all those years ago, anyway.

I could never figure out how you could set a phaser to "stun" though -- does it just change the phase of some molecules while ignoring the bulk of them?

Re:Disintegration (0)

Anonymous Coward | about a year ago | (#44845251)

StarGate zat'n'ktel

They did eventually explicitly make fun of how stupid that was in episode 100, after quietly removing the disintegrate feature in season 2. They continue to use the stun feature throughout the series, though.

Writer: We could always go back to the way it was in the script.
Director: No, we can't. We've already established that one shot stuns and two shots kills, and Victor shot everybody twice.
Martin Lloyd: So three shots disintegrates them!
Director: I'm gonna pretend you didn't say that, because that is quite possibly the stupidest thing I've ever heard you say. [walks away] [this is an obvious reference to the way Zat guns originally worked]
Martin Lloyd: [to writer] Why are you looking at me like I'm an idiot? Why are you even on set? Go write something!

Reintegration (3, Funny)

VortexCortex (1117377) | about a year ago | (#44844949)

They're called "Phasers". I like to think that they don't disintegration or vaporize people, they just phase them into another dimension, a dimension where all the other folks who got zapped are hanging out, bitching about the Federation in some kind of distributed cosmic basement...

...and that's why the A.C.s here are so maladjusted.

Re:Reintegration (1)

SuricouRaven (1897204) | about a year ago | (#44845161)

No, you're thinking of the Positronic Ray.

Re:Disintegration (1)

Tobenisstinky (853306) | about a year ago | (#44844951)

What do disrupters do then?

Re:Disintegration (1)

Anonymous Coward | about a year ago | (#44845097)

What do disrupters do then?

They disrupt something, obviously.

Look, the terms "vaporize" and "disintegrate" are common through sci-fi which predates Star Trek, so the Trekkies need to get the knot out of their panties about this.
Neither term has ever been well-defined in a general sense across the genre. But in general we could base it on the actual meaning of the word. To vaporize something is to turn it into a vapor, or more specifically cause the object to become such small particles as could be suspended in a gas. This does not require any molecules actually be torn apart, or even reduced to the size of single molecules.
A complete disintegration, however, would imply that the object be torn apart at least down to the molecular level. And more than likely down to the atomic level, although that point could also be argued, but if we're going that far we'd have to take it as small as possible, and so why don't we just cut to the chase and call it the point at which all the matter has been converted into energy.

In any case, the authors are assuming that you must tear the molecules apart, and frankly speaking breaking it down into individual molecules would be enough to satisfy most people in real life.

Re:Disintegration (1, Insightful)

msobkow (48369) | about a year ago | (#44845151)

Disrupt molecular bonds, I guess.

While phasers phase molecular bonds.

In some theoretical sci-fi future, there is a difference.

Perhaps the reason they are hand-held is they actually produce the energy needed as part of their discombobulation process by capturing the existing energy of the molecular bonds and redirecting it, sort of like a nuclear chain reaction. So it only needs a little zap of energy to kickstart the process.

Re:Disintegration (1)

shrikel (535309) | about a year ago | (#44844955)

Agreed. I don't see why "vaporization" must be defined as "completely separating all atoms within a molecule." Evaporation and boiling are two means of vaporizing (making into vapor) without complete atomic separation.

Re:Disintegration (2)

ultranova (717540) | about a year ago | (#44845167)

I don't see why "vaporization" must be defined as "completely separating all atoms within a molecule." Evaporation and boiling are two means of vaporizing (making into vapor) without complete atomic separation.

Because most molecules in the human body are simply too big: the energy needed to separate them from each other is greater than the energy needed to break them apart. You can observe this behavior if you have a fireplace: a log of wood will first burn with a flame as volatiles evaporate and mix with the air (and burn), but even after the flame goes out there'll be a lot of charcoal which smolders as its breaks apart burn while it still remains solid.

Re:Disintegration (2)

riverat1 (1048260) | about a year ago | (#44845481)

I think the most logical way a phaser on disintegrate setting could work would be some effect that neutralizes the strong nuclear force. [wikipedia.org] Then whatever you hit with it would just disintegrate to a cloud of quarks.

Vaporize or ionize? (5, Informative)

swamp_ig (466489) | about a year ago | (#44845527)

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!

JiggaWatts (-1)

Anonymous Coward | about a year ago | (#44844859)

What's that it JiggaWatts? I'll be freaked out if it's 1.21!

Re:JiggaWatts (3, Insightful)

compro01 (777531) | about a year ago | (#44844965)

Depends on how quickly you want it done.

If you wanted it done in 2.5 seconds, 1.21 gigawatts would be perfect.

Re:JiggaWatts (2)

Kell Bengal (711123) | about a year ago | (#44844977)

Jiggawatts is just jiggagoules over time.

Re:JiggaWatts (0)

Anonymous Coward | about a year ago | (#44845005)

What's that it JiggaWatts? I'll be freaked out if it's 1.21!

Hmm, let's see...

$ units 2.99gigajoules jiggawatts
Unknown unit 'jiggawatts'

Great Scott!

Re:JiggaWatts (1)

swan5566 (1771176) | about a year ago | (#44845041)

You're forgetting to account the DeLorean surrounding surrounding the person. An orange vest should probably be thrown in there too.

2.47 s (1)

tepples (727027) | about a year ago | (#44845207)

Apply 1.21 GW of power for 2.47 seconds and you will have done 2.99 GJ of work.

Bad science (5, Interesting)

Dunbal (464142) | about a year ago | (#44844877)

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.

Re:Bad science (1)

reeno49 (1558221) | about a year ago | (#44844909)

I believe that's why there was an emphasis on *true vaporization*. I don't have a guess on what they're talking about, however, as my understanding of vaporization aligns quite nicely with yours.

Re:Bad science (0)

Anonymous Coward | about a year ago | (#44845187)

I believe that's why there was an emphasis on *true vaporization*. I don't have a guess on what they're talking about, however, as my understanding of vaporization aligns quite nicely with yours.

Ignoring the 'true Scotsman' in the room...
A vapor is defined as a substance diffused or suspended in air, and traditionally that's what Sci-Fi has meant when someone is "vaporized" ... literally "turned into a vapor". You don't need to go sub-molecular to achieve that result.
Disintegration has always been a little bit different- the end State of the matter is not really specified, rather the meaning is that the object is totally torn apart, down to its most base State. I would say that the term disintegrate might apply to what they're calculating.

Re:Bad science (3, Insightful)

DarkOx (621550) | about a year ago | (#44844957)

Even so when you go from a liquid to a gas let alone a solid to a gas you increase volume by well allot! Considering the epic calamity that is ~man sized boiler, say the type that was used to power to power stream tractors makes when it bursts; it should be clear that a phaser blast is not turning the victim into a gas or plasma. If it did that, it would be very disruptive and probably harmful to anyone in the immediate vicinity. Yet in Star Trek you can safely stand next to someone that is being disintegrated by phaser/disruptor.

Re:Bad science (1)

reeno49 (1558221) | about a year ago | (#44844989)

Yet in Star Trek you can safely stand next to someone that is being disintegrated by phaser/disruptor.

I wouldn't say "safely"...

Re:Bad science (2)

NoMaster (142776) | about a year ago | (#44845051)

Yet in Star Trek you can safely stand next to someone that is being disintegrated by phaser/disruptor.

Only if you stand perfectly still while they're being shot, then don't react until just after they've disappeared ...

Re:Bad science (4, Funny)

JustOK (667959) | about a year ago | (#44845263)

depends if you're wearing a red shirt or not

Re:Bad science (1)

imidan (559239) | about a year ago | (#44845279)

One thing I've never understood: how do the phaser beam know when to stop vaporizing? I mean, if I'm sitting in a desk chair and get vaporized by a phaser, then the chair usually remains there, completely unharmed and pristine. How does that work? Is it just super-sensitive to boundaries of conductivity? Shouldn't my clothes be left behind, too?

Re:Bad science (0)

Anonymous Coward | about a year ago | (#44845325)

Rangefinder.

Re:Bad science (4, Interesting)

mysidia (191772) | about a year ago | (#44845031)

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.

I can't wait to see how much energy people say the transporter requires.

I assume it is a similar principle.... except the phaser set to disintegrate just has to scramble and disperse their molecules, so that the person or thing no longer exists in a recognizable form; the transporter has to reassemble people.

Re:Bad science (1)

VortexCortex (1117377) | about a year ago | (#44845065)

> 2013
> Not vaporizing your water with electrolysis.

> Not enjoying the rich flavor of combustion brewed tea.
At least ditch that wet drip coffee and try Fuel-Air-Coffee -- It's the bomb.

Re:Bad science (0)

Anonymous Coward | about a year ago | (#44845073)

Thank You

Re:Bad science (2)

ericloewe (2129490) | about a year ago | (#44845089)

van der Waals forces are not the main factor that keeps water molecules together - it's hydrogen bridges and dipole-dipole interactions.
In fact, in a water molecule, van der Waals forces are tiny.

Re:Bad science (1)

Dunbal (464142) | about a year ago | (#44845521)

It's been a long, long time since I've done chemistry.

Re:Bad science (1)

demonlapin (527802) | about a year ago | (#44845127)

Water is kept liquid more by hydrogen bonds than van der Waals. Compare boiling points of water (0 C, two free electron pairs to participate in H bonds), ammonia (-33 C, one free electron pair to H bond), and methane (-164 C, no free pairs).

Lethal injection is less poetic (0)

Anonymous Coward | about a year ago | (#44844883)

Texas should consider the method.

Since when did a phaser VAPORIZE its target? (2)

harvestsun (2948641) | about a year ago | (#44844889)

The phasers I remember just made their target clutch their chest and fall to the ground dramatically.

Re:Since when did a phaser VAPORIZE its target? (0)

Anonymous Coward | about a year ago | (#44844925)

That's before they set it to 11!

Re:Since when did a phaser VAPORIZE its target? (0)

Anonymous Coward | about a year ago | (#44844961)

It's one more horrifying.

Re:Since when did a phaser VAPORIZE its target? (1)

jfdavis668 (1414919) | about a year ago | (#44844969)

It's one louder

Re:Since when did a phaser VAPORIZE its target? (1)

multisync (218450) | about a year ago | (#44844983)

The phasers I remember just made their target clutch their chest and fall to the ground dramatically

The phasers you remember were obviously set to Stun.

Re:Since when did a phaser VAPORIZE its target? (1)

mysidia (191772) | about a year ago | (#44845137)

The phasers you remember were obviously set to Stun.

Even kill didn't do anything other than make the target drop dead.

That is what disruptors do.

At some point the Enterprise hand phasers got a Disrupt-B or Maximum setting besides overload, that makes the target glow, and vanish.

You have to remember that star trek is a TV show; and the disintegration was clearly for dramatic affect. They were essentially making the phaser like alien death rays that had appeared in other television shows.

The phaser is not a real thing ---- what people actually wind up creating is sure to be more interesting, possibly an energy-based weapon with AI, so it can never miss the target.

My suggestion would be that the phaser does not vaporize the target on disintegrate; it just generates so much heat, that the target immediately catches on fire, and their entire body thermalizes.

Humans are basically made out of carbon materials that are highly combustible. When the temperature rises to 80000 degrees kelvin in 0.01 seconds; the target collapses into a pile of ash, in a bright light --- all the molecules are still there, or in the air; it's just that a chemical reaction has made them unrecognizable.

Re:Since when did a phaser VAPORIZE its target? (1)

yurtinus (1590157) | about a year ago | (#44845303)

Vhy don't zey just waporize them?

There's always room for another setting on a prop dial!

Re:Since when did a phaser VAPORIZE its target? (1)

cervesaebraciator (2352888) | about a year ago | (#44845371)

It happens in the presence of Khan Noonien Singh. Clearly the extra energy required to vaporize is derived from the presence of Ricardo Montalban [imdb.com] .

Self Bootstrapping Death Ray (4, Interesting)

Zan Lynx (87672) | about a year ago | (#44844907)

Directly providing the power to vaporize a person is not the elegant way to do it. The correct, elegant mad scientist method is to use the power contained in the vaporized mass to power the vaporization.

Consider if you develop a means to "program" a plasma such that it generates a contracting magnetic field that causes fusion inside the vaporizing object and then absorbs some of the energy from this fusion reaction to power itself.

Now you're talking! Now you've got an effect that can vaporize any object provided you can provide the initial energy requirement.

There could be variants on this. Perhaps you've got an effect that flips matter into antimatter and absorbs some of the released energy to continue the effect.

If this is an expanding effect instead of a collapsing effect you've got a world killer like the weapons in Ender's Game.

Re:Self Bootstrapping Death Ray (1)

udachny (2454394) | about a year ago | (#44845297)

It's called a chain reaction.

Re:Self Bootstrapping Death Ray (0)

Anonymous Coward | about a year ago | (#44845413)

Have you considered writing science fiction? ;)

We already know lightning doesn't vaporize people. (0)

Anonymous Coward | about a year ago | (#44844911)

And if you're going to say that the death ray isn't the lightning bolt, then I challenge you to prove you can make a 100% electrically efficient death ray.

useful info (2)

Tumbleweed (3706) | about a year ago | (#44844945)

*turns knob up to 8*

Ready Player One...

Potential? (2)

wonkey_monkey (2592601) | about a year ago | (#44844967)

around the same energy that a 2,000-pound car going 70 miles per hour on the highway has in potential.

Wouldn't that be kinetic?

Re:Potential? (1)

ericloewe (2129490) | about a year ago | (#44845093)

Could be an elevated highway...

Re:Potential? (0)

Anonymous Coward | about a year ago | (#44845253)

Yeah, I know, but "in potential" and "in potential energy" MIGHT carry different implications. I'd give him the benefit of the doubt there. /sigh

Re:Potential? (0)

Anonymous Coward | about a year ago | (#44845471)

They didn't say it was driving, so it could be falling instead.

TWO POINT NINE NINE GIGAJOULES?! (0)

Anonymous Coward | about a year ago | (#44844991)

It just doesn't have the same ring to it, Doc.

Now, what would 3GJ of hyper heated matter... (1)

Derekloffin (741455) | about a year ago | (#44845015)

...do to the immediate environment? I suspect the poor soul that god disintegrated would be the lucky one.

Re:Now, what would 3GJ of hyper heated matter... (1)

SuricouRaven (1897204) | about a year ago | (#44845153)

Actually, I can answer that question. It just happens that some friends and I like to dabble in high-voltage fun. We don't have a 3GJ test, but I do have a video showing what just 800J does to a tomato:
http://birds-are-nice.me/explodium/MK8a_fruit.webm [birds-are-nice.me]

Up-one to see more things go pop.

Re:Now, what would 3GJ of hyper heated matter... (1)

rotorbudd (1242864) | about a year ago | (#44845217)

Neat!
Now shoot it in slo-mo and use a head!

Re:Now, what would 3GJ of hyper heated matter... (1)

Derekloffin (741455) | about a year ago | (#44845225)

Yeah, that looks about right.

Re:Now, what would 3GJ of hyper heated matter... (0)

Anonymous Coward | about a year ago | (#44845339)

3 GJ of [...] matter

At the going rate,
(3 gigajoules) / (the speed of light^2) = 33.3795017 micrograms
probably won't bother anyone too much.

Say ... (0)

rossdee (243626) | about a year ago | (#44845019)

Doesn't that depend on the weight of the person? Its gonna take a lot more energy to vaporize a 200 Kg american than sn 85 Kg asian.

Re:Say ... (0)

Anonymous Coward | about a year ago | (#44845593)

There is no a single American that weights 200Kg. Clearly they weigh 441 pounds.

2.47 seconds (0)

Anonymous Coward | about a year ago | (#44845023)

With a bit of plutonium borrowed from terrorists, or a lightning bolt, you could vaporize someone in 2.47 seconds.

Overkill (2)

Sponge Bath (413667) | about a year ago | (#44845025)

Vaporization isn't needed to kill. I assume that's what death rays are all about. I suppose it would take a little extra to make the remains difficult to identify. If you've gone the death ray route, using lots of power is part of the "send a message" image thing anyway. For an eco-friendly kill, it is still best to club the victim and let hungry pigs dispose of the corpse.

THANKYOU (0)

Anonymous Coward | about a year ago | (#44845027)

My son has been asking me how someone would get disintegrated. He's been obsessed after I let him watch Mar's Attacks. He keeps asking me how the Martian guns work and I try to explain to him it's Science Ficition. Maybe I'll show this too him and then I'll have to explain what a Joule is. Thank you for submitting this now I have a good point of refrence when dealing with a 6 year old's imagination.

Simple math... (1)

Iniamyen (2440798) | about a year ago | (#44845033)

They simplified this too much. Anyone could have plugged in the numbers for water. I want to see them take into account the non-water content of the human body. And maybe assume a non-uniform heating model, since presumably the energy would be transferred via a ray from a phaser.

Totally Wrong (0)

Anonymous Coward | about a year ago | (#44845039)

"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."

First, it's 1.21 gigawatts [wikipedia.org] , not 2.99 gigajoules.

Second, it's 88 miles per hour, not 70 miles per hour.

what about 9/11 ?? (0)

Anonymous Coward | about a year ago | (#44845083)

Most 911 victims were vaporized. If you believe the official story.
Like all victims on American Airlines Flight 77 Pentagon Crash - Sept. 11, 2001

Nope, just boil water and burn most other matter (1)

iamacat (583406) | about a year ago | (#44845087)

Doesn't take gigajoules, just what is commonly done in crematoriums, but done at much faster speed for cinematic effect. I am sure most people will not mind a small puddle of calcium-based ashes, but if they do we can focus on sublimating that and still save lots of juice. For even more savings, add corrosive acid that would produce residue with lower sublimation point.

Kickstater to raise 2.99GJ to vaproize Justin Bieb (2)

JoeyRox (2711699) | about a year ago | (#44845109)

If successful we can work our way down list with future kickstarters:

Ashton Kutcher
Miley Cyrus
Kate Perry
Guy from Verizon Wireless commericals
Congress

Re:Kickstater to raise 2.99GJ to vaproize Justin B (0)

Anonymous Coward | about a year ago | (#44845255)

Or we could line them up in order of annoyance in front of a rail gun and demonstrate the effectiveness of a tungsten projectile fired at 1600 m/s.

Huh, whad'ya know... (1)

CCarrot (1562079) | about a year ago | (#44845111)

On things I've never wondered about, this would be pretty much right at the top of the list...now how much energy is required on the 'stun' setting?

Must be Friday the 13th or something. :)

Question (0)

Anonymous Coward | about a year ago | (#44845209)

Who says the phaser vaporizes them?

Phasers (0)

Anonymous Coward | about a year ago | (#44845219)

I do remember some 'hard' numbers being mentioned on Enterprise once.
A testbed phaser being overcharged to ten megajoules output(per second, presumably) burning a hole through some unidentified metal target.
Given that's about equivalent to five pounds of tnt in the same room as you, I doubt they had any actual physicists advising them on the show.

Also seems to indicate phasers have a pretty beefy reactor in them...

Re:Phasers (0)

Anonymous Coward | about a year ago | (#44845659)

It was fairly common in ToS for them to disassemble their phasers and use their power sources for some other purpose, such as launching a shuttlecraft.

Doesn't add up (0)

Anonymous Coward | about a year ago | (#44845235)

So if 2.99 GJ is enough to vaporize a person, and enough to simulate a lightning bolt, then shouldn't people hit by lightning get vaporized?

I hate to be pedantic (0)

Anonymous Coward | about a year ago | (#44845237)

But the phasers had three settings.

Stun
Kill
Disintegrate

TFA sounds like it's referring to #3

Transporter of the future? (1)

cyberjock1980 (1131059) | about a year ago | (#44845247)

So does this also give an indication of how much energy an transporter(Star Trek like) would consume(assuming 100% efficiency of course)?

I've always wondered how much energy would be needed for transportation like that. Always wanted to see if its more/less efficient than driving your SUV to work.

Awful calculation - the real answer is almost zero (3, Informative)

craighansen (744648) | about a year ago | (#44845447)

I'm going to do some rough calculations - the paper's computation is also pretty rough - just to get the right order of magnitude.

First of all, to vaporize water, you don't even need to boil it. Spill some water on the floor and it vaporizes pretty darn quick just from the ambient environment - it changes from liquid water at room temperature to water vapor at room temperature. The only heat that needs to be added is the "Enthalpy of vaporization" which is 2260 kJ/Kg. For the 78kg human described in the paper, if it were all water, that would only be 176 Megajoules. Given that a human is normally at about 37C and room temperature about 25C, you can also take away 4kJ/Kg*78Kg*(37-25) = 4 Megajoules that the water vapor releases as you cool it from 37C to 25C. The net result is that with 172 Megajoules, you can turn a human body's mass of water to vapor.

However, as the paper suggests, the body isn't all water - it's about 85% water and 15% "dried pork." That means 172MJ*0.7 for the water, 146MJ, and the 11.7Kg of pork releases about 4KCal/g when oxidized (4 dietary Calories/g), 1 Kcal=4.2KJ, so burning the "dried pork" releases 196MJ. Assuming the "dried pork" gets fully oxidized (i.e burned) into CO2, the result is a gas. So overall, vaporizing a human body (in the sense of turning all the body into a gas) can release more energy than you started with - about 50MJ.

The paper estimates the energy required to break every molecular bond. However, all those bonds are going to reassemble into something else, whether into H2, O2, or H2O, or including the "dried pork," CO2, releasing much of the energy back.

10 minutes (0)

Anonymous Coward | about a year ago | (#44845461)

The laser in "Real Genius" was 5 megawatts (sustained), so it would take about 10 minutes to vaporize a person with that thing.

Secret Nazi Weapon (1)

Baldrson (78598) | about a year ago | (#44845501)

Holocaust deniers keep prattling on about how hard it would be to incinerate 6 million Jews. They full of sh*t because, as Nazis, Holocaust deniers know about the secret Nazi weapon that could vaporize entire cities and boil oceans [youtube.com] . With such a super Nazi death ray it was a sinch to vaporize millions of human bodies.

190 Megajoules (1)

MrChips (29877) | about a year ago | (#44845525)

To turn 75kg of water (165lbs) starting at 37C to steam at 100C requires 190 megajoules. Wouldn't that be enough to vaporize a human body? I suppose the bones would be left behind.

Suspiciously accurate (1)

linuxwrangler (582055) | about a year ago | (#44845537)

It is ridiculous to use "roughly" and "2.99" in the same measurement. Seriously?!? A professor informed my engineering class that adding extra decimal places implied that that level of precision was known and/or required. It is at all plausible that the variability in the "average" human body is less than a one part per thousand?

Sounds a lot like Karl Marx when he took material costs in "round numbers", "assumed" costs for spindles and rates of waste, arbitrarily "put" wear and tear at 10% and "supposed" a value for rent then somehow, miraculously, calculated that surplus value equaled 153-11/13%

Kudos to Scientific American for being sensible enough to say "about three."

what happens when you use that at 88MPH? (1)

Joe_Dragon (2206452) | about a year ago | (#44845601)

what happens when you use that at 88MPH?

one mole? (0)

Anonymous Coward | about a year ago | (#44845667)

when i saw the word mole i was thinking of the animal http://en.wikipedia.org/wiki/Mole_%28animal%29

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