Let’s examine Enel’s goro goro no mi attacks and the nature of electricity.
To really understand how Enel’s electric attacks affected the Straw Hats, we’ll have to start with a mini lesson on the nature of electricity. Now, Enel’s attacks which hit you with millions of volts may sound absurdly crazy. After all, your standard AA batteries only supply a measly 1.5 volts. But then again, a tabletop Van-DeGraff generator can hit you with 100,000 volts. Hell, even a well placed socks-on-carpet induced static shock can carry around 40,000V. These can definitely hurt a bit (or a lot), but they certainly won’t kill you. Why is that?
The most common answer you’ll hear is “It’s not the voltage that kills you, it’s the current!”. I don’t want to say this answer is wrong, because there is some truth to it….kind of….. At best, it’s partially right, at worst it’s horribly misleading. Okay, okay, let me back up for a second. It’s true, static shocks come with a huge voltage, and a tiny current. But here’s the thing, current and voltage are inexorably linked together by this thing called Ohm’s law. Ohm’s law says that voltage is equal to the current times the resistance of the system. V=I*R. Rearranged, the current is equal to the Voltage divided by the resistance. I=V/R. But humans have a pretty consistent resistance which means the only way you can deliver a shock with a bigger current is to raise the voltage. Put more simply, since I=V/R and R must stay constant, the only way to make I bigger is to make V bigger. Conversely, if you deliver a shock with a bigger current, you must have upped the voltage as well! so if the current kills you doesn’t the voltage kill you too??? See, it’s misleading. But I’m here to clear this all up.
When people bring up the “It’s not the voltage, it’s the current” thing they usually refer to something like a wall outlet, which can kill you under the right circumstances, but only has about 120 volts. Given the large resistance of the human body (around 1000 Ohms), outlets can only deliver a current of around .12Amps. Going back to our previous case with static electricity, you’re getting a peak shock of 10,000/1000=10A which is way more than our wall socket. What gives!!??
Okay , here’s the secret: TIME. You see, current is a description of electric current flowing per second. When discussing lethality, quoting a current is basically useless without also including HOW LONG THE CURRENT WAS APPLIED. Looking back to our static shock example, that huge current of 10A was applied for a little less than a millionth of a second. That’s less than 1 micro second in science terms. On the other hand, something like a wall socket will supply a current for as long as you’re in contact with it. Furthermore, given the nature of our nervous systems, you’re likely to clamp down on whatever is shocking you: maintaining contact. So this relatively small current is applied for a much longer time which leads to a much higher volume of electric charge transferred through your body.
To sum this up in a nice little package, we can look at the total ENERGY transferred from the shocking source to you. To do this, we just look at the power (V * I) which gives us watts, and multiply that by the total time the shock was applied. For our static shock this gives us a total energy of about (100,000V) * 10A * (10-7 S)= .1 Joule. On the other hand, if you’re shocked by your wall outlet for about 1 second, you’re getting hit by about (120V) * .12 * 1 = 14.4. Typical sources cite about 5 Joules as the requirement to kill you which illustrates why a static shock probably won’t kill you but an outlet certainly could. Now, these are absurdly simplified calculations for discussing resultant current, discharge times, and overall lethality of an electric shock. Simply take this as a basic conceptual guideline.
So the next time you hear from someone that “it’s not the voltage that kills you, it’s the current!” you can (politely of course) let them know that it really comes down to the total energy delivered in the shock which often has more to do with the duration than voltage or amperage.
Okay, so how does this apply to the world of One Piece? As I discussed above the key to determining the lethally of Enel’s shocks lies the duration of each attack. The problem here is that the original source material, the manga, gives little clue to the passage of time and the anime is notorious for being very liberal with time. Enel’s goro goro no mi, the thunder fruit, gives Enel’s power a connection to lightning. Not just electricity, but specifically with lightning. Since this would technically make all of his attacks some form of lighting, I’m going to use lighting as the basis for his attack duration.
Lighting isn’t composed of a single strike but rather a series of strokes and return strokes as the clouds and ground reach electrostatic equilibrium. However, the bulk of the energy is transferred in a single stroke of about 30 microseconds. In one of his first attacks that he names a voltage, Enel hits Gan Fall with 30,000 Volts. Using 1000 Ohms as a standard human resistance, we get a total energy transfer of V * I * T= V * V * T / R = (30,000,0002 ) * 3 * 10-5 / 1000 = 2.7 * 107 Joules. This is a pretty monstrous transfer of energy. At this point I could try to rationalize this some more; discussing the lower air pressure on skypeia, path the charge took, clothing, ect. but in reality I don’t think I can explain this one away. Put simply, by real world terms, Enel’s attacks would kill just about anyone. But what about Luffy?
As we all know Luffy is a rubber man. That means in assigning a resistance value we have to treat him as rubber. The resistance coefficient of rubber is about 1013 ; about a billion times larger than water. However to assign it a resistance value in Ohms, we have to take into account the volume of substance the current is flowing through. To make things simple I’ll just say the path the current wooed take is through 2/3 the total volume of a human body worth of rubber. This gives .07 * (2/3) * 1013 = 4.6 * 1011 Ohms. This is about 100 million times the resistance of a normal human. Doing the same calculations with Enel’s “200 Million volt Vari” attack, we get (200,000,0002 ) * 3 * 10-5 / 4.6 * 1011 = 2.6 Joules which is definitely less lethal dose of 5 Joules.
I’m pretty happy with this. Sure, Enel’s attacks should have killed every non-rubber human, but keeping in line with some very simplified physics calculations, it looks like Luffy really would be immune to even Enel’s strongest attacks! That’s awesome!!!
TL/DR In the real world, Enel’s attacks would kill everyone except for Luffy. Luffy would actually be fine.