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Comment by amluto | Hacker News Reader

This is utter nonsense. Let’s play along:

Take a 2 TiB flash drive. That’s 1e13 bytes or 1e16 bits. Suppose it’s one electron per bit. That’s approaching 1% of a Coulomb! So you take two flash drives, charge them up, and hold them 1cm apart, and they fly apart with several hundred meganewtons of force! The electrostatic force is strong!

This is, of course, completely wrong. When you write to flash, you are moving electrons around, not adding net electrons. The whole device stays electrically neutral (on average), and any mass change is due solely to minuscule relativistic effects if you add or remove energy.

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Exactly, I was going to point out the same thing. The flash cells might be charged or discharged of electrons, but the whole flash drive can't have a net charge or else you will certainly feel it. And because no solid/liquid/gaseous matter is exchanged between the computer and flash drive, there are no positive particles (nuclei/protons) moving either.

This is similar to what it means to "charge" a capacitor. It doesn't mean injecting or removing electrons from it, because that would cause a net charge. It actually means shifting electrons from one electrode to the other, separated by an insulated gap. http://amasci.com/emotor/cap1.html

Calling it a shift is not right either. It's not the same electron that leaves one side and makes it way to the other. Electrons injected on one side and removed on the other.

True. It's not the same electron... but electrons are also perfectly fungible. Quantum physics guarantees that.

They made a coulomb bomb https://gravityandlevity.wordpress.com/2013/05/22/what-if-i-...

> I worked on all sorts of problems that involved the Coulomb interaction, and occasionally my proposed solution would be very wrong. The worst kind of wrong was the one that made my advisor remark “What you just created is a Coulomb bomb,” which meant that I had proposed something that wasn’t neutral on the large scale.

Also consider that most high density Flash today is made from TLC cells which have 8 distinct Vt levels each. That means in average case (i.e. random data) there is a minimum of 3.5 electrons per cell required.

In reality, much more than 1 electron is required to store a 0 or 1 with any level of reliability. On the order of 10s to 100s of electrons per bit even on leading processes.

Never mind the difficulty of stuffing so many electrons in a space the size of a flash drive, and keeping them contained…

(Also, 2 TiB is just 2e12 bytes, and 2e12 bytes only equals 1.6e13 bits, it’s log2(8) that’s 3, but that doesn’t really affect your conclusion.)

  $ units -t 'coulombconst * (2 TiB * atomiccharge/bit / cm) ** 2' 
  714.00592 kg m / s^2

Not quite meganewtons, but still a lot.

Sigh, I mixed up some powers of two with powers of ten in my head.

Yeah, I figured =D

Here we see the effects of a computer science education on the author. Not enough physics.

Don't blame this on CS, this is just Dunning-Kruger effect in action.

DK doesn't exist anywhere near what is commonly claimed.

Ironically, that makes a Dunning-Kruger Effect effect.

https://gwern.net/doc/iq/2020-gignac.pdf

Do you think a physicist would be less certain that OP is wrong, than how certain OP is that he is right?

> Do you think a physicist would be less certain that OP is wrong, than how certain OP is that he is right?

This is not the correct application of the effect.

A physicist would have been sure about this particular case being wrong, but would likely be a lot more careful and concise about what he's talking about. Also a physicist is supposed to be more confident, as they are on the far right side of the curve.

Being at the bottom of that curve is reserved for folks like me who rely on common sense but cannot be certain outside of extremely basic cases like knowing that electrons are not leaving the USB en masse.

Since this is all silly anyways...

What about the mechanical strain caused by the charges? Would the device be more compressed due to the attraction between the opposite charges associated with charged bits? Since the device is in air, it would then displace less air. Even though the device mass would be the same, the weight would be more.

Right. The only actual effect would be like, having two charged (or two uncharged? maybe?) elements right next to each other entails some repulsive force, and so it takes additional energy to get to that state. That energy has mass via E=mc^2.

How does one send this message to BBC? They should be ashamed of themselves.

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