Comment by maggit | Hacker News Reader

Comment by maggit | Hacker News Reader

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The comment is accurate, and electricity should not be considered as having mass.

In a direct current (DC) setup, electrons will be moving continuously though the wires in a big loop. But the displacement of the electrons is not the electrical energy we are interested in.

It is instructive to think about alternating current (AC). In this case, electrons will be moving a bit forward, and then a bit back. So, basically wiggling more or less in place. There is still a lot of energy transferred.

A metaphor is a chain, like in a bicycle. You can use the chain to transfer energy, but it is not the chain links that are the energy. The movement is the energy. This is similar to electricity; it is not the electrons that move that is the electrical energy, instead the electrical energy is the movement itself.

(Due to Einstein's theory of relativity, we know that E=mc^2, which can be summarized as "all forms of energy are also mass". Considering this, all transfer of energy is transfer of mass. But it is miniscule. A small nuclear power plant could produce 4450 GWh in one year. The relativistic mass of this is 180g. All the energy produced in one full year of this plant has a total mass of 180g. So you should not consider electricity to be transfer of mass, even though it technically is :P )

(Also, since you asked for a physicist: I am not a physicist)

The "big loop" concept is fundamental: the power lines we use to move energy around are all closed loops, so, even with DC, the mass of electrons that flow in one direction is the same as the mass that flows in the opposite direction. There is no transfer of mass.

This is different from ectrostatic generators: there, AFAIK, there should be an actual transfer of mass. https://en.wikipedia.org/wiki/Van_de_Graaff_generator

No worries, I'm using a loose definition of 'physicist' - anyone knowing about physics is fine :)

Thanks for your contribution; as I mentioned below, I've gotten some different answers, e.g. on http://physics.stackexchange.com/questions/2188/does-electri... where I asked the first time. Essentially, are you saying that with DC current, there is transfer of 'mass', but with AC, there isn't? In the case such as I've explained it elsewhere in this thread, this might mean that it matters how a computer is build to decide on whether the virtual sword can be stolen or not... (maybe, I haven't really looked hard at it in a few years, so I'm probably forgetting some details of it).

[Similar disclaimers about not being a physicist go here]

Something that's going to be a bit tricky here is that electrons are really, really slow when we're talking about electricity through a wire. The electrons will bounce around very quickly at random, but the average flow caused by a current is slow. Really, really slow.

https://en.wikipedia.org/wiki/Drift_velocity

For a specific but not unreasonable example:

> Therefore in this wire the electrons are flowing at the rate of −0.000023 m/s. At 60 Hz alternating current, this means that within half a cycle the electrons drift less than 0.2 μm. In other words, electrons flowing across the contact point in a switch will never actually leave the switch.

That kind of speed means that any messages sent over a copper wire are not going to be sending electrons all the way for that message. The electrons that 'carry' the message "I AM A VIRTUAL SWORD" will not go from my machine to yours as a rushing block. Instead all I'll be doing is tapping the end of a very long pole connecting our two properties, so you can read the message by the patterns of the end of the pole in your house moving ever-so-slightly.

So, I guess I am transferring mass, but nothing that comes from me goes to you.

This also assumes a very particular direction. There's nothing, as far as I'd understand, that requires me to be pushing electrons at you. I could be pulling on the pole slightly rather than pushing.

I'd love any corrections or additions to this, purely my lay understanding of the topic.

Even ignoring the speed of the electrons, this ignores that several steps of that route will almost certainly be done over fibre anyway, and at that point there is clearly no transfer or electrons from the "seller" to the "buyer". Although I have no idea whether or not this is relevant to the legal question at hand…

Water is another good analogy. When you turn on a tap/faucet, the water that comes out is the water that was just sitting there in that last few inches of pipe, it didn't come all the way from the city's dam in that time.

Also with waves in water; put a ball floating at the beach and it'll mostly stay put bobbing up and down. (It's only when the waves actually break that there is substantial movement of actual "bits" of water.)

https://en.wikipedia.org/wiki/Effective_mass_(solid-state_ph...

Ah, I apologize, but I have to join the unhelpful choir ;)

It seems to me that the question of whether or not electricity has mass is a proxy for whether or not information is tangible. This is the same interpretation that "Greg Graviton" at stackexchange has. And it is hard to meaningfully answer by yes or no; information needs material in order to exist, but by itself it is not tangible. Both yes and no are misleading.

My advice, which is completely ignorant of how law is practiced, is to find another way to settle the original question of whether or not the coerced obtaining of the virtual sword could be named "stealing". When taking intuitive notions such as "is this a _thing_ or not?" to the fundamental levels, the questions often stop making sense, as it has in this case, because the intuition is dependent on another level of abstraction. At this point it is no longer constructive to attempt obtaining answers to the questions as posed, and maybe this is why you have struggled to find a good answer. That's probably not helpful to you, but it is my best attempt at resolving this question :)

(About DC: It is more accurate to say that there is an exchange of mass. The same count of electrons go down the wire as up the other wire. There is no net transfer of mass. See also https://news.ycombinator.com/item?id=14087221 )

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