Magical lifespan in Harry Potter
Jul. 30th, 2005 07:40 am![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
conuly
We know that some spells last only a short time before they wear off. Harry's shamrock stopped reciting names not long after the World Cup, hidden Fanged Frisbees eventually lose the energy to hover, and so on.
Other spells end when the wizard who cast them dies - we know this because this is how Harry knew that Dumbledore was dead. We only know that this works for one spell, and we don't know if that span has a natural lifespan as the spells involved in the earlier category.
Some spells outlast their casters - the Black house was made unplottable by one of his ancestors, the room of requirement (which even the headmaster didn't know about!) has been around probably since the start of Hogwarts, and I'll put forth the idea that this must have been a complicated piece of spellwork.
We can also venture a theory that some spells must be capable of being mass-produced. I very much doubt if Fred and George are actually putting spells on every magical item in their shop individually, there's no way they could keep up with demand that way! But maybe they have time turners. This is unrelated, I just thought I'd throw that in there.
Assuming that the laws of physics are somewhat the same when dealing with magic, and that there are no new laws to take into consideration, this runs us up neatly into the conservation of energy: Energy can neither be created nor destroyed. (Don't talk to me about the conservation of matter. Clearly, when McGonnagal transfigures into a cat, she's either a very *heavy* cat or her extra mass is going somewhere. Maybe another universe, which would also allow them to have tents that are bigger on the inside than the outside? Is that even possible? It's a cool idea, I'll grant you, but....)
Basically, every magical working must have a power source - either it turns matter into energy, or it deals with energy that's already there. In some of these magical workings, I'll hypothesise that the power source is the caster - these are probably workings that don't require too much energy, or we would've heard about Harry getting tired after all those DA meetings. That would explain why those spells end when the caster dies - their power is cut off.
But what about the rest? What about that shamrock? I don't think its creator just died suddenly, so why did it stop working? Clearly, its power source is limited.
So far, so good. But now we get into the hard part: What about those spells which seem to last an indefinite period of time? How do the spells at Hogwarts work? Do they simply have a longer lifespan, and eventually they'll run down too? 1,000 years is a long time to wait!
I'll think of something more when I'm a little more awake.
Other spells end when the wizard who cast them dies - we know this because this is how Harry knew that Dumbledore was dead. We only know that this works for one spell, and we don't know if that span has a natural lifespan as the spells involved in the earlier category.
Some spells outlast their casters - the Black house was made unplottable by one of his ancestors, the room of requirement (which even the headmaster didn't know about!) has been around probably since the start of Hogwarts, and I'll put forth the idea that this must have been a complicated piece of spellwork.
We can also venture a theory that some spells must be capable of being mass-produced. I very much doubt if Fred and George are actually putting spells on every magical item in their shop individually, there's no way they could keep up with demand that way! But maybe they have time turners. This is unrelated, I just thought I'd throw that in there.
Assuming that the laws of physics are somewhat the same when dealing with magic, and that there are no new laws to take into consideration, this runs us up neatly into the conservation of energy: Energy can neither be created nor destroyed. (Don't talk to me about the conservation of matter. Clearly, when McGonnagal transfigures into a cat, she's either a very *heavy* cat or her extra mass is going somewhere. Maybe another universe, which would also allow them to have tents that are bigger on the inside than the outside? Is that even possible? It's a cool idea, I'll grant you, but....)
Basically, every magical working must have a power source - either it turns matter into energy, or it deals with energy that's already there. In some of these magical workings, I'll hypothesise that the power source is the caster - these are probably workings that don't require too much energy, or we would've heard about Harry getting tired after all those DA meetings. That would explain why those spells end when the caster dies - their power is cut off.
But what about the rest? What about that shamrock? I don't think its creator just died suddenly, so why did it stop working? Clearly, its power source is limited.
So far, so good. But now we get into the hard part: What about those spells which seem to last an indefinite period of time? How do the spells at Hogwarts work? Do they simply have a longer lifespan, and eventually they'll run down too? 1,000 years is a long time to wait!
I'll think of something more when I'm a little more awake.
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no subject
Date: 2005-07-30 05:45 pm (UTC)no subject
Date: 2005-07-31 12:11 am (UTC)The thing is, though, that when we're working on quantum scales we generally have a vast multitude of particles or events, all with different energies ranging from zero to some maximum energy. If the maximum energy is lower than the energy needed to escape, the the quantum effect is staggering as we get some successes where we'd classically predict that we'd get none. If the maximum energy is bigger than the required energy, then we might end up with a few failures where we'd expect successes, but we don't tend to notice these so much, because we usually have a whole lot of particles/events which don't have enough energy anyway, so it tends to even out a bit.
As to the actual amount of energy that you can get out this way, it's far too small to have any effect in the macroscopic human world. It all comes from Heisenberg's uncertainty principle. I forget the exact details but the product of the energy and the time you have it for cannot be greater than something of the order of planck's constant. I think it might be ℏ/2 as the upper limit, but I wouldn't swear it. Any which way, it's something like 10-35, which is far too small to be of any interest to our wizards.
</physics geek>
Of course, some of this is an oversimplification, but it's a fairly accurate oversimplification, I think