Magical lifespan in Harry Potter

[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.

Comments

[beccak1961.livejournal.com]

Maybe they are some sort of universal spell that's renewed by other wizards.

[sporks5000.livejournal.com]

Perhaps there's a complicated bit of spellwork that allows them to link the spell to another energy source besides themselves. Perhps some spells don't require an energy source to keep going (I.E. you create a frying pan out of thin air. All of the energy is expended in the creation of the frying pan, but now that it's created it can remain indefinitely.)

[lakidaa.livejournal.com]

to cop out: They used their Permanant Spell metamagic feat and spent the EXP. Or they discarded an Island to Foil that other dude's spell. *geek.*

That is, they gave something of themselves up to make the spells last permanantly. That's how it's handled in D&D and Magic: The Gathering.

That makes sense.

[mortaine.livejournal.com]

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.

Actually, wasn't that a standard freezing spell, similar to the one used on poor Neville in Book 1?

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....)

Dumbledore's office is larger on the inside than the outside, and Hogwart's itself is full of pocket dimensions.

I think the energy for magical places is slightly different from the energy for magical spells. In the Black's case, the spells may be tied to bloodline or possession, essentially feeding off of the current possessor of the house, or just off of the current bloodline. If that were the case, then any such Slytherin-line spells would either be very weak (having only one to feed off of) or extremely desperate (being funnelled essentially through just one).

I think Hogwart's feeds off of the energy generated by learning magic. I mean, let's face it: young wizards are very wasteful of magical energy when they're starting out.

[conuly]

Yes, it is - and we don't know if that one spell has a natural lifespan or not.

[aquamizuko.livejournal.com]

Interestingly, I've heard that the conservation of energy law can be violated (new energy coming out of nowhere), but it can only happen for a short amount of time and the new energy has to disappear again. XD I don't know if that's the same for destroying it though, don't think so..

[rho]

It is the same for destroying energy, but that's generally less useful so you don't hear about it so much. Generally, this effect is used to explain quantum phenomena where something needs a certain amount of energy to get over a barrier and doesn't quite have it. It can then "borrow" the energy to get over the barrier and then "give it back" when it's over the other side. The canonical examples of this are beta decay, quantum tunneling, and Hawking radiation.

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

[rho]

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.

The other option would be for the mass to be converted to energy. Of course, the drawback to this method is that it would create an absolutely huge nuclear explosion that would probably blow up the whole of Scotland.

[conuly]

Like I said... she's either very heavy, or the mass goes elsewhere.

[joeymew.livejournal.com]

Animorphs used the whole matter going elsewhere thing when they would morph into animals smaller then themselves. The extra mass would sit in a giant floating glob in space, with the chances of it being hit by a passing spaceship impossibly low. So of course one of the books had their mass being hit by a spaceship. Globs of mass floating in space is more SF then Fantasy though.

Sort of off topic.

[leora.livejournal.com]

Well, when we make things in our world, say a flashlight, it can only keep producing light until the energy stored in it runs out, unless you then give it more energy. But if you want a rock on top of a hill, it takes a lot of energy to get it there, but once there it stays there until something else affects it. So, maybe being unplottable is more along the lines of being on the top of a hill.

The sort of spells that seem to run out seem to be the sort that are more active. Containing someone who wants to move, speaking, etc. Whereas the sorts of spells that seem to last are usually, but not always, more just ways of something being. Artifacts seem to usually be embued with energy at time of creation, and I think if they are low energy needs, they will last long enough for it to be effectively forever for practical purposes.

However, I'm more curious about the conservation of identity... those paintings of real people are kind of creepy... and how does that work. Bits of a person are replicated and they can gain information through where their images are... and then aspects of this linger even after death. I think that's far weirder than any minor mass/energy oddities.

When Ron and his family were in the paper, did they have a huge spy network of all the places where the paper was? Ron didn't seem to have any access to the info from his picture's locations... maybe learning how to use that is more advanced magic.

[beccak1961.livejournal.com]

Maybe they are some sort of universal spell that's renewed by other wizards.

[sporks5000.livejournal.com]

Perhaps there's a complicated bit of spellwork that allows them to link the spell to another energy source besides themselves. Perhps some spells don't require an energy source to keep going (I.E. you create a frying pan out of thin air. All of the energy is expended in the creation of the frying pan, but now that it's created it can remain indefinitely.)

[lakidaa.livejournal.com]

to cop out: They used their Permanant Spell metamagic feat and spent the EXP. Or they discarded an Island to Foil that other dude's spell. *geek.*

That is, they gave something of themselves up to make the spells last permanantly. That's how it's handled in D&D and Magic: The Gathering.

That makes sense.

[mortaine.livejournal.com]

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.

Actually, wasn't that a standard freezing spell, similar to the one used on poor Neville in Book 1?

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....)

Dumbledore's office is larger on the inside than the outside, and Hogwart's itself is full of pocket dimensions.

I think the energy for magical places is slightly different from the energy for magical spells. In the Black's case, the spells may be tied to bloodline or possession, essentially feeding off of the current possessor of the house, or just off of the current bloodline. If that were the case, then any such Slytherin-line spells would either be very weak (having only one to feed off of) or extremely desperate (being funnelled essentially through just one).

I think Hogwart's feeds off of the energy generated by learning magic. I mean, let's face it: young wizards are very wasteful of magical energy when they're starting out.

[conuly]

Yes, it is - and we don't know if that one spell has a natural lifespan or not.

[aquamizuko.livejournal.com]

Interestingly, I've heard that the conservation of energy law can be violated (new energy coming out of nowhere), but it can only happen for a short amount of time and the new energy has to disappear again. XD I don't know if that's the same for destroying it though, don't think so..

[rho]

It is the same for destroying energy, but that's generally less useful so you don't hear about it so much. Generally, this effect is used to explain quantum phenomena where something needs a certain amount of energy to get over a barrier and doesn't quite have it. It can then "borrow" the energy to get over the barrier and then "give it back" when it's over the other side. The canonical examples of this are beta decay, quantum tunneling, and Hawking radiation.

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

[rho]

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.

The other option would be for the mass to be converted to energy. Of course, the drawback to this method is that it would create an absolutely huge nuclear explosion that would probably blow up the whole of Scotland.

[conuly]

Like I said... she's either very heavy, or the mass goes elsewhere.

[joeymew.livejournal.com]

Animorphs used the whole matter going elsewhere thing when they would morph into animals smaller then themselves. The extra mass would sit in a giant floating glob in space, with the chances of it being hit by a passing spaceship impossibly low. So of course one of the books had their mass being hit by a spaceship. Globs of mass floating in space is more SF then Fantasy though.

Sort of off topic.

[leora.livejournal.com]

Well, when we make things in our world, say a flashlight, it can only keep producing light until the energy stored in it runs out, unless you then give it more energy. But if you want a rock on top of a hill, it takes a lot of energy to get it there, but once there it stays there until something else affects it. So, maybe being unplottable is more along the lines of being on the top of a hill.

The sort of spells that seem to run out seem to be the sort that are more active. Containing someone who wants to move, speaking, etc. Whereas the sorts of spells that seem to last are usually, but not always, more just ways of something being. Artifacts seem to usually be embued with energy at time of creation, and I think if they are low energy needs, they will last long enough for it to be effectively forever for practical purposes.

However, I'm more curious about the conservation of identity... those paintings of real people are kind of creepy... and how does that work. Bits of a person are replicated and they can gain information through where their images are... and then aspects of this linger even after death. I think that's far weirder than any minor mass/energy oddities.

When Ron and his family were in the paper, did they have a huge spy network of all the places where the paper was? Ron didn't seem to have any access to the info from his picture's locations... maybe learning how to use that is more advanced magic.