Debts

[Moonsong]

I was re-reading SYWTBAW and it dawned on me, Nita and Kit never repayed Carl for the timeslide!!! Am I just not reading close enough in the other YW novels? Did they already pay them back? Sorry, it isn't like me to be a nitpicker, but I was just curious.

[PK]

Well, do remember that they're generally implied to be doing a lot more than we actually get to read about in detail. And, after all, they're under Tom and Carl's authority/jurisdiction in terms of, um, wizarding administration and mentoring -- there have probably been plenty of chances, I'd guess.

I'd also be unsurprised if in at least some sense that sort of debt is likely to be "paid forward" -- at any rate the service done in return might be substitution or help with something Tom and Carl need to do for their wizardry.

I'm not sure this is very coherent. *frowns* Apologies.

[Moonsong]

<span class="ev_code_GREEN">Yeah, that all makes sense. But this is going to drive me nuts!!! Argh! I'm a little obsessive. Oh well. Yeah, ,maybe they have paid it already but DD didn't put it in the books. Or maybe if they haven't, Carl let it be like a gift of sorts to welcome Kit and Nita into wizardry. I don't know, just a thought from an insane mind.</span>

[Nathan]

I actually remember the timeslide being paid for in advance:

When Nita and Kit first meet up with Tom and Carl, I seem to remember either Tom or Carl remarking that Nita and Kit already had some 'credit' (leading either Tom or Carl to exclaim "Since when did the Powers start giving out door prizes?" [quoting from memory here]). This 'credit' was used to pay Carl for the timeslide, if my memory serves me correctly.

I don't think that it's ever firmly established what exactly Nita and Kit did to obtain this 'credit', though they do hypothesize that it was at least partly for 'inviting' Fred with their spell.

In fact, the whole subject of energy supplied by the wizard versus energy supplied by the Powers is a fascinating one, as we are pretty clearly told that the Powers invest a significant amount of energy in a new wizard, but also that actually performing a wizardry deducts energy from the wizard (though, as introduced in Holiday, this can be done on an 'installment plan'). In addition, the Powers will subsidize various 'expenditures' (as we have seen in the SYWTBAW reference above as well as in Holiday [I won't mention specifics to avoid spoilers]). My personal feeling is that the expenditure of personal energy on the wizard's part is mainly 'activation energy' (it is explicitly mentioned that various objects can help lower this 'activation energy') required to access energy provided by the Powers, especially as going from the Earth to the Moon (which seems to be treated as a routine wizardry) is energetically quite expensive (I calculated the energy required once, but I don't have the result with me at the moment and don't have time to recalculate it, though it's not at all difficult to get a 'back-of-the-envelope' estimate). There are more speculations about where wizards obtain their energy in the thread ' "There's no higher payment that can be made." ' in the 'Deep Wizardry' section of these forums (which is perhaps where I should have stuck these speculations --I'll [hopefully] put a fuller and more substantiated version there sometime).

Nathan

[Moonsong]

Nathan, if you ever find the energy calculations again I'd love to see them. I imagine it would leave you some what drained, but compared to Mars, the moon is pretty close to us.

[PK]

Nathan, thanks, I'd forgotten about the credit, but yeah.

And to complicate the energy business, there's The Book of Night with Moon where... um, explaining would spoil the climax. Heh. Also there's the matter of directly invoking the Powers as in A Wizard Abroad (which I'm guessing is pretty spoiler-safe now), where it's mentioned that if you run into one of the Bright Powers about Its business, identify it as a Power and ask for help with an intervention, it's obligated to help you.

The energetic implications of buying the Lone Power a hot dog (as opposed to doing so for another given entity) may be undetermined.

[Moonsong]

Wait! Does anyone else remeber NIta and Kit talking about not having much moeny? Then Tom and Carl said it was okay because wizards paid in service that wasn't even done for a few years in most cases. They didn't mention anything about it being paid for with the credit.

[Nathan]

Moonsong: I don't have access to a copy of SYWTBAW at the moment, but I remember that exchange taking place prior to Tom and Carl's discovery of Nita and Kit's credit.

On a related note, I finally unearthed my energy calculations and had a few moments to check over them (as I mentioned before, they're not really at all difficult, but they are full of lots of places to make careless mistakes [that said, if anyone wants to check them, go right ahead --I won't mind and, in fact, encourage it]).

One would expend 6650 kilocalories per pound * doing work against the Earth's gravitational field in going from its surface to the Moon's. The Moon's gravitational field will give you back only 300 kcal/lb and, depending on the position of the Moon, you may have to expend as much as 270 kcal/lb in doing work against its gravitational field (this maximum is for full Moon --alternatively, you could get back 270 kcal/lb [at new Moon]). These values all clearly support my contention that this trip is, energetically, far too expensive for wizards to undertake as lightly as they seem to if all of the energy was provided from their body's energy.

However, there is one major caveat to all of this: time. These energy calculations say nothing about how long it would take one to get to the Moon, and wizards seem to arrive practically instantaneously, which, of course, violates the famous special relativistic stricture against traveling faster than the speed of light (unless there is some sort of 'wormhole' arrangement, but we know, regardless, that canonically, wizardry is not affected by that stricture [via Nita's comment in Dilemma]). This, however, calls into question my entire energy analysis, because one way of deriving the speed of light as the ultimate limiting velocity is based on energy considerations. However, I remember it being pretty clearly stated (in Deep Wizardry, I believe) that a wizard does indeed do work against the Earth's gravitational field in going from the Earth to the Moon, so, I would imagine that my analysis is correct, though it is, of course, possible that the energy required is somehow lowered to the point that it can all be withdrawn from the wizard's body's available energy.

For comparison, to go to Mars, you must expend 6770 kcal/lb against the Earth's gravitational field, Mars' gravitational field gives you back 1420 kcal/lb and climbing that far out of the Sun's gravitational well demands an expenditure of 33050 kcal/lb.

For those who are interested, here are a few salient (slightly more technical) points about how I went about these calculations: These values were all obtained from the Newtonian gravitational potential (making all the usual 'back-of-the-envelope' simplifications of circular, coplanar orbits and spherical planets --I also neglected such 'niceties' as conservation of angular momentum [which I don't think would affect the answer much anyway]). The answers were also rounded to the nearest ten.

Nathan

* I chose these units as most people probably have a reasonably good intuitive feel for them (certainly better that for ergs/g, I would think). However, it is important to note that the Calorie used in quoting the energy content of food is, in fact, one kilocalorie.

[Wilf]

Originally posted by Nathan:
...
One would expend 6650 kilocalories per pound *
....
* I chose these units as most people probably have a reasonably good intuitive feel for them (certainly better that for ergs/g, I would think).

Out of interest, does *anyone* these days use the CGS system (which uses ergs for enery and grammes for mass)? It seems to be the universal norm to use the SI system (with kilos for mass, joules for energy) in science, and some places use imperial (pounds and calories) in everyday life.

[Nathan]

Originally posted by Wilf:
Out of interest, does *anyone* these days use the CGS system (which uses ergs for enery and grammes for mass)?

Astrophysicists do, though not consistently --they also use all sorts of other units when they find them to be convenient (such as kilometers, years, parsecs, solar masses, etc.). I'm used to doing these sorts of calculations in cgs units (and have some of the relevant numbers memorized in cgs units), which is why I mentioned ergs/g instead of J/kg.

I just realized that I didn't clear up the potentially misleading use of pounds in my pervious post, though: The units really should be kilocalories per slug *. However, the slug is such an obscure unit that I felt that it was probably better to use the pound in this context as a unit of mass (as it is probably thought of in nonscientific circles), even though it is properly a unit of force.

Nathan

* The slug is the imperial unit of mass: one slug feels a force of one pound in one Earth gravity.

[eveningstar]

Wait... doesn't it say in DW that Ed repaid the timeslide for them? Nita was supposed to be the Silent Lord and die, but Ed took her place. Isn't that repying for the timeslide?

[PK]

Eveningstar: No, we're talking about different things. The blank-check spell that had to be repayed in any manner necessary, including life-price, wasn't for the timeslide. The timeslide wasn't, as far as I can tell, an exceptionally expensive spell -- relatively speaking. And the life-price was paid back to the Powers, not to Tom and Carl. The blank-check wizardry was done in order to take the Eldest fireworm's den and cut it off from normal space forever, remember? (I wonder about that, actually. Won't it run out of air or things to eat? Meep.)

[semiramis]

Oh! For those who have read the exerpt, maybe they're going to repay by *spoiler* <span class="ev_code_WHITE">senioring</span> */spoiler*, no? Although they may have wound up doing that whether or not they got the timeslide at all.... hm.....

[Ardub]

Originally posted by Nathan:
One would expend 6650 kilocalories per pound doing work against the Earth's gravitational field in going from its surface to the Moon's.

Ah, but let's not constrain our thoughts to us lowly oxidizing humans :-) If we work under the assumption that some wizard somewhere is employed as an energy broker between our half and the presumable antimatter half of the universe, the energy you mention (for, let's say, a 120lb person) could be supplied by about 55 nL (nanoliters) of water, or the equivalent amount of dust brushed off an arm, etc. Plus a little extra dust as a commission to the broker :-)

[eveningstar]

PK: I AM talking about the blank-check wizardry. I remember, after DW at least 10 times, that, in the end, correct me if I get the spelling wrong: Mobius spell...repayed...