The Science of the YW Universe

[cheshire]

Young Wizards is the only fantasy I've read that takes science so seriously. And I like it! And Duane's scientific concepts have very real roots in the real world...for example,scientists have speculated the existence of white holes in the universe,which are the opposite of black holes:they spew out matter and radiation instead of sucking everything in.Some think the stuff they throw out might come from other universes.
But these white holes are not as anthropomorphic or mobile as Fred,of course...

[cheshire]

Young Wizards is the only fantasy I've read that takes science so seriously. And I like it! And Duane's scientific concepts have very real roots in the real world...for example,scientists have speculated the existence of white holes in the universe,which are the opposite of black holes:they spew out matter and radiation instead of sucking everything in.Some think the stuff they throw out might come from other universes.
But these white holes are not as anthropomorphic or mobile as Fred,of course...

[Selden]

Well, some of her science is, ummm, shall we say... extrapolated.

Dairene's planet of the silicon intelligence, for esample. It's trillions of light years away, which (so far as we know) can't happen in our universe. The furthest object can only be as far away in light years as the age of the universe: about 13.7 billion (in U.S. terms, 13.7 thousand million in British).

Selden

[Nathan]

Careful, Selden! All you have shown is that "Dairene's [sic] planet of the silicon intelligence" cannot lie in the observable universe, given the distance you quoted. The entire universe extends further (in all probability much further, especially if inflation actually occurred) than the observable universe --in fact, if it did not, then the Copernican principle (that the Earth does not occupy any preferred [spatial] location in the universe) would be violated.

Of course, you are entirely correct that much of DD's science is, indeed, "extrapolated." The important point (and why 'extrapolated' is such an apt term to describe her science, in general) is that her 'jumping-off points' are well-grounded in modern-day science (albeit very speculative modern-day science at times [I'm thinking of Fred, in particular]). Perhaps even more striking than the (frequent) appearances of science in her works is the underlying scientific ethos, which, to me, even more so than the specifics, arises directly from her early love for astronomy and astrophysics and her later study of the biological sciences (see, e.g., her bio and her post in 'ARG... can't wait any longer' in the 'Forthcoming Books' section of these forums).

Nathan

Ubi materia, ibi geometria. --Johannes Kepler

Non doctrinam, sed perspicuitatem quaero.

[Selden]

Copernicus was wrong.

We are where we are because conditions here are right for our kind of life. (e.g. amount of metallicity in the neighborhood where the solar system formed: without enough carbon, we'd be in trouble and the same goes for too much uranium, for example.) Obviously, one must be careful in one's definition of a "preferred location" so as to avoid being there

This is, to a certain extent, a sophistry, of course. I realize you're talking about a non-preferred location which corresponds to a type of Platonic ideal. My problem with it is that everything we learn about how the universe is structured seems to suggest that our location is very special on almost every distance scale. On the largest scale, for example, the multitudinous clusters of galaxies, large, brilliant and numerous as they are, are arranged in filmy threads and surfaces surrounding vast, gaping holes of nothingness...

(I finally managed to find some reasonable pictures at http://www.tac.dk/~lars_c/thesis/nod...00000000000000

Now to find a copy of their merged catalog to use in Celestia...)


Obviously the LP has been very successful in most of the universe.

Selden

[cheshire]

Duane is a fantasy writer:if she didn't 'extrapolate', she'd be better off writing science textbooks. Discussion of her scientific ideas is best limited to the context of the YW books...

you'll never be an artichoke;even vegetables have a heart

[Quill]

Cheshire--well, she does it in science fiction, too, see her Trek books for examples. String theory, Wolf-Rayet stars, "taub-NUT universes," heh, heh...

I agree with most of what's been said... I'm a bit out of my league with this, but I'm working on it!

Has anybody seen a theory or scientific fact or something like that in one of her books and done more research on it? Or am I the only one (like right now, I'm comparing a barred spiral galaxy to the Milky Way, and I got my older brother and dad in a lecture about string theory and other things like that)?

[Nathan]

Originally posted by Selden:
Copernicus was wrong.

You mean about the epicycles?

More seriously, I don't think that the composition of the solar nebula can be used to argue that the Earth occupies a "preferred [spatial] location" --that is far more of a temporal argument, considering that the interstellar medium (the ISM, in professional parlance) must have been enriched with metals * before terrestrial planets could form. Given our knowledge of stellar nucleosynthesis (and how supernovae and [to a lesser extent] planetary nebulae enrich the ISM), it is not at all surprising that carbon will be prevalent and uranium weakly represented. As far as I know, uranium is not generated in large quantities even in supernovae --in general, abundance decreases with increasing mass number (a notable exception [beyond the usual fluctuations] is the "iron peak" --for an illustration, see [if you have the ability to view encapsulated PostScript files on your computer] this figure [from Carroll and Ostlie's An Introduction to Modern Astrophysics] showing solar photospheric atomic abundances [data are the standard Grevesse and Anders abundances --all abundances are normalized to 10 ^ 12 hydrogen atoms] --the "trough" at lithium, beryllium and boron is an artefact of the Sun's burning of those elements). See this abstract (I haven't read the article) for evidence of solar photospheric abundances being in pretty good agreement with (galactic) ISM abundances.

Incidentally, were you alluding to the hypothesis that a nearby supernova triggered the collapse of the solar nebula (and deposited radioactive elements) when you brought up the metallicity of the solar neighborhood? This still, I feel, cannot be used argue a preferred location for the Sun, given that supernovae occur quite frequently in the galaxy (a Type II [core-collapse] supernova is thought to occur in the Milky Way about every 44 years [we can't see most of them because of obscuration by the ISM]) and the short life spans (astronomically speaking) of massive stars mean that there will most likely still be significant amount of ISM nearby when they go supernova. The radioactive elements that are generated in a supernova explosion (and there are a goodly number of them) are all far lighter than uranium and have very short half-lives, astronomically speaking (some of the half-lives are very short indeed! [~1 week]) --in fact, these short half-lives are an integral part of the argument in favor of this hypothesis.

The Copernican principle is, of course, merely a guideline, but has seemed to be upheld at ever larger distance scales (your arguments notwithstanding) and thus cosmologists are loath to violate it. Your understanding of what is meant by a "preferred location" seems to differ from mine, as I see no conflict with us residing in a galaxy in one of the "filmy threads and surfaces," as, ipso facto, a galaxy not residing in one of them would be "preferred" in at least one sense (analogous to a 'free-floating' planet). From my understanding of the Copernican principle, you are correct in stating that it applies in a Platonic ideal (or, nearly equivalently [and my preferred way of thinking about it {sorry about the pun!}] a geometric "preferred location"), for its initial applications (or validity checks, to probably be more accurate) were to the position of the Earth relative to the Sun and the position of the Sun in the galaxy. However, if my memory serves me correctly, the Copernican principle has also been applied to the 'positions' of the Earth in the distribution of planetary sizes, the Sun in the spectral sequence and the Milky Way in the distribution of galaxy sizes --in this formulation, it seems to become "our location is as 'ordinary' as possible" (though this, of course, requires a careful definition of 'ordinary'). Interestingly enough, as I see it, the two most compelling arguments for the Earth being in a "preferred location" are our position in the Sun's 'habitable zone' and the Sun not being a binary (or multiple) star system.

I actually would not take the existence of voids (in the distribution of galaxies in the [observable] universe) as evidence of the success of the Lone Power, for, considering the (hypothesized) existence of both dark matter and dark energy, it is possible (nay, likely) that life in some form would have developed (in the YW cosmology) using one (or perhaps both) of these for its constituents (here assuming that dark matter is non-baryonic --otherwise this statement is not saying anything new [concerning dark matter as a constituent, at least]). (Of course, the existence of dark matter in the 'voids' is, as far as I know, up for debate [but see Holes in space are not empty], as is the existence of dark matter and dark energy, period. But, these are important parts of the current best-fit model, and, as such, warrant serious consideration.)

[Note: I have, in an attempt to offer more detail to those forum members with a good astronomy background while still not leaving the rest of the members completely 'in the dark,' most likely been both far too abstruse and far too basic in this post. That said, please let me know if I have failed in either of my aims (especially the latter).]

Nathan

* For those who are following this discussion, I am using (and I assume Selden is, as well) the stellar astrophysics jargon that every element heavier than helium is a metal (this and the use of 'burning' for nuclear fusion are probably the most amusing [and potentially perplexing] bits of stellar astrophysics jargon).

Ubi materia, ibi geometria. --Johannes Kepler

Non doctrinam, sed perspicuitatem quaero.

[This message was edited by Nathan on 30 November 2003 at 10:35.]

[PK]

This is not my field, and I have probably missed something. That said, I read Selden's statement

The furthest object can only be as far away in light years as the age of the universe: about 13.7 billion (in U.S. terms, 13.7 thousand million in British).

as referring not to the furthest object away from earth but to how far any two objects could be from each other, based on the notion that nothing could move faster than light (relative to any other object...) and therefore wouldn't have had the chance to get any greater distance away than the age of the universe in light years.

Most likely I am missing something, probably including a significant point in relativity theory.

[FireWitch]

I'm struggling through A Brief History of time, just so that I can understand some of what all of you are saying.

From my VERY limmited knowledge, all that I can add is that I find it absolutely wonderful to read about some scientific something in a fantasy book, and then see it explained in a physics textbook, even if the definitions are slightly different...

Oh well, that's my two cents.

A Jedi Ewok
And proud of it...

Loyal reader and Young Wizards books, great lover of Moon Cakes, and Princess of Pennames...

[Nathan]

PK: This is a famous (fairly) subtle point in relativistic cosmology. While there is the well-known stricture that "information/influences cannot travel faster than the speed of light" from special relativity, nothing prevents two points in spacetime itself from receding from each other faster than light, and this expansion of spacetime is the cause of these great separation distances (and, incidentally, the fact that the special relativity stricture still holds in this case causes problems for noninflationary cosmologies [the so-called horizon problem] ... but I probably shouldn't digress too much ).

Nathan

Ubi materia, ibi geometria. --Johannes Kepler

Non doctrinam, sed perspicuitatem quaero.

[meteorite]

As I recall, the 'iron spike' is due to a peculiarity of nuclear fusion. For elements heavier than iron, you can't generate them in a 'conventional' star core, because the energy required to fuse elements that heavy is greater than the energy released by their fusion. You need the burst of energy released by a nova or supernova to make them.

"Thus is Balance maintained." A Wizard of Earthsea
"Condensing fact from the vapor of nuance." Neal Stephenson, Snow Crash