How the mind plays tricks.
Tony Williams
supposedly passes for my memory cells.
In 'Scales' I included a plot device related to alternate worlds: that
there were different levels of such worlds, depending on the nature of
the point of departure. To quote:
"'Tell me more about your alternate worlds. How many are there?'
'Very few. Our scientists concerned with alternate worlds theory
believe that although there is one force which causes the different
worlds to branch off, there is an opposing force which acts to draw
them together again. It is a bit like a shallow river with many small
obstacles sticking up; the water parts to flow around them, then joins
up again at the other side. They call this the "braided worlds"
hypothesis. So the many minor changes which happen every day only
create temporary "Stage 4" alternate worlds; they merge back again
after a while. Only if the event which caused the worlds to diverge is
significant enough - in other words, at Stage 3 - is the separation
permanent.'"
When I wrote this I thought it was an entirely original idea. Until
yesterday, that is, when after a gap of about 15 years I was re-reading
Sheri Tepper's 'Marianne' trilogy (my favourite contemporary fantasy,
BTW - very strange, with not an elf, vampire or barbarian sword in
sight). And I came upon this:
"'Theory of convergence', she mused. 'You mean the tendency of
time-lines to knit together again if they are not very far apart.'
'Yes. I don't understand the logic or mathematics of it, but
seemingly there is no room for an infinite number of alternative
universes. They split, then converge. At any given time, only so many
different ones exist. Like a river finding a new channel in flood, but
staying in the same flood plain and returning to the original channel
eventually."
So much for my "original idea"....I had certainly read this 15 years
ago, but had forgotten all about it. When I reached the appropriate
point in my story, the idea popped into my head, all newly-minted and
shiny. Oh well, at least I did invent the term "braided worlds" - or
was that in another story?
It does make me wonder how often this happens to other authors. And it
puts an interesting perspective on those who claim to have remembered
"past lives" in great detail. I do recall reading about one such case,
when it transpired that all of the details "remembered" were included
in a novel which she might have read a long time before. I now have an
idea of what that feels like...
Tony Williams
Scales (2007)
The Foresight War (2004)
http://www.quarry.nildram.co.uk
Nicola Browne
news:1169328239.5...@51g2000cwl.googlegroups.com
> snip>> It does make me wonder how often this happens to other authors. And it
> puts an interesting perspective on those who claim to have remembered
> "past lives" in great detail. I do recall reading about one such case,
> when it transpired that all of the details "remembered" were included
> in a novel which she might have read a long time before. I now have an
> idea of what that feels like...
>
The first book I wrote - a children's story for 6-9s involved
a stange magical dinner-lady called Mrs Marchpane. It was only when
I reread 'A Wrinkle in Time' that I realised I'd lifted her from there.
Luckily, it was a borrowing blurred by the twenty five years since
I'd read it, so I don't think you can tell. I probably steal
every one of my ideas - I just don't know where from.
I think it's OK if you muddle them up well enough people
call it 'creativity' and 'originality.'
Nicky
--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG
Alma Hromic Deckert
I think ideas like that, which originated in OTHER places but somehow
surfaced in our own work a quarter of a century later, are the bit of
grit that irritates the oysters of our creativity to come up with a
pearl that might be a story. Sometimes the pearls are flawed, sure,
and there had to have been SOME original idea, somewhere, that had
nothing at all to do with ANYTHING else - but by and large we do what
we do with stories by making old stories into new ones rather than by
re-inventing the storytelling art from scratch every time we sit down
to write...
A.
Nicola Browne
news:p635r2lmn3sqn3s23...@4ax.com
> I think ideas like that, which originated in OTHER places but somehow
> surfaced in our own work a quarter of a century later, are the bit of
> grit that irritates the oysters of our creativity to come up with a
> pearl that might be a story.
>
You may come up with a pearl, Alma, I think I just came up with
a story with a bit of grit in it, and a bit of grit borrowed
from another book at that : )
Graham Woodland
> "Alma Hromic Deckert" <ang...@vaxer.net> wrote in message
> news:p635r2lmn3sqn3s23...@4ax.com
>
>> I think ideas like that, which originated in OTHER places but somehow
>> surfaced in our own work a quarter of a century later, are the bit of
>> grit that irritates the oysters of our creativity to come up with a
>> pearl that might be a story.
>>
> You may come up with a pearl, Alma, I think I just came up with
> a story with a bit of grit in it, and a bit of grit borrowed
> from another book at that : )
>
Your stories do have a certain amount of grit to them, but there's nowt
wrong with that!
Since David has not got in fast enough, I shall quote one of my own Kipling
favourites which seems apposite here:
"When 'Omer smote 'is bloomin' lyre,
'E'd 'eard men sing by land an' sea,
An' what 'e thought 'e might require
'E went an' took -- the same as me!"
...
--
Cheers,
Gray
Bill Swears
> On Sat, 20 Jan 2007 21:37:42 +0000 (UTC), "Nicola Browne"
> <nicky.m...@btinternet.com> wrote:
>
>> "Tony Williams" <Tony.W...@quarry.nildram.co.uk> wrote in message
>> news:1169328239.5...@51g2000cwl.googlegroups.com
>>
>>> when it transpired that all of the details "remembered" were included
>>> in a novel which she might have read a long time before. I now have an
>>> idea of what that feels like...
>>>
>> The first book I wrote - a children's story for 6-9s involved
>> a stange magical dinner-lady called Mrs Marchpane. It was only when
>> I reread 'A Wrinkle in Time' that I realised I'd lifted her from there.
>>
> we do with stories by making old stories into new ones rather than by
> re-inventing the storytelling art from scratch every time we sit down
> to write...
>
> A.
Trouble With Tribbles/ was released that Tribbles had appeared earlier
as Martian Sand Cats. He had read Heinlein's /The Rolling Stones/, so
he wrote to Heinlein to apologize. He got a letter back saying not to
worry about it, because Heinlein had lifted the idea from some earlier
stories, and figured it was public domain.
Bill
--
Ourdebate.com lifts free debate between writers and dilutes it with ads.
rec.arts.sf.composition is a USENET group, and can be accessed for free.
Ourdebate.com therefore sucks (the life from discourse),
and dribbles (deceit when integrity would have worked just as well).
Will in New Haven
Bill Swears wrote:
> Alma Hromic Deckert wrote:
> > On Sat, 20 Jan 2007 21:37:42 +0000 (UTC), "Nicola Browne"
> > <nicky.m...@btinternet.com> wrote:
> >
> >> "Tony Williams" <Tony.W...@quarry.nildram.co.uk> wrote in message
> >> news:1169328239.5...@51g2000cwl.googlegroups.com
> >>
> >>> I do recall reading about one such case,
> >>> when it transpired that all of the details "remembered" were included
> >>> in a novel which she might have read a long time before. I now have an
> >>> idea of what that feels like...
> >>>
> >> The first book I wrote - a children's story for 6-9s involved
> >> a stange magical dinner-lady called Mrs Marchpane. It was only when
> >> I reread 'A Wrinkle in Time' that I realised I'd lifted her from there.
> >>
> > . . . by and large we do what
> > we do with stories by making old stories into new ones rather than by
> > re-inventing the storytelling art from scratch every time we sit down
> > to write...
> >
> > A.
> I don't know the earliest story, but David Gerrold found out after /The
> Trouble With Tribbles/ was released that Tribbles had appeared earlier
> as Martian Sand Cats. He had read Heinlein's /The Rolling Stones/, so
> he wrote to Heinlein to apologize. He got a letter back saying not to
> worry about it, because Heinlein had lifted the idea from some earlier
> stories, and figured it was public domain.
It was "Pigs is Pigs" by Ellis Parker Butler.. It's a kids story about
guinea pigs. It came out in 1905 or so.
Will in New Haven
--
"Pot-Limit has more thinking involved; young people can't think"
Norm Chad
Dan Goodman
I don't think Tepper was the first writer to use that idea, either.
--
Dan Goodman
All political parties die at last of swallowing their own lies.
John Arbuthnot (1667-1735), Scottish writer, physician.
Journal http://dsgood.livejournal.com
Links http://del.icio.us/dsgood
Political http://www.dailykos.com/user/dsgood
Dan Goodman
Pigs is Pigs by Ellis Parker Butler | A story about guinea pigs ...
"Why do I say dago pigs is pigs because they is pigs and will be til
you say they ain't which ... 'Pigs is pigs.' I'll have to get authority
on this thing. ...
www.ellisparkerbutler.info/epb/pigsispigs_html.asp - 28k - Cached -
Similar pages - Note this
Crowfoot
"Nicola Browne" <nicky.m...@btinternet.com> wrote:
I see the whole literary enterprise as a long conversation, all of
us picking up material from the people before us and our
contemporaries, making our own versions, or our replies, rebuttals,
hommages, etc. And then, if we're published and get read, other
authors do the same to us. We're all in this together, and it shows.
I'm not talking, of course, about deliberate plagiarism, which has
*nothing* to do with the conversation and is a pathetic attempt
to horn in on it without actually having anything of one's own to
say . . . My first novel was a riff on and reply to, of all things, "The
Prisoner of Zenda". "The Vampire Tapestry" was a reply to both
Stoker and Rice, as texts and (in the case of Stoker) as stage
drama. And replies have been made to me as well. We really are
all in this together.
Suzy
Graham Woodland
It's an obvious way of making alternate histories recognisable instead of
wildly divergent. I would be only mildly surprised if Tepper were the
first to use it for other purposes.
I think it's fair to guess that no-one else has *ever* written anything very
much like _Marianne_, though I am certainly all ears if anyone can think of
any. I enjoyed those books a lot.
--
Cheers,
Gray
Patricia C. Wrede
"Crowfoot" <page...@swcp.com> wrote in message
news:pagemail-EDF6DB...@iruka.swcp.com...
> I see the whole literary enterprise as a long conversation, all of
> us picking up material from the people before us and our
> contemporaries, making our own versions, or our replies, rebuttals,
> hommages, etc. And then, if we're published and get read, other
> authors do the same to us. We're all in this together, and it shows.
I've seen this metaphor before, and one of my good friends subscribes to it
very strongly. I'm not sure why the metaphor doesn't work for me. The
actual incidents described -- doing versions or revisions or hommages or
whatever of things I've read -- is very much an accurate description of
what's going on, which just makes me more puzzled as to why the
"conversation" metaphor just doesn't feel right to me.
Mmmmph. I think maybe that for me, a conversation is mutually participatory
and responsive, even if it's very drawn-out (as in a correspondence). The
interaction between what I read and what I write can't be a conversation
because, except in very rare cases, it lacks that mutuality -- a dead author
can't respond to me, and even my contemporaries are as likely as not to be
unfamiliar with my writing (this of course changes as one's sales and
reputation increases, but there are plenty of wildly-bestselling authors
whom I have not read; in the unlikely event that any of them are bouncing
off what I do, I'm not going to know about it, and I assume the same will
apply to me, should I ever attain such exalted sales figures).
> My first novel was a riff on and reply to, of all things, "The
> Prisoner of Zenda". "The Vampire Tapestry" was a reply to both
> Stoker and Rice, as texts and (in the case of Stoker) as stage
> drama. And replies have been made to me as well. We really are
> all in this together.
I can sorta see it, when you put it that way, but the metaphor still doesn't
quite work for me. I am going to have to think about this for a while; the
"conversation" thing works for enough people that I'd like to at least have
a handle on *why* it isn't working for me, so as to be able to come up with
more sensible responses than a mere rant about how it doesn't work for me,
when it next comes up.
Patricia C. Wrede
Michelle Bottorff
> I can sorta see it, when you put it that way, but the metaphor still doesn't
> quite work for me. I am going to have to think about this for a while; the
> "conversation" thing works for enough people that I'd like to at least have
> a handle on *why* it isn't working for me, so as to be able to come up with
> more sensible responses than a mere rant about how it doesn't work for me,
> when it next comes up.
My best guess is that they're seeing it as one layer more abstract than
you are. For you the conversation is supposed to be between you as an
author and another author, and that isn't there. They see the
conversation as being a group thingy of which they are a part -- it's
between the genre and the genre, rather than between individual authors,
but the individual authors are the ones carrying it forth, so to speak.
--
Michelle Bottorff -> Chelle B. -> Shelby
L. Shelby, Writer http://www.lshelby.com/
Livejournal http://lavenderbard.livejournal.com/
rec.arts.sf.composition FAQ http://www.lshelby.com/rasfcFAQ.html
Nicola Browne
news:12r71rk...@corp.supernews.com
>
> > I can sorta see it, when you put it that way, but the metaphor still doesn't
> quite work for me. I am going to have to think about this for a while; the
> "conversation" thing works for enough people that I'd like to at least have
> a handle on *why* it isn't working for me, so as to be able to come up with
> more sensible responses than a mere rant about how it doesn't work for me,
> when it next comes up.
>
It doesn't work for me either. I mish- mash everything I've ever read
plus all the tv I've ever watched together in my head and what comes
out is, well, whatever comes out, owing its origins to poor mental
organisation and inefficient memory storeage as much as anything else.
I'm not responding to stuff I've read in the past in any conscious
way - except on those rare occasions when I do know what I'm
stealing/subverting. A conversation suggests a reasoned response to
known respondent and that certainly isn't happening where I am.
Patricia C. Wrede
"Nicola Browne" <nicky.m...@btinternet.com> wrote in message
news:14e4a371eb822b7a1b...@mygate.mailgate.org...
> "Patricia C. Wrede" <pwred...@aol.com> wrote in message
> news:12r71rk...@corp.supernews.com
>
>>
>> > I can sorta see it, when you put it that way, but the metaphor still
>> > doesn't
>> quite work for me. I am going to have to think about this for a while;
>> the
>> "conversation" thing works for enough people that I'd like to at least
>> have
>> a handle on *why* it isn't working for me, so as to be able to come up
>> with
>> more sensible responses than a mere rant about how it doesn't work for
>> me,
>> when it next comes up.
>>
> It doesn't work for me either. I mish- mash everything I've ever read
> plus all the tv I've ever watched together in my head and what comes
> out is, well, whatever comes out, owing its origins to poor mental
> organisation and inefficient memory storeage as much as anything else.
Yeah. Compost works a whole lot better for me, as a metaphor, than
conversation. The stuff all goes into a warm, dark bit of my backbrain and
sits there working away quietly on its own, until it comes out all brown and
moist and crumbly and ready to grow new stuff. And occasionally I poke it
or turn it over and it steams a bit.
> I'm not responding to stuff I've read in the past in any conscious
> way - except on those rare occasions when I do know what I'm
> stealing/subverting. A conversation suggests a reasoned response to
> known respondent and that certainly isn't happening where I am.
Well, not in my writing, anyway. I *try* for reasoned responses on rasfc...
:)
Patricia C. Wrede
Brian M. Scott
<bill....@taylorandfrancis.com> wrote in
<news:1169343266.7...@51g2000cwl.googlegroups.com>
in rec.arts.sf.composition:
> Bill Swears wrote:
[...]
>> I don't know the earliest story, but David Gerrold found
>> out after /The Trouble With Tribbles/ was released that
>> Tribbles had appeared earlier as Martian Sand Cats. He
>> had read Heinlein's /The Rolling Stones/, so he wrote to
>> Heinlein to apologize. He got a letter back saying not
>> to worry about it, because Heinlein had lifted the idea
>> from some earlier stories, and figured it was public
>> domain.
> It was "Pigs is Pigs" by Ellis Parker Butler.. It's a
> kids story about guinea pigs. It came out in 1905 or so.
A genuine classic. I first read that when I was a kid, and
I think I ended up with the hiccups. It still makes me
laugh. 'What if thim dago pigs had been elephants!'
Brian
Brian M. Scott
<gr...@quilpole.demon.co.uk> wrote in
<news:eov6g4$rvh$2$8300...@news.demon.co.uk> in
rec.arts.sf.composition:
[...]
> I think it's fair to guess that no-one else has *ever*
> written anything very much like _Marianne_, though I am
> certainly all ears if anyone can think of any. I enjoyed
> those books a lot.
I know that I've read the third, which I definitely liked,
and I think that I've read at least one of the other two.
(It's not quite right, but I tend to think of them as
'Tepper playing McKillip'.) You might try _A Rumor of
Gems_, by Ellen Steiber (Tor); it's not as outright strange,
but for me it has some of the same real-but-unreal feel.
Brian
Graham Woodland
> On Sun, 21 Jan 2007 08:01:58 +0000, Graham Woodland
> <gr...@quilpole.demon.co.uk> wrote in
> <news:eov6g4$rvh$2$8300...@news.demon.co.uk> in
> rec.arts.sf.composition:
>
> [...]
>
>> I think it's fair to guess that no-one else has *ever*
>> written anything very much like _Marianne_, though I am
>> certainly all ears if anyone can think of any. I enjoyed
>> those books a lot.
>
> I know that I've read the third, which I definitely liked,
> and I think that I've read at least one of the other two.
> (It's not quite right, but I tend to think of them as
> 'Tepper playing McKillip'.)
The Man from El Stonebridge, he say 'boggle!'. I think this
is one of the places where Tepper uses her undeniable talent for the
farcical to its best effect. In some of her other works it just seems to
surface at unexpected moments, like a sudden custard pie of ultimate evil.
> You might try _A Rumor of
> Gems_, by Ellen Steiber (Tor); it's not as outright strange,
> but for me it has some of the same real-but-unreal feel.
>
Ah! Totally unfamiliar to me and a very promising recommendation: it's on
my to-get list already. Thanks!
--
Cheers,
Gray
Jonathan L Cunningham
> Dan Goodman wrote:
>
> > Tony Williams wrote:
> >
> >> Yesterday I had a salutary lesson in the erratic behaviour of what
> >> supposedly passes for my memory cells.
> >> "'Theory of convergence', she mused. 'You mean the tendency of
> >> time-lines to knit together again if they are not very far apart.'
> > I don't think Tepper was the first writer to use that idea, either.
> >
>
> It's an obvious way of making alternate histories recognisable instead of
> wildly divergent. I would be only mildly surprised if Tepper were the
> first to use it for other purposes.
IIRC, and AIUI, if you use QM to get your diverging timelines[*], then
they ought to diverge *backwards* in time just as much as they diverge
forwards. I.e. there are as many possible "pasts" to explain where we
are now, as there are possible futures in front of us.
Diverging as you go back in time is the same as converging as you go
forward, of course.
Disclaimer: I don't think this is the orthodox view.
It raises some interesting questions though. For example, if we have
many possible pasts, how come memory of a single past? It's not
difficult to postulate answers. But then turn the answers around, and
see what the implications are for alternate futures.
As I said in a posts a few weeks/months ago, people often assume "every
possible choice leads to a different future" means that all possible
things happen. It doesn't. Nor does "everything possible happens in some
parallel world" mean that "everything imaginable happens in some
parallel world".
Jonathan
[*] "Collapse of the wave function" is necessary to *avoid* diverging
timelines. Nowadays, "decoherence" is the current buzzword as an
alternative, but AIUI doesn't prevent alternate timelines, it just
explains how when Schrodinger's cat is alive, your brain records that it
is alive. (The states where it's still alive but you see it dead or
vice-versa become increasingly improbable.) Crops up a lot when people
talk about quantum computers.
Dan Goodman
> I'd like to at least have a handle on why it isn't working for me, so
> as to be able to come up with more sensible responses than a mere
> rant about how it doesn't work for me, when it next comes up.
Would it work better for you if time travel was common enough that, for
example, Shakespeare could write a play in response to West Side Story?
Julian Flood
>> a long conversation
> I'm not sure why the metaphor doesn't work for me.
I've responded to things, but I wouldn't call the structure of the...
exchange as a conversation. Flat contradiction, yes, a shout of rage,
maybe, but conversation? No, not really.
Students may search out Horse meat by Brian Aldiss and try to work out
which of my short stories is a riposte to that. No peeking on Google.
JF
Tony Williams
Jonathan L Cunningham wrote:
> IIRC, and AIUI, if you use QM to get your diverging timelines[*], then
> they ought to diverge *backwards* in time just as much as they diverge
> forwards. I.e. there are as many possible "pasts" to explain where we
> are now, as there are possible futures in front of us.
> [*] "Collapse of the wave function" is necessary to *avoid* diverging
> timelines. Nowadays, "decoherence" is the current buzzword as an
> alternative, but AIUI doesn't prevent alternate timelines, it just
> explains how when Schrodinger's cat is alive, your brain records that it
> is alive. (The states where it's still alive but you see it dead or
> vice-versa become increasingly improbable.) Crops up a lot when people
> talk about quantum computers.
Now there I was, winding down on a relaxing Sunday evening, and you
have to go and give me a headache...
Tony Williams
Brian M. Scott wrote:
> You might try _A Rumor of
> Gems_, by Ellen Steiber (Tor); it's not as outright strange,
> but for me it has some of the same real-but-unreal feel.
Thanks, I've noted that.
Some other fantasies I enjoyed and recall as being decidedly odd (which
is really all they have in common) are three linked pairs:
The High House, and The False House, by James Stoddard.
The Infinity Concerto, and The Serpent Mage, by Greg Bear
Tea with Black Dragon, and Twisting the Rope, by R A MacAvoy
Logan Kearsley
news:1hsb0g9.cloksynz8ozkN%sp...@sofluc.co.uk.invalid...
> Graham Woodland <gr...@quilpole.demon.co.uk> wrote:
>
> > Dan Goodman wrote:
> >
> > > Tony Williams wrote:
> > >
> > >> Yesterday I had a salutary lesson in the erratic behaviour of what
> > >> supposedly passes for my memory cells.
>
> > >> "'Theory of convergence', she mused. 'You mean the tendency of
> > >> time-lines to knit together again if they are not very far apart.'
>
> > > I don't think Tepper was the first writer to use that idea, either.
> > >
> >
> > It's an obvious way of making alternate histories recognisable instead
of
> > wildly divergent. I would be only mildly surprised if Tepper were the
> > first to use it for other purposes.
>
> IIRC, and AIUI, if you use QM to get your diverging timelines[*], then
> they ought to diverge *backwards* in time just as much as they diverge
> forwards. I.e. there are as many possible "pasts" to explain where we
> are now, as there are possible futures in front of us.
>
> Diverging as you go back in time is the same as converging as you go
> forward, of course.
>
> Disclaimer: I don't think this is the orthodox view.
>
> It raises some interesting questions though. For example, if we have
> many possible pasts, how come memory of a single past? It's not
> difficult to postulate answers. But then turn the answers around, and
> see what the implications are for alternate futures.
The idea was discussed here a while ago as part of a discussion on various
fictional models of time travel.
My solution is that people forget things, and every bit of information about
the past that is lost causes another set of universes to merge since you can
no longer distinguish between them. Archeology causes an enormous number of
re-divergences as multiple possible pasts are re-discovered.
-l.
------------------------------------
My inbox is a sacred shrine, none shall enter that are not worthy.
Kat R
> Yesterday I had a salutary lesson in the erratic behaviour of what
> supposedly passes for my memory cells.
>
> "'Theory of convergence', she mused. 'You mean the tendency of
> time-lines to knit together again if they are not very far apart.'
> 'Yes. I don't understand the logic or mathematics of it, but
> seemingly there is no room for an infinite number of alternative
> universes. They split, then converge. At any given time, only so many
> different ones exist. Like a river finding a new channel in flood, but
> staying in the same flood plain and returning to the original channel
> eventually."
>
> So much for my "original idea"....I had certainly read this 15 years
> ago, but had forgotten all about it. When I reached the appropriate
> point in my story, the idea popped into my head, all newly-minted and
> shiny. Oh well, at least I did invent the term "braided worlds" - or
> was that in another story?
<snippery />
Don't feel bad, Tony. It's an often-discussed theory in quantum physics
and quite a few people have played with it. Jack Finney's FROM TIME TO
TIME had an interesting use of the collapsing alternate worlds idea that
involved the apparently "false" memories of people being actual memories
of alternate histories which would finally collapse back into the
dominate timeline once the last person with that memory died. But so
long as the alternate existed in that memory, people with the right
equipment could time-travel to it. It was, sadly, not a particularly
good book.
--
Kat Richardson
Greywalker (Roc, 2006)
Website: http://www.katrichardson.com/
Bloggery: http://katrich.wordpress.com/
Tony Williams
Kat R wrote:
> Don't feel bad, Tony. It's an often-discussed theory in quantum physics
> and quite a few people have played with it. Jack Finney's FROM TIME TO
> TIME had an interesting use of the collapsing alternate worlds idea that
> involved the apparently "false" memories of people being actual memories
> of alternate histories which would finally collapse back into the
> dominate timeline once the last person with that memory died. But so
> long as the alternate existed in that memory, people with the right
> equipment could time-travel to it. It was, sadly, not a particularly
> good book.
That title sounds familiar, although I can't recall reading it. Not
that that means much these days. I rather like Patricia's analogy of
the brain as a compost heap - sums up mine perfectly, it's slowly
decomposing...
Gerry Quinn
sp...@sofluc.co.uk.invalid says...
> IIRC, and AIUI, if you use QM to get your diverging timelines[*], then
> they ought to diverge *backwards* in time just as much as they diverge
> forwards. I.e. there are as many possible "pasts" to explain where we
> are now, as there are possible futures in front of us.
>
> Diverging as you go back in time is the same as converging as you go
> forward, of course.
Surely it's the divergence that defines which way is forward?
'Yesterday' is a simpler and literally smaller parallel universe,
innocent of the myriad recent wave function collapses that are part of
the history of alternate 'Todays'.
- Gerry Quinn
Paul Clarke
> So much for my "original idea"....I had certainly read this 15 years
> ago, but had forgotten all about it. When I reached the appropriate
> point in my story, the idea popped into my head, all newly-minted and
> shiny. Oh well, at least I did invent the term "braided worlds" - or
> was that in another story?
I'm pretty sure I've heard the term before, but not with the same
meaning. A Google search finds:
http://www.amazon.com/Braided-World-Kay-Kenyon/dp/0553583794
but I don't think that's nagging at my memory.
Jonathan L Cunningham
> In article <1hsb0g9.cloksynz8ozkN%sp...@sofluc.co.uk.invalid>,
> sp...@sofluc.co.uk.invalid says...
>
> > IIRC, and AIUI, if you use QM to get your diverging timelines[*], then
> > they ought to diverge *backwards* in time just as much as they diverge
> > forwards. I.e. there are as many possible "pasts" to explain where we
> > are now, as there are possible futures in front of us.
> >
> > Diverging as you go back in time is the same as converging as you go
> > forward, of course.
>
> Surely it's the divergence that defines which way is forward?
If it did, it would. I.e. if the divergence only happened forward, then
we could use it to define which way is forward.
As it happens, I don't think it does, and I'll say why.
First, notice that a deterministic universe always converges (or
diverges into the past). In case this seems counter-intuitive, you are
almost certainly familiar with an example: Conway's Life (or any
deterministic cellular automaton).
Even if you don't believe it's possible for self-reproducing intelligent
life forms to exist in Life, it's possible to design more complex
systems where it can be proved (ok, not the "intelligent" bit - let's
not get into that - but self-reproducing organisms containing a general
purpose computing unit capable of carrying out any computation).
Try running Life backwards: start with a single "live" cell in an
infinity of "dead" cells. We know its future: it will die off, and the
universe will then be dead for all eternity. But how did we get here?
If the cell was dead in the previous generation, it must have been
surrounded by exactly three live cells. But in which positions?
Going far enough back, was the Life universe destroyed by a war between
two competing civilisations? Certainly. For some of the (infinitely
many) possible "pasts". And also not (for even more of them).
Or suppose a Newtonian universe: in theory, we know it is completely
deterministic in both directions. But if you allow a little uncertainty,
it certainly diverges forwards (think butterfly effect and weather
forecasts). But it also diverges backwards (think butterfly effect and
weather forecasts).
Given today's weather, what was the weather like yesterday? Depends
whether or not a butterfly flapped its wings in the Amazon a week ago.
Or look at planetary orbits. There the equations of motion are exactly
the same backwards or forwards, so if you have a chaotic orbit (i.e.
more than one planet around one sun) it's unpredictable backwards.
> 'Yesterday' is a simpler and literally smaller parallel universe,
> innocent of the myriad recent wave function collapses that are part of
> the history of alternate 'Todays'.
Well, that's why I mentioned wave function collapse: it's a way to avoid
diverging "multiple worlds". I actually think it makes a *converging*
universe *more* likely. (There are lots of different wave functions
which could collapse to the same state, but once it collapses, you get
rid of all the alternate futures.)
As for deciding which direction time flows, I think a better way to
define it would be based on some notion of entropy. Here is my cup of
tea at times T1 and T2. It is colder at time T1 than at time T2, so it
is reasonable to suppose it has cooled down, and T1 is later than T2.
(The entropy of the system "cup of tea + air in my living room" has
increased.)
But there are a lot of gotchas with that approach: for example, I may
have put the cup in the microwave between times T1 and T2.
Jonathan
Jonathan L Cunningham
Not one of my clearer posts. :-)
Have a look at my followup to Gerry Quinn. :-)
Jonathan
Jonathan L Cunningham
> "Jonathan L Cunningham" <sp...@sofluc.co.uk.invalid> wrote in message
> news:1hsb0g9.cloksynz8ozkN%sp...@sofluc.co.uk.invalid...
> > It raises some interesting questions though. For example, if we have
> > many possible pasts, how come memory of a single past? It's not
> > difficult to postulate answers. But then turn the answers around, and
> > see what the implications are for alternate futures.
>
> The idea was discussed here a while ago as part of a discussion on various
> fictional models of time travel.
Was it? I vaguely remember discussions about varieties of time travel,
but it must have been quite a while.
> My solution is that people forget things, and every bit of information about
> the past that is lost causes another set of universes to merge since you can
> no longer distinguish between them. Archeology causes an enormous number of
> re-divergences as multiple possible pasts are re-discovered.
Yes.
And people mis-remember things. So I have two pasts: one where I got up
and had a cup of coffee this morning, and another where I got up and had
a cup of tea, but misremember it as coffee. (I *hope* that past is much
less likely <g> -- or my mind must be going!)
But also, from my POV, I have many pasts where you got up, had orange
juice, or tea, or drank a bottle of brandy or ... none of those can be
excluded from *my* knowledge.
I've actually written a couple of short stories exploring these ideas,
or one particular consequence anyway, but even the most complete version
is sitting in the "needs to be polished before sending out" folder ...
Jonathan
Tony Williams
Paul Clarke wrote:
> Tony Williams wrote:
> > Oh well, at least I did invent the term "braided worlds" - or
> > was that in another story?
>
> I'm pretty sure I've heard the term before, but not with the same
> meaning. A Google search finds:
>
> http://www.amazon.com/Braided-World-Kay-Kenyon/dp/0553583794
>
> but I don't think that's nagging at my memory.
At least I do know where this came from (as far as I'm concerned) and
it was directly from the analogy in my story (and Tepper's); the
geomorphological term for a river which keeps splitting up and
reforming along its main channel is "braided channel".
Tony Williams
Logan Kearsley wrote:
> The idea was discussed here a while ago as part of a discussion on various
> fictional models of time travel.
> My solution is that people forget things, and every bit of information about
> the past that is lost causes another set of universes to merge since you can
> no longer distinguish between them. Archeology causes an enormous number of
> re-divergences as multiple possible pasts are re-discovered.
I had to do a bit of arm-waving in 'Scales' concerning the potential
implications of converging alternate worlds:
"'Doesn't that cause all sorts of paradoxes? I mean, suppose a woman
chose one husband in one Stage 4 world, and a different one in another?
She would have different children, and a different family tree would be
created which could run on indefinitely. How could they be merged
together?'
'That's the main counter-argument, to which our scientists have not so
far come up with a simple answer. All they will point to is the clear
evidence that there are very few alternate worlds, whereas there
otherwise ought to be an infinite number.'"
Jonathan L Cunningham
That argument wouldn't convince me. It just suggests that many alternate
worlds cease to exist.
Think of cats (on topic). For a constant cat population, adult cats have
two kittens, on average. If some cats have more kits, then others must
have less (or none), i.e. their line dies out.
Perhaps a better analogy would be amoebae, since they reproduce by
splitting. By now, either the entire universe is a solid mass of amoeba
protoplasm, or some of them must have died.
Or, possibly, two amoebae merge and shed the excess mass. And that this
happens as often as they split to reproduce. Sound likely? No? Then I
don't buy it as an arm-waving explanation either for a small number of
alternate worlds.
Incidentally, in my ideas file, I *do* have the idea that alternate
worlds vanish. It's based on quantising probability. If the probability
of an alternate world falls below the minimum quantum of probability,
then it must vanish (it has zero probability).
As an example, suppose the quantum of probability is 1%, then if you
threw three dice, you would never get 3 sixes (or 3 ones) because the
probability is less than 1%. You *can* get 2 sixes and a five, say, and
it would occur with probability 1% or 2% (1/100 or 1/50) instead of the
"classical" probability of 1/72. (It would be one of 1% or 2% -- but I'd
have to work it out which of those it is.)
Of course the *actual* quantum of probability would be some incredibly
tiny number, or we would have noticed by now :-).
Jonathan
(That's not to say that I object to alternate worlds merging: maybe they
do. Perhaps that's why hard SF is hard? Because it's hard to do it.)
Tony Williams
Jonathan L Cunningham wrote:
> That argument wouldn't convince me. It just suggests that many alternate
> worlds cease to exist.
It wasn't meant to be an argument - simply an acknowledgement that a
contradiction existed to which an answer had not yet been found. I
think that the technical literary term is a "cop-out" :-)
Brian M. Scott
<sp...@sofluc.co.uk.invalid> wrote in rec.arts.sf.composition:
[...]
> Incidentally, in my ideas file, I *do* have the idea that alternate
> worlds vanish. It's based on quantising probability. If the probability
> of an alternate world falls below the minimum quantum of probability,
> then it must vanish (it has zero probability).
> As an example, suppose the quantum of probability is 1%, then if you
> threw three dice, you would never get 3 sixes (or 3 ones) because the
> probability is less than 1%. You *can* get 2 sixes and a five, say, and
> it would occur with probability 1% or 2% (1/100 or 1/50) instead of the
> "classical" probability of 1/72. (It would be one of 1% or 2% -- but I'd
> have to work it out which of those it is.)
On what basis would you work it out? That is, what assumptions
about this quantized probability are you making?
[...]
Brian
Joann Zimmerman
dsg...@iphouse.com says...
> Patricia C. Wrede wrote:
> > Mmmmph. I think maybe that for me, a conversation is mutually
> > participatory and responsive, even if it's very drawn-out (as in a
> > correspondence). The interaction between what I read and what I
> > write can't be a conversation because, except in very rare cases, it
> > lacks that mutuality -- a dead author can't respond to me, and even
> > my contemporaries are as likely as not to be unfamiliar with my
> > writing (this of course changes as one's sales and reputation
> > increases, but there are plenty of wildly-bestselling authors whom I
> > have not read; in the unlikely event that any of them are bouncing
> > off what I do, I'm not going to know about it, and I assume the same
> > will apply to me, should I ever attain such exalted sales figures).
[...]
> Would it work better for you if time travel was common enough that, for
> example, Shakespeare could write a play in response to West Side Story?
I'm reminded of David Lodge's _Small World_, in which a dissertation
examining Eliot's influence on Shakespeare is postulated.
Turns out that what's really being discussed is Eliot's influence on the
interpretation of Shakespeare.
--
"I never understood people who don't have bookshelves."
--George Plimpton
Joann Zimmerman jz...@bellereti.com
Logan Kearsley
And from that we can conclude that in some parallel worlds, a machine to
implement the Quantum Bogosort (theoretically the fastest possible sorting
algorithm) has been invented.
By way of explanation, QBS works as follows:
1. Obtain a list of data.
2. Randomly re-arrange the data, using nuclear decay or some other genuinely
random physical process as your random number generator.
3. Check if the data is sorted. If yes, you're done. If not, destroy the
universe.
Thus, the only universe which is allowed to exist is the one in which the
data is sorted, and the probability of successfully sorting the data in O(n)
time becomes 1.
Marilee J. Layman
<Tony.W...@quarry.nildram.co.uk> wrote:
*Mine* is shrinking. Not as much as most 51-year-olds, but I'm still
displeased.
--
Marilee J. Layman
http://mjlayman.livejournal.com/
Ric Locke
That's not a "gotcha" for entropy. It simply means that the system must
be extended to include the microwave oven and Foxhall(?) Power Station.
Regards,
Ric
--
Posted via a free Usenet account from http://www.teranews.com
Ric Locke
_A Greater Infinity_, Michael McCollum. "Time lines simply cannot be
thought of as parallel..."
Chris Dollin
> I'm reminded of David Lodge's _Small World_, in which a dissertation
> examining Eliot's influence on Shakespeare is postulated.
>
> Turns out that what's really being discussed is Eliot's influence on the
> interpretation of Shakespeare.
Pearse (I think that's how it's spelt, but I'm not going to
look) improvises that topic when his original intention -- to
discuss S's influence on E -- is seen as old hat. If I recall
correctly.
--
Barmy Hedgehog
"Who do you serve, and who do you trust?" /Crusade/
Gerry Quinn
sp...@sofluc.co.uk.invalid says...
> Gerry Quinn <ger...@DELETETHISindigo.ie> wrote:
> > In article <1hsb0g9.cloksynz8ozkN%sp...@sofluc.co.uk.invalid>,
> > sp...@sofluc.co.uk.invalid says...
> >
> > > IIRC, and AIUI, if you use QM to get your diverging timelines[*], then
> > > they ought to diverge *backwards* in time just as much as they diverge
> > > forwards. I.e. there are as many possible "pasts" to explain where we
> > > are now, as there are possible futures in front of us.
> > >
> > > Diverging as you go back in time is the same as converging as you go
> > > forward, of course.
> >
> > Surely it's the divergence that defines which way is forward?
>
> If it did, it would. I.e. if the divergence only happened forward, then
> we could use it to define which way is forward.
How else do we define which way is forward?
> As it happens, I don't think it does, and I'll say why.
>
> First, notice that a deterministic universe always converges (or
> diverges into the past). In case this seems counter-intuitive, you are
> almost certainly familiar with an example: Conway's Life (or any
> deterministic cellular automaton).
Or it could be cyclic. Or expanding. But in any case our universe
does not appear to have a deterministic structure of this form. It is
no coincidence that quantum theory and thermodynamics are so closely
allied nowadays.
[Snip examples.]
> > 'Yesterday' is a simpler and literally smaller parallel universe,
> > innocent of the myriad recent wave function collapses that are part of
> > the history of alternate 'Todays'.
>
> Well, that's why I mentioned wave function collapse: it's a way to avoid
> diverging "multiple worlds". I actually think it makes a *converging*
> universe *more* likely. (There are lots of different wave functions
> which could collapse to the same state, but once it collapses, you get
> rid of all the alternate futures.)
There's only one wave function; the wave function of the universe. You
can't create two separate wave functions without getting entangled with
both of them. Just because we often apply Copenhagen-like
interpretations to particular experiments doesn't mean the universe
works that way.
> As for deciding which direction time flows, I think a better way to
> define it would be based on some notion of entropy. Here is my cup of
> tea at times T1 and T2. It is colder at time T1 than at time T2, so it
> is reasonable to suppose it has cooled down, and T1 is later than T2.
> (The entropy of the system "cup of tea + air in my living room" has
> increased.)
It depends on whether you let it cool irreversibly, or used the thermal
gradient to operate a heat engine and charge a battery. If you did the
former, you allowed it to write a lot of arbitrary information into the
microstate description of the universe which is now for the most part
inaccessible. (There may be traces such as a scorch mark on the table.
These traces are what we call history. The rest of the information -
the part we've lost track of - is entropy.)
> But there are a lot of gotchas with that approach: for example, I may
> have put the cup in the microwave between times T1 and T2.
No gotcha involved here, as Ric pointed out.
- Gerry Quinn
Gerry Quinn
sp...@sofluc.co.uk.invalid says...
> Tony Williams <Tony.W...@quarry.nildram.co.uk> wrote:
> > I had to do a bit of arm-waving in 'Scales' concerning the potential
> > implications of converging alternate worlds:
> >
> > "'Doesn't that cause all sorts of paradoxes? I mean, suppose a woman
> > chose one husband in one Stage 4 world, and a different one in another?
> > She would have different children, and a different family tree would be
> > created which could run on indefinitely. How could they be merged
> > together?'
> > 'That's the main counter-argument, to which our scientists have not so
> > far come up with a simple answer. All they will point to is the clear
> > evidence that there are very few alternate worlds, whereas there
> > otherwise ought to be an infinite number.'"
>
> That argument wouldn't convince me. It just suggests that many alternate
> worlds cease to exist.
Or that Fate has a very powerful impact on peoples' lives in all of the
universes - or all but one of the universes. Now there's an idea!
Suppose there's one preferred (for some unknown reason) universe that
looks like our own - where events seem to be mostly random, people
appear to have free will, prophecies don't usually come out right.
Then there are the other universes, which are physically compelled to
eventually fall back into alignment with the preferred universe. In
these universes, ordinary probabilities are often violated if the more
likely event would have caused too much drift in the 'wrong' direction.
People who will have children in the preferred universe never get run
over by buses, unless they live so dangerously that it's more likely
that the same genetic combinations will arise elsewhere by chance. But
most likely they just don't live dangerously. They feel they have free
will - they just aren't the sort who would be likely to run across the
street without looking.
How does such a universe differ from our own, exactly? Maybe you have
to look deep to find the strange correlations; maybe they're as hard to
find as the Bell's Inequality violations. Maybe we're not in the
preferred universe after all...
Some ideas there anyway.
- Gerry Quinn
Jonathan L Cunningham
> "Jonathan L Cunningham" <sp...@sofluc.co.uk.invalid> wrote in message
> news:1hsctlw.h03oiuumgyi0N%sp...@sofluc.co.uk.invalid...
> > That argument wouldn't convince me. It just suggests that many alternate
> > worlds cease to exist.
>
> And from that we can conclude that in some parallel worlds, a machine to
> implement the Quantum Bogosort (theoretically the fastest possible sorting
> algorithm) has been invented.
>
> By way of explanation, QBS works as follows:
> 1. Obtain a list of data.
> 2. Randomly re-arrange the data, using nuclear decay or some other genuinely
> random physical process as your random number generator.
> 3. Check if the data is sorted. If yes, you're done. If not, destroy the
> universe.
>
> Thus, the only universe which is allowed to exist is the one in which the
> data is sorted, and the probability of successfully sorting the data in O(n)
> time becomes 1.
It's an interesting idea. The "destroy the universe" bit in step 3
sounds a bit tricky. This is something Evil Mad Geniuses have been
researching for ages.
On my "quantised probability" scheme, you'd have to arrange that the
universes in which the answer is wrong (the data is not sorted) become
infinitely improbable in some way.
Or you might come up with an alternative method. But whatever method you
choose has to also take time O(n). :-)
Jonathan
Jonathan L Cunningham
Well, it's not a serious fully-worked out thesis! It's a story seed :-)
The first thing that springs to mind is that the quantised probabilities
should sum to 1 exactly.
Secondly, it would be nice if it remained symmetrical, and that the
probability of, say 2 sixes and a five is the same as 2 sixes and a
three.
I suspect (rather I'm 100% confident: "suspect" is math-speak for "I
can't be bothered to demonstrate it") this is not possible in general.
I can see several possible approaches to finding a solution, but [three
paragraphs deleted] off the top of my head they all start getting
complicated pretty quickly.
In my preferred scheme(s), I think the probabilities might have to be
different depending on the overall probability of the world you are in.
For example, in a world which is on the point of vanishing anyway, you
are guaranteed to score 10 or 11 if you throw three dice: any other
result would drop the world below the threshold of existence. And you
maybe can't observe *how* you scored 11: was it two 3s and a 5, or was
it a 1 a 4 and a 6? That ties in with the "converging" timelines idea.
An analogy with QM would be Young's double slit experiment: you know the
electron (or photon) must have gone through one of the slits, but you
can't know which one (if you measure it, you destroy the interference
pattern).
None of this would really be observable at the macro level[*], just as
people seldom worry about being diffracted when they walk through a
door, or ending up in their neighbour's bedroom by quantum
tunneling[**].
Jonathan
[*] For all but the absolutely tiny fraction of worlds which were on the
threshold of vanishing: there you might observe macroscopic effects.
[**] Free story seed there, if anyone wants it! :-)
Jonathan L Cunningham
> In article <1hscgpw.1432j9h18c7fajN%sp...@sofluc.co.uk.invalid>,
> sp...@sofluc.co.uk.invalid says...
> > But there are a lot of gotchas with that approach: for example, I may
> > have put the cup in the microwave between times T1 and T2.
>
> No gotcha involved here, as Ric pointed out.
The "gotcha" is not in the laws of physics. The gotcha is in how to
apply them. The gotcha is if you only consider part of the whole system.
And, in the worst case, the system is the entire universe.
In which case entropy might not be increasing anyway (AIUI) because of
gravity (gas clouds clumping into stars) and expansion (of space).
I don't claim to understand this, so an explanation would be welcome,
but AIUI, entropy increases in a closed system, but the entire universe
isn't a closed system for this purpose.
For comparison: salt crystallising out of a hot, saturated solution is
*decreasing* in entropy. No problem, because the solution is cooling,
and the heat escaping is *increasing* the entropy of the rest of the
universe.
Similarly, stars condensing out of a gas cloud are *decreasing* in
entropy, and the heat escaping is ... what? Is itself cooling, along
with the microwave background, as the universe expands?
But I may be misremembering some article about it. I'd much prefer to
believe that "entopy never decreases" if you include the whole universe.
Jonathan
Paul Clarke
> And from that we can conclude that in some parallel worlds, a machine to
> implement the Quantum Bogosort (theoretically the fastest possible sorting
> algorithm) has been invented.
>
> By way of explanation, QBS works as follows:
> 1. Obtain a list of data.
> 2. Randomly re-arrange the data, using nuclear decay or some other genuinely
> random physical process as your random number generator.
> 3. Check if the data is sorted. If yes, you're done. If not, destroy the
> universe.
As used by Greg Egan in _Quarantine_, though to crack passwords rather
than sorting.
Brian M. Scott
<sp...@sofluc.co.uk.invalid> wrote in
<news:1hse6w1.aawqo91j5wncwN%sp...@sofluc.co.uk.invalid> in
rec.arts.sf.composition:
> Brian M. Scott <b.s...@csuohio.edu> wrote:
>> On Mon, 22 Jan 2007 18:56:40 +0000, Jonathan L Cunningham
>> <sp...@sofluc.co.uk.invalid> wrote in rec.arts.sf.composition:
>> [...]
>>> Incidentally, in my ideas file, I *do* have the idea that alternate
>>> worlds vanish. It's based on quantising probability. If the probability
>>> of an alternate world falls below the minimum quantum of probability,
>>> then it must vanish (it has zero probability).
>>> As an example, suppose the quantum of probability is 1%, then if you
>>> threw three dice, you would never get 3 sixes (or 3 ones) because the
>>> probability is less than 1%. You *can* get 2 sixes and a five, say, and
>>> it would occur with probability 1% or 2% (1/100 or 1/50) instead of the
>>> "classical" probability of 1/72. (It would be one of 1% or 2% -- but I'd
>>> have to work it out which of those it is.)
>> On what basis would you work it out? That is, what assumptions
>> about this quantized probability are you making?
> Well, it's not a serious fully-worked out thesis! It's a story seed :-)
> The first thing that springs to mind is that the quantised probabilities
> should sum to 1 exactly.
> Secondly, it would be nice if it remained symmetrical, and that the
> probability of, say 2 sixes and a five is the same as 2 sixes and a
> three.
> I suspect (rather I'm 100% confident: "suspect" is math-speak for "I
> can't be bothered to demonstrate it") this is not possible in general.
Yes, a similar suspicion underlay the question.
[...]
Brian
Tim S
>
> Similarly, stars condensing out of a gas cloud are *decreasing* in
> entropy, and the heat escaping is ... what?
Expanding. This increases entropy, as you may have noticed when allowing
an ideal gas into the other half of the box.
> Is itself cooling, along
> with the microwave background, as the universe expands?
That as well, but it's also expanding: see above.
>
> But I may be misremembering some article about it. I'd much prefer to
> believe that "entropy never decreases" if you include the whole universe.
Pretty much.
Tim
Ric Locke
It would appear from this layman's point of view that the current
thought is that "Universe is expanding" and "entropy is always
increasing" are just two ways of saying the same thing, or possibly two
depictions of the same thing from different angles, like a POV choice.
Depending on what is under immediate analysis, one formulation or the
other might be more convenient.
David Goldfarb
Also used by Dan Slott in the start of the new story arc of
_JLA Classified_. (Due to a plot device, a man has access to
6 billion parallel timelines. He makes himself rich, famous,
and beloved. Then he decides to rule the world, which is
very difficult in a world containing the Justice League.
So he uses up a bunch of timelines making himself into an
ultra-supervillain. Now he's about to start...with just
four timelines left. It's an interesting premise, and Dan
Slott is a good writer; I'm excited to see where it goes.)
--
David Goldfarb |"Understanding is a three-edged sword."
gold...@ocf.berkeley.edu |
gold...@csua.berkeley.edu | -- Babylon 5, "Deathwalker"
Jonathan L Cunningham
> Jonathan L Cunningham wrote:
>
> >
> > Similarly, stars condensing out of a gas cloud are *decreasing* in
> > entropy, and the heat escaping is ... what?
>
> Expanding. This increases entropy, as you may have noticed when allowing
> an ideal gas into the other half of the box.
I can't remember (if I ever knew) how to calculate the entropy change
here.
It's neither isothermal expansion (because no work is done) nor
adiabatic expansion (because the temperature of the gas doesn't
change[*].)
> > Is itself cooling, along
> > with the microwave background, as the universe expands?
>
> That as well, but it's also expanding: see above.
Not exactly comparable, because the ideal gas doesn't cool.
The cooling reduces entropy, but the expansion increases it. Which
effect predominates? And does it balance the decrease in entropy because
of gravitational collapse?
I resisted following up on this, because it's probably too off-topic
here to persist with (but at least it's not a heated argument, it's an
argument about heat <g>). And I have neither time nor inclination to
research it or ask in a more appropriate newsgroup. So I'm going on my
memory of thermodynamics from when I was studying it back in Atlantis.
But, to quote the Vogons, "Resistance is futile."
Jonathan
[*] Assume a box divided by a partition into two halves. Gas in one
half, vacuum in other half. Remove parition. Gas expands into vacuum but
does no work and therefore doesn't cool. If *instead* you had moved the
partition (like a piston) to one side, then the gas would expand either
adiabatically (insulated box) doing work, or isothermally (box in
equilibrium with outside temperature) also doing work (a bit more work,
actually).
Gerry Quinn
sp...@sofluc.co.uk.invalid says...
> Tim S <T...@timsilverman.demon.co.uk> wrote:
>
> > Jonathan L Cunningham wrote:
> >
> > >
> > > Similarly, stars condensing out of a gas cloud are *decreasing* in
> > > entropy, and the heat escaping is ... what?
> >
> > Expanding. This increases entropy, as you may have noticed when allowing
> > an ideal gas into the other half of the box.
>
> I can't remember (if I ever knew) how to calculate the entropy change
> here.
>
> It's neither isothermal expansion (because no work is done) nor
> adiabatic expansion (because the temperature of the gas doesn't
> change[*].)
Isothermal means 'no change of temperature'.
Adiabatic means 'no heat going in or out'.
So it's both.
> > > Is itself cooling, along
> > > with the microwave background, as the universe expands?
> >
> > That as well, but it's also expanding: see above.
>
> Not exactly comparable, because the ideal gas doesn't cool.
Here we get into tricky issues. In general relativity, conservation of
energy can't be naively applied to space-time foliations where space is
non-flat.
> The cooling reduces entropy, but the expansion increases it. Which
> effect predominates? And does it balance the decrease in entropy because
> of gravitational collapse?
If it's expanding, it isn't gravitationally collapsing overall. Also,
gravitational collapse doesn't necessarily decrease entropy. If I pour
a bucket of water on the ground, I have induced a minor gravitational
collapse, but entropy has increased.
- Gerry Quinn
Tim S
> Tim S <T...@timsilverman.demon.co.uk> wrote:
>
>> Jonathan L Cunningham wrote:
>>
>>> Similarly, stars condensing out of a gas cloud are *decreasing* in
>>> entropy, and the heat escaping is ... what?
>> Expanding. This increases entropy, as you may have noticed when allowing
>> an ideal gas into the other half of the box.
>
> I can't remember (if I ever knew) how to calculate the entropy change
> here.
>
> It's neither isothermal expansion (because no work is done) nor
> adiabatic expansion (because the temperature of the gas doesn't
> change[*].)
>
>>> Is itself cooling, along
>>> with the microwave background, as the universe expands?
>> That as well, but it's also expanding: see above.
>
> Not exactly comparable, because the ideal gas doesn't cool.
>
> The cooling reduces entropy, but the expansion increases it. Which
> effect predominates? And does it balance the decrease in entropy because
> of gravitational collapse?
Well, the clue is that the 2nd law of thermodynamics is not violated.
The rest is left as an exercise for the reader.
Tim