Interesting non-FTL interstellar settings?
DataPacRat
FTL - pick any two." Well, I'd like to pick the first two - and still read
some good SF stories that deal with more than one star system.
Tales that take place /entirely/ within a ship, such as the classic
generation ship whose inhabitants forget where they are, aren't especially
what I'm looking for... nor are ones where the protaginists simply go from
Earth to colony-of-choice and, when they get there, stop.
Can you think of any books that at least approach this mold, if not fit
it?
Thank you for your time,
--
DataPacRat
Wayne Throop
: I'm sure everybody here knows the catchphrase, "Relativity, causality,
Well, Vinge's "A Deepness in the Sky" springs to mind. Of course, the
larger context has the Zones of Thought which pick FTL and something
else outside the galaxy, but this background is not apparent within the
story. Within the story, it's strictly relativity/causality, STL
ramships, the whole nine yards, and the Queng Ho culture is an
interesting take on an STL intersteller organization of sorts.
Might also consider Walter John Williams' "Aristoi". I may be
forgeting something, but iirc, it was strictly relativity/causality also.
Possibly Sheffield's "Between the Strokes of Night".
Hmmmm. I seem to be coming up dry; as you say, most of the others
involve a setting centered around a single STL trip. Or at least,
that's all my memory is offering up right now.
For examples, you might take Le Guin's "Rocannon's World", but you
can count the central round-trip STL gimick as a single trip.
Or you might count Clarke's "Childhood's End", but the background
has violations of relativity/causality; it's just the overseer
culture that's stuck STL.
Ah, thinking of Childhood's end makes me think of "Songs of Distant Earth",
but the focus there isn't on interstellar going's-on, but on events on
a single planet through a short-ish period of time (though there is
a multi-star background).
I'll be interested in others in this category.
It seems there "should be" more... but I'm blocked.
Wayne Throop thr...@sheol.org http://sheol.org/throopw
Mike Schilling
"Wayne Throop" <thr...@sheol.org> wrote in message
news:10732...@sheol.org...
> : DataPacRat <spam.da...@warren.kill.com.invalid>
> : I'm sure everybody here knows the catchphrase, "Relativity, causality,
> : FTL - pick any two." Well, I'd like to pick the first two - and still
> : read some good SF stories that deal with more than one star system.
> : Tales that take place /entirely/ within a ship, such as the classic
> : generation ship whose inhabitants forget where they are, aren't
> : especially what I'm looking for... nor are ones where the
> : protaginists simply go from Earth to colony-of-choice and, when they
> : get there, stop.
> : Can you think of any books that at least approach this mold, if not
> : fit it?
The backstory of Cherryh's Union-Alliance universe works this way: space
stations are established around the neaer stars via STL travel. I'm not
sure if any of the books are set before the invention of FTL, though.
John Hill
Ken MacLeod's _Cosmonaut Keep_ has AFAL starships. I don't
remember if more than one star system is shown within the story.
What other novels or short stories feature AFAL travel? How old
is the AFAL idea anyway? Did any Golden Age writers use it?
--
John Hill
Amit Kotwal
<delurk>
Larry Niven's _Protector_
Alastair Reynolds' _Revelation Space_ and _Redemption Ark_
- Amit
Gary R. Schmidt
Moor" is one of the shorts, there are others.
Cheers,
Gary B-)
--
______________________________________________________________________________
Armful of chairs: Something some people would not know
whether you were up them with or not
- Barry Humphries
Wakboth
Alistair Reynolds' "Inhibitor" sequence ("Revelation Space", "Chasm
City", "Redemption Ark" & "Absolution Gap") comes pretty close.
Space travel is STL, although with very high relativistic speeds.
There are mentions of causality-breaching ways of FTL communications
and travel in the books, but these are beyond human capabilities, and
_very_ dangerous to use.
-- Wakboth
Mark Atwood
> I'm sure everybody here knows the catchphrase, "Relativity, causality,
> FTL - pick any two." Well, I'd like to pick the first two - and still read
> some good SF stories that deal with more than one star system.
>
> Can you think of any books that at least approach this mold, if not fit
> it?
All of Egan's stories with intersteller travel are very strictly
"no FTL".
--
Mark Atwood | When you do things right,
m...@pobox.com | people won't be sure you've done anything at all.
http://www.pobox.com/~mra
Ashland Henderson
Poul Anderson
Starfarers
Genesis
Alfred Coppel
Glory, Glory's People, Glory's War
Damien R. Sullivan
>Ken MacLeod's _Cosmonaut Keep_ has AFAL starships. I don't
>remember if more than one star system is shown within the story.
Not within the Second Sphere, but we see more of it in the next books. The
third even has a round trip -- 3 or 4 planets in that one.
>What other novels or short stories feature AFAL travel? How old
>is the AFAL idea anyway? Did any Golden Age writers use it?
I don't think I've seen it anywhere besides MacLeod, apart from Egan AIs
beaming themselves across the void, but that needs a receiver on the other
end.
Another question might be who has interstellar trade? MacLeod, because AFAL
is cheap and the tech distribution is deliberately weird. Cherryh's storyless
STL period, because it makes so much sense to ship ore between stars. Ahem.
Reynolds's Ultra transport passengers and tech. I forget what the Qeng Ho
did, or the Leshy Circuit. Egan's informorphs don't trade since they only use
ships for range expansion; civilized transport is via radio or laser.
Vinge has had other STL settings, but not the in-story back and forth or
civilization the original poster wanted. Della Lu's travels in _Marooned in
Realtime_. (STL extra-galactic round trip, yeah!) The anarchist aliens in
"Conquest by Default". "Long Shot". "Just Peace". I'm not sure about
"Original Sin".
I think Poul Anderson's _Genesis_ was STL. As was _Tau Zero_, of course.
To recap:
Vinge's _Deepness in the Sky_
MacLeod's Engines of Light trilogy
Alastair Reynolds's Inhibitor books and stories.
Early Niven books and stories -- not just Protector; the Man-Kzin Wars start
out STL, and there's a story of a couple of ramscoops chasing each other
eternally. Reynolds re-used that concept himself in "Galactic North".
Egan's _Diaspora_ and _Schild's Ladder_
The Leshy Circuit, which I never read much of.
LeGuin's Hainish novels are in an STL universe, with NAFAL (nearly as fast as
light, I think she coined the term) ships. I don't know if any novel shows
much movement. And they have FTL ansibles.
Orson Scott Card's Ender universe starts with STL and ansibles; I forget how
fast the STL was, and don't know how much they moved, or if the magic physics
from the end of Xenocide changed things.
-xx- Damien X-)
Colin campbell
John H
> : I'm sure everybody here knows the catchphrase, "Relativity,
causality,
> : FTL - pick any two." Well, I'd like to pick the first two - and
still
> : read some good SF stories that deal with more than one star system.
> : Tales that take place /entirely/ within a ship, such as the classic
> : generation ship whose inhabitants forget where they are, aren't
> : especially what I'm looking for... nor are ones where the
> : protaginists simply go from Earth to colony-of-choice and, when they
> : get there, stop.
> : Can you think of any books that at least approach this mold, if not
> : fit it?
>
> Well, Vinge's "A Deepness in the Sky" springs to mind. Of course, the
> larger context has the Zones of Thought which pick FTL and something
> else outside the galaxy, but this background is not apparent within
the
> story. Within the story, it's strictly relativity/causality, STL
> ramships, the whole nine yards, and the Queng Ho culture is an
> interesting take on an STL intersteller organization of sorts.
(not so minor nit -- since he made a point of mentioning the
pronunciation.)
"Qeng Ho" pronounced "Cheng Ho"
"Queng Ho" unfortunately sounds too much like Queen Ho.
Michael S. Schiffer
news:pdjKb.7056$E97....@newssvr25.news.prodigy.com:
>...
> (not so minor nit -- since he made a point of mentioning the
> pronunciation.)
> "Qeng Ho" pronounced "Cheng Ho"
Though I've never been sure if that was an error on Vinge's part, a
romanization scheme I've missed, or an indication that Pham Nuwen's
Qeng Ho were still using our alphabet but were romanizing Chinese
differently. (I know three different ways of romanizing that
particular name, and that isn't any of them.) The fact that Nuwen
is presumably the Vietnamese name Nguyen does suggest a broad
future spelling reform.
Mike
--
Michael S. Schiffer, LHN, FCS
msch...@condor.depaul.edu
John H
"Michael S. Schiffer" <msch...@condor.depaul.edu> wrote in message
news:Xns946790AEE7C0...@130.133.1.4...
I didn't really have a problem with it. I had a highschool classmate
whose romanized Chinese name is Qing, pronounce somewhere between King
and Ching, but who everyone else always called Queen. Then there's qi
which I usually pronounce as "chee."
john
Michael S. Schiffer
> message news:Xns946790AEE7C0...@130.133.1.4...
>> "John H" <chandin169*DON'TUSETHIS*@yahoo.com> wrote in
>> news:pdjKb.7056$E97....@newssvr25.news.prodigy.com:
>...
>>
>> Though I've never been sure if that was an error on Vinge's
>> part, a romanization scheme I've missed, or an indication that
>> Pham Nuwen's Qeng Ho were still using our alphabet but were
>> romanizing Chinese differently. (I know three different ways
>> of romanizing that particular name, and that isn't any of
>> them.) The fact that Nuwen is presumably the Vietnamese name
>> Nguyen does suggest a broad future spelling reform.
> I didn't really have a problem with it. I had a highschool
> classmate whose romanized Chinese name is Qing, pronounce
> somewhere between King and Ching, but who everyone else always
> called Queen. Then there's qi which I usually pronounce as
> "chee."
Sure, AFAIK (which isn't much) that's proper pinyin. It's just
that in pinyin, the explorer the fleet is named after is rendered
as Zheng He, not Qeng Ho. (I don't know nearly enough about
Chinese pronunciation to distinguish between the sound rendered by
"q" and that rendered by "zh", but it's evidently important, since
IIRC the other romanizations schemes also distinguish them.
It's Vinge's prerogative to do whatever he likes with the
orthography-- he could spell it Peng Mo and tell us that in the
future p=ch and m=h. I've just been curious for a while if it was
a deliberate decision on his part, or it was an attempt to use a
standard scheme without looking it up. :-)
David Cowie
> I'm sure everybody here knows the catchphrase, "Relativity, causality,
> FTL - pick any two." Well, I'd like to pick the first two - and still read
> some good SF stories that deal with more than one star system.
>
_Anvil of Stars_ by Greg Bear has a mission of vengeance at STL speeds. It
sets off from Sol and visits two other systems.
--
David Cowie david_cowie at lineone dot net
Containment Failure + 1252:17
EdLincoln
How about the rather odd _A Gathering of Stars_ series by Donald Moffit? An
interesting solution to the problems of establishing an interstelle empire
without FTL...
There is also the _Phoenix Exultant_ series.
What does _AFAL_ stand for?
What is "Reynolds's Ultra transport passengers and tech. "?
<< Subject: Re: Interesting non-FTL interstellar settings?
From: thr...@sheol.org (Wayne Throop)
Date: Mon, Jan 5, 2004 1:22 AM
Message-id: <10732...@sheol.org>
>><BR><BR>
Doug
Do wormholes count?
If so, there are a bunch of stories that might fit, like _Forever War_
by Joe Haldeman or _Mote in God's Eye_ by Niven & Pournelle.
If not, then we're left with... um... lessee... _Starfarers_ by Poul
Anderson and _Protector_ by Larry Niven. Sort of.
Doug
David Cowie
> What does _AFAL_ stand for?
>
It stands for "As Fast As Light"
> What is "Reynolds's Ultra transport passengers and tech. "?
>
I would expand this to "In Reynolds' books the faction called Ultras
transport passengers and technology."
--
David Cowie david_cowie at lineone dot net
Containment Failure + 1254:00
Steve Coltrin
> Orson Scott Card's Ender universe starts with STL and ansibles; I forget how
> fast the STL was, and don't know how much they moved, or if the magic physics
> from the end of Xenocide changed things.
The STL is VNAFAL. IIRC ships in transit are still reachable by ansible,
but nobody bothers because they're too time-dilated to say much to.
The magic physics introduces instantaneous FTL with the nasty side effect
that all your dreams come true. I don't recall if the method was divulged
to the universe at large.
Daniel Hatch had some stories in _Analog_ a while back that used AFAL.
Wonder what became of them; he seemed to be aiming at a fixup novel.
--
Steve Coltrin spco...@omcl.org WWVBF?
"Even special children need to be beaten sometimes." - Brian Bruns
Justin Bacon
>Another question might be who has interstellar trade? MacLeod, because AFAL
>is cheap and the tech distribution is deliberately weird. Cherryh's storyless
>STL period, because it makes so much sense to ship ore between stars. Ahem.
I've kinda suspected that that's why Cherryh hasn't set any stories in that
time period. She has a need to handwave that interim period, because the issue
of interstellar trade is extremely problematic.
It's a problem I've never really been able to explain. Trade over long
distances/times on Earth have always been the result of local availability. But
what isn't available in our own solar system that we would find elsewhere?
(That would also be valuable enough to make us go back and forth.)
Even with FTL, this can be a problematic question. The only time it really goes
away is with extremely *cheap* FTL.
JB
how...@brazee.net
how...@brazee.net
On 5-Jan-2004, "Michael S. Schiffer" <msch...@condor.depaul.edu> wrote:
> Though I've never been sure if that was an error on Vinge's part, a
> romanization scheme I've missed, or an indication that Pham Nuwen's
> Qeng Ho were still using our alphabet but were romanizing Chinese
> differently. (I know three different ways of romanizing that
> particular name, and that isn't any of them.) The fact that Nuwen
> is presumably the Vietnamese name Nguyen does suggest a broad
> future spelling reform.
Realistically, one can expect that spelling and pronunciation would both
have changed significantly between now and then.
Nopporn Wongrassamee
>t's a problem I've never really been able to explain. Trade over long
>distances/times on Earth have always been the result of local availability.
>But
>what isn't available in our own solar system that we would find elsewhere?
>(That would also be valuable enough to make us go back and forth.)
Naquadah? Dilithium?
Or any material with exotic, physics-as-we-know-them-defying properties that
is mysteriously absent from our solar system but seemingly plentiful everywhere
else.
- Nopporn Wongrassamee
Homepage: http://hometown.aol.com/evilauthor/myhomepage/index.html
Justin Bacon
>Or any material with exotic, physics-as-we-know-them-defying properties that
>is mysteriously absent from our solar system but seemingly plentiful
>everywhere
>else.
Which explains why we would want to go there and get it. But there's a
fundamental instability in that system: Earth has nothing to trade for it,
unless the other system is (for some reason) poor in the common elements we can
find laying around our own backyard. This scenario has the advantage (from a
storyteller's POV) of spurring a war as soon as the colony becomes sufficiently
self-sufficient (and tired of being exploited by Earth).
And even if you overcome the difficulty of a complete trade imbalance, you
still can't get a trade network -- just a hub with Earth at its center:
Everybody trades with Earth, but has no desire to trade with each other.
(Unless you postulate an even more unlikely system of mutually compatible
insufficiencies.)
Justin Bacon
tria...@aol.com
Wayne Throop
:: elsewhere? (That would also be valuable enough to make us go back
:: and forth.)
: evila...@aol.com (Nopporn Wongrassamee)
: Naquadah? Dilithium?
Illudium Pu-36? No, wait; that's available on mars.
OK, so Quantium-40. But then, if you find it, you're
no longer in an STL universe, sigh.
Niall McAuley
> John Hill <john...@fuse.net> wrote:
> >What other novels or short stories feature AFAL travel? How old
> >is the AFAL idea anyway? Did any Golden Age writers use it?
> I don't think I've seen it anywhere besides MacLeod, apart from Egan AIs
> beaming themselves across the void, but that needs a receiver on the other
> end.
Niven's teleporting stories have interstellar AFAL teleporting ships,
but they need a receiver at the other end to return to STL travel.
I don't think he ever got around to trade in that universe, only
exploration.
--
Niall [real address ends in com, not moc.invalid]
Steve Coltrin
> I'm sure everybody here knows the catchphrase, "Relativity, causality,
> FTL - pick any two." Well, I'd like to pick the first two - and still read
> some good SF stories that deal with more than one star system.
Benford's _Across the Sea of Suns_. (Also the later books of the series,
but they cheat; they're set where stars are _much_ closer together.)
Egan's _Diaspora_ cheats in an interesting way: the characters copy
themselves numerous times and head off for several systems in parallel.
Mark Blunden
Such a system would also require either entirely owner-operated trade
fleets, effective longevity treatment or an extremely forward-looking
society. I doubt many people today would be willing to invest massive
amounts of resources in a trade that wouldn't turn a profit for generations,
especially given that such periods would cover a great deal of technological
development - by the time you manage to ship your highly-valuable unobtanium
back home, there's every chance that in the meantime someone's found a way
to synthesise it, or do without it, or the people who want it can no longer
afford it.
--
Mark.
* Feed me!
Urban Fredriksson
DataPacRat <spam.da...@warren.kill.com.invalid> wrote:
> I'm sure everybody here knows the catchphrase, "Relativity, causality,
>FTL - pick any two." Well, I'd like to pick the first two - and still read
>some good SF stories that deal with more than one star system.
Robert Reed's _The Remarkables_ almost qualifies, but the
trick there to get people from where they live to an alien
world and back in reasonable time is that they don't
actually live in our star system, but in interstellar
space. And all action is basically on the planet in
question, so it's not really what you asked for but I
thought the method deserved mentioning.
His _Sister Alice_ qualifies.
--
Urban Fredriksson http://www.canit.se/%7Egriffon/
A weapon is a device for making your enemy change his mind.
Matt Austern
> Nopporn Wongrassamee wrote:
> >Or any material with exotic, physics-as-we-know-them-defying properties that
> >is mysteriously absent from our solar system but seemingly plentiful
> >everywhere
> >else.
>
> Which explains why we would want to go there and get it. But there's a
> fundamental instability in that system: Earth has nothing to trade for it,
> unless the other system is (for some reason) poor in the common elements we can
> find laying around our own backyard.
In Cherryh's universe, the unique thing that Earth has and none of the
colonies do is a huge and self-sufficient ecosystem that humanity
evolved in.
If Earth ever does have colonies on other planets, and if the
colonists are humans instead of some kind of radically changed
posthumans, that strikes me as pretty realistic. We can't expect to
find another world with a naturally human-friendly ecosystem, and we
can't expect terraforming to be fast.
James Nicoll
Most modern trade is not in raw materials but services and finished
goods. I bet an Earth that can send out STL ships, whether privately or
subsidized, will have a much wider array of goods and services than we
do.
Unfortunately given plausible no-surprises tech (no AFAL drives,
no previosuly unsuspected anti-ice deposits etc) it's hard to invision
what material goods would be worth shipping light years (aside from people).
Information would be inexpensive to send, though. Radio telescope tech is
already up to the job.
--
"The Union Nationale has brought [Quebec] to the edge of an abyss.
With Social Credit you will take one step forward."
Camil Samson
Bryan Derksen
>It's a problem I've never really been able to explain. Trade over long
>distances/times on Earth have always been the result of local availability. But
>what isn't available in our own solar system that we would find elsewhere?
>(That would also be valuable enough to make us go back and forth.)
For Kardashev II-level civilizations, how about "metals" in the
cosmological sense (ie, elements heavier than helium). If you've
stripped all the naturally occurring heavy elements from your solar
system to build stuff, the only options for getting more are star
lifting (slow and potentially very disruptive to your existing
infrastructure), bulk transmutation (likely to be very inefficient) or
trade with extrasolar souces. Trade goods could be energy (beamed
directly or in the form of antimatter) and information/computation. As
for why they don't just colonize wherever it is they're taking metals
from, perhaps the civilization wants to try building a megastructure
that requires a few dozen Jupiter masses of material.
It's a bit hard to base a story on, though, since a Kardashev II
civilization is likely to be post-Singularity. Might make an
interesting background feature, though - humanity could be like ants
living at the edge of a strip mine. :)
Mike Van Pelt
> I'm sure everybody here knows the catchphrase, "Relativity, causality,
> FTL - pick any two." Well, I'd like to pick the first two - and still read
> some good SF stories that deal with more than one star system.
Nothing by G. David Nordley is likely to have FTL.
He's pretty hard-core about fantasy crutches like FTL.
Most of his stories are in the solar system, but ones which I
especially recall which covers another star system is "Poles
Apart" (novella, Analog, Mid December 1992)
It takes place on a joint colony between humans and two very
non-humanoid alien species. I liked this one a lot.
There was a sequel, but I don't recall its title. He has
also written a couple of short stories which take place in the
same world.
He's also completing a novel colaboration which doesn't have
any aliens, but involves a rather remarkable engineering
project which spans several star systems.
--
The more things change, | Mike Van Pelt
the more they stay insane. | mvp at calweb.com
-- Mike Jittlov | KE6BVH
Charles Talleyrand
"Justin Bacon" <tria...@aol.com> wrote in message news:20040105181843...@mb-m15.aol.com...
> Damien R. Sullivan wrote:
> It's a problem I've never really been able to explain. Trade over long
> distances/times on Earth have always been the result of local availability. But
> what isn't available in our own solar system that we would find elsewhere?
> (That would also be valuable enough to make us go back and forth.)
>
Tourism. Didn't you ever want to see the triple-moons of Venga Four. The
trip itself is not too bad since you sleep through it.
And then there is the interstellar trade in globular art-voice-vid-smell boxes
from Fergie Six. Everyone loves to have them, and no one except the Fergies
know how to make them. If only we could steal their secret. Or if we could
buy their secret, but the Fergies won't even sell it.
And how about the soft cushy auto-chairs from Gogle Nine. The patent will
run out in a few more decades, but until them they have quite the monopoly.
Dang intellectual property laws. I would have though the Gogles would have
set up a local manufactoring center here on Earth, but apparently Gogle
brains (and the resulting Gogle lawbooks) don't allow for that.
Bryan Derksen
<bryan....@shaw-spamguard.ca> wrote:
>For Kardashev II-level civilizations, how about "metals" in the
>cosmological sense (ie, elements heavier than helium). If you've
>stripped all the naturally occurring heavy elements from your solar
>system to build stuff, the only options for getting more are star
>lifting (slow and potentially very disruptive to your existing
>infrastructure), bulk transmutation (likely to be very inefficient) or
>trade with extrasolar souces. Trade goods could be energy (beamed
>directly or in the form of antimatter) and information/computation.
It just occurred to me today that if you can manufacture bulk
antimatter, bulk transmutation probably wouldn't be all that much
harder. Guess that leaves computation resources as the major trade
good.
Justin Bacon
> "Justin Bacon" <tria...@aol.com> wrote in message news:20040105181843...@mb-m15.aol.com...
> > Damien R. Sullivan wrote:
> > It's a problem I've never really been able to explain. Trade over long
> > distances/times on Earth have always been the result of local availability. But
> > what isn't available in our own solar system that we would find elsewhere?
> > (That would also be valuable enough to make us go back and forth.)
>
> Tourism. Didn't you ever want to see the triple-moons of Venga Four. The
> trip itself is not too bad since you sleep through it.
But coming home will be pretty nasty, since everyone you knew will
probably be dead, your job long gone, and your skills horrendously
outdated. Unless we revolutionize what it means to be human, such a
trip is unlikely to be possible.
If space travel became cheap enough, I could easily see humanity's
diaspora happening as a result of "tourism": People heading out to see
the wonders beyond our own solar system. I just don't see such people
ever coming *back*. And such activity wouldn't really include trade
(although I could see some people setting up "tourism stations"
catering to the diaspora).
> And then there is the interstellar trade in globular art-voice-vid-smell boxes
> from Fergie Six. Everyone loves to have them, and no one except the Fergies
> know how to make them. If only we could steal their secret. Or if we could
> buy their secret, but the Fergies won't even sell it.
Okay. But you've still got the unbalanced trade aspects (now the
Fergies have something we want; but what do we have that the Fergies
want?), and you're begging the question of why the Fergie colony got
established in the first place. (Let alone managed to invent something
which can't be reverse-engineered.) (Unless the Fergies are aliens, in
which case the scenario doesn't really match-up with the thread.)
> And how about the soft cushy auto-chairs from Gogle Nine. The patent will
> run out in a few more decades, but until them they have quite the monopoly.
> Dang intellectual property laws.
Oh, c'mon. The first thing that will happen in that scenario is
Earth's government voiding the validity of Gogle patents. Earth isn't
going to spend trillions of dollars just to get *to* Gogle Nine, when
they could be raking in money by voiding the patent.
Justin Bacon
tria...@aol.com
James Nicoll
Justin Bacon <tria...@aol.com> wrote:
reasons to travel STL
>> Tourism. Didn't you ever want to see the triple-moons of Venga Four. The
>> trip itself is not too bad since you sleep through it.
>
>But coming home will be pretty nasty, since everyone you knew will
>probably be dead, your job long gone, and your skills horrendously
>outdated. Unless we revolutionize what it means to be human, such a
>trip is unlikely to be possible.
>
extended life combined with a most convenient tendency for stars
to have one or more Earthlike (or at least Mars-like) worlds (with
natives in most case) so round trips were only fractions of a life-
span. Oh, and stay-at-homes could in theory put themselves on ice
to wait for travellers to return although I think the one time that
option is mentioned it is in the context of a man's wife not being
willing to sleep away twenty years.
Christian Weisgerber
> It's a problem I've never really been able to explain. Trade over long
> distances/times on Earth have always been the result of local availability. But
> what isn't available in our own solar system that we would find elsewhere?
> (That would also be valuable enough to make us go back and forth.)
SPOILER for Poul Anderson, _The Byworlder_
Artistic inspiration.
--
Christian "naddy" Weisgerber na...@mips.inka.de
Chris Thompson
Urban Fredriksson <griffon...@canit.se> wrote:
>In article <766Kb.10$k97....@news20.bellglobal.com>,
>DataPacRat <spam.da...@warren.kill.com.invalid> wrote:
>
>> I'm sure everybody here knows the catchphrase, "Relativity, causality,
>>FTL - pick any two." Well, I'd like to pick the first two - and still read
>>some good SF stories that deal with more than one star system.
>
>Robert Reed's _The Remarkables_ almost qualifies, but the
> His _Sister Alice_ qualifies.
Well, no FTL - agreed, but causality takes a bit of a beating as well as a
result of <spoiler> ...
Chris Thompson
Email: cet1 [at] cam.ac.uk
Brendan Hogg
> In article <ead87502.04010...@posting.google.com>,
> Justin Bacon <tria...@aol.com> wrote:
>
<STL round trips>
> >
> >But coming home will be pretty nasty, since everyone you knew will
> >probably be dead, your job long gone, and your skills horrendously
> >outdated. Unless we revolutionize what it means to be human, such a
> >trip is unlikely to be possible.
> >
> The solutions used in the Viagens stories [... were by
> rather unrealistic universe design on the part of the author.]
> Oh, and stay-at-homes could in theory put themselves on ice
> to wait for travellers to return although I think the one time that
> option is mentioned it is in the context of a man's wife not being
> willing to sleep away twenty years.
There's something rather similar to this in Egan's _Schild's Ladder_,
where an entire planet's worth of humans-running-in-robot-bodies slow down
their processing speed every time anyone goes away (transmitting
themselves AFAL to be downloaded elsewhere), so that elapsed subjective
time remains the same for everyone when the tourist gets home (creepy,
really, if you ask me). There's a bit of a plot point about the fact
that one of the main protagonists is from this world, and has no intention
of returning, but I forget whether he announced this before leaving, or
whether there'll all still sat there in Slow Mode waiting for him ...
Cheers,
Brendan
William December Starr
Wakbo...@yahoo.com (Wakboth) said:
> Alistair Reynolds' "Inhibitor" sequence ("Revelation Space", "Chasm
> City", "Redemption Ark" & "Absolution Gap") comes pretty close.
>
> Space travel is STL, although with very high relativistic speeds.
>
> There are mentions of causality-breaching ways of FTL
> communications and travel in the books, but these are beyond human
> capabilities, and _very_ dangerous to use.
Dangerous in and of themselves, or dangerous in that their use tends
to attract the attention of certain parties (or automated systems)
whose attention one really, _really_ does not want to attract?
-- William December Starr <wds...@panix.com>
Steve Coltrin
The latter is not impossible; the former is _very_ much so. One way
Reynolds' universe deals with egregious violations of causality is to
<rot13>rqvg gur ivbyngbe bhg bs uvfgbel</rot13>. This is very upsetting
to bystanders.
--
Steve Coltrin spco...@omcl.org WWVBF?
"God forbid that a child know what a member of the opposite sex looks
like naked before they're 13 and gangbanging each other in a back alley
after huffing paint." - drdoody
Matt Austern
Wakboth
Both; botched use of FTL drive causes the universe to self-correct the
causality breach... by retroactively editing the offending party from
existence. It happens a couple of times in Reynolds' books; if you
were close enough to the breach, but not so close as to become erased,
you may retain memories of both timelines, which tends to cause
nervous breakdowns.
-- Wakboth
Wayne Throop
::: and travel in the books, but these are beyond human capabilities,
::: and _very_ dangerous to use.
: Wakbo...@yahoo.com (Wakboth)
: botched use of FTL drive causes the universe to self-correct the
: causality breach... by retroactively editing the offending party from
: existence. It happens a couple of times in Reynolds' books; if you
: were close enough to the breach, but not so close as to become erased,
: you may retain memories of both timelines, which tends to cause
: nervous breakdowns.
FWIW, an actually-discussed-by-physicists-semi-seriously resolution to
the causality problems in time travel (and hence in FTL), is that if you
attempt to open a wormhole (or otherwise bring into existance a global
spacetime geometry) which allows closed timelike loops to form, it will
not work; it will be slammed closed due to (essentially) quantum
feedback. That is roughly, virtual particles following the potential
loop would disrupt the geometry. There is some reason to think this
model might actually correspond to reality (but it's still way
speculative). Called "the chronoprotection hypothesis" IIRC;
you can search google groups for past discussions in various
newsgroups, including some sci groups.
So the notion would be, you could travel FTL as long as you don't
follow a trajectory into your own past; such an attempt would fail.
I have some questions about how you know which spacetime geometries
were established "first" so that "later" ones fail, since the spacetime
geometry is what defines "first" and "later"... one can get a sort
of brainfreeze attempting to picture it. Sigh.
Justin Bacon
>So the notion would be, you could travel FTL as long as you don't
>follow a trajectory into your own past; such an attempt would fail.
>I have some questions about how you know which spacetime geometries
>were established "first" so that "later" ones fail, since the spacetime
>geometry is what defines "first" and "later"... one can get a sort
>of brainfreeze attempting to picture it. Sigh.
Well, I suppose that any spacetime geometry which allowed me to travel into my
own past would be dependent upon the existence of that past. That's probably
how the theory maintains causality.
Here's the thing, though: Is this theory somehow claiming a special privilege
for sentience, or is it just concerned with specific physical matter looping
back into its own past? If I could transmit my sentience to a completely
different physical form, would I then be able to travel back into my own past?
Conceptually I'm having a hard time wrapping my head around that one. I suppose
I'll need to track down the math at some point.
Justin Bacon
tria...@aol.com
Robert Shaw
"Justin Bacon" <tria...@aol.com> wrote
> Wayne Throop wrote:
> >So the notion would be, you could travel FTL as long as you don't
> >follow a trajectory into your own past; such an attempt would fail.
> >I have some questions about how you know which spacetime geometries
> >were established "first" so that "later" ones fail, since the
> >spacetime geometry is what defines "first" and "later"... one can get
> >a sort of brainfreeze attempting to picture it. Sigh.
>
> Well, I suppose that any spacetime geometry which allowed me to travel
> into my own past would be dependent upon the existence of that past.
> That's probably how the theory maintains causality.
>
> Here's the thing, though: Is this theory somehow claiming a special
> privilege for sentience, or is it just concerned with specific
> physical matter looping back into its own past?
The latter.
The hypothesis actually only forbids closed lightlike loop; i.e, a path
such that light travelling along it gets back to its starting point at
the same time it left.
Matter travelling into its own past is not a problem.
To a first (classical) approximation light takes the path of least time
between points. If there is more than one such path, light takes all
of them, producing interference. Light does also take the other,
non-extremal, paths but this is a negligible correction when the
wavelength is small.
If we have a closed lightlike loop a photon that goes round it once
takes the same time to get from A to B as does a photon that doesn't
go round it at all, or one that goes round the loop a googol times,
therefore that photon will do each of those things simultaneously.
[Photons can circle the loop three times, then get off, because they're
quantum. Really, classical metaphors don't apply, but this one is close
enough, and more friendly than the maths.]
To get the intensity of the light travelling the loop we must combine
the contributions from photons circling it once, twice, thrice,
fourfold, ... , a googolfold ...
Not surprisingly, the result turns out to be infinity, rarely a good
sign.
By itself this needn't rule out closed lightlike loops, but the energy
of that light will itself bend space significantly, with various effects
that prevent closed lightlike loops being acceptable solutions to
the equations.
Closed timelike curves don't have the same problem, since it does take
time to circle them (and costs positive action for matter), so they are
still permitted.
However, as total travel time round the timelike curve approaches zero
the chance of a photon taking an almost-least-time trip round the loop
increases, and therefore the intensity of the light circling the loop,
until (if the total travel time is sufficiently small) the energy
density of the light curves space strongly enough to break the loop.
--
Matter is fundamentally lazy:- It always takes the path of least effort
Matter is fundamentally stupid:- It tries every other path first.
That is the heart of physics - The rest is details.- Robert Shaw
Wayne Throop
:: Is this theory somehow claiming a special privilege for sentience, or
:: is it just concerned with specific physical matter looping back into
:: its own past?
: "Robert Shaw" <Rob...@shavian.fsnet.co.uk>
: The latter. The hypothesis actually only forbids closed lightlike
: loop; i.e, a path such that light travelling along it gets back to its
: starting point at the same time it left.
Um... that seems to be a mutation of the standard terminology, where
timelike refers to an interval between events such that the one can be
causally connected to the other in SR (ie, light is fast enough to carry
information from one event to the other), spacelike refers to an
interval between two events such that the one cannot be causally
connected to the other in SR (ie, light is not fast enoughto carry
information from one event to the other), and lightlike refers to an
interval where light is exactly fast enough to carry information from
one event to the other (or in SR terms, the spacetime interval is zero).
Or more mathematically put, d^2-t^2 (where d is the distance separating
the events in some given coordinates in which c=1 and F=dp/dt, and t is
the time separating the events in the same coordinates) is negative for
timelike separation, positive for spacelike separation, and zero for
lightlike separation.
But I digress. The point is, an attempt to "change history", ie an
attempt to form a closed causal loop of events where some of the events
have a timelike separation (ie, "a closed timelike loop") will disrupt
the geometry in such a way that it never forms. In much the same way
(well... vaguely-sort-of-metaphorically the same way) as allowing sound
from a speaker to reach a microphone which drives that speaker will
cause a feedback squeal.
: To a first (classical) approximation light takes the path of least
: time between points. If there is more than one such path, light takes
: all of them, producing interference. Light does also take the other,
: non-extremal, paths but this is a negligible correction when the
: wavelength is small.
: If we have a closed lightlike loop a photon that goes round it once
: takes the same time to get from A to B as does a photon that doesn't
: go round it at all, or one that goes round the loop a googol times,
: therefore that photon will do each of those things simultaneously.
: By itself this needn't rule out closed lightlike loops, but the energy
: of that light will itself bend space significantly, with various
: effects that prevent closed lightlike loops being acceptable solutions
: to the equations.
Right (aside from conflicting terminologies for "mumble-like").
: Closed timelike curves don't have the same problem,
Sure they do, since massive particles also "take all paths".
It's just that their wavelengths are so small nobody noticed
this until fairly recently (ie, <100 years).
Unless of course I'm misunderstanding your teminology.
Robert Shaw
"Wayne Throop" <thr...@sheol.org> wrote in message
news:10745...@sheol.org...
> ::: [chronoprotection hypothesis]
>
> :: Is this theory somehow claiming a special privilege for sentience,
or
> :: is it just concerned with specific physical matter looping back
into
> :: its own past?
>
> : "Robert Shaw" <Rob...@shavian.fsnet.co.uk>
> : The latter. The hypothesis actually only forbids closed lightlike
> : loop; i.e, a path such that light travelling along it gets back to
its
> : starting point at the same time it left.
>
> Um... that seems to be a mutation of the standard terminology, where
> timelike refers to an interval between events such that the one can be
> causally connected to the other in SR
That's the standard SR terminology. This is GR
If the path is locally timelike/lightlike/spacelike
at every point on it, then so is the path itself.
In SR all paths between two events are the same type
so it makes sense to talk about space/time/light -like
event pairs.
In GR one event pair can be linked by paths of three
different types, so the SR simplification doesn't hold.
>
> But I digress. The point is, an attempt to "change history", ie an
> attempt to form a closed causal loop of events where some of the
events
> have a timelike separation (ie, "a closed timelike loop") will disrupt
> the geometry in such a way that it never forms.
And your proof for that is?
The argument quote below prohibits closed lightlike paths, but
not closed timelike paths.
>
> : To a first (classical) approximation light takes the path of least
> : time between points. If there is more than one such path, light
takes
> : all of them, producing interference. Light does also take the
other,
> : non-extremal, paths but this is a negligible correction when the
> : wavelength is small.
> : If we have a closed lightlike loop a photon that goes round it once
> : takes the same time to get from A to B as does a photon that doesn't
> : go round it at all, or one that goes round the loop a googol times,
> : therefore that photon will do each of those things simultaneously.
> : By itself this needn't rule out closed lightlike loops, but the
energy
> : of that light will itself bend space significantly, with various
> : effects that prevent closed lightlike loops being acceptable
solutions
> : to the equations.
>
> : Closed timelike curves don't have the same problem,
>
> Sure they do, since massive particles also "take all paths".
> It's just that their wavelengths are so small nobody noticed
> this until fairly recently (ie, <100 years).
No, because circling the loop uses a non-zero, and possibly
quite large, quantity of action.
In GR the action for matter is proportional to rest mass-energy
times the integral over the path of the time elapsed in that particles
rest frame. (That is, matter also takes the path of least time)
If it takes a year to circle the timelike loop, as measured by a
clock travelling that loop then the extra action of that path for
an electron is mc^2*1 yr=2.5E-6 kg m^2 s^-1, or about
10^28 times Planck constant.
Because this action is so much larger than plancks constant,
paths which take the loop are suppresed by approximately
exp(-10^28). The resultant correction is utterly neglible.
It only becomes significant when the time to circle the loop
falls to around 10^-21, almost lightlike.
Quantum effects are only significant when plancks constant
is large, compared to the typical actions under consideration.
For lightlike loops, the difference in action is zero, so
paths that circle the loop a trillion times, or more, make
just as strong a contribution as those that never circle it.
For timelike loops of macroscopic duration, the difference
in action is enormously larger than plancks constant, and
quantum effects can be ignored, therefore those timelike
loops are stable against this problem.
Wayne Throop
: In GR one event pair can be linked by paths of three different types,
: so the SR simplification doesn't hold.
True enough. Still, the "timelike" in "closed timelike loop" means that
each event in the loop is in its own past and future, causally. Which
is what it is necessary that the chronoprotection conjecture prohibit
in order to rule out the possibility of paradox.
: No, because circling the loop uses a non-zero, and possibly quite
: large, quantity of action.
What's a "quantity of action"? Nevermind, you explain in a bit.
Point being, lightlike paths take zero time, so (metaphorically)
nothing has time to leak out of the loop.
Still, I was under the distinct impression that virtual particles in
a closed loop blow up, whether the particles are photons or something else.
But in poking around previous posts to check why I thought that,
I see the argument prohibiting closed timelike loops is via wormhole
transport, and before you can transport a wormhole anywhere INTO its
pastward lightcone, it'll be ON the pastward lightcone.
Therefore the argument is a lot more specific than I was remembering;
it prohibits the transport of wormholes to create a timelike loop, but
other even-more-exotic-methods aren't necessarily prohibited. The
references I chased lead back to Kip Thorne's pop book "Black Holes and
Time Warps", and along the way, it was paraphrased as being "you can get
a closed timelike loop [but] the self-interference of virtual particles
prevents you from actually getting this to work". But a better paraphrase
elsewhere was "in the process of trying to create a closed timelike
loop, there comes a moment just before you succeed, when you create
a closed *lightlike* loop".
Thanks for provoking me to rethink.