> Oerjan Ohlson wrote:
> djwj wrote:
> (3) In all the sci-fi that I have been exposed to Jump engines need
> Examples of sci-fi backgrounds that do not require specific
Real Theoretical physics here, you have been warned: "Warp" "Hyperspace" and
"Jump" drives are based on diffrent ways of manipulating space. "Warp" drives
isolate the warping ship in it's own pocket of space and propell that pocket
at FTL speeds, a doubious method of FTL at best, but it does neatly get around
the fact that a ship in some way traveling through "realspace" at FTL speeds
is very likely to hit something and be destroied. "Warp engines are used in
"Star Trek" (the origination of the scientific use), Possibly Star Wars, only
because Star Wars casually ignores the Realities of 3Relativity.
"Hyperspace" drives assume that a ship can turn itself at right angles to
reality (travel through the 4th dimention of 4D space) and cross gaps between
the folds in space. Hyperdrives are limited in how far someone can travel by
how much space is between the fold. Example:
Take a long strip of paper with three dots on it, two on the ends and one in
the middle
* * *
if you bend the paper so that the first two dots line up horizontally, put one
finger between them so the paper isn't touching itself,(Diagram, edge view of
paper, * = dot, 0 = finger):
_ /
*\0/*
| |
U
you can see that the distance traveled through "Realspace" (the paper) is
greater than the distance traveled through "Hyperspace" (your finger) Now bend
the excess paper and the third dot back down to line up with the second
(Diagram, edge view of paper)
n
_ / \
*\0/* 0 \*_
| |
U
If you are traveling from point 1 to point three you have three options. The
fastest is to travel through each point, jumping into hyperspace as soon as
your drives will permit it. For the second option you could hyperjump between
two points, and travel the rest of the way in realspace.The last option is to
go around the entire region, completely in hyperspace, but this can be tricky
as the fold of space is relgated by the gravitational wells that are inside it
(the calssic black hole image of a 2D plane with the middle pulled out into a
cone is one of the original models of what would happen to the space of a 2D
plane with a Black Hole in the center) The more time you spend in realspace
the more predictable your flight time will be, Hyperspace is much more
unpredictable.) This is why, In reality,
hyperjumps are more dangerous in-system. The orbits of the planets,
moons, the motion of the star itself will create spikes, valleys and other
rapidly changing spacial features. Hitting realspace while in hyperspace is
not adviseable. You will simoultaneously exist in both places and be affected
by the currents in both dimentions, not to mention the hazards of having a 4D
hole ripped in your 3D hull. These drives are used in Babylon 5, likely in
Star Wars, but rember Star Wars is decidely apathetic about the realities of
relativity.
Finally Real "Jump" drives. These things actually FOLD space. Take the paper
strip from before and touch the dots together, flatten the entire thing. This
takes IMMENSE amounts of energy, which makes it both more dangerous and safer
than hyperdrive. Your ship never actually leaves 3D space so you avoid all the
hazards of 3D to 4D interspacial travel, BUT if something does go wrong you
may release enough energy to take out a small section of reality.
These drives are used in Dune ("travelling without moving")
Full thrust's PSB indicates a highly efficient Hyper-Jump drive, not
quite as powerfull as a Jump Drive but closes the gap in a fold before turning
at right angles to reality, and crosses it.
Anyways back to
> Oerjan Ohlson wrote:
> Let's hope your buoys are extremely cheap,
> extremely long-ranged
> and
> You'll need huge amounts of them otherwise.
Give the man a prize, He's got it. These things are so cheap that the orbit is
nearly saturated with them. They are small, easily replaceable, and they blend
in with the debris in an oort cloud. A system ship could carry hundreds of
these things and replace lost ones quickly and easily. Sensor readings are
coallated at a main base, individual sensors are located in a method similar
to GPS, replacements are sent out to fill any gaps....
They are not for sophisticated detection, they are for "General! something has
just entered the system at coords..."
> (2) If a planet is worth
> Certainly. But is it able to support them? Value can be other than
That's a decision for the government involved. Siege warfare makes a
return....
> Laserlight wrote:
Not if your ranges are in Light-Seconds. A beam will be visible coming
if you are at more than one lightsecond. Although if the range is great enough
a ship may have the time to avoid an entire salvo of batteries.
I'm still not sure that I agree with the ranges postulated, or if I agree with
DSII taking 15 minute turns, modern tank warfare is over very quickly, unless
both sides can secure sniping positions. I average 6 turns in a DSII game:
that makes one conflict last about an hour and a half at 15min turns. Maybe
someone knows some historical times to completeion (rember the DSII conflict,
excepting artillery and aerospace, is limited to a 3 mile by 2 mile area) The
other question is how much faster will advanced technology
finish the battle, in the middle ages one battle took from sun-up to
sun-down (average 12 hours) in the world war II tank battles (excepting
Blitzkreig, which was a kind of sneak attack.) lasted up to 5 or even 6 hours.
Simply making contact with the enemy was often enough to stop them for the
remainder of the day. In desert storm the U.S. ran over armored positions in
minutes, never more than an hour when they actually fought back, but they were
fighting a demoralized and green (if not untrained) force. The trend places
advanced technology at minutes to sucess not hours. Kosovo cannot be gauged as
of yet as ground forces haven't been sent in (although this is exactly the
kind of enemy, and enviroment that the Integrated Armed Forces model was
intended for).
Anyways back to FT: As a play balance note if starships start "evading" then
weapons need to have a higher chance of hitting their targets, or everyone
will spend three hours, Real time not Game Time, evading before someone gets
the first kill. I like the GZG line of wargames because they are quick, 2
hours average, 3 max.
> djwj wrote:
Speed-of-light
> >weapons mean you need to be dodging _before_ you know someone is
Oh yeah? And how do you detect the beam coming at you? The light from the
weapon firing will reach you at exactly the same time as the laser (or other
speed of light weapon) itself. There's nothing magical about a range of one
light second.
Unless you have some way of detecting a weapon firing that gets the data to
you at FTL speeds. And I'd bet that weapons designers would shield they're
weapons to prevent that.
If the weapons are particle beams at just below light speed then you'll get
some warning, but how fast can a starship take evasive
action? At ranges of the order of _many_ light seconds you may have a
chance.
> At 2:55 PM -0700 4/28/99, Nyrath the nearly wise wrote:
> There are actually some other FTL drives that have been
This gets carried to a ridiculous extreme in Starfire. Warfare becomes a
matter of warppoint assaults. Its The Great War in space. And you thought
trench warfare was bad. I don't mind losing a chunk of my Wall in open combat,
but knowing I'm going to lose most of the first wave is somehow repugnant.
I've been pondering the concept of making Starfire warp points delievr ships
over a larger area, which will make warp point assaults less like charging
entrenched machine guns on foot. Has anyone else tried something like this?
In the Honor Harrington books Weber gets around the 'combat only at fixed
points' issue (not necessarily a problem) by postulating that ship's drives
can be seen a looong way off, plus 500g gives lots of delta V for generating
intercepts. Of course, most of his intercepts happen a long way from planets,
but the base course for the attacker usually terminates at a fixed point.
> On Wed, 28 Apr 1999, Nyrath the nearly wise wrote:
> The reason most jump drives in SF use fixed jump points
i really must read that...
> Without the choke points mandated by
a common theory. i'm not entirely sure i believe it (who woulda thunk it,
eh?). basically, the theory is that without special points in space, there can
be no battles, as battles have to take point at a certain point (well, within
a certain relatively small volume). i have two objections.
firstly, there are plenty of special points other than jump points: planets,
for instance, and artificial orbiting bodies such as space stations. if i have
a planet in a system, and an enemy invasion fleet jumps in, i think i have a
pretty good idea where he's heading, and that there will be a battle there.
secondly, i don't think battles do need special points. the same theory,
applied to modern naval or aerial warfare, would predict a lack of battles,
when in reality there is certainly no shortage. in these cases, the sites of
battles are decided by interception: one side will chase the other until they
meet, and then they will fight. this, in turn, depends on the relative speed
and points of origin of the forces.
consider how few major naval or aerial engagements have been fought at
targets: the battle of Jutland was at Jutland because that's where the fleets
were when they met, not because someone was going to Jutland. the battle of
Britain was fought over a gigantic patch of sky, not around the targets the
germans were attacking.
example: if i have a fleet at anchor in orbit around Gamma Hydri Prime, and my
enemy jumps in to the system at local coordinates 3728 mark 489 stroke 90 dash
ZZ9 plural Z alpha, then i have two defined points; it is then just a matter
of maneuver until we meet. or, i could hang around and we could fight at the
planet.
the main objection to this objection centres on distance; my interception
objection only holds water if a fleet can detect another fleet in the system
at multiple AU range. the FT background suggests it can, and i think it's
legitimate within a space opera context.
i'm not so sure about the hard-sf edge: it all depends on how bright
your drives are, i suppose. i reckon with a 3m telescope mounted in each
FireCon centre in the fleet (in a typical fleet, maybe 20 telescopes?), ganged
up as an interferometer (possibly by aperture synthesis, or am i barking up
the wrong tree here?), and spread out over a sphere with a radius on the order
of a quarter of an AU (purely arbitrary) you'd have a decent chance of being
able to track an enemy fleet.
you would have to initially acquire them by their jump signature (think
gravity waves, tachyons and magnetic fields, etc). the attacking fleet would
probably be able to figure out where the defending fleet was from the
positions of planets.
Tom
> Thomas Anderson wrote:
I believe it is collected in Pournelle's A STEP FARTHER OUT. Long out of
print, it has lots of valuable information in it. Perhaps Pandora's books or
other used book finder has it.
> > Without the choke points mandated by
> On Wed, 28 Apr 1999, djwj wrote:
> Real Theoretical physics here, you have been warned:
You mean "real" from the point of science fiction, not fact, right? Speaking
as a theoretical physicist (and my research is in general relativity), I'd
have to disagree that any of the FTL systems proposed inyour message are real
in the sense of "real in our world". But each fictional universe defines its
own physical laws, so what's "real" in one universe may not be "real" in
another (or ours).
> >extremely long-ranged
Sensor
> readings are coallated at a main base, individual sensors are located
I don't think you quite realize how big the Oort Cloud is. It ranges from
10,000 to 100,000 AU. That's about 4 x 10^15 cubic AU you've got to cover. You
say they aren't long range, so let's say each probe can cover
a cubic AU (a -lot- of space). If you can crank out 10 probes a day,
it's going to take you approximately 3 billion years to have your net in
place...
Just some thoughts...
> At 2:35 AM -0700 4/29/99, Thomas Anderson wrote:
I though the full text of the novel was in the FAQ for this list?
> Without the choke points mandated by
contrast the number of land battles over the last 100 years to the number of
naval battles. You'll find that naval battles are *very* scarce by comparison.
In almost all cases I can think of, naval battles, even deep water
interceptions such as Midway, took place in relationship to a fixed point.
This happens even when the objective is the enemy fleet and not a specific
target.
> consider how few major naval or aerial engagements have been fought at
the
> battle of Britain was fought over a gigantic patch of sky, not around
I'm afraid the history does not support this point.
At Jutland the Germans were intercepted on a sortie from a fixed point, and
while passing through a narrow stretch of sea. Although, due to the strong
influence of Mahan's theories, both fleets were trying to find each other.
This is about the exception to the rule. Mahan's theories are very strong in
picking strong points off a map for selection of defensive points that must be
held or taken (similarly, in Go there's a specific term for a point which both
sides should take as soon as possible, I'm just not looking it upo at 6:30am).
I strongly recommend reading Mahan. His analyses just beg to be applied to a
wargame, or preferrably wargames. It's on my list already.
At Trafalgar, Nelson intercepted the Allied fleet on leaving port, it justr
took a long chase to bring them to battle. At Tsushima, Togo intercepted the
Russians at Tsushima Straight. Check a map, that's a fixed point if I ever saw
one; they Russians were also heading for a known port (the only one they had
left). Ditto for Midway, Intel helped here. The Solomons campaign is also a
good example of combat at
At the Battle of Britain, asides from some ill-advised fighter sweeps
(the defenders had a couple hours less time in the cockpit), the Germans were
going after specific targets (just changing the selection
at ill-advised intervals). The RAF vectored their interceptors in on
the bombers. Admittedly, the fighter sweeps were pure attrition, and the
Germans didn't come out anywhere near asd well as they had too.
In the strategic bombing campaigns of the 20th C., defending fighters attacked
bombers heading to specific targets. There are a few cases of deception as to
the intended destination of the bomber stream, these attempts frequently
caught the defenders working the wrong target. The individual combats took
place all over Europe, but then so were the targets.
In all cases in air combat. the defending fighters tried to intercept before
the targets. It is far better to shoot down a loaded bomber than one that has
already dropped its bombs.
> On Thu, 29 Apr 1999, Michael Llaneza wrote:
> At 2:35 AM -0700 4/29/99, Thomas Anderson wrote:
lol!
> >> Without the choke points mandated by
agreed, readily. i seem to recall reading that Jutland was in fact the only
significant fleet engagement of ww2. i'm not sure that this necessarily
reflects on my argument, though. one of the key reasons land battles have been
so common is that they are somewhat easier: in many cases you can just march
your troops in over the border. however, in a
mostly non-balkanised interstellar environment, that's not an option.
*every* planetary assault must be predeced by a convoy, which is an
opportunity for a fleet action. thus, naval actions have considerably more
importance.
perhaps the best comparison is the island-hopping in the pacific in ww2,
where there was a constant naval element. of course, this took place in a
situation where the allies had a significant naval superiority, so there
weren't as many naval battles in defence of islands as there could have been.
> In almost all cases I can think of, naval
isn't that what i was saying? looking back now i see i wasn't very clear.
> This happens even when the objective is
this is *exactly* what i said - battles need not take place *at* special
points, because you can derive a new point from any two existing special
points - midway between a planet (fixed special point) and a jump-in
point
(non-fixed special point, ie only special because that is where the
fleet jumped in this morning; it won't be special tomorrow).
> >consider how few major naval or aerial engagements have been fought
the
> >battle of Britain was fought over a gigantic patch of sky, not around
i was afraid it might not. history has a tendency to do that to me :-).
> At Jutland the Germans were intercepted on a sortie from a fixed
ah; my memory of the geography of jutland is rather hazy, i must say.
> Although, due to the
i'm not familiar with Mahan, nor his theories; could you by any chance
provided a pointer to some info, or some sort of potted "Mahan for Dummies"
version?
> I strongly recommend reading Mahan. His analyses just beg to be
well, point me in his direction, and he can start keeping Sun Tzu company on
my shelf!
> At Trafalgar, Nelson intercepted the Allied fleet on leaving port, it
i'm assuming that was going to be "at sea" but that the 0630 effect got in
the way :-).
but i take your point. tsushima is certainly an example of combat at a fixed
point. i think trafalgar is sort of what i was saying: although the fleets
closed at a port, the actual interception (as in where the battle was) was
some way away. midway is a bit of a funny example, as it was basically a
carrier action, which has different logistics from line action (the "weapon"
ranges are comparable to the strategic distances). that
said, substitute leyte gulf (iirc - the last real battleship action?)
and your point holds, as that was fought in, well, leyte gulf, a restricted
piece of water.
> At the Battle of Britain, the
so, the germans sent bombers to, say, Leeds. did the battle take place at
Leeds? no, it took place at a point determined by the speed and starting
points of the bombers and interceptors. that is exactly what i was saying:
start with two special points (bomber base, Leeds) and make a third
(interception area).
> In all cases in air combat. the defending fighters tried to intercept
precisely; this is why it's better to intercept an attacking fleet well away
from your planet, as if you leave it until they're close, they can just lob in
a few nukes anyway.
now, i suspect we really agree on the essential concept (engagements occur at
certain points, but not necessarily permanent points), but differ over a
detais and the wording. what an unprecedented situation in the annals of
humanity :-).
Tom
[quoted original message omitted]
Michael Llaneza wrote [on fixed warp points]:
> This gets carried to a ridiculous extreme in Starfire. Warfare
Has
> anyone else tried something like this ?
Yep. The Jc drives, first appearing in the Starfire module "Akelda Dawn", do
this. Ariving up to 100 tactical hexes away from the WP was a
bit excessive, though - the necessary game map would've covered my
entire living room floor :-/ The AD tech has been toned down since
(SM#2, 3rd ed. revised), but we're not satisfied with them yet.
The big problem in Starfire WP assaults is that campaign fleets -
including WP defences - were so d**n huge. With the reduced income
levels in the SM#2 economic rules, extreme WP defences are a lot less
common - they still exist, but only in key systems... and over the past
two years, I've seen lots of first-wave ships survive assaults.
Battered, usually, but alive :-/
Best wishes,
> On Thu, 29 Apr 1999, Andrew Evans wrote:
> >On Wed, 28 Apr 1999, djwj wrote:
this reminds me of two things.
firstly, i remember reading somewhere that relativity only forbids travelling
at lightspeed or integer multiples thereof; thus, it is perfectly allowable to
travel at 1.5c. the trouble is, of course, that it's rather hard to get from
0c to 1.5c without going through 1c. there are a three ways round this i can
think of:
(i) exploit the granularity of time (quantum theory and that) to make the
transition from travelling at (1 - iota) c to (1 + iota) c, where iota
is some very small quantity, in a quantum of time, so at no point in time are
you doing exactly c.
(ii) find some way of going round 1c. i suspect this is what the infamous
hyperspace bypass of the Vogon-bulit ilk is for ..
(iii) hope nobody important is looking (i have visions of Einstein's ghost
shouting "Oi! Kirk! NO!"), although this basically amounts to (i) (explanation
for quantisation of time: god only checks the universe every
so often :-).
i might have read this non-integer-c thing somewhere scientific
(although certainly not recent or reputable), but it's more likely it was some
dire 1950s SF.
secondly, i would reproduce this from "STAR DRIVES IN SCIENCE FICTION: A
Catalog" by Geoffrey A. Landis <geoffrey.landis@lerc.nasa.gov>:
----- BEGIN -----
url: http://www.clark.net/pub/nyrath/stardrv.txt
[2.2.1.3] TACHYONIC TRAVEL
Tachyonic travel notes that faster than light speeds are in fact permitted by
relativity for bodies of imaginary rest mass, and assumes that there is some
way to reach the faster than light state (often invoking "tunneling") from
slower than light states without leaving "real" spacetime. (nb: tachyonic FTL
travel still has causality paradoxes in special relativity).
----- END -----
which is similar. i add that in the star trek (TOS) technical manual, there
was a chart of space vs time or something which clearly indicated
that there were goings-on with imaginary time and space at warp speeds.
anyway, my money's on the back rays every time*.
Tom
* ha! get *that* reference!
> Keith Watt wrote:
> I don't think you quite realize how big the Oort Cloud is. It ranges
'Course, if you're satisfied with a single-probe deep shell around the
10,000 AU perimeter you only need 400,000,000 probes, so if you can emplace 10
per day it only takes you about 110,000 years to build the net. (Building the
things probably isn't that much of a problem compared to getting them all in
position!)
'Course, since these things were also not supposed to be extremely durable the
first ones emplaced probably won't last 110,000 years...
Djwj, I think I'll return the price you gave me <g>
> On Thu, 29 Apr 1999, Andrew Evans wrote:
> Ah ha! A Physicist. This is also my Doctoral subject, although
This is more or less right, but the real problem in getting to lightspeed is
that your mass goes to infinity as you get closer to lightspeed. In other
words, it becomes harder and harder to go any faster to the point
where you need an infinite amount of energy to actually -reach-
lightspeed. The idea you're talking about is basically the tachyon argument:
if I have a particle that is travelling faster than light then it requires an
infinite amount of energy to slow it down to lightspeed.
But there's no way for us to interact with these particles, so it's something
that's hard to theorize about. Pretty neat though...
Now, effective faster-than-light travel is -not- prohibited by general
relativity (for different reasons), and therein I think lies the loophole for
stardrives.
> On Thu, 29 Apr 1999, Thomas Anderson wrote:
> firstly, i remember reading somewhere that relativity only forbids
there
> are a three ways round this i can think of:
Hmm. No, I don't think so. There's no "quantizing" of lightspeed that I know
of, though you may be remembering the argument that it's only
technically impossible for a massive particle to travel -at- lightspeed,
but tachyons would be able (and required) to exceed it. See my previous
message about that, but I bet that's what you're thinking of.
Unless you're referring to some thoughts towards a theory of quantum gravity,
which some people in my group are working on, but no one in the world is
really even close to. I'm afraid I'm out of my depth, beyond the very basics,
with that subject though...
TTYL..
[quoted original message omitted]
> > The reason most jump drives in SF use fixed jump points
I am reasonably sure it's also in Niven's collection N-Space.
> Laserlight wrote:
Um....a beam of light won't be visible until it gets there. If that takes a
full second, it *still* won't be visible before it gets there.
However, it makes perfect sense to me that a potential
target's sensors would detect a lock-on *before* the
beam fires, giving the battle computers the opportunity
to jink the ship (unless, of course, some hot-dog pilot
has it on manual--his funeral).
...targetting lock detected...evasive action taken..targetting lock evaded
...structural integrity failure, decks 4-8
...hull breach on decks 5 and 6...secondary combat control offline...damage
control notified
- Sam
> At 9:33 AM -0700 4/29/99, Oerjan Ohlson wrote:
that sounds about right to me. Just as well I'm filling in my Starfire
collection via eBay, but I'll check The SDS Starfire Home
(http://www.starfiredesign.com/) for Akelda Dawn (nobody has one listed
outside a bundle w/ stuff I have; ye gods, I love this new job). That
removes what bugged me about Starfire (first wargame I ever played, c. 1979,
so I'm happy about this). Now to do something about the 2d6 to d10
conversion.... [1]
[1] Yes, I know a fistful of d10 rolls faster, but I've always
preferred a simple bell curve. Then again, I started gaming before the d10 was
introduced...
[quoted original message omitted]