Implications of the Langston Field...
Johnny1a
about some of the implications of the magic technology called the
Langston Field. The phyics of this are never described, but the
authors do describe what it _does_ consistantly and fairly
completely.
A quick review: in essence, it is a volume of space that absorbs
radiation and kinetic energy, storing it and radiating the stored
energy outward as electromagnetic radiation. Thought the Field isn't
matter, it has an approximation of temperature in that as the total
stored energy rises, the frequency of the radiation of that energy
also rises.
Most of the time the mostly-uncharged Field radiates at wavelengths
far too long for human eyes to perceive, giving it the appearance of
an utter-black volume of space (probably usually a sphere or ovoid).
As the energy density gets higher, the wavelength can reach the
'visible' band, and the Field will begin to glow red. Keep pouring
energy in and the color will rise through the spectrum, until it
eventually reaches a point where it just can't hold any more energy,
and collapses, releasing all that stored energy in one brilliant flash
of light. ('Brilliant' in this case can easily be bright enough to
vaporize starships or more.)
The natural form of the FIeld is a solid volume, but a space can be
maintained inside it for a spacecraft or city or whatever you want to
protect that will fit inside, and the Field can protect it from nukes,
lasers, cosmic rays, just about anything, by absorbing the photons and
draining off the kinetic energy of material objects.
(I don't recall the authors commenting on momentum transfers, but
presumably it's conserved somehow. The details of that could be
important tactically or in terms of propulsion.)
When a Field overloads, it collapses inward as well as outward, into
the hollow interior, vaporzing whatever is inside it. It's an easy
death, the flash of energy is so enormous that the contents of the
interior are vaporized instantly. OTOH, the Field can overload
_locally_, letting _some_ energy through to the interior, and that can
damage a ship or wound a person without being lethal.
OK...
The Field is excellent wartime protection. Even weapons like poison
gas have a problem with it, since the gas is slowed down by the Field
before it seeps through, giving time to take protective steps. A
strong enough Field could stop the gas in place by absorbing its
energy of motion. (Just how deep this goes is not made clear, it's
never explained whether a Field could absorb enough heat energy to
freeze an object down to absolute zero or the like.)
While a fully charged Field is _very_ obvious, a low-charge Field
could make 'stealth in space' semi-viable. At the least, you could
probably use one to get quite a bit closer before being detected,
since you can radiate in selective directions, if you keep your
Field's radiation cone pointed away from the direction of the sensors
you're worried about, you'll be able to get much closer before being
detected. This also solves the problem of radiating your low-grade
heat from your habitable areas and your hotel load (since the Field
makes for a dandy heat radiator anyway) and you can selectively
radiate directionally.
Also note that a Langston Fielded ship ought to be essentially
invisible to radar and related active detection technologies, the
Field will just absorb the signal entirely.
(You still aren't completely stealthy. Eventually, if you keep
radiating in just one direction, you'll get enough acceleration to
mess with your desired trajectory. It also leaves the question of
your drive plume.)
Regarding the drive plume, in MIGE it's implied that _MacArthur_ and
the other Imperial ships are propelled by photon drives. In fact,
it's stated specifically at one point that _MacArthur_ gets at least
_some_ of its impressive acceleration by photon pressure from the
drive. The text descriptions are not perfectly consistant with the
idea that _MacArthur_ is a _pure_ photon drive ship, however.
If an Imperial ship _was_ a pure photon drive, though, if it kept the
light of the drive pointed _away_ from the planet it was approaching,
and kept it's Field up, what would be the first thing to reveal to the
planet it's approaching that it's coming? Radar won't work, and there
is no hot, radiating drive plume, as such. Just light heading _away_
from the planet. Some of the light might reflect off something, and
interplanetary dust/gas will reflect it as well, but how close could
yet get before that became noticeable?
(Photon drives for large ships necessarily emit _vast_ power,
petawatts or more.)
Of course, to decelerate to make orbit, the ship has to spray light in
the direction of the planet at some point, at which point it becomes
_very_ detectable, but if it just wanted to launch a sneak attack, a
fast flyby might be just fine.
So what makes a Fielded ship noticeable in the direction toward which
it travels?
alie...@gmail.com
Impacting gas molecules donate their kinetic energy to the field,
eh? That means the gas comes to rest WRT the field.
The ship is approaching Earth. All the interstellar/interplanetary
(depending on how far out it is) gas and dust, small to large rocks,
etc. impacts the field and imparts all its kinetic energy to the
field.
Then what happens to the stuff? It slides off to the sides and piles
up into a bow wave slamming into the stuff the field didn't interact
with, that's what. Velocity -> temperature, so the faster the ship's
planetward velocity, and the denser the stuff, the brighter the bow
wave is.
The little black spot in the middle is where you aim.
(BTW the Langston field always reminded me of Smith's [Campbell's?]
shields that radiated through the spectrum til they went UV and blew
up.)
Mark L. Fergerson
Derek Lyons
>Most of the time the mostly-uncharged Field radiates at wavelengths
>far too long for human eyes to perceive, giving it the appearance of
>an utter-black volume of space (probably usually a sphere or ovoid).
>As the energy density gets higher, the wavelength can reach the
>'visible' band, and the Field will begin to glow red. Keep pouring
>energy in and the color will rise through the spectrum, until it
>eventually reaches a point where it just can't hold any more energy,
>and collapses, releasing all that stored energy in one brilliant flash
>of light. ('Brilliant' in this case can easily be bright enough to
>vaporize starships or more.)
And oddly enough it invariably collapses before the re radiated energy
reaches wavelenghts short enough to again be invisible to the human
eye.
In reality, the Field doesn't move through the spectrum, it moves
through the color/temperature chart IIRC. It moves through red,
yellow, and white.
D.
--
Touch-twice life. Eat. Drink. Laugh.
http://derekl1963.livejournal.com/
-Resolved: To be more temperate in my postings.
Oct 5th, 2004 JDL
Shawn Wilson
> And oddly enough it invariably collapses before the re radiated energy
> reaches wavelenghts short enough to again be invisible to the human
> eye.
I assumed that the radiation was black body and it would never become
invisible as there would always be some being radiated as visible
light.
Johnny1a
That's actually a good question. The Field isn't matter so
comparisons to objects made of atoms are suspect, we don't know if the
radiation is a narrow band or if it has a wider spread.
Nyrath the nearly wise
> Regarding the drive plume, in MIGE it's implied that _MacArthur_ and
> the other Imperial ships are propelled by photon drives. In fact,
> it's stated specifically at one point that _MacArthur_ gets at least
> _some_ of its impressive acceleration by photon pressure from the
> drive. The text descriptions are not perfectly consistant with the
> idea that _MacArthur_ is a _pure_ photon drive ship, however.
I don't have a reference for you, but I remember reading that
the drive is a photon drive, and it is a direct outgrowth of
the Langston field.
A field is set up so it envelopes a fusion reaction. The
field absorbs all the energy of the reaction. The field
is set to radiate said energy collimated into a beam
for purposes of propulsion.
Nyrath the nearly wise
> In reality, the Field doesn't move through the spectrum, it moves
> through the color/temperature chart IIRC. It moves through red,
> yellow, and white.
It should do that if it obeyed the laws of physics. But
I vaguely remember a passage where it glowed green.
(this could have been in the omitted first chapter of TMIGE.
It was later published as a short story called "Reflex"
in the collection THERE WILL BE WAR vol 1)
Nyrath the nearly wise
as the field fills up with hostile energy.
http://www.projectrho.com/rocket/rocket3y.html#forcefield
(scroll down)
The field wants to be a solid volume, creating a void
in the middle for your ship to nestle in requires energy.
The field wants to explosively radiate any stored
energy from hostile weapons fire. It requires energy
from your ship to prevent this from happening. The
more hostile energy stored, the more energy it takes.
So the more your field fills up, the more energy
is required from your power plant to prevent your
field from exploding or imploding.
When a weapon impacts on the field, a small proportion
of its energy penetrates as a "local burn-through."
This does serious but not instantly fatal damage to
your ship. The result is that having a well trained
damage control crew is a valuable asset in a battle,
instead of being utterly worthless.
Keep in mind the purpose of the Langston field.
It was carefully crafted as designed handwavium to
allow Niven and Pournelle to write cinematic
stories of space battles.
Realistically in such a battle the first ship that
launches a nuclear weapon wins the battle (i.e.,
weapons have a high single-shot kill probability).
This makes for a very dull SF story. The Langston
field transforms this sorry state of affairs into
something dramatic and exciting.
Johnny1a
<nyr...@project.rho.invalid> wrote:
> On 2/25/2010 11:26 AM, Derek Lyons wrote:
>
> > In reality, the Field doesn't move through the spectrum, it moves
> > through the color/temperature chart IIRC. It moves through red,
> > yellow, and white.
>
> It should do that if it obeyed the laws of physics.
Which laws of physics? Remember, the Field is not matter.
> But
> I vaguely remember a passage where it glowed green.
> (this could have been in the omitted first chapter of TMIGE.
> It was later published as a short story called "Reflex"
> in the collection THERE WILL BE WAR vol 1)
At least once it was mentioned that MacArthur's Field was glowing
yellow with a green tinge, IIRC when they were penetrating the
outermost layers of the red giant to reach the jump point.
The descriptions of the Fields in cases just before collapse have them
brilliantly glowing. It seems improbable that they would just happen
to reach 'overload' density at the top of the human visual spectrum.
So if the Field radiates everything in one narrow band, then before it
overloaded it ought to go black again, as it climbs up through the UV
and higher. The text descriptions of Field failure have it glowing,
so we can likely assume that, at least, it radiates in frequencies
below its 'peak' frequency.
(Thus even when a Field was dumping most of its energy as hard X-rays
or the like, it would still be brilliantly glowing to the human eye.)
Note also that at least once in a semi-canonical text it was mentioned
that Fields could radiate far above human visual range. In _A Step
Farther Out_, N*P published their article on the background
assumptions behind MIGE, and included a bit cut from the novel in
which the following scene occured on New Scotland, during the
Secession Wars:
<That was the night a ship from New Ireland fell from sky, its shield
blazing violet with friction. It was low when the shield overloaded
and collapsed, releasing stored energy in one ferocious blast. Gammas
and photons washed across the plains beyond the city, and Potter and
Edwards were carried into the University hospital by worried
students.>
Aside from the odd redundancy of a reference to 'gammas and photons',
this scene does describe a Langston Field glowing violet at high
load. One suspects it was pumping out even more UV than visible light
before it blew up.
Johnny1a
<nyr...@project.rho.invalid> wrote:
> On 2/25/2010 12:27 AM, Johnny1a wrote:
>
> > Regarding the drive plume, in MIGE it's implied that _MacArthur_ and
> > the other Imperial ships are propelled by photon drives. In fact,
> > it's stated specifically at one point that _MacArthur_ gets at least
> > _some_ of its impressive acceleration by photon pressure from the
> > drive. The text descriptions are not perfectly consistant with the
> > idea that _MacArthur_ is a _pure_ photon drive ship, however.
>
> I don't have a reference for you, but I remember reading that
> the drive is a photon drive, and it is a direct outgrowth of
> the Langston field.
I rememeber that reference, or rather two, since I just reread MIGE.
In one Blaine is thinking that MacArthur gets propulsion from a
spreading cone of light using light pressure, i.e. a photon drive.
Later, a Motie Brown muses that the propulsion system of _MacArthur_
seems to make use of the properties of the Langston Field.
However, the rest of the text is not _totally_ consistent on that.
For one thing, there's a scene where _MacArthur_ is coming in to land
at a fueling station maintained by the Empire on an iceball moon of a
gas giant. The scene reads:
"...then she descended directly into the protective Langston Field of
the base on the moonlet, a small black dart descending toward a
tremendous black pillow, _the two joined by a thread of intense
white_. Without the Field to absorb the energy of thrust, the main
drive would hve burned enormous craters into the snowball moon._
'...the two joined by a thread of intense white..."
In a vacuum, the light emission of a pure photon drive ought not to be
a 'thread of intense white', it ought not even be directly visible
unless we were in its path, which would likely be rather unhealthy.
Further, there's another oddity. During the chase sequence of the
Motie probe, Renner tells Blaine he's worked out a course that'll led
them accelerate up to .06c, match course and velocity with the probe,
and decelerate back down to sane velocities, arriving in orbit around
New Ireland with 'dry tanks', as Renner puts it. Now, that could just
be how they happen to say, 'tanks full of helium', but it would be an
odd expression for such a thing. The phrasing 'dry tanks' sounds more
like 'empty' fuel tanks.
But if they're a _pure_ photon drive, the helium produced by fusing
all that hydrogen (and powering a photon drive for a big ship would
require quite a bit of hydrogen if fusion is the power source) is
presumably still aboard. I would think they wouldn't want that, it's
thousands of tons of dead mass that has to be accelerated and
decelerated. Be ejecting it they'd gain quite a bit of thurst fairly
easily _and_ lighten the load. Plus in that event Renner's 'dry
tanks' comment suddenly makes sense.
Mike Ash
<dda1ffa3-7ed8-4ee9...@j27g2000yqn.googlegroups.com>,
Johnny1a <sherm...@hotmail.com> wrote:
> "...then she descended directly into the protective Langston Field of
> the base on the moonlet, a small black dart descending toward a
> tremendous black pillow, _the two joined by a thread of intense
> white_. Without the Field to absorb the energy of thrust, the main
> drive would hve burned enormous craters into the snowball moon._
>
> '...the two joined by a thread of intense white..."
>
> In a vacuum, the light emission of a pure photon drive ought not to be
> a 'thread of intense white', it ought not even be directly visible
> unless we were in its path, which would likely be rather unhealthy.
Space isn't a pure vacuum. There is stuff in it, just not a lot. I'll
bet that at the power output needed to accelerate a space battleship
with hundreds of crew to a significant degree, a photon drive will light
up that little bit of stuff to a degree that could be described as
"intense".
--
Mike Ash
Radio Free Earth
Broadcasting from our climate-controlled studios deep inside the Moon
Erik Max Francis
> I recently reread _The Mote In God's Eye_, and it set me to thinking
> about some of the implications of the magic technology called the
> Langston Field. The phyics of this are never described, but the
> authors do describe what it _does_ consistantly and fairly
> completely.
>
> A quick review: in essence, it is a volume of space that absorbs
> radiation and kinetic energy, storing it and radiating the stored
> energy outward as electromagnetic radiation. Thought the Field isn't
> matter, it has an approximation of temperature in that as the total
> stored energy rises, the frequency of the radiation of that energy
> also rises.
>
> Most of the time the mostly-uncharged Field radiates at wavelengths
> far too long for human eyes to perceive, giving it the appearance of
> an utter-black volume of space (probably usually a sphere or ovoid).
> As the energy density gets higher, the wavelength can reach the
> 'visible' band, and the Field will begin to glow red. Keep pouring
> energy in and the color will rise through the spectrum, until it
> eventually reaches a point where it just can't hold any more energy,
> and collapses, releasing all that stored energy in one brilliant flash
> of light. ('Brilliant' in this case can easily be bright enough to
> vaporize starships or more.)
Note that the canonical universe-building source for information on
_Mote_ is "Building the Mote in God's Eye" by Niven and Pournelle in
Niven's _N-Space_ collection. (I had recently lent it, and, of course
therefore lost it, but I recently bought another paperback edition to
correct that error.) The Langston Field is described on p. 352.
> Regarding the drive plume, in MIGE it's implied that _MacArthur_ and
> the other Imperial ships are propelled by photon drives. In fact,
> it's stated specifically at one point that _MacArthur_ gets at least
> _some_ of its impressive acceleration by photon pressure from the
> drive. The text descriptions are not perfectly consistant with the
> idea that _MacArthur_ is a _pure_ photon drive ship, however.
I don't recall this. Scanning the essay I don't see it mentioned
explicitly, but I may be missing reference to the ship propulsion.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
Longevity has its place. But I'm not concerned about that now.
-- Dr. Martin Luther King, Jr.
Erik Max Francis
I don't believe it's said that the Langston Field radiation was
blackbody, though the "Building" essay describes it as absorbing and
storing "in proportion to the fourth power of the incoming particle
energy," so perhaps it's something like that.
But even if it were a blackbody, your conclusion doesn't follow. Even
non-blackbody objects effectively radiate _something_ at all
wavelengths; the question is at what rate. For something to be visible
to the human eye, it has to radiate enough energy in the visible range
for a human eye to reasonably detect it. There are certainly plenty of
warm objects, even blackbodies, that do not radiate enough in the
visible region to be visible. Without presuming too much, you and I are
both examples.
Luke Campbell
> On Feb 25, 8:46 pm, Nyrath the nearly wise
>
> <nyr...@project.rho.invalid> wrote:
> > On 2/25/2010 11:26 AM, Derek Lyons wrote:
>
> > > In reality, the Field doesn't move through the spectrum, it moves
> > > through the color/temperature chart IIRC. It moves through red,
> > > yellow, and white.
>
> > It should do that if it obeyed the laws of physics.
>
> Which laws of physics? Remember, the Field is not matter.
The assumptions that go into deriving black body radiation make no
reference to matter. Merely that the absorbing/radiating surface is
in equilibrium with its radiation field. At every frequency at which
the surface can absorb or radiate, the surface will be emitting an
intensity proportional to the emissivity times the third power of the
frequency times a Bose-Einstein factor* (the Bose-Einstein factor is
the fraction of available states populated at a given temperature - if
the energy of the state is E and the temperature in energy units is T,
then the Bose-Einstein factor is 1/(exp(E/T) -1). The relevant energy
of the state, here, is h-bar times the frequency of light).
Thermodynamics requires that the emissivity at every wavelength is
equal to the absorptivity at that wavelength. Since the Langston
field is described as completely absorbing at every frequency, either
it radiates as a black body or it violates the laws of
thermodynamics. Since this is fiction, and since the authors are
Niven and Pournell, I suspect the latter. The fact that the fields
are not used to make perpetual motion machines can be attributed to
authorial oversight.
* As an exercise for the curious, it is easy to show by integrating
over all wavelengths that the total intensity is proportional to the
fourth power of temperature.
Luke
Wayne Throop
: But if they're a _pure_ photon drive, the helium produced by fusing
: all that hydrogen (and powering a photon drive for a big ship would
: require quite a bit of hydrogen if fusion is the power source) is
: presumably still aboard. I would think they wouldn't want that, it's
: thousands of tons of dead mass that has to be accelerated and
: decelerated. Be ejecting it they'd gain quite a bit of thurst fairly
: easily _and_ lighten the load. Plus in that event Renner's 'dry
: tanks' comment suddenly makes sense.
The "thread of intense white" makes sense, then, too. If what they
do is eject spent plasma along with the photons, then the get the
increased thrust, but there's something to scatter the drive photons.
So, quite possibly, it's a hybrid drive; mostly photons, but seeded with
helium atoms. Or, nuclei and electrons-n-stuff.
Wayne Throop thr...@sheol.org http://sheol.org/throopw
Luke Campbell
> Since the Langston
> field is described as completely absorbing at every frequency, either
> it radiates as a black body or it violates the laws of
> thermodynamics.
Now that I think of it, one other possibility is that, in certain
circumstances, it might not have a well defined temperature. This is
a rather inefficient method of radiating heat, and is impossible in
some cases (such as when the field has time to come into thermal
equilibrium with its surroundings).
Luke
Erik Max Francis
> Shawn Wilson wrote:
>> On Feb 25, 9:26 am, fairwa...@gmail.com (Derek Lyons) wrote:
>>
>>> And oddly enough it invariably collapses before the re radiated energy
>>> reaches wavelenghts short enough to again be invisible to the human
>>> eye.
>>
>> I assumed that the radiation was black body and it would never become
>> invisible as there would always be some being radiated as visible
>> light.
>
> I don't believe it's said that the Langston Field radiation was
> blackbody, though the "Building" essay describes it as absorbing and
> storing "in proportion to the fourth power of the incoming particle
> energy," so perhaps it's something like that.
I should point out that Niven inserts a caveat that it's not quite this
the fourth power, but he neglects to go into detail (again referring to
the possibly-apocryphal pages of differential equations regarding the
Alderson Drive/Langston Field), but certainly if that's as far as he's
willing to describe its important features, we can take that on face value.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
You'll learn / Life is worth it / Watch the tables turn
-- TLC
Derek Lyons
>However, the rest of the text is not _totally_ consistent on that.
Niven & Pournelle inconsistent? Say it isn't so!
Derek Lyons
>Keep in mind the purpose of the Langston field.
>It was carefully crafted as designed handwavium to
>allow Niven and Pournelle to write cinematic
>stories of space battles.
>
>Realistically in such a battle the first ship that
>launches a nuclear weapon wins the battle (i.e.,
>weapons have a high single-shot kill probability).
Assuming that some form of magic handwavium coats the warhead such
that it is impervious to the wide variety of countermeasures available
today - sure.
Greg Goss
>I should point out that Niven inserts a caveat that it's not quite this
>the fourth power, but he neglects to go into detail (again referring to
>the possibly-apocryphal pages of differential equations regarding the
>Alderson Drive/Langston Field), but certainly if that's as far as he's
>willing to describe its important features, we can take that on face value.
Niven had a supergenius friend at JPL who designed a lot of his
planetary systems and ironed out the details in systems like this. (I
think I read somewhere that either the Alderson Drive or the Langston
Field were named for this friend). So it's likely that Niven doesn't
understand the pages of equations himself.
--
Tomorrow is today already.
Greg Goss, 1989-01-27
Wayne Throop
:: this the fourth power, but he neglects to go into detail (again
:: referring to the possibly-apocryphal pages of differential equations
:: regarding the Alderson Drive/Langston Field)
: Greg Goss <go...@gossg.org>
: Niven had a supergenius friend at JPL who designed a lot of his
: planetary systems and ironed out the details in systems like this.
: (I think I read somewhere that either the Alderson Drive or the
: Langston Field were named for this friend)
The friend's name was Dan Alderson, so I suspect it may have been the drive.
http://en.wikipedia.org/wiki/Dan_Alderson
And it's still possible that the "pages of differential equations"
are apocryphal, even if a syooooper-genius came up with the idea.
James Nicoll
>
>> Regarding the drive plume, in MIGE it's implied that _MacArthur_ and
>> the other Imperial ships are propelled by photon drives. In fact,
>> it's stated specifically at one point that _MacArthur_ gets at least
>> _some_ of its impressive acceleration by photon pressure from the
>> drive. The text descriptions are not perfectly consistant with the
>> idea that _MacArthur_ is a _pure_ photon drive ship, however.
>
>I don't recall this. Scanning the essay I don't see it mentioned
>explicitly, but I may be missing reference to the ship propulsion.
>
and it turns out I stll have the page book-marked:
Page 42 of the 4th printing of the Pocket Books MMPK edition:
"Of course light pressure could be used for propulsion. In fact
MacArthur did exactly that, using hydrogen fusion to generate
photons and emitting them in an enormous spreading cone of light."
This of course means the MacArthur has to generate an enormous amount
of energy to get a picayune amount of thrust.
--
http://www.livejournal.com/users/james_nicoll
http://www.cafepress.com/jdnicoll (For all your "The problem with
defending the English language [...]" T-shirt, cup and tote-bag needs)
Luke Campbell
> Page 42 of the 4th printing of the Pocket Books MMPK edition:
>
> "Of course light pressure could be used for propulsion. In fact
> MacArthur did exactly that, using hydrogen fusion to generate
> photons and emitting them in an enormous spreading cone of light."
>
> This of course means the MacArthur has to generate an enormous amount
> of energy to get a picayune amount of thrust.
It is also quite inefficient. For the same amount of fuel (hydrogen),
they could get far more delta-V by shooting the spent fuel (helium
isotopes? neutrons?) out the back as propellant.
Luke
James Nicoll
short time.
Wayne Throop
: Page 42 of the 4th printing of the Pocket Books MMPK edition:
:
: "Of course light pressure could be used for propulsion. In fact
: MacArthur did exactly that, using hydrogen fusion to generate photons
: and emitting them in an enormous spreading cone of light."
:
: This of course means the MacArthur has to generate an enormous amount
: of energy to get a picayune amount of thrust.
One shorthand way of thinking about it, which doesn't distort things
too horribly, I think, is to treat the fraction of hydrogen's mass
that's converted to energy by fusion as the reaction mass. Which
does mean that there's a lot of dead weight being carried along.
And it only makes sense to throw that away with the photons.
So I expect it gets thrust from both. But the fraction it can emit
as photons gives it the best isp. Um. Or so I expect; I could be
thinking about it sideways here...
In any event, using photons as your reaction mass works best if
you've got total mass conversion, and in which case aiui it's the
best result possible But I'm not sure just how much
you benefit if the conversion isn't total.
Michael Stemper
>On Feb 25, 2:34=A0pm, Shawn Wilson <ikonoql...@gmail.com> wrote:
>> On Feb 25, 9:26=A0am, fairwa...@gmail.com (Derek Lyons) wrote:
>
>> > And oddly enough it invariably collapses before the re radiated energy
>> > reaches wavelenghts short enough to again be invisible to the human
>> > eye.
>>
>> I assumed that the radiation was black body and it would never become
>> invisible as there would always be some being radiated as visible
>> light.
>
>That's actually a good question. The Field isn't matter so
>comparisons to objects made of atoms are suspect,
But, a "black body" isn't matter, either.
--
Michael F. Stemper
#include <Standard_Disclaimer>
91.2% of all statistics are made up by the person quoting them.
Luke Campbell
> One shorthand way of thinking about it, which doesn't distort things
> too horribly, I think, is to treat the fraction of hydrogen's mass
> that's converted to energy by fusion as the reaction mass. Which
> does mean that there's a lot of dead weight being carried along.
> And it only makes sense to throw that away with the photons.
> So I expect it gets thrust from both. But the fraction it can emit
> as photons gives it the best isp. Um. Or so I expect; I could be
> thinking about it sideways here...
To get technical, the Isp (specific impulse) is the amount of impulse
you get from a given mass of expendable (fuel, propellant). The
complete fusion of 1 kg of D-T mix followed by 100% capture of the
energy of fusion and 100% conversion of that energy into a directed
beam of electromagnetic radiation nets you 1.13e6 N s of impulse, for
a specific impulse of 1.13e6 N s/kg = 1.13e6 m/s. If you use your
magic field thingy to reflect the exhaust neutrons and alphas out the
back at full energy, that 1 kg of hydrogen isotopes gives you an
impulse of 1.47e7 N s, for a specific impulse of 1.47e7 m/s - an order
of magnitude better than a photon drive even if you vent the cold
exhaust out of the craft.
Luke
James Nicoll
> Page 42 of the 4th printing of the Pocket Books MMPK edition:
>
> "Of course light pressure could be used for propulsion. In fact
> MacArthur did exactly that, using hydrogen fusion to generate
> photons and emitting them in an enormous spreading cone of light."
>
> This of course means the MacArthur has to generate an enormous amount
> of energy to get a picayune amount of thrust.
Sorry, read "power" for "energy".
Erik Max Francis
Yes, the person in question is Dan Alderson. He helped for both the
Alderson Drive and the Langston Field, but obviously naming them both
after him would have gotten boring.
--
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San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
It is dangerous to be right in matters on which the established
authorities are wrong. -- Voltaire
Erik Max Francis
The reason I say "possibly apocryphal" is because these "pages of
differential equations" got mentioned in several (non-fiction) works.
Alderson himself is obviously deceased, but at various times over the
years I've asked both Niven and Pournelle directly about them, and they
both quickly demurred. Which isn't to say that Alderson didn't write
something down, but more likely they were just briefly shown them and/or
didn't quite understand them enough to bother getting copies for
themselves. The "pages of differential equations" line probably makes
it sound cooler than it was.
--
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San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
Erik Max Francis
That may have been the thinking -- to be honest, I don't recall this
passage from _Mote_ at all, so I didn't remember the propulsion being
photon drives -- but as Luke points out, if you have an energy
production process you want to turn into propulsion and you generate
both energy (photons and/or kinetic energy) and waste (reaction mass),
if you're actually interested in getting somewhere, you're much better
off dumping that energy into the reaction mass for thrust rather than
using the photons themselves. If it's specifically fusion to start
with, then lots of that energy is going to be in the kinetic energy of
the fusion products, so you're already starting what you want for higher
thrust (and the gammas that are generated in the reaction will be hard
to recover and use anyway).
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
Johnny1a
> : Johnny1a <shermanl...@hotmail.com>
My point exactly, the description doesn't match a _pure_ photon drive,
and assuming they use a hybrid drives let them get by with a slightly
more plausible power requirement.
Johnny1a
Actually, in MIGE they were mostly pretty careful of the details.
Johnny1a
> Wayne Throop wrote:
> > : jdnic...@panix.com (James Nicoll)
> San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
> It is dangerous to be right in matters on which the established
>
> - Show quoted text -
The Langston Field would let you capture the gammas and soak up the
kinetic energy of the fusion products, if you want to convert that to
light, but it _still_ makes more sense to use a 'conventional'
approach along wiith the photon approach, both for the reasons of Isp
and because otherwise you have to haul around a load of helium that is
very close to as massive as your initial fuel load.
Further, _MacArthur_ is canonically capable of four gees of
acceleration, and maintaining it for four days+ at a time. That's a
_lot_ to ask of a photon drive without total conversion!
Let's take a look at _MacArthur's_ performance profile when she really
struts her stuff in the New Cal System. The ship arrives at the jump
point, accelerates over to the refueling base on Briget, a twenty-hour
trip at one gee of acceleration and deceleration. I make it a bit
over 200 miles/sec at turnover, and a total trip distance of ~8
million miles, quick and dirty.
(In passing, Rod tells Sally he doesn't have enough fuel aboard to go
'direct' to New Scotland in less than a year, and it's mentioned the
New Scotland is about 930 million miles away when they arrive at the
jump point from their previous star. I assume that means he doesn't
have enough fuel to go at constant acceleration and would have to use
some kind of free-fall trajectory to reach New Scotland.)
The above parenthetical must mean that _MacArthur_ is _very_ low on
fuel, because once Rod fill his tanks at the Naval base on Briget,
with full tanks Rod goes wild. _MacArthur_ proceeds to accelerate at
four gees, climbing up to match velocities with the Crazy Eddie Probe
down near New Cal's photosphere, at .06c. Then she takes on the added
mass of the captured alien ship and decelerates back down to a stable
orbit around New Ireland, a habitable planet in the New Cal system.
Four gee thrusts for days on end, a demonstrated delta-V of over 12%
of the velocity of light, this is one seriously impressive
spacecraft. If it was so low on fuel it would have needed a _year_ to
travel ten AU, she must have been just about dry when she arrived in
the New Cal System.
(Since it's mentioned that _MacArthur_ arrived in New Ireland orbit
with 'dry tanks', that above .12c delta-V is probably close to her
performance limit.)
It's hard to imagine this sort of performance on photons alone.
Johnny1a
possible, albeit tricky and _very_ expensive, way to attack a Fielded
ship would be to make use of antimatter. If one manufactured a few
grams of anti-hydrogen, and packaged it in such a way that you could
shoot it through a Field with enough momentum to make it past the
Field, then there's no reason why the Field would be of any further
protection.
We know (a character in MIGE says so at one point) that it's possible
in principle to ram a Fielded ship with another vessel fast enough to
carry through and penetrate, it's a way (insanely risky they admit) to
board an enemy ship. In theory you could deliver a nuke that way too,
of course, but they're probably on guard against that. An anitmatter
warhead, OTOH, could be just a very small containment vessel (it's
_much_ easier to store AM in vacuum), too small to be a viable nuclear
warhead, the mischief no more than a few grams of antihydrogen. It
wouldn't take much.
This probably wouldn't work on a regular basis, once it got used a few
times they'd be on guard against it. But it might well be
spectacularly effective those first few times.
OR...if the Field stops your antimatter warhead, then the target ship
still has a big headache, since they've now got a few grams of sudden
death held motionless in their Field, maybe sliding around along the
surface of the volume, waiting to strike something made of matter like
a stopped normal missile or a meteoroid...in battle, that sudden surge
on an already-charged Field could be lethal. Yet getting ride of the
bomb without turning off the Field (quickly lethal in battle) would
also be headachy and dangerous.
OR...if you had your supply of antimatter ready, you could try
something like spraying the enemy ships with dust streams or the like,
and hope they don't guess that what you're doing is making sure their
Fields are full of gunk for when you inject your antimatter into the
Field, say at some point in the battle when their Field is already
blazing in the UV...the goal being to overload the Field with a sudden
huge surge of energy.
Greg Goss
>OR...if the Field stops your antimatter warhead, then the target ship
>still has a big headache, since they've now got a few grams of sudden
>death held motionless in their Field, maybe sliding around along the
>surface of the volume, waiting to strike something made of matter like
>a stopped normal missile or a meteoroid...in battle, that sudden surge
>on an already-charged Field could be lethal. Yet getting ride of the
>bomb without turning off the Field (quickly lethal in battle) would
>also be headachy and dangerous.
Would they even know that they'd stopped a bomb? A week later,
they're settling into their berth at DS9, turn off the field, and drop
a supernuke onto their cradle.
alie...@gmail.com
> ...if the Field stops your antimatter warhead, then the target ship
> still has a big headache, since they've now got a few grams of sudden
> death held motionless in their Field, maybe sliding around along the
> surface of the volume, waiting to strike something made of matter like
> a stopped normal missile or a meteoroid...in battle, that sudden surge
> on an already-charged Field could be lethal. Yet getting ride of the
> bomb without turning off the Field (quickly lethal in battle) would
> also be headachy and dangerous.
The ship will be dragging around everything it ran into since it
last turned the Field on? Is this canonical?
If so, that negates my comments about stuff sliding off the sides of
the Field of a ship in motion and lighting up interplanetary gases,
but it just doesn't sound *reasonable*, if for no other reason than
Greg Goss' mention of the landing cradle being showered with all sorts
of possibly extremely dangerous debris.
Mark L. Fergerson
Nyrath the nearly wise
> Assuming that some form of magic handwavium coats the warhead such
> that it is impervious to the wide variety of countermeasures available
> today - sure.
And once again the "Purple-Green" debate rises from the grave.
http://www.projectrho.com/rocket/rocket3y.html#pointdefense
(scroll down)
Nyrath the nearly wise
fact a Langston field under hostile weapons fire
starts glowing red and gradually works it way up
the spectrum is a tip-of-the-hat to the ray-screens
found in E.E."Doc" Smith's Lensman and Skylark
series.
Smith's ray screens start flickering in the
ultraviolet just before they collapse.
Greg Goss
>Four gee thrusts for days on end, a demonstrated delta-V of over 12%
>of the velocity of light, this is one seriously impressive
>spacecraft.
Yet the limitations of the new empire equipment compared to the
wonders of the first empire are mentioned many times in the story,
especially by the crew of that ship. They may have been seriously
impressive, but they didn't think of themselves as such because of a
previous golden age.
Larry Caldwell
says...
It doesn't take much effort to generate "pages of differential
equations." I remember one problem that defeated me. I hoofed off to a
math help session, where a grad student managed to state it as a set of
equations that covered 40 feet of blackboard. Then he waved at it and
said, "reducing this to a solution is just an exercise in mechanics."
No, I didn't complete the assignment. Neither did anyone else in the
class.
Johnny1a
Hmmm...good point.
But I think they couldn't help but know pretty soon, if there was
exposed antimatter trapped in their Field, because the Field also
traps interplanetary dust and gas, so there would be a reaction.
That's why I think the antimatter technique would be most useful _in_
battle. If you did it right, you might even be able to use it to
force an otherwise battle-ready ship to withdraw or surrender.
Johnny1a
Hmm...the Field stops things are are moving slowly enough that it can
absorb all their kinetic energy, at least radial to the ship. Whether
they move around _whithin_ the Field...I don't recall that ever being
addressed.
But yeah, I hadn't thought about it like that, but the Field _does_
trap things, so over time it would get gunked up with dust, gas,
meteroids, battle debris, etc. I hadn't thought about that, but
probably every so often an Imperial ship turns their Field off to let
the junk go. They might use their lasers at low power to give the
small stuff a 'push' radially away from the ship when they do.
Derek Lyons
I'm not debating anything - I'm stating a bald fact based on real
world engineering. A single nuclear weapon (as specified in the
portion you snipped) isn't a battle winner absent something that
negates the countermeasures of the defender or the defender being
abysmally stupid and not equipping countermeasures in the first place.
Yes, with multiple weapons and multiple ships, and varying
technologies, the outcome changes. But that's not the situation
specified.
Johnny1a
>
> (In passing, Rod tells Sally he doesn't have enough fuel aboard to go
> 'direct' to New Scotland in less than a year, and it's mentioned the
> New Scotland is about 930 million miles away when they arrive at the
> jump point from their previous star. I assume that means he doesn't
> have enough fuel to go at constant acceleration and would have to use
> some kind of free-fall trajectory to reach New Scotland.)
I think this above must be based on a typo or misprint. I started
thinking about it after I signed off and that number doesn't fit the
rest of the scenario. The New Cal System is a class F star system, so
it ought to be _bigger_ than Sol in terms of interplanetary distances,
and the jump point is in the outer system. So 900 million miles is a
pretty short trip to requrie a full _year_ for a shp that demonstrably
still has enough propellent for a delta-V of over 400 miles/sec.
Also, the later chase after the alien probe, four gees for four days,
gives a distance of about 900 _billion_ miles, so my guess is that the
reference to the shorter distance was just a slip, since the
discrepency was almost exactly a factor of ten.
David Given
[...]
> Hmm...the Field stops things are are moving slowly enough that it can
> absorb all their kinetic energy, at least radial to the ship. Whether
> they move around _whithin_ the Field...I don't recall that ever being
> addressed.
>
> But yeah, I hadn't thought about it like that, but the Field _does_
> trap things, so over time it would get gunked up with dust, gas,
> meteroids, battle debris, etc.
I'm actually just rereading it --- it's surprisingly well done; the
style is definite cut above either Niven or Pournelle's solo work ---
and I note the passage where they capture the probe: they ram the probe
at quite high velocity, and rely on the Field to absorb enough kinetic
energy so that they don't wreck either ship.
This tells us that the Field won't absorb *all* kinetic energy. It is
explicitly stated that the efficiency scales according to the cube power
of the *mumble* (mass? velocity? Sorry, my copy isn't actually to hand).
Either way, slow-moving dust would be relatively unaffected. So while
dust would tend to collect in the vicinity of a Field of a coasting
ship, it would still drift through relatively easily. Of course, as soon
as the ship boosts, it'll get deflected and fall behind.
So I'm not sure antimatter dust would be useful in an actual combat
situation. More useful, I reckon, would be actual antimatter missiles.
Mmm, antimatter --- the original fail-dangerous weapon.
--
┌─── ｄｇ＠ｃｏｗｌａｒｋ．ｃｏｍ ───── http://www.cowlark.com ─────
│
│ 𝕻𝖍'𝖓𝖌𝖑𝖚𝖎 𝖒𝖌𝖑𝖜'𝖓𝖆𝖋𝖍 𝕮𝖙𝖍𝖚𝖑𝖍𝖚
│ 𝕽'𝖑𝖞𝖊𝖍 𝖜𝖌𝖆𝖍'𝖓𝖆𝖌𝖑 𝖋𝖍𝖙𝖆𝖌𝖓.
Erik Max Francis
Well, true, and that's why I got a copy of Mathematica. I want to set
up the problem and get the answer, not trundle through that shit :-).
Especially since I've been poking around with tensor calculus, there are
a ridiculous amount of partial derivatives and summing (and summing and
summing), so I'll let something else do the heavy lifting.
The bigger issue I'm referring to here, with respect to the Alderson
Papers :-), is not so much whether or not something was written down
somewhere as whether or not Niven and/or Pournelle really had access to
it, studied carefully, and/or understood in detail, rather than just
accepting Alderson's conclusions about the ramifications (which is,
let's be honest, all they were interested in, after all). Like I said,
when I asked Niven and Pournelle themselves (but separately), neither of
them had the pages nor could go into much detail. So the Papers, if
they indeed concretely exist somewhere, are probably for all intents and
purposes inaccessible.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
Moving to the rhythm / Can you feel me breathe / What else do we need
-- Oleta Adams
Steve Hix
<0fc42c4c-6332-413c...@o30g2000yqb.googlegroups.com>,
Johnny1a <sherm...@hotmail.com> wrote:
Shouldn't that be a factor of 1000? 900 x 10^6 vs 900 x 10^9, right?
Erik Max Francis
> On 28/02/10 19:07, Johnny1a wrote:
> [...]
>> Hmm...the Field stops things are are moving slowly enough that it can
>> absorb all their kinetic energy, at least radial to the ship. Whether
>> they move around _whithin_ the Field...I don't recall that ever being
>> addressed.
>>
>> But yeah, I hadn't thought about it like that, but the Field _does_
>> trap things, so over time it would get gunked up with dust, gas,
>> meteroids, battle debris, etc.
>
> I'm actually just rereading it --- it's surprisingly well done; the
> style is definite cut above either Niven or Pournelle's solo work ---
Not to mention it's also quite unique.
> and I note the passage where they capture the probe: they ram the probe
> at quite high velocity, and rely on the Field to absorb enough kinetic
> energy so that they don't wreck either ship.
"Building" says the fourth power of the energy.
> This tells us that the Field won't absorb *all* kinetic energy. It is
> explicitly stated that the efficiency scales according to the cube power
> of the *mumble* (mass? velocity? Sorry, my copy isn't actually to hand).
"Building," which I just checked out the other day, says "absorbs and
stores energy in proportion to the fourth power of the incoming particle
energy."
Johnny1a
> In article
> <0fc42c4c-6332-413c-b4c9-901e7be87...@o30g2000yqb.googlegroups.com>,
>
> - Show quoted text -
No, because the 'right' distance (to fit the rest of the sequence) is
9 billion miles, rather than 900 million, a factor of ten. For
whatever reason, in my copy of MIGE, Rod refers to New Scotland being
'one and a half billion kilometers away', i.e. 900 million miles. But
the rest of the sequence and scenario all fit a figure closer to 9
billion miles.
Greg Goss
>On Feb 27, 6:30�am, "n...@bid.nes" <alien8...@gmail.com> wrote:
>> � If so, that negates my comments about stuff sliding off the sides of
>> the Field of a ship in motion and lighting up interplanetary gases,
>> but it just doesn't sound *reasonable*, if for no other reason than
>> Greg Goss' mention of the landing cradle being showered with all sorts
>> of possibly extremely dangerous debris.
>>
>> � Mark L. Fergerson
>
>Hmm...the Field stops things are are moving slowly enough that it can
>absorb all their kinetic energy, at least radial to the ship. Whether
>they move around _whithin_ the Field...I don't recall that ever being
>addressed.
>
>But yeah, I hadn't thought about it like that, but the Field _does_
>trap things, so over time it would get gunked up with dust, gas,
>meteroids, battle debris, etc. I hadn't thought about that, but
>probably every so often an Imperial ship turns their Field off to let
>the junk go. They might use their lasers at low power to give the
>small stuff a 'push' radially away from the ship when they do.
As I was writing my comment, I realized that pulsing the field off
before approaching the landing cradle would probably be SOP. At least
after the first time this happened.
alie...@gmail.com
> Johnny1a <shermanl...@hotmail.com> wrote:
> >On Feb 27, 6:30 am, "n...@bid.nes" <alien8...@gmail.com> wrote:
> >> If so, that negates my comments about stuff sliding off the sides of
> >> the Field of a ship in motion and lighting up interplanetary gases,
> >> but it just doesn't sound *reasonable*, if for no other reason than
> >> Greg Goss' mention of the landing cradle being showered with all sorts
> >> of possibly extremely dangerous debris.
>
> >> Mark L. Fergerson
>
> >Hmm...the Field stops things are are moving slowly enough that it can
> >absorb all their kinetic energy, at least radial to the ship. Whether
> >they move around _whithin_ the Field...I don't recall that ever being
> >addressed.
OK, how about the Field just absorbs *incoming* KE but ignores any
outgoing? Is there any mention of interaction between the Field and
outgoing missiles? Do holes have to be provided to shoot through?
How about aiming; do sensors see through it? Does the gunk obscure
them?
(Been a while since I read them, can you tell?)
> >But yeah, I hadn't thought about it like that, but the Field _does_
> >trap things, so over time it would get gunked up with dust, gas,
> >meteroids, battle debris, etc. I hadn't thought about that, but
> >probably every so often an Imperial ship turns their Field off to let
> >the junk go. They might use their lasers at low power to give the
> >small stuff a 'push' radially away from the ship when they do.
>
> As I was writing my comment, I realized that pulsing the field off
> before approaching the landing cradle would probably be SOP. At least
> after the first time this happened.
Even then a responsible Captain would make sure the released gunk
wouldn't hit anything important. That could get awkward, especially in
wartime. Hell, it could even be used as a weapon; do some passes
through an asteroid belt or Saturn-ian ring system to load up your
field and do a reverse-Crazy Ivan. Run straight toward an enemy and
briefly drop your field then jink hard to port; the gunk becomes a
kinetic-kill-cloud weapon against a ship with a weaker/weakened Field.
That's why I asked if it's canonical; if it isn't mentioned in the
novel it certainly should have made it into the "fixup" _Building the
Mote in God's Eye_ since it's so bleeding *obvious* (once it's pointed
out).
Mark L. Fergerson
Johnny1a
> On Feb 28, 9:45 pm, Greg Goss <go...@gossg.org> wrote:
>
> > Johnny1a <shermanl...@hotmail.com> wrote:
> > >On Feb 27, 6:30 am, "n...@bid.nes" <alien8...@gmail.com> wrote:
> > >> If so, that negates my comments about stuff sliding off the sides of
> > >> the Field of a ship in motion and lighting up interplanetary gases,
> > >> but it just doesn't sound *reasonable*, if for no other reason than
> > >> Greg Goss' mention of the landing cradle being showered with all sorts
> > >> of possibly extremely dangerous debris.
>
> > >> Mark L. Fergerson
>
> > >Hmm...the Field stops things are are moving slowly enough that it can
> > >absorb all their kinetic energy, at least radial to the ship. Whether
> > >they move around _whithin_ the Field...I don't recall that ever being
> > >addressed.
>
> OK, how about the Field just absorbs *incoming* KE but ignores any
> outgoing? Is there any mention of interaction between the Field and
> outgoing missiles? Do holes have to be provided to shoot through?
Yes. At one point a character 'falls out' of a rotating MacArthur's
docking bay, and his momentum carries him into the Field...which stops
him. This both saves his life (since it keeps him from getting too
far away from the ship to rescue in time) and nearly kills him because
the Field drains the heat from his body.
And yes, they have to open holes in the Field to shoot through.
>
> How about aiming; do sensors see through it?
At least some sensors have to be on extended (and expendable) booms
that are poked through the Field, including radio antennae. In fact,
one of the ways a ship can be lose a battle is that it's Field is so
charged up that it can't take any more energy and they can't open a
hole to extend a sensor without the enemy destroying them. In that
circumstance, the ritual of surrender allows the cornered ship to
extend a plain, no-frills radio antenna to transmit a request to
accept surrender.
One implication of the Field is that a ship can be on the very edge of
destruction, its Field so supercharged that basically all the enemy
has to do is shine a flashlight at it and it'll overload and collapse,
destroying everything within it. At that point the enemy is helpless
and on the edge of total destruction, surrender is called for.
And yet...if the winners accept the surrender, they have a problem,
because the losing ship, on the very edge of vaporization, may very
well even so be totally undamaged within its Field. The crew may all
be alive and hale, everything in perfect working order, the hull
intact and plenty of fuel. So if the winners accept surrender and let
the defeated ship live, once its Field cools down, it's completely
ready to fight again, just a few minutes after being on the brink of
destruction.
So there's an involved ritual involved in surrendering a starship,
usually requiring a boarding by a man with a deadman switch attached
to a bomb.
Erik Max Francis
> One implication of the Field is that a ship can be on the very edge of
> destruction, its Field so supercharged that basically all the enemy
> has to do is shine a flashlight at it and it'll overload and collapse,
> destroying everything within it. At that point the enemy is helpless
> and on the edge of total destruction, surrender is called for.
>
> And yet...if the winners accept the surrender, they have a problem,
> because the losing ship, on the very edge of vaporization, may very
> well even so be totally undamaged within its Field. The crew may all
> be alive and hale, everything in perfect working order, the hull
> intact and plenty of fuel. So if the winners accept surrender and let
> the defeated ship live, once its Field cools down, it's completely
> ready to fight again, just a few minutes after being on the brink of
> destruction.
It's also stipulated that under heavy combat conditions, bleed-throughs
are common. So it's quite unlikely that a ship on the verge of having
its Langston Field overloaded and totally destroyed will be completely
unharmed.
> So there's an involved ritual involved in surrendering a starship,
> usually requiring a boarding by a man with a deadman switch attached
> to a bomb.
You state this as a fact. Was this procedure demonstrated in the books?
I don't remember it.
At any rate, even if what you're suggesting is canonical, there's an
easy solution to the problem: If you have a situation where the
potential surrenderer can trick you and fight on, then you don't accept
the surrender. Which means if someone intends to surrender, they must
surrender well before it gets to that point.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
It's better to be quotable than to be honest.
-- Tom Stoppard
Steve Hix
Erik Max Francis <m...@alcyone.com> wrote:
> Johnny1a wrote:
>
> > So there's an involved ritual involved in surrendering a starship,
> > usually requiring a boarding by a man with a deadman switch attached
> > to a bomb.
>
> You state this as a fact. Was this procedure demonstrated in the books?
> I don't remember it.
Yes, in the prelude to Mote.
Ensign Horst Staley gets sent over with a bomb and deadman switch to
take the surrender of an enemy cruiser.
Erik Max Francis
Cool. It's been a while since I've read it, obviously.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
Trying to mend our hearts in vain
-- Sandra St. Victor
Johnny1a
>
> It's also stipulated that under heavy combat conditions, bleed-throughs
> are common. So it's quite unlikely that a ship on the verge of having
> its Langston Field overloaded and totally destroyed will be completely
> unharmed.
True, but it's not utterly improbable, and even a certain amount of
damage doesn't mean the ship can't still be an effective combat unit
once its Field cools down.
>
> > So there's an involved ritual involved in surrendering a starship,
> > usually requiring a boarding by a man with a deadman switch attached
> > to a bomb.
>
> You state this as a fact. Was this procedure demonstrated in the books?
> I don't remember it.
>
> At any rate, even if what you're suggesting is canonical, there's an
> easy solution to the problem: If you have a situation where the
> potential surrenderer can trick you and fight on, then you don't accept
> the surrender.
They don't always accept it. If nobody on the winner ship volunteers
to be the 'deadman' officer, it's considered acceptable to destroy the
ship that offered to surrender.
Johnny1a
> In article <weWdnQc-OYzYzhHWnZ2dnUVZ_v8AA...@giganews.com>,
I could imagine other ways. For ex, you could order the surrendering
ship to open a hole in their Field, and use that to attach a bomb-
drone to their hull, linking to it magnetically or something.
But...they could conceivably jam the signal later, or maybe find a way
to sabotage it. So there's probably a reason why they use the way
they do.
Wayne Throop
: I could imagine other ways. For ex, you could order the surrendering
: ship to open a hole in their Field, and use that to attach a bomb-
: drone to their hull, linking to it magnetically or something.
: But...they could conceivably jam the signal later
Duh, you have the signal *stop* the drone from exploding.
You use cryptography so they can't spoof the signal. If the drone
doesn't receive a two-way heartbeat signal back to its ship, kablooie.
Simple shared secret cryptography, a big one-time-pad, which also puts
a finite lifetime on this parole. Easy peasy.
: or maybe find a way to sabotage it.
Shrug. Maybe they find a way to sabotage the dead man mechanism
carried by a human. Nothing's foolproof, given clever enough fools.
Wayne Throop thr...@sheol.org http://sheol.org/throopw
Greg Goss
>Steve Hix wrote:
>> In article <weWdnQc-OYzYzhHW...@giganews.com>,
>> Erik Max Francis <m...@alcyone.com> wrote:
>>
>>> Johnny1a wrote:
>>>
>>>> So there's an involved ritual involved in surrendering a starship,
>>>> usually requiring a boarding by a man with a deadman switch attached
>>>> to a bomb.
>>> You state this as a fact. Was this procedure demonstrated in the books?
>>> I don't remember it.
>>
>> Yes, in the prelude to Mote.
>>
>> Ensign Horst Staley gets sent over with a bomb and deadman switch to
>> take the surrender of an enemy cruiser.
>
>Cool. It's been a while since I've read it, obviously.
The remaining prelude, or the "lost prelude"? I have both, in boxes
somewhere and I don't remember that scene, either.
("The Lost Prelude" was a fairly long item in the same Galaxy as
Pournelle's "Making of" item. I think Making Of was in ASFO, but it
might have been a separate item.)
Erik Max Francis
Am I correct in assuming this is "Motelight," included with "Building
the Mote in God's Eye" in Niven's _N-Space_ (which I remember even less
than the novel)? Niven and Pournelle are both referred to in the third
person in it, so it would make sense if it were the same thing that was
published elsewhere by Pournelle.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
Maybe soul mates exist / After all
-- Des'ree
Johnny1a
> : Johnny1a <shermanl...@hotmail.com>
True, but I trust human judgement over automation in that sort of
situation, unless you've got a level of AI technology that the
Imperials don't.
Wayne Throop
: True, but I trust human judgement over automation in that sort of
: situation, unless you've got a level of AI technology that the
: Imperials don't.
The Imperials don't have telepresense? Remember, the drone is
constantly exchanging signals with the mothership. So, inlcude
video feed, or whatnot.
Sure sure, robots or telefactor widgets can't do what a human explorer
can, but since in this case the human explorer is just keeping his thumb
on the deadman switch, and watching the goings-on, it doesn't seem beyond
the capability of a telefactor widget.
Steve Hix
Erik Max Francis <m...@alcyone.com> wrote:
> Steve Hix wrote:
> > In article <weWdnQc-OYzYzhHW...@giganews.com>,
> > Erik Max Francis <m...@alcyone.com> wrote:
> >
> >> Johnny1a wrote:
> >>
> >>> So there's an involved ritual involved in surrendering a starship,
> >>> usually requiring a boarding by a man with a deadman switch attached
> >>> to a bomb.
> >> You state this as a fact. Was this procedure demonstrated in the books?
> >> I don't remember it.
> >
> > Yes, in the prelude to Mote.
> >
> > Ensign Horst Staley gets sent over with a bomb and deadman switch to
> > take the surrender of an enemy cruiser.
>
> Cool. It's been a while since I've read it, obviously.
Me neither, not for about 25 years.
This thread prompted me to get Mote and Gripping Hand ebook files from
Baen a couple days ago. Good unwinding reading.
Greg Goss
>Greg Goss wrote:
>> The remaining prelude, or the "lost prelude"? I have both, in boxes
>> somewhere and I don't remember that scene, either.
>>
>> ("The Lost Prelude" was a fairly long item in the same Galaxy as
>> Pournelle's "Making of" item. I think Making Of was in ASFO, but it
>> might have been a separate item.)
>
>Am I correct in assuming this is "Motelight," included with "Building
>the Mote in God's Eye" in Niven's _N-Space_ (which I remember even less
>than the novel)? Niven and Pournelle are both referred to in the third
>person in it, so it would make sense if it were the same thing that was
>published elsewhere by Pournelle.
I don't remember the version in N-Space. The "making of" article I
remembered had a lot of "Niven and I", rather than third person.
"Motelight" sounds like a good title for the lost prelude -- the laser
launch cannon from the Mote pushing the probe out of their system
outshone the eitnre Murcheson's Eye. The eye was green instead of
red.
David Given
[...]
> The Imperials don't have telepresense? Remember, the drone is
> constantly exchanging signals with the mothership. So, inlcude
> video feed, or whatnot.
Imperial technology is distinctly manual. There are advanced robots ---
Imperial Autonetics specialises in automated robotic factories --- but
most stuff on board ship appears to be done by hand.
I suspect this is largely because _Mote_ was written in 1974, but
in-canon this can be explained by considering that most warships are
*warships*, and tend to break a lot, and doing stuff by hand is a good
way to get flexibility. Plus, it's stated explicitly that computers
suffer badly from jump sickness, so if you want your ship to fight
immediately upon coming out of a jump, it's got to be run manually.
Erik Max Francis
> On 02/03/10 05:34, Wayne Throop wrote:
> [...]
>> The Imperials don't have telepresense? Remember, the drone is
>> constantly exchanging signals with the mothership. So, inlcude
>> video feed, or whatnot.
>
> Imperial technology is distinctly manual. There are advanced robots ---
> Imperial Autonetics specialises in automated robotic factories --- but
> most stuff on board ship appears to be done by hand.
>
> I suspect this is largely because _Mote_ was written in 1974, but
> in-canon this can be explained by considering that most warships are
> *warships*, and tend to break a lot, and doing stuff by hand is a good
> way to get flexibility. Plus, it's stated explicitly that computers
> suffer badly from jump sickness, so if you want your ship to fight
> immediately upon coming out of a jump, it's got to be run manually.
Wait, but don't humans suffer from it too? Or is it that the humans
recover faster?
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
A people birthed in sorrow will die in sorrow.
-- (a Vasudan proverb)
Wayne Throop
: David Given <d...@cowlark.com>
: Imperial technology is distinctly manual.
Um. Most of the upper staff is carrying around networked PDAs.
If they can do that but not manage a few remote drones... well...
it gets pretty implausible. On the other hand, they seem to need
a multi-gigawatt maser to communicate across planetary distances...
I can imagine how they could arrive at their surrender protocol.
Once upon a time, someobdy tried to surrender, and they hadn't throught
about how to do it, so they send an actual warm body with a radio and
bomb to report on what's up, etc, etc, etc. Once they had that solution,
jsomebody put it in The Manual and it gets enshrined.
But upthread, we were (or at least, I was, insert Brust/Vlad comment here)
talking about what they oughter done, not what they actually tended to
do, nor yet whether what they oughter done was a natural incremental
evolution of prevailing circumstance.
Derek Lyons
>On 02/03/10 05:34, Wayne Throop wrote:
>[...]
>> The Imperials don't have telepresense? Remember, the drone is
>> constantly exchanging signals with the mothership. So, inlcude
>> video feed, or whatnot.
>
>Imperial technology is distinctly manual. There are advanced robots ---
>Imperial Autonetics specialises in automated robotic factories --- but
>most stuff on board ship appears to be done by hand.
>
>I suspect this is largely because _Mote_ was written in 1974, but
>in-canon this can be explained by considering that most warships are
>*warships*, and tend to break a lot, and doing stuff by hand is a good
>way to get flexibility.
It's interesting that in real life the armchair admirals and bean
counters are trying to push us in the opposite direction - higher
automation and smaller crews, often vastly smaller.
Wayne Throop
:: in-canon this can be explained by considering that most warships are
:: *warships*, and tend to break a lot, and doing stuff by hand is a
:: good way to get flexibility. Plus, it's stated explicitly that
:: computers suffer badly from jump sickness, so if you want your ship
:: to fight immediately upon coming out of a jump, it's got to be run
:: manually.
: Erik Max Francis <m...@alcyone.com>
: Wait, but don't humans suffer from it too? Or is it that the humans
: recover faster?
Yes. But aiui, more complex things suffer more; moties suffered worse
than humans. So my memory is that machines recovered *faster*, and the
moties were at a disadvantage because controlled everything with Browns.
"What can Brown do for you today?" --- UPS slogan
Nyrath the nearly wise
> Greg Goss wrote:
> Am I correct in assuming this is "Motelight," included with "Building
> the Mote in God's Eye" in Niven's _N-Space_ (which I remember even less
> than the novel)?
No. It is called "Reflex", and can be found in
the collection THERE WILL BE WAR vol 1.
It describes in dramatic detail the battle between the MacArthur
and the rebel ship Defiant. This is the battle that causes all
the damage the MacArthur is suffering from at the start of the
novel. It also explains why Ensign Stanley is in such a
depressed mood. Stanley was the one with the bomb attached to
a dead man's switch.
It does explain quite a bit about the mechanics and implications
of starship combat in the Mote universe.
You can find excerpts from the story here:
http://www.projectrho.com/rocket/rocket3y.html#forcefield
Nyrath the nearly wise
> On 02/03/10 05:34, Wayne Throop wrote:
> [...]
>> The Imperials don't have telepresense? Remember, the drone is
>> constantly exchanging signals with the mothership. So, inlcude
>> video feed, or whatnot.
>
> Imperial technology is distinctly manual. There are advanced robots ---
> Imperial Autonetics specialises in automated robotic factories --- but
> most stuff on board ship appears to be done by hand.
>
> I suspect this is largely because _Mote_ was written in 1974, but
> in-canon this can be explained by considering that most warships are
> *warships*, and tend to break a lot, and doing stuff by hand is a good
> way to get flexibility. Plus, it's stated explicitly that computers
> suffer badly from jump sickness, so if you want your ship to fight
> immediately upon coming out of a jump, it's got to be run manually.
>
From "Reflex" by Larry Niven and Jerry Pournelle (the deleted first chapter
of The Mote in God's Eye, collected in There Will Be War I)
In principle Defiant was a better ship than she'd been when she left New
Chicago. The engineers had automated all routine spacekeeping tasks, and no
United Republic spacer needed to do a job that a robot could perform. Like all
of New Chicago's ships, and like few of the Imperial Navy's, Defiant was as
automated as a merchantman.
Colvin wondered. Merchantmen do not fight battles. A merchant captain need not
worry about random holes punched through his hull. He can ignore the risk that
any given piece of equipment will be smashed at any instant. He will never
have only minutes to keep his ship fighting or see her destroyed in an instant
of blinding heat.
No robot could cope with the complexity of decisions damage control could
generate, and if there were such a robot it might easily be the first item
destroyed in battle. Colvin had been a merchant captain and had seen no reason
to object to the Republic's naval policies, but now that he had experience in
warship command, he understood why the Imperials automated as little as
possible and kept the crew in working routine tasks: washing down corridors
and changing air filters, scrubbing pots and inspecting the hull. Imperial
crews might grumble about the work, but they were never idle. After six
months, Defiant was a better ship, but...
Johnny1a
> : situation, unless you've got a level of AI technology that the
> : Imperials don't.
>
> The Imperials don't have telepresense? Remember, the drone is
> constantly exchanging signals with the mothership. So, inlcude
> video feed, or whatnot.
>
> Sure sure, robots or telefactor widgets can't do what a human explorer
> can, but since in this case the human explorer is just keeping his thumb
> on the deadman switch, and watching the goings-on, it doesn't seem beyond
> the capability of a telefactor widget.
Sure, they could, but that still leaves you at the mercy of a remote
link.
Johnny1a
Humans as a rule recover faster than either computers or Moties, and
the Moties suffer more. Plus there's a lot of variation between
individual humans, and apparently experience doesn't matter. The
shock effect hits Rod far worse than it does Sally, and she's a
civilian with limited space experience.
It also mentions that it gets worse with age, but the humans don't
really understand what causes it either in living things or machines.
Johnny1a
Who do _you_ think is closer to being right?
Steve Hix
Erik Max Francis <m...@alcyone.com> wrote:
> David Given wrote:
> > On 02/03/10 05:34, Wayne Throop wrote:
> > [...]
> >> The Imperials don't have telepresense? Remember, the drone is
> >> constantly exchanging signals with the mothership. So, inlcude
> >> video feed, or whatnot.
> >
> > Imperial technology is distinctly manual. There are advanced robots ---
> > Imperial Autonetics specialises in automated robotic factories --- but
> > most stuff on board ship appears to be done by hand.
> >
> > I suspect this is largely because _Mote_ was written in 1974, but
> > in-canon this can be explained by considering that most warships are
> > *warships*, and tend to break a lot, and doing stuff by hand is a good
> > way to get flexibility. Plus, it's stated explicitly that computers
> > suffer badly from jump sickness, so if you want your ship to fight
> > immediately upon coming out of a jump, it's got to be run manually.
>
> Wait, but don't humans suffer from it too? Or is it that the humans
> recover faster?
Yep, and younger crew tended to recover faster than older.
A lot of their tech level and usage, by implication, follows from having
lost a good deal, and that likely unevenly, following the collapse of
the first empire in the Secession Wars.
They *knew* that better materials, for example, were possible, they had
examples to hand. They just couldn't duplicate the old technology (yet).
Steve Hix
It's also in the current incarnation of Mote published by Baen.
Erik Max Francis
> On 3/1/2010 11:20 PM, Erik Max Francis wrote:
>> Am I correct in assuming this is "Motelight," included with "Building
>> the Mote in God's Eye" in Niven's _N-Space_ (which I remember even less
>> than the novel)?
>
> No. It is called "Reflex", and can be found in
> the collection THERE WILL BE WAR vol 1.
>
> It describes in dramatic detail the battle between the MacArthur
> and the rebel ship Defiant. This is the battle that causes all
> the damage the MacArthur is suffering from at the start of the
> novel. It also explains why Ensign Stanley is in such a
> depressed mood. Stanley was the one with the bomb attached to
> a dead man's switch.
Well, there ya go. That would certainly explain why I didn't remember
anything like that :-).
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
I wonder if heaven got a ghetto
-- Tupac Shakur
Wayne Throop
: Sure, they could, but that still leaves you at the mercy of a remote
: link.
And... having a person actually strapped to the bomb helps... how, exactly?
The only case I can see where it's a benefit at all, is if you somehow
lose the link to innocent causes. Which isn't a risk for the ship
offering to accept surrender.
Erik Max Francis
So? As Wayne proposed, if the link is severed or lost, the bomb goes
off. It's in the surrenderer's best interest to make sure that the link
remains active. Worst case, someone you might have been trying to
surrender ends up getting slagged, but you haven't lost any of your crew.
--
Erik Max Francis && m...@alcyone.com && http://www.alcyone.com/max/
San Jose, CA, USA && 37 18 N 121 57 W && AIM/Y!M/Skype erikmaxfrancis
Why do we give ourselves away / 'Till only emptiness remains
-- Chante Moore
Michael Stemper
read Mote. Watching this conversation has moved it onto my "time to
reread" heap.
--
Michael F. Stemper
#include <Standard_Disclaimer>
91.2% of all statistics are made up by the person quoting them.
Shawn Wilson
> > You can find excerpts from the story here:
> >http://www.projectrho.com/rocket/rocket3y.html#forcefield
>
> It's also in the current incarnation of Mote published by Baen.- Hide quoted text -
Ah! Most excellent! I was worried about never seeing it again, and
it actually occurred to me to recommend to /someone/ that it be
included in tMiGE.
David Given
[...]
> Um. Most of the upper staff is carrying around networked PDAs.
> If they can do that but not manage a few remote drones... well...
> it gets pretty implausible. On the other hand, they seem to need
> a multi-gigawatt maser to communicate across planetary distances...
I found a specific reference, towards the end of the book:
"...we employ humans as a backup to automatic systems, although we will
often omit the automation in order to give constant employment to humans
needed for emergencies but otherwise superfluous."
This fits warships to a T, because they're specifically designed to
operate in emergencies.
I agree with you about the drones, though. There'd have been useful in
several places in the novel, and could well have saved the midshipmen;
if the _Lenin_ had sent one after them after the had bailed out of the
_MacArthur_ in the Watchmaker escape capsules, they'd have retained
contact and the Moties couldn't have pulled their deception. Plus, the
midshipmen could have jumped out once they realised they had no control
over the capsules and the drone could have retrieved them.
Tim Little
> I hadn't thought about that, but probably every so often an Imperial
> ship turns their Field off to let the junk go. They might use their
> lasers at low power to give the small stuff a 'push' radially away
> from the ship when they do.
I expect most of the tiny stuff leaves again. Even a "cold" field
will have some thermal energy and hence diffusion within it and out
from it. Also as the ship accelerates, the stuff in the field should
drift downwards to some degree (where "down" is defined to be opposite
the direction of the ship's acceleration). In either case some of it
will come out of the field on the inside, some will go outside.
- Tim
Thomas Koenig
> It doesn't take much effort to generate "pages of differential
> equations."
The Navier-Stokes equations can be written explicitly in four lines,
or in vector notation in two lines, and solving these is definitely
NOT trivial.