Setting the Clock: the Planet way, the navy way, and the w..

On Thu, 01 May 2008 20:17:46 -0800, Offbreed
<offbreed_106 DeleteThis @hotmail.com> wrote:

>Loren Pechtel wrote:
>> On Tue, 29 Apr 2008 19:11:42 -0800, Offbreed
>> <offbreed_106 DeleteThis @hotmail.com> wrote:
>>
>>> Yes, I'm assuming that. But, how would acceleration _increase_ the risk
>>> of a relativistic collision if there is no inverse? What is the risk
>>> increased from?
>>
>> It's the relative velocity between you and the object.
>>
>> If you're going .99c you're in as much danger from the local medium as
>> you would be standing still and facing stray debris whipping past at
>> .99c.
>>
>> Alternately, you're standing still on the debris and facing the risk
>> from the local star system whizzing by at .99c.
>
>Yup. So, why does accelerating increase the hazard?

It's not accelerating per se, it's reaching those speeds and the only
way you do that is accelerate.
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On Fri, 02 May 2008 01:29:29 -0400, mike weber <fairportfan.TakeThisOut@gmail.com>
wrote:

>On Thu, 01 May 2008 20:29:58 -0800, Offbreed
><offbreed_106.TakeThisOut@hotmail.com> wrote:
>
>>If they are talking about junk loose in interstellar space, then they
>>are wrong. Accelerating will not increase risk.
>
>Well, actually, it will.
>
>(Assuming your speed actually increases relative to the local
>average...)
>
>Because there's a certain amount of junk per cubic kilometer.
>
>The faster you go, the more cubic kilometers you pass through in a
>unit time, and the greater your risk factor for collision.

And the faster you are going the harder the junk hits. Also, if you
mount any sort of active defense against it the defense will have less
time to deal with it.
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On Thu, 01 May 2008 23:38:47 -0400, mike weber <fairportfan.DeleteThis@gmail.com>
wrote:

>On Thu, 01 May 2008 20:04:14 -0700, Loren Pechtel
><lorenpechtel.DeleteThis@hotmail.invalid.com> wrote:
>
>>On Tue, 29 Apr 2008 09:14:00 -0700 (PDT), "rlbell.nsuid@gmail.com"
>><rlbell.nsuid.DeleteThis@gmail.com> wrote:
>
>
>>>The most devastating thing known was the chemical explosive,
>>>heptadetonate (before they started lobbing planets and found two
>>>planets with superluminal intrinsic vectors 180 degrees apart).
>>
>>Sure it's chemical?? The yields seemed like low-end nuclear.
>>
>
>Yes, it was chemical, but, no, it wasn't (as i've said) heptadetonate,
>it was duodecaplatylatomate.
>
>A giant molecule consisting of twenty-six atoms of nitrogen.

I don't recall it ever being defined. Where does he describe it?

>Not gonna be stable at any real-world conditions, i think, but the
>potential energy release...

Yeah, I squawked at Robert L. Forward over his rocket fuel in one
story. A very high energy monopropellant (single stage to Saturn
orbit with a quite reasonable mass ratio) based on some exotic cage
type molecule whose structure I don't recall at present.

What's going to happen when a cosmic ray slams through your fuel tank?

He didn't want to admit his monopropellant would be prone to going
boom but he at least admitted that he missed the fact that a cable by
itself can act as a counterweight. They were having to limp home
critically short of fuel and had to discard every ounce they could.
They still had a 200mi cable, though, as they needed it to get
velocity boosts from the moons (put an anchor on the ned of the cable,
fire it into a moon, like a normal sling turn NASA does but with a lot
more oomph.) to get back to their return module.

They returned in zero-g because they didn't have the stuff that would
have been the counterweight to spin with--but just that 200 mi cable
alone would have given them a counterweight!
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On Fri, 2 May 2008 09:27:23 -0700 (PDT), "rlbell.nsuid@gmail.com"
<rlbell.nsuid.DeleteThis@gmail.com> wrote:

>The amazing thing about the lensmen series is how good and moral the
>heroic figures are. There is the one vignette where the two inventors
>of the bergenholm discuss, without the least hint rancor, why it is
>named for neither of them. Bergenholm got all of the credit by
>wandering into a discussion and suggesting that they fuel it with
>uranium, instead of allotropic iron (apparently the peak of the
>nuclear binding energy curve meant something else in the lensmen
>universe), making it perfom much better than either inventor had
>imagined possible.

They realized that Bergenholm was the real mind behind it.

They didn't realize he really was controlled by the Arisians.
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On Fri, 02 May 2008 16:01:57 -0700, Loren Pechtel
<lorenpechtel DeleteThis @hotmail.invalid.com> wrote:

>On Thu, 01 May 2008 23:38:47 -0400, mike weber <fairportfan DeleteThis @gmail.com>
>wrote:
>

>>Yes, it was chemical, but, no, it wasn't (as i've said) heptadetonate,
>>it was duodecaplatylatomate.
>>
>>A giant molecule consisting of twenty-six atoms of nitrogen.
>
>I don't recall it ever being defined. Where does he describe it?

Well, actually, he doesn't describe it in any of the "Lensman" books,
but basically the same thing *is* described in the non-series book
"Spacehounds of IPC", and "The Universes of E.E.Smith", a concordance
to the "Skylark" and "Lensman" books says that he confirmed that
duodec was the same stuff
>
>>Not gonna be stable at any real-world conditions, i think, but the
>>potential energy release...
>
>Yeah, I squawked at Robert L. Forward over his rocket fuel in one
>story. A very high energy monopropellant (single stage to Saturn
>orbit with a quite reasonable mass ratio) based on some exotic cage
>type molecule whose structure I don't recall at present.

Buckyballs?
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On Fri, 2 May 2008 09:27:23 -0700 (PDT), "rlbell.nsuid@gmail.com"
<rlbell.nsuid.TakeThisOut@gmail.com> wrote:

>The amazing thing about the lensmen series is how good and moral the
>heroic figures are. There is the one vignette where the two inventors
>of the bergenholm discuss, without the least hint rancor, why it is
>named for neither of them. Bergenholm got all of the credit by
>wandering into a discussion and suggesting that they fuel it with
>uranium, instead of allotropic iron (apparently the peak of the
>nuclear binding energy curve meant something else in the lensmen
>universe), making it perfom much better than either inventor had
>imagined possible.

No, he's telling them to use uranium and not iron as a core for a coil
or something like that; they develop the inertialess drive *before*
they encounter the Nevians, and have to learn from them how to use
allotropic iron for fuel.
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On Fri, 02 May 2008 16:01:57 -0700, Loren Pechtel
<lorenpechtel.DeleteThis@hotmail.invalid.com> wrote:


>They realized that Bergenholm was the real mind behind it.
>
>They didn't realize he really was controlled by the Arisians.

Not "controlled by" - "was", essentially.

One of the things i regret was Doc's rewrites from the magazine
serials, and the backstory he put into the "Triplanetary" fixup book
and "First Lensman", which was written for book publication, last of
all.

In the original serials, we know what Kinnison knows - no more,
noless. So when Kinnison goes "Well, that's that!" at the end of one
story, we believe it. And when Mentor'swraning comes crashing in on
the first page of the next serial, we are just as shocked as Kinnison.

I don't think we find out about the Ploorans, let alone the Eddorians,
till "Children of the Lens" in the original serials.
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On Fri, 02 May 2008 20:09:22 -0400, mike weber <fairportfan RemoveThis @gmail.com>
wrote:

>On Fri, 02 May 2008 16:01:57 -0700, Loren Pechtel
><lorenpechtel RemoveThis @hotmail.invalid.com> wrote:
>
>
>>They realized that Bergenholm was the real mind behind it.
>>
>>They didn't realize he really was controlled by the Arisians.
>
>Not "controlled by" - "was", essentially.
>
>One of the things i regret was Doc's rewrites from the magazine
>serials, and the backstory he put into the "Triplanetary" fixup book
>and "First Lensman", which was written for book publication, last of
>all.
>
>In the original serials, we know what Kinnison knows - no more,
>noless. So when Kinnison goes "Well, that's that!" at the end of one
>story, we believe it. And when Mentor'swraning comes crashing in on
>the first page of the next serial, we are just as shocked as Kinnison.
>
>I don't think we find out about the Ploorans, let alone the Eddorians,
>till "Children of the Lens" in the original serials.

I never saw the original serials, only the books.

One thing I don't understand: Why did the Arisians need human help in
the first place? Yes, they couldn't crack the final base on
Eddore--but what if they destroyed the base first and then took on the
Eddorians without their defenses? If their mental strike hit a
hundreth of a second after an n-space planet they should have been
able to deal with the Eddorians themselves.

And do you have any idea what the threat was supposed to be in the
next (unwritten) book? It's obvious why it wasn't written but not
what the threat was supposed to be--yet from the end of Children of
the Lens it's apparent we should know something of it.
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On Fri, 02 May 2008 19:54:42 -0700, Loren Pechtel
<lorenpechtel DeleteThis @hotmail.invalid.com> wrote:


>I never saw the original serials, only the books.

I never did, either, i just know the history, as it wewre.
>
>One thing I don't understand: Why did the Arisians need human help in
>the first place? Yes, they couldn't crack the final base on
>Eddore--but what if they destroyed the base first and then took on the
>Eddorians without their defenses? If their mental strike hit a
>hundreth of a second after an n-space planet they should have been
>able to deal with the Eddorians themselves.

Te Arisians and the Eddorians were too perfectly-matched for either to
be able to destroy the other withot a special weapon - Civilasation
was the Arisians', Boskone was the Eddorians'.

>
>And do you have any idea what the threat was supposed to be in the
>next (unwritten) book? It's obvious why it wasn't written but not
>what the threat was supposed to be--yet from the end of Children of
>the Lens it's apparent we should know something of it.

Actually, i think not. I think the postscript to "Children" is
suposed to imply that something we can't conceive of is going on.
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On May 3, 2:18 am, mike weber <fairport....RemoveThis@gmail.com> wrote:
> On Fri, 02 May 2008 19:54:42 -0700, Loren Pechtel
>
> <lorenpech....RemoveThis@hotmail.invalid.com> wrote:

>
> >One thing I don't understand: Why did the Arisians need human help in
> >the first place? Yes, they couldn't crack the final base on
> >Eddore--but what if they destroyed the base first and then took on the
> >Eddorians without their defenses? If their mental strike hit a
> >hundreth of a second after an n-space planet they should have been
> >able to deal with the Eddorians themselves.
>
> Te Arisians and the Eddorians were too perfectly-matched for either to
> be able to destroy the other withot a special weapon - Civilasation
> was the Arisians', Boskone was the Eddorians'.
>
The morality tale embedded in the lensmen series is that good triumphs
over evil because the forces of good unite out of love, but the forces
of evil only unite out of fear. The Eddorians only work together to
fight the Arisians, because they know that no individual eddorian is
powerful enough to resist the collective arisian will, and their
efforts concentrate on creating divisions within civilization to
prevent that terrifying (to them) unity of purpose
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On Sat, 03 May 2008 04:18:36 -0400, mike weber <fairportfan.RemoveThis@gmail.com>
wrote:

>On Fri, 02 May 2008 19:54:42 -0700, Loren Pechtel
><lorenpechtel.RemoveThis@hotmail.invalid.com> wrote:
>
>
>>I never saw the original serials, only the books.
>
>I never did, either, i just know the history, as it wewre.
>>
>>One thing I don't understand: Why did the Arisians need human help in
>>the first place? Yes, they couldn't crack the final base on
>>Eddore--but what if they destroyed the base first and then took on the
>>Eddorians without their defenses? If their mental strike hit a
>>hundreth of a second after an n-space planet they should have been
>>able to deal with the Eddorians themselves.
>
>Te Arisians and the Eddorians were too perfectly-matched for either to
>be able to destroy the other withot a special weapon - Civilasation
>was the Arisians', Boskone was the Eddorians'.

Except it was specifically said that Arisia could have destroyed all
of the Eddorians except that final citadel. The citadel itself
wouldn't survive a n-space planet and the Eddorians in it would be
weakened by having their physical forms blasted.
 >> Stay informed about: Setting the Clock: the Planet way, the navy way, and the w.. 

This is an old thread that I was reminded of the other day, so I decided
to do some actual calculating.

In article
<c094f330-559a-4a04-b22b-90f5781bf4e5 DeleteThis @e10g2000prf.googlegroups.com>,
"rlbell.nsuid@gmail.com" <rlbell.nsuid DeleteThis @gmail.com> writes
>The clock problem is actually worse than we thought. Special
>Relativity allows us to calculate the time dilation for relative
>velocities, but General Relativity is needed to account for dilation
>effects due to spacetime curvature. The further down you are in a
>gravity well, the slower that your clock runs. The impeller works by
>creating extreme curvatures in spacetime, so there will be dilaion
>effects as soon as the drive kicks in.

Yes, but it isn't that simple.

After some digging around I was able to find two relevant sets of
formulae. So I can present two scenarios.

Let's consider a spaceship at (approximate) rest relative to its home
port. It accelerates at a constant 500g (4.905km/s^2) for 8 hours
according to its onboard clock. This will bring it up to 0.439c [1] -
let's assume for arguments sake that that's the limit of its particle
shielding. It then coasts for 8 hours (ship time), then does a turnover
and decelerates at the same rate to come to rest. It then repeats the
manoeuvre so as to return to home port orbit (we'll ignore the movement
of the home planet in that time).

The four acceleration phases will each take 8.299 hours according to the
home port clock, while the coasting phases will each be 8.903 hours.
This makes a total trip time of 51 hours and a few seconds, compared
with 48 hours on the ship's clock, a ratio of 1.063 (or about 4 minutes
per hour).


Moving to the GR aspects and gravitational wells, it turns out to be
more complicated and yet more simple. The formula for time dilation of
an accelerating box is:

tau = 1/(1 + ar/c^2)

where a is the acceleration of the box and r is the distance between the
box and observer along the axis of movement of the box (I have no way to
explain why that is relevant, but apparently it is), while that for a
body at rest in a planetary gravitational well is:

tau = sqrt (1 - 2gr/c^2)

where g is the local gravity and r the distance to the centre of the
planet.

Checking this latter, for the earth's surface we have g=10 and
r=6400000. That gives a tau of 1-7e-10, or 42 nanoseconds per minute.
This is close enough to the 30 nanoseconds per minute figure I found for
the correction that GPS satellites have to make that I'm happy with it.

So how do we apply this to an Honorverse ship? If we use a value of
100km for r in each case (being related to the size of the wedge), and
again assume 500g, we get values for tau that represent a time dilation
of around 300 nanoseconds per minute. Even at 10,000km the dilation is
still under 4 microseconds per minute. Which means that we can
effectively ignore it [2].

[1] Simple arithmetic comes up with 0.488c, but that neglects to take
account of time dilation within the ship.

[2] With a value of r of 1000km, which I think is the most you can get
away with, you need an acceleration of 90 *million* g to get a 1% time
dilation. If David Weber was to handwave and claim that it was the
spacing between adjacent nodes that mattered - what's that, 50 metres? -
then that becomes 1.8 million million g.

--
Clive D.W. Feather | Home: <clive DeleteThis @davros.org>
Tel: +44 20 8495 6138 (work) | Web: <http://www.davros.org>
Fax: +44 870 051 9937 | Work: <clive DeleteThis @demon.net>
Please reply to the Reply-To address, which is: <clive DeleteThis @davros.org>
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