Re: [LoGH] The Great Debate - Beowulf vs. Werewolf
Walter Amos (amos@sedl.org)
Fri, 13 Oct 2000 13:15:18 -0500 (CDT)
On Thu, 12 Oct 2000, Justin Ho wrote:
> I have the seed of such a page in process at:
>
> http://iluvatar.home.netcom.com/logh.html
>
> SPOILER warning: Since these files are written as if from a historical
> perspective, there can be spoilers. If you wish to avoid spoilers as to
>
> Any help, especially any physics or gear headers out there, is
> appreciated.
Physics to the rescue!
> Three problems have been noted already
> 1. What is the exact travel time to Iserlohn from Heinessen? There has
> been one instance of 2 weeks and one of 4. This apparent contradiction
> might be expected to affect warp jump distance.
I won't speculate on this one because it is fanspec and not something
involving real physics, and I don't know what they said it was in the
episodes, if indeed they ever said at all...
> 2. The neutron cannons given for a standard FPA cruiser have a listed
> power output of 120 MW and a bore diameter of 12.3 cm. The problem is that
> from those numbers it seems that the power at its listed maximum range of
> 18 light seconds would be incredibly small.
Why is that? A beam of neutrons would experience almost no
self-interaction causing beam spreading (as is a problem with a charged
particle beam, the like charges repelling one another and therefore
causing the focused beam to disperse). Since it is almost impossible
to make a perfectly coherent particle beam there would still be some
dispersion though, and probably 18 light seconds is the range at which
the spreading would mean that the amount of energy delivered per unit
area at the target is less than that needed to melt battleship armor.
> 3. How the hell does a magnetic field deflect a stream of uncharged
> neutrons? The data appears to indicate the shields have at least a
> magnetic field component, and the main cannons are most definitely listed
> as neutron cannons.
This one I can go into in more detail. If I may also quote Graeme Lennon's
response:
> It is perhaps worth noting that a neutron is not *really* a particle with
> no charge at all. It is a group of quarks with opposing half-charges that
> average out to a zero net charge. (Fact)
> Thus, it stands to reason that at a certain scale there is some form of
> polarization. Given a strong enough (er, very, very strong) magnetic
> field, some sort of effect must be possible. (Pure, 100% speculation)
Well, yes and no. You don't really have to resort to electrical charge
of quarks to explain this, although that may be a component of the
deeper particle physics explanation. The neutron, like the proton and
electron, has a "spin magnetic moment", which an external magnetic
field can act on. Unlike the electron and proton, it is not subject to
the "Lorentz Force", the force felt by a charged particle moving
through a magnetic field. The force resulting from the interaction of
an external field with the spin magnetic moment (which doesn't mean the
neutron is spinning, that's just what the quantum number describing
this property is called) is much smaller than the Lorentz force
interaction. So while it is very hard to cause neutron beams to bend,
for example, one can use this force to magnetically focus such beams.
==============================================================================
"Zu jeder Zeit, an jeder (sic) Ort, bleibt das Tun | Walter Amos
der Menschen das gleiche..." - Galactic Heroes II | amos(at)sedl.org
