Metlay says:
>...
>premise that the Sun runs on "ordinary hydrogen" is correct, but you've
>failed to realize what "ordinary hydrogen" IS. It's mostly protium, but
>there's a plenty large enough trace percentage of deuterium and tritium
>in it to let a deuteron+deuteron=alpha+gammas reaction take place. The
I am not a nuclear physicist but an astrophysicist and as such should
point out that deuterium+deuterium is not a primary reaction in the sun.
The level of deuterium is kept depleted by interactions with hydrogen
(protons) forming helium-3 (+gamma). In low temp stars this is the end
product of fusion. In slightly higher temp stars He-3 + He-3 -> He-4 + 2H
also occurs however note that NONE of these reactions release neutrons like
the D+D reaction! At about 2E7 K a whole slew of additional reactions
become possible all still falling under the title of p-p chain nuclear
fusion. None of those release neutrons either.
Here on Earth the D+D and D+T reactions are used because they are better
reactions for fusion technology at our TL and we can use whatever material
we like (as opposed to what is available). And you are right they DO give
off neutrons.
Perhaps a better fuel choice at the TL of Traveller would be D+p which is
fairly easy to do but has a relatively low energy yield (about the same
as D+D and about 1/3 D+T) or Li-7 + p or B-8 + positron both of which
have large energy yields (3-4 time D+p). Bear in mind these numbers are
for conditions *inside* a star ie high temp, high pressure, high density,
plasma reactions. Needless to say, ground (ship) based reactors will
work differently but not that differently. Think of the breakthroughs
in EM containment fields or laser ignition systems. And, hey, let's not
rule out various forms of cold fusion!
Robert P Poole says:
>neutrinos. If the physics is right, then detectible neutrinos should be
>converted to undetectible types with greater and greater probability as the
>distance from the source increases. This should probably play a role in the
>TDR rules, just to put a limitation on the range of neutrino scanners that is
>"realistic.")
Two things: First we detected neutrinos from 1987a (the supernova) from
distances much larger then the ranges given for the neutrino detectors in
Traveller (of course there were a hell of a lot of neutrinos coming out
of 1987a). Second the detection technology will have improved greatly by
that TL (they not running around with large vats of cleaning fluid after
all) so more of the neutrinos that are detectable will be detected.
A different issue (referencing both of the above) if you choose the
"correct" fusion chain then you can use reactions that do not emit neutrinos
thus rendering your power plants "invisible" to neutrino detectors! Which
brings up a different point - if Traveller says that neutrino detectors
can detect power plants (because of the fusion presumably) then they must
be using reactions that give off neutrinos rendering our arguments mute
unless we want to remove the utility of neutrino detectors from the game
(which I don't). That is the use of the neutrino detectors isn't it?
Points to Ponder
TLH
- - --
T.L.Hayes |
MIT/Lincoln Laboratory |
Lexington, MA |