Date: Fri, 9 Sep 88 01:06:20 PDT
From: Ted Anderson <ota@angband.s1.gov>
Message-Id: <8809090806.AA04926@angband.s1.gov>
To: Space+@andrew.cmu.edu
Reply-To: Space+@andrew.cmu.edu
Subject: SPACE Digest V8 #355

SPACE Digest                                      Volume 8 : Issue 355

Today's Topics:
	     Re: The sun as a trashcan (was : Plutonium)
			   Re: Time travel
	   Re: Transmutation (was: Interstellar Mining (?)
		  Re: space news from July 11 AW&ST
		    Re: 95% vs. 99.9% reliability
		       Re: Berserker hypothesis
		      Nanotechnology and roaches
			  "Violent urges..."
			  Re: Why no aliens
			      Plutonium
			    Re: plutonium
	     Re: Why *THEY* might want to eat our lunch.
----------------------------------------------------------------------

Date: 29 Aug 88 01:06:18 GMT
From: bobmon@iuvax.cs.indiana.edu  (RAMontante)
Subject: Re: The sun as a trashcan (was : Plutonium)

Actually, I don't think we HAVE to get the dangerous stuff all the way to
the sun.  An orbital radius of maybe .7 AU  (just inside Venus) should be
plenty far enough away.  Of course any orbital decay would be gratefully
accepted.

Still prohibitively expensive to launch the stuff on chemical rockets,
I suspect; and I'd hate to be the Range Safety Officer if a launch
went awry....

How about an electromagnetic launch and a fission motor to boost to "final
orbit"?  Let the waste be its own propellant.  Southern Indiana and the
Love Canal in Albany, New York could contribute some toxic payload, as
well.
-- 
--    bob,mon			(bobmon@iuvax.cs.indiana.edu)
--    "Aristotle was not Belgian..."	- Wanda

------------------------------

Date: 28 Aug 88 04:59:35 GMT
From: portal!cup.portal.com!Dave_Ninjajr_Flory@uunet.uu.net
Subject: Re: Time travel


     I dont think FTL time travel, if possible, will be anything like I
have seen described so far. If an object goes the speed of light time does
not stop for the universe, only for the object going the speed of light will
time stop. So the only thing that going faster than light will do is make you
younger. The universe around you will be the same old place and still in the
same time. The only way to really go back would be to make the COMPLETE
UNIVERSE go faster than light. (Now that would be something!) Otherwise the
affect will only be on the object that is going FTL. Understand? It cant
happen that way.


The Party Pooper

------------------------------

Date: 26 Aug 88 16:44:53 GMT
From: att!alberta!mnetor!utzoo!henry@ucbvax.Berkeley.EDU  (Henry Spencer)
Subject: Re: Transmutation (was: Interstellar Mining (?)

In article <6413@ihlpl.ATT.COM> knudsen@ihlpl.ATT.COM (Knudsen) writes:
>Unless I'm missing something, we should be able to transmute
>small quantities of elements with current technology.

Remember that essentially all plutonium on Earth is made by transmutation.
There's rather a lot of it about, too.  (It is admittedly an unusually
favorable case, since neutron bombardment of uranium suffices.)  Many of
the isotopes used in tracer work are also made by transmutation.

>I once read that the Atomic Energy Commission built a huge
>machine to make Pu out of U by bombarding it with protons,
>using simple electrostatic acceleration...

I'm not aware of that gadget, although it might have existed.  There was,
at one point, a proposal to build a large and specialized accelerator for
making tritium; perhaps you saw a garbled report of that.

Another possibility is that this was a garbled report of the Oak Ridge
mass spectrometers, which were built to do uranium isotope separation
(which they did quite successfully, but not as well as gaseous diffusion)
but have been used since for gram-quantity isotope separation of other
elements for research.
-- 
Intel CPUs are not defective,  |     Henry Spencer at U of Toronto Zoology
they just act that way.        | uunet!attcan!utzoo!henry henry@zoo.toronto.edu

------------------------------

Date: 28 Aug 88 18:15:27 GMT
From: dasys1!tneff@uunet.uu.net  (Tom Neff)
Subject: Re: space news from July 11 AW&ST

In article <1988Aug16.040406.5434@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes:
>NASA is studying an internal proposal to launch Columbia unmanned next year
>using old SRBs.  It would carry one of the DoD satellites scheduled for an
>early mission.  Some modifications would probably be needed, notably a
>braking chute to assist landing.  JSC is opposed to the idea because of
>the orbiter modifications; Marshall is in favor.  The problem is that NASA
>has about 13 pre-Challenger SRBs left, containing about 11 million pounds
>of oxidizer that cannot be recovered, and the oxidizer shortage is looking
>worse and worse.  There are several schemes for minor mods to the old SRBs
>to increase reliability.  Unmanned shuttle flights have been considered
>before, and generally rejected due to risks and lack of need.  The proposal
>is just an idea as yet.  An alternative would be to buy more expendables
>and shift payloads to them, since they use less ammonium perchlorate, but
>NASA does not have the money for that.

Excuse me, but are we really supposed to believe that omitting the
flight crew makes using the old SRBs an acceptable risk?  Challenger is
every bit as "dead" as its crew, and we cannot afford to lose another
orbiter under any circumstances, whether or not astronauts are killed
in flight along with it.  (Anyway, rocket accidents can kill people on
the ground too.)

As I recall, one of the options NASA originally studied was modifying the
existing SRB fleet.  This was rejected in favor of the redesign for cost
and peace-of-mind reasons, BEFORE the perchlorate plant exploded.  Why not
just admit that the explosion changes the picture, and that SRB modification
is now attractive?  Toss in every safety mod we can think of and then
use them for manned missions, perhaps only in warm weather.

Trying to fly Columbia unmanned means tinkering dangerously with a vanishing
resource, namely orbiters.  Dammit Jim, that thing NEEDS a pilot!  :-)
-- 
Tom Neff			UUCP: ...!cmcl2!phri!dasys1!tneff
	"None of your toys	CIS: 76556,2536	       MCI: TNEFF
	 will function..."	GEnie: TOMNEFF	       BIX: t.neff (no kidding)

------------------------------

Date: 26 Aug 88 09:22:08 GMT
From: agate!sag4.ssl.berkeley.edu!link@ucbvax.Berkeley.EDU  (Richard Link)
Subject: Re: 95% vs. 99.9% reliability

>
>Well, we can see there's not schedule pressure in this newsgroup.
 
I didn't get any responses from my first posting, so I'm going to try
again. I worked at the Max Planck Institut fur Aeronomy on the design
of particle detectors for the Giotto (Comet Halley) and Galileo
(Jupiter Orbiter) spacecraft. 

Giotto (a European Space Agency project) has returned some spectacular
images of comets. Galileo has not been launched yet. I worked on these
projects in 1980.

Well, I can see there's not any pressure from NASA personnel in this
newsgroup.

Come on, Eugene, do you only readnews or do you NASA types also
contribute to the space program? 

Dr. Richard Link
Earth and Planetary Atmospheres Group
Space Sciences Laboratory,
University of California, Berkeley
link@ssl.berkeley.edu

------------------------------

Date: 29 Aug 88 15:21:17 EDT
From: Hans.Moravec@rover.ri.cmu.edu
Subject: Re: Berserker hypothesis
To: BBoard.Maintainer@a.cs.cmu.edu

	
commenting on
> Date: 17 Aug 88 23:53:42 GMT
> From: vsi1!unisv!vanpelt@ames.arc.nasa.gov  (Mike Van Pelt)
> Subject: Re: SETI: Why don't we hear anything?

	The bug in the Berserker hypothesis for the interstellar silence, in
which roving interstellar machines stamp out any budding technological
civilizations, is that the Berserkers themselves will the be a technological
civilization inhabiting the galaxy, and their actions should be visible in
the sky.

	Now maybe the Berserkers were originally programmed to be very quiet
between executions, and carefully designed to prevent mutations in their
goals.  But they would be present in such large numbers across the galaxy
that sooner or later a near fatal run-in with a comet, or radiation from a
stellar flare would modify the program in one in such a way as to remove its
inhibitions against change.  That event would seed a Darwinian evolution
of self-reproducing Berserker-derived machines that would acquire the
survival-oriented goals of normal life.  You can't fool Mother Nature
forever.

				-- Hans Moravec

------------------------------

Date: 29 Aug 88 07:06:42 GMT
From: amdahl!drivax!macleod@ames.arc.nasa.gov  (MacLeod)
Subject: Nanotechnology and roaches

In article <572@unisv.UUCP> vanpelt@unisv.UUCP (Mike Van Pelt) writes:

:...The more you look at it, the problem of making a
:machine that can do even what a cockroach does is not as easy as
:it may appear at first glance.  (Which is one of the brick walls
:I think the nanotechnology folks are going to run into.)

This may just be a loose analogy, but I have to add that cockroaches are
generalized creatures; even if the reductionists were correct, a description
of their state machinery would probably come out to some nearly-infinite
model that approached a complete mapping of all chemical reactions.

The kinds of machines proposed by Drexler, as I read _Engines of Creation_,
are >specialized< devices that are produced to address specific problems, 
like the machine that goes into cut out the Tay-Sachs gene in the ovaries.
Later there will be a *more* generalized  "doctrobe" that repairs a host
of problems, but the problem is one of linear extensions to a program, not
generalizing the behavior of something high up on the evolutionary scale.

If problems in nanotechnology arise anywhere, I suspect it will be in 
implementation of ironclad error-correction algorithms.  I have not 
kept up with developments in either subbranch of CS theory, but I 
believe that Error Correction is doing far better than Artificial 
Intelligence. 

Michael Sloan MacLeod   (amdahl!drivax!macleod)

------------------------------

Date: 29 Aug 88 07:31:37 GMT
From: amdahl!drivax!macleod@ames.arc.nasa.gov  (MacLeod)
Subject: "Violent urges..."

In article <8808190000.AA15832@venera.isi.edu> cew@VENERA.ISI.EDU 
("Craig E. Ward") quotes:

:     Due to the great distances involved, any communication with
:extraterrestrials would be very one-sided.  The exchange of pleasantries
:could take 100,000 years.  Even with that, we have sent several messages
:into the deep space.  Pioneers 10 and 11 and Voyagers 1 and 2 all
:contain messages for some inter-stellar traveler to find.  

Using EM waves for interstellar communications is about as feasible as 
putting messages in a bottle and tossing them in the sea.  Better minds than
mine suggest that if interstellar communications traffic takes place with
any regularity it must use some mechanism not bound by the speed of light.

: Any species which
:survives long enough to develop interstellar space travel will likely
:have controlled its more violent urges, something Humanity has not yet
:done.

I'll bet this canard has been advanced at every juncture in human history.
"We can't sail the Great Sea - men would fight and kill each other
before we reached shore!"  "The Germans could never develop jet planes - 
they're too evil!" 

We may not have "advanced" enough to please this foolish scientist, but
somehow we made it this far.  True, the game is not over, but I'm betting on
spacefaring races as being pretty heterogenous groups.  

Back here on Earth we seem wedded to two archetypes: Peaceful Space
Babies (ET, Close Encounters, etc.) or Nietzche's Nightmare (Alien and 
many other movies).  Surely the truth will be somewhere in between.

Michael Sloan MacLeod  (amdahl!drivax!macleod)

------------------------------

Date: 29 Aug 88 16:40:37 GMT
From: cat.cmu.edu!dep@pt.cs.cmu.edu  (David Pugh)
Subject: Re: Why no aliens

In article <Added.0X6Kjdy00Ui306kk9I@andrew.cmu.edu> RAM9@LEHIGH.BITNET ("Richard Mauren -  RAM9") writes:
>     The reason for us not having had extraterrestial contact may be
>simply that it is too dangerous. ... They would
>be stupid to contact us because it would be so easy for us to
>annihilate the planet with nukes.

If ETI's are avoiding contact because they are afraid we might nuke them,
then they are probably afraid enough to nuke just to be on safe the safe
side (after all, we might find them even if they don't contact us).

You may be half right, though -- it may be the case that any race "advanced"
enough to make contact over interstellar distances always ends up destroying 
itself (either with nukes or something worse). Suppose, for example, that it
is possible to build a weapon that would kill everyone on the planet. Now
make it easy enough to build that any country/company/terrorists can build it.
Any bets on how long we would survive? Don't laugh -- something like this
may happen in the next 20 years (probably a biological weapon, but who
knows).
-- 

						David Pugh
						....!seismo!cmucspt!cat!dep

------------------------------

Date:     Mon, 29 Aug 88  15:47:22 EDT
From: =3545*** <pcp2g@cdc.acc.virginia.edu>
Subject:  Plutonium

Well, it looks like I have to flame my own flame. I made several errors 
in my last mailing.
1) Plutonium is Pu, not Pt. Someone already e-mailed a correction to me.
   I'm an astronomer, not a chemist, dammit!
2) Replace "emission line" with "absorption line". Cold matter against
   a hot background absorbs radiation.
3) I was wrong about having to decelerate the package by 18.5 miles/sec
   to collide it with the Sun. Using Jupiter or the moon or even the
   Earth itself for a gravity assist (slingshot) would do the trick. It 
   would still be difficult, but not impossible. 
4) There are two problems I overlooked--one is that  what happens if
   the rocket carrying the Pu blows up twenty miles up? Scratch one eco- 
   sphere, that's what. A payload like that is too risky to launch. The 
   other problem was pointed out to me by a friend: To create an absorption 
   line, the absorber must be in the upper atmosphere of the sun, where the
   solar gas is tenuous enough to see through. A payload would tend to sink
   out of sight. Perhaps blowing up the payload might keep it in the upper
   atmosphere temporarily , but convection would eventually suck it down.
   And there still is the problem that you need a shitload of Plutonium 
   to be visible even from the Earth, let alone from another star. 

   So, I have fanned my own flame. Next time I'll open my brain before I 

open my mouth. 
PS- There may be another copy of this (a first draft, actually) that may
get sent. The tin box I use to get Digest on tends to massively screw up 
e- 
e-mail, as that last line shows (the editor is about ten years old on
this machine). 

{Philip Plait/PCP2G@cdc.Virginia.acc.edu/UVa Dept of Astronomy} 
[If you laid all statisticians end to end, they would all point in 
 diferent directions]

------------------------------

Date: 29 Aug 88 16:54:40 GMT
From: concertina!fiddler@sun.com  (Steve Hix)
Subject: Re: plutonium

In article <1909@iscuva.ISCS.COM>, jimk@iscuva.ISCS.COM (Jim Kendall) writes:
> 
> I'll add a third; the likelyhood of a mishap during launch.
> 
> Imagine a rocket full of Pt exploding over Florida............

Tell me when!!  I'll be there!!  (Unless you meant Pu, which is lots
less useful in the bank than platinum.)

------------------------------

Date: 29 Aug 88 17:53:23 GMT
From: att!ihlpf!lukas@ucbvax.berkeley.edu  (00704a-Lukas)
Subject: Re: Why *THEY* might want to eat our lunch.

In article <3695@drivax.UUCP> macleod@drivax.UUCP (MacLeod) writes:
>Given the unlikelihood of cheap transmutation of elements, even spacefaring
>races will probably continue to be interested in rare elements.  If Earth's

I think that cheap transmutation of elements is actually MORE likely then
routine interstellar mining of metals. The first problem is more-or-less
well understood from a physics standpoint, and is held up by mere
engineering difficulties :^). The latter is much less well understood.
-- 

	John Lukas
	ihnp4!ihlpf!lukas
	312-510-6290

------------------------------

End of SPACE Digest V8 #355
*******************