Space & Astronomy/Space and Astronomy (October 1993).iso/mac/TEXT/SPACEDIG/V08/V8_340.TXT

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Date: Mon, 29 Aug 88 01:04:27 PDT
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Subject: SPACE Digest V8 #340

SPACE Digest                                      Volume 8 : Issue 340

Today's Topics:
                 Planetariums
                Re: Aerospike
             Re: E-Stamps and cat brains
         Re: ET phone home? (SETI)   RESPONS
        Re: SETI: Why don't we hear anything?
        Re: SETI: Why don't we hear anything?
             Re: HOTOL funding cancelled
        Re: Space Station Name chosen -- Fred
            Re: 95% vs. 99.9% reliability
                   Re: Seti
----------------------------------------------------------------------

Date: 16 Aug 88 14:55:41 GMT
From: bbking![e-mail]  (Richard Marks)
Subject: Planetariums

Over the past year my little daughter and I have gone to two planetariums.
We went to the one in Philadelphia at the Franklin Institute and the
one in New York at the Hayden Planetarium.  Both have the Zeiss
Projectors and put on rather impressive shows.  I wonder what experiences
others have had with the various planetariums.

The show at the Franklin Institute was called "Death of the Dinosaurs" and
explored evolution and development of pre-historic life.  It discussed the
various cosmic (comets, interstellar gas, etc) events that may have lead
to the sudden disappearence of the dinosaurs.  There were several neat special
effects, including a simulation of the BIG BANG.  The show was not the
traditional "the night sky" planetarium show.  The cost was reasonable
and parking and access was good.

The show at the Hayden was in two parts.  I forget the first part, but the
second part was about the Hubble Space Telescope.  It was interesting but
was a bit of a PR (we can do nothing wrong) pitch.  The special effects
were OK, but not up to the Franklin's level.  THe Hayden has some interesting
space exhibits outside of the dome.  (The Franklin has many exhibits, but none
related to the planetarium.)  Being New York, the cost was high and parking
was hard.

Richard Marks
[e-mail]

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

Date: 16 Aug 88 18:18:01 GMT
From: telesoft![e-mail]  (Roger Arnold @prodigal)
Subject: Re: Aerospike

In article <[e-mail]>, [e-mail] (WARMINK) writes:
> [e-mail] (J Storrs Hall) writes:
>
> > What is an aerospike?  What is meant by its being (or not being)
> > "plugged"?
> An aerospike is a sharp extension of a (usually) blunt nose cone.
> [..]

That's a likely sounding definition, but I don't think it's the one
that josh was inquiring about.  I've heard Gary Hudson talk about an
"aerospike" as a configuration of rocket engines, in which a large
number of (relatively) small engine nozzles are arranged in a circle
around the periphery of a blunt disk.  The idea, as I understand it,
is that the configuration exhibits the aerodynamic behavior of a long
tapering tail, thereby reducing atmospheric drag.  Must confess I
don't have a good sense of the physics behind such behavior, but
presume there's something to it.  I know it was the configuration
proposed by Boeing for one of their HLLV designs in the SPS studies
they did in the 70's.  That design was a VTVL, SSTO design.  (Aren't
acronyms a riot; nothing like 'em to separate the cognoscenti from
the hoi polloi, and, BTW, announce which camp YOU're in).  Looked
kind of like a giant Apollo capsule.  Where's Dani?

A "plugged" aerospike is one with a conical structure (the "plug") in
place of the blunt disk inside the ring of engines.  The exhaust gases
expand against the structure, providing additional thrust.  A plugged
aerospike effectively has a variable expansion ratio, a function of
ambient atmospheric pressure.  It's an efficient design for booster
stages; the problem is cooling the plug.

- Roger Arnold                ..ucsd!telesoft!roger

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

Date:    Wed, 17 Aug 88 08:09:25 PDT
From: [e-mail]
Subject: Re: E-Stamps and cat brains
X-St-Vmsmail-To: JPLLSI::"[e-mail]"

    Adding to the debate on the "E" stamp, actually McCall's drawing of
the terminator isn't that far off from being correct (or at least as best
you can tell from that tiny picture).  We've played around with a globe
here with the north pole tilted 23 degrees towards a single light source
(which is the geometry you would get on the summer solstice) and the
terminator does fall so that South America is in darkness while most
of North America is still in light (looks like it would be around 8pm
Eastern Daylight Time).  Still McCall's picture looks like the Earth
is tilted another 10 degrees or so, but that doesn't change the overall
effect of the picture that much.  As for the background colors, that's
definately artistic license, flat black space just isn't that interesting
visually.  If you remember the Shuttle stamps back in 1981, those were
done by McCall and also had the blue, orange, and yellow backgrounds.
(McCall isn't the only artist to "take license" with space.
Those of you who have seen the 1978 NASA book on "Space Settlements"
may have noticed that most of the artwork there showed space to look
like a field of deep purple cotton puffs.  It wasn't accurate, but
it did look nice.)  Additional trivia note: McCall did the space
mural at Johnson Space Center Vistor Center as well as the one at
the Air and Space Musuem.
    In the discussion of wiring the brain up to hardware for
space travel, James Symon (V8 #321) mentioned a scifi story where
cat brains were used in conjuction with human brains to fly starships.
He's refering to the short story "The Game of Rat and Dragon" by
Cordwainer Smith.  The story was first published in 1955, so this idea
has been bounced around (in scifi, at least) for a while.  In his novel
"Norstrilia", Smith comes up with an interesting variation on these ideas.
Since the cost of interstellar travel is based on weight and enormously
expensive, he imaged a future where a traveller has his or her head
removed and put into a freeze-dried hibernation.  The rest of the body
is dehydraded and perserved.  The greatly "lightened" person is then
shipped off to its destination.  Once there the body is reconstituted,
the head is reattached, and the person revived.  I think I'll stick to
taking the bus, thank you.

Marc Hairston--Center for Space Sciences--University of Texas at Dallas
SPAN adress  UTSPAN::UTADNX::UTD750::HAIRSTON

The opinions are my own. When I find out what the official UT system
opinion on interstellar body shipments is, I'll let you know.

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

Date: 16 Aug 88 11:31:00 GMT
From: cca!mirror!datacube![e-mail]
Subject: Re: ET phone home? (SETI)   RESPONS


>The fact is, we *don't know* why they aren't here now, and it's a major
puzzle.
--
Intel CPUs are not defective,  |     Henry Spencer at U of Toronto Zoology
they just act that way.        | uunet!attcan!utzoo!henry [e-mail]


      Actually, the puzzle isn't quite that complex; we as a race have
proven ourselves to be capable of the most pernicious acts directed against
ourselves for some fairly modest differences of opinion. Religious
and racial intolerance are still at the top of the list of "causes" that we
are willing to kill each other for. As an open question to all of you in
Netland, how do you think we as a race would react to somebody as wildly
different as an Extraterrestrial form of life? I feel that if their tech-
nology allows for inter-stellar or even intergalactic travel, it must
certainly allow for some form of remote surveying or monitoring of our planet
and it's people. And given our fairly unimpressive track record, their
elusive behavior could be due to a desire not to contact us. After all,
how we treat ourselves is a mirror of how we would treat others. This all
may sound a little trite, but surely not too far off the mark.

Chris Munschy
Datacube

/* End of text from datacube:sci.space */

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

Date: 17 Aug 88 16:59:53 GMT
From: cfa!cfa250![e-mail]  (Steve Willner P-316 x57123)
Subject: Re: SETI: Why don't we hear anything?

From article <[e-mail]>, by [e-mail] (Mike Van Pelt):
> Presumably it wouldn't be all that difficult for an advanced
> civilization to build probes that would be more than a match for
> any civilization that had only a few years before mastered the use
> of radio, on which the probes would home in.
>
> I like to think of this as preposterously unlikely.

If it is possible for an advanced civilization to build and deploy
self-reproducing, interstellar probes, probes could be continuously
resident in each solar system.  If the civilization constructing the
probes were irrationally hostile to other life forms, the probes
could be programmed to detect life and sterilize any planets long
before radio could be developed.  Obviously this has not happened, so
at least one of the assumptions is wrong (or else we are just
incredibly lucky that all the probes in our solar system have
malfunctioned).
--
Steve Willner            Phone [phone]         Bitnet:   willner@cfa
60 Garden St.            FTS:      830-7123           UUCP:   willner@cfa
Cambridge, MA 02138 USA                 Internet: [e-mail]

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

Date: 17 Aug 88 23:53:42 GMT
From: vsi1!unisv![e-mail]  (Mike Van Pelt)
Subject: Re: SETI: Why don't we hear anything?

In article <[e-mail]> [e-mail] (Peter Kinsella) writes:
>In article <[e-mail]>, [e-mail] (Mike Van Pelt) writes:
>> [description of the "berserker hypothesis"

Understand, my arguments here are of a "devil's advocate" nature.
I do not think that this is the answer to the silence problem.
(Maybe I'm being overly optimistic...)

>Why would would they get along fine with each other but be afraid of a
>a little puny underdeveloped planet.

Perhaps they can get along fine with each other because 'each other'
aren't *ALIENS*, thus don't trigger the xenophobia.  Perhaps the
planet is inhabited by the sole surviving group of centuries of
genocidal wars, so on that planet there are no 'others' to be
xenophobic about.

Remember, if we're talking about self-replicating robots doing the
dirty work, the original xenophobes aren't afraid of us; they probably
don't even know about us even if they aren't extinct.  Their robots,
multiplying and filling the galaxy, seek out and destroy civilizations
all on their own.

>If we assume that the galaxy is as expansive as most people claim.

This supports the Berserker Hypothesis.  If the galaxy (or universe
if we allow for intergalactic travel) is so big, it almost doesn't
matter how fantastically improbable the Berserker Hypothesis is.  It
only has to happen ONCE in fifteen billion years of the history of
the entire galaxy/universe.  If anyone, anywhere, anytime, built
self-replicating robots programmed to seek out and destroy all life
(Saberhagen's version) or even all technological civilizations
(Benford's version), they could fill the galaxy in on the order of
a million or two years.  That what makes it so scary.

>And if we assume that the Race is
>suffiently developed to send probes to wipe out other planets, wouldn't
>they also be advanced enough to harvest resources from uninhabited worlds.
>Wouldn't the later also be more economically efficent, especially if the
>world be taken over detonates atomic weapons in its self defense.

This all assumes that they are rational, that their rationality includes
a need and desire to harvest resources from uninhabited worlds, economic
efficiency, etc.  Remember, in the Berserker Hypothesis, they don't
care beans about extraplanetary resources -- they just want to stamp
out those awful, ugly, obscene, disgusting *alien* *horrors*.  (That's
us, if we attract their attention.)

And it also assumes that nuclear weapons are the Ultimate Weapon.
Talk to some of the nanotechnology people, and you'll see that nukes
are just peashooters compared to Gray Goo -- just a pinch will consume
an entire planet right down to the magma in short order.  (I'm not
entirely convinced about nanotechnology, either, but the topic sure is
interesting.)

(*GAD* but this message is depressing.  I sure hope it isn't true.)
--
"Dreams of flight are universal among space-faring races.| Mike Van Pelt
 Indeed, such dreams may form much of the motivation for | Unisys Silicon Valley
 becoming space-faring."   --  T'chaih Hrinach           | [e-mail]

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

Date: 16 Aug 88 16:41:20 GMT
From: mcvax!ukc!etive![e-mail]  (Bob Gray)
Subject: Re: HOTOL funding cancelled

In article <[e-mail]> [e-mail] (WARMINK) writes:
>I was rather surprised at the lack of comments (or maybe I shouldn't have been)
>when it was announced that the British government had decided to stop funding
>the HOTOL program. Apparently British Aerospace and Rolls Royce are expected
>to fund to development themselves.

I posted an article on the subject last week.

There have been a couple of developments since then.
Rolls Royce are said to be reluctant to continue development
withour Government backing. They hold all the patents on the
airbreathing engine.

Second, a group of financial backers are said to have raised
120 million pounds to continue development over the next
two years. The backers do not include BAe or RR.

Now, if British private enterprise can manage to compete
with the Government funded projects elsewhere in the world
there might be some hope for the future yet.

The old pattern is repeating itself yet again.
    Bob.

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

Date: 16 Aug 88 16:44:58 GMT
From: mcvax!ukc!etive![e-mail]  (Bob Gray)
Subject: Re: Space Station Name chosen -- Fred

In article <[e-mail]> [e-mail] ( Todd/Dr. Nethack ) writes:
>> yea, yea...space station "Fred Om", or "Fred" for short...

>The "Fred-Om" was from a suggestion by Eddie "Superfrog" Caplan.

Is there any truth in the rumor that he is to develop the
next generation of US launch vehicles for servicing the
space station?




:-> :-> :->

Ducks quickly to avoid the bricks.
    Bob.

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

Date: 16 Aug 88 16:48:03 GMT
From: mcvax!ukc!etive![e-mail]  (Bob Gray)
Subject: Re: 95% vs. 99.9% reliability

In article <[e-mail]> [e-mail] (Henry Spencer) writes:
>As somebody wrote in Aviation Week a few months afterward (roughly, from
>memory):  "If the same thing had happened to the Soviets, they would have
>swept the debris off the launch pad, hoisted the next launcher onto the
>pad, and started the countdown.

Much more importantly, they don't scrap the old launch system
until the new one is working reliably, and can do all that
the old one could.
    Bob.

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

Date: 18 Aug 88 03:59:18 GMT
From: [e-mail]  (Paul F. Dietz)
Subject: Re: Seti

In article <[e-mail]> [e-mail] (Gerry Roston) writes:
>Working with some assumptions:
>1) Intelligent life forms elsewhere have life spans that are similar in
> magnitude to ours (say 50-500 years)

This is debatable, especially for mature technological civilizations.  Things
like nanotechnology, genetic engineering, the ability to load/backup the
state of a nervous system could all affect this estimate.

A spacefaring society, even one restricted to a single stellar system,
could have many trillions of members (but technology may make the concept
of an individual obsolete), and each member could have a productivity orders
of magnitude greater than 20th century Americans.  I would be very careful
when proclaiming limits on what technological advances such a society might
accomplish given millions of years.

>2) Advanced civilizations are energy bound (I know, fusion might solve
> that, but...)

Solar (stellar?) energy is more than adequate, although I suppose one
could call that fusion.  One trillionth of the output of the sun for
four years equals the kinetic energy of a 100,000 tonne spacecraft
travelling at 0.1 c.  This is a trivially small fraction of the available
energy.  Using this energy is an engineering exercise -- one with many
solutions, I'm sure.

>3) Advanced societies have limited budgets and would expect a return on
> investment

The cost of building a starship, for a sufficiently advanced society,
will be a very small fraction of the total available wealth.  Small projects
don't necessarily have to have a ROI in the usual sense.  What's the ROI
of charitable contributions, for instance?

Also, for a mission that returns information, the value of the information
is proportional to the number of consumers of the information.  There
could be very many such consumers.  A 10 trillion population civilization
that was 1% scientists would have 100 billion scientists -- and NSS/L5,
if scaled proportionally from a 250M to a 10T population, would have
some 800 million members!

>1) Financially feasible; if they are so advanced, what would the hope to get
> from us?
>   If it is raw materials, wouldn't they be better off getting them from a
> planet not inhabited by intelligent life forms?

Arguments that aliens wouldn't visit this solar system that depend on some
property of the human race miss the point:  why didn't the aliens colonize
the solar system hundreds of millions of years ago?  Why haven't they
colonized nearby star systems?  Where are all the Dyson spheres?  The
disassembled stars?  The Kardashev type-III civilizations?

>2) Politically practical; what would be the point of an interstellar
> (commerce, trade agreement, cultural exchange, etc. ), if it takes tens
> to hundreds of years for messages to get from on civilization to the other.
>
>3) Easily understandable from an individual perspective; what individual would
>   leave behind FOREVER, everything he/she/it knows about on the very remote
>   possibility of discovering another intelligent species?  And would this
>   being possess the necessary skills to communicate, etc.

Why should communicating with other intelligent be the only reason for
going to another stellar system?  This seems odd coming from a person
working at an organization that devotes great effort to understanding
and visiting the apparently sterile bodies of our own solar system.

Also, it is not obvious to me that colonizing another stellar system
requires sending anyone.  One might imagine, for example, a very
sophisticated machine that, on arrival, manufactures an incubator from
local materials and grows colonists.

To summarize, it seems to me that the pro-SETI, anti-interstellar travel
viewpoint suffers from excessive timidity in projecting the capabilities
of alien civilizations.  Assessments based on comparisons to current
technology or current rates of energy use are worthless, considering our
technological immaturity and what a tiny fraction of the available energy
and material resources we currently use.

Paul F. Dietz
[e-mail]

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

End of SPACE Digest V8 #340
*******************