X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson
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Thu, 19 Apr 90 01:36:01 -0400 (EDT)
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Date: Thu, 19 Apr 90 01:35:21 -0400 (EDT)
Subject: SPACE Digest V11 #283
SPACE Digest Volume 11 : Issue 283
Today's Topics:
Re: space tomatoes
Interstellar Radio Communications
Re: Discovery's Spin in 2010 (Was Re: Artificial gravity)
From: pasteur!helios.ee.lbl.gov!hellgate.utah.edu!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!watdragon!watyew!jdnicoll@ucbvax.Berkeley.EDU (Brian or James)
Subject: Re: space tomatoes
Aren't tomatos related to plants like Deadly Nightshade? I wonder how
they came to be regarded as a foodstuff, since I know that as recently as
the 18th century people assumed they were as deadly as their relatives.
Probably some poor bastard starving to death and deciding to end his
misery fast [There's a plant from the Amazon that's safe after cooking
causes its toxins to break down that was discovered by a starving
explorer making a similar decision. He didn't care for a cold last meal,
so he cooked it before eating. I think its what tapioca's made from,
but I wouldn't swear tp it].
JDN
------------------------------
Date: 18 Apr 90 14:48:01 GMT
From: pasteur!helios.ee.lbl.gov!hellgate.utah.edu!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!watdragon!watyew!jdnicoll@ucbvax.Berkeley.EDU (Brian or James)
Subject: Interstellar Radio Communications
Most of the discussion I've seen assumes that that communication
we're trying to 'eavesdrop' is only by chance detectable by us. If
you are trying to spot other technological cultures, it gets a
lot easier if they are trying to be heard [I have this mental image
of forty million civilisations listening carefully to the radio
bands while trying to be perfectly silent themselves]. While it
is probably true that older cultures could be using 'exotic' means
of communication that we, in our technologically primitive and
intellectually fallen state, cannot imagine, there's not much point
in trying to listen for means of communication that are currently
inconceivable to us :). If you assume [and I realise that there is no
binding reason to do so] that there might be a culture which *wants*
to be heard from, the EMR is a good choice to listen to, since it seems
likely to be used for communication for at least some point in a
technological culture's history. It's like the wheel; a likely
although not inevitable tool for sapients to discover, and if you
want to be heard, it's a good guess at a communications technology
that's likely for most technological cultures to be aware of.
Now, the *motives* for a culture to broadcast to other cultures
are open to question, and while currently, humans find it hard to
justify any activity that lasts longer than a decade [Let's hear it
for the Harvard Business School of thought!], even we lowly primates
have had projects which took lifetimes to finish [cathedrals in Europe,
for example], so it doesn't seem unreasonable to speculate about another
species having activities that last multiple centuries or millenia. As
someone else pointed out, even though broadcasting in all directions is
inefficient, there are groups, like Voice of America or Radio Moscow
that have motives for doing so. I hope this doesn't mean that most
detected SETI signals are things like 'Quantification of Angel Packing
in a Infinitesimal Volume' :)
I wonder if there other ways of detecting ETIs at range. We have had
an impact on our planet's atmosphere, but I have no idea if that kind
of thing is detectable given *big* telescopes [100 km mirrors out beyond
pluto, :) ] or obvious that humans caused the change. It could be that
life forms like plants are much easier to spot than other high tech
species [Any world with lots of O2 in its atmosphere has got to have
something constantly replacing the oxygen]. Back in the '70s, there
was speculation that a nuclear war is detectable for ~50ish LY, but
that's not the kind of technique that is useful for long term detection
of signals. I suppose in a few decades, we could do things like dumping
a megatonne of rare elements [like Plutonium] into the sun and hope
that if any ETI notices the weird emission lines in Sol's spectrum,
they don't just create a model of stellar evolution that includes a
class of 'stars that really should not have plutonium emission lines
but do anyway'. Back when they found LGM 1, and after they realised
that it looked much more like a natural source than a technologically
produced signal, someone commented that, while pulsars are a stupid way
to try and communicate, he knew of no binding reason why high tech
