Aucbvax.6275
fa.space
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Wed Feb 24 03:37:16 1982
SPACE Digest V2 #114
>From OTA@S1-A Wed Feb 24 03:32:48 1982
SPACE Digest Volume 2 : Issue 114
Today's Topics:
Quasars
Intergalactic Colonization - How hard is it}?
L-5 Society
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Date: 23-Feb-82 8:52:52 PST (Tuesday)
From: Reed.ES at PARC-MAXC
Subject: Quasars
To: Space@MIT-MC
Reply-To: Reed
cc: Reed
A recent article in the LATimes 'dramatized' the plight of an astronomer
(whose name escapes me at the moment) who may lose his viewing priveleges
at Mt. Palomar, presumably because he holds controversial beliefs with
respect to the nature of quasars.
The article described the astronomer as believing that quasars are not
necessarily the extremely distant objects most other astronomers believe
they are. The committee responsible for allocating observatory time was
considering a cutback of time to this astronomer because his research
showed no direction or something of that nature.
An article on quasars in the Feb. Scientific American espoused the
conventional view with no more than a reference to the fact that some
astronomers believe that quasars are nowhere as distant as is generally
accepted.
The LATimes article was a reasonably balanced account of both sides with
respect to the allocation problem, but neither it nor the SA article gave
any information as to what the alternative theory might be or why the
astronomer's investigations towards proof might be considered inadequate
and therefore worthy of termination.
Anyone out there know anything more?
-- Larry --
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Date: 23 Feb 1982 0745-PST
From: Paul Dietz <DIETZ AT USC-ECL>
Subject: Intergalactic Colonization - How hard is it}?
To: space at MIT-MC
There was an argument on this digest a few months ago about extraterrestrial
intelligence. One argument against it said that if it existed in any
great profusion, at least one race would have expanded out through the
galaxy. They aren't here, so there aren't very many ETI's.
While this argument isn't watertight, it can be extended. What about
intergalactic colonization. This at first seems ludicrous (millions and
millions of light years). But, a ship travelling at .5c would reach
the M-31 in only 4 megayears, or the virgo cluster in 120 megayears, a small
fraction of the age of the universe.
I'll assume that we can design a payload that can stay dormant for millions
of years, activating itself at the end. A problem here might be damage
to electronics and other information due to radiation. A lot of shielding
may be required. This depends on the density of intergalactic gas.
A bigger problem is to accelerate the ship to .5c. Even this seems possible.
Bussard ramjets would be ideal, but we don't know how to make them work.
Carrying fuel for acceleration seems impractical (antimatter?).
One scheme that seems 'practical' is an overgrown mass driver. While
the mass of a rocket goes up exponentially with the desired final
velocity, the mass of a linear accelerator is proportional to the square
of the final velocity. So, let's build a mass driver that can accelerate
payloads at 1000g's. To reach .5c at 1000g's take around 1.5E4 seconds
(a little over 4 hours), so the mass driver is around 700 million km long.
[I know it's picky but it's 7e8 miles, and 1.125e8 km -ota]
Energy requirements are high, but not impossible. The sun puts out 4.0E26
joules/sec. A mass of 1E9 kg traveling at .5c has kinetic energy of around
7.0E24 joules. The rate of energy usage could be decreased by launching
the ship in pieces.
If we increase the acceleration by a factor of k we decrease the length
of the accelerator by k, and increase the rate of energy consumption by k.
An accelerator capable of doing 1 million gees would be only ~700,000 km
long, although I don't know what you'd accelerate in it.
Building structures this big that use this much energy will not be possible
soon. But they seem easier to build than dyson spheres or ringworlds.
------------------------------
Date: 24 February 1982 04:24-EST
From: Jerry E. Pournelle <POURNE MIT-MC AT>
Subject: L-5 Society
To: POURNE at MIT-MC
cc: SPACE-ENTHUSIASTS at MIT-MC
I spoke to Mr. Heinlein today and he definitely is coming to the
L-5 Conference. Those interested shld send money:
regular banquet professional
l-5 member $25 $25 $65 (includes banquet)
non-member $35 $25 $75
student L5 $20 $25
student n $30 $25
Send to L-5 Society Box 92056 Los Angeles CA 90009
Conference is April 2-4 (Fri-Sunday) Los Angeles Airport Hyatt
------------------------------
End of SPACE Digest
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