🚀 go-pugleaf

>From OTA@S1-A Sun Jan 17 03:42:35 1982

SPACE Digest                                      Volume 2 : Issue 82

Today's Topics:
		      Absolute velocity of the Earth
			   Re: life from comets
			      Physical laws
	    Firms sign up to use less costly European rockets
			   Dean Machine History
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Date: 16 January 1982 17:56-EST
From: Gene Salamin <ES at MIT-MC>
Subject: Absolute velocity of the Earth
To: SPACE at MIT-MC

     The tenets of special relativity, that absolute velocity is physically
meaningless and that there is no lumeniferous ether, are generally considered
as established because of the agreement between the predictions of the
theory and experimental results.  Although there is no ether with respect
to which we can measure the velocity of the Earth, the vacuum of space is
actually filled with black body radiation at a temperature of 3 K, and
it is possible to define one's velocity with respect to this radiation.
An observer is at rest when the radiation is isotropic (independent of
direction).  An observer in motion with respect to the black body
radiation will measure a higher temperature in the direction toward which
he is moving, and a lower temperature in the direction opposite, as a
consequence of Doppler shift.  The optical absorption length for this
radiation is larger than the radius of the known universe, so the reference
frame defined by the radiation is of a cosmological scale (although not
necessarily of the entire universe).  Using balloon carried microwave
sensors, the "absolute" velocity of the Earth has been measured.  It
is something like 300 km/sec.

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Date: Sat Jan 16 01:46:57 1982
To: Space at MIT-MC
From: decvax!watmath!jcwinterton at Berkeley
Subject: Re: life from comets
Source-Info:  From (or Sender) name not authenticated.


I wish people would not post newswire stuff to this network.  It is not
all that useful, and I am not even sure it can be legal.  What about the
copyright of the wire service?

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Date: 16 Jan 1982 2028-EST
From: Jon Webb <WEBB at CMU-20C>
Subject: Physical laws
To: Space at MIT-MC

The Michelson-Morley experiment was one of the major problems that led
to the creation of the theory of special relativity, but if it turned
out to be in error today we would still have to keep a lot of relativity
around.  This is because physicists observe every day things that are
consistent with the "strange" predictions of relativity, like time
dilation and increase in mass with velocity.  They observe these things
in particle accelarators.  So just finding an error in M-M won't make it
possible to build FTL ships after all.

The same thing applies much more strongly to things like the Dean Drive,
of course.  If we're going to find ways around the obstacles we've
encountered, those ways will probably be at the frontiers of science,
not way back someplace which has been overlooked by mankind and Mother
Nature all these millenia.

Jon
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Date: 17 Jan 1982 0000-EST
From: JoSH <JoSH at RUTGERS>
Subject: Firms sign up to use less costly European rockets
To: space at MIT-MC

According to a news story (Gannet) under this title, three
US companies, Western Union, Southern Pacific Comm., and
GTE have signed up for a total of 5 satellites so far on
the "mostly-French" Ariane.  At $20 million a shot that
comes to $100 million, instead of spending $125 to $135 
million at NASA (which would have used McDonnell-Douglass
Deltas).

"Despite the shuttle's potential as an efficient cargo
carrier into space, America's space transportation system
could price itself out of the market by the end of the 
decade if--as expected--NASA raises its shuttle cargo 
rates due to escalating costs of the external tanks and 
solid rocket boosters."

The story says the French completed the Ariane test flight
program last month after four launches.  The satellites
are scheduled to go up in 83 and 84.

--JoSH
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From: Marvin Minsky@MIT-AI (Sent by MINSKY@MIT-AI)
Date: 01/17/82 00:25:30
Subject: Dean Machine History

Marvin Minsky@MIT-AI (Sent by MINSKY@MIT-AI) 01/17/82 00:25:30 Re: Dean Machine History
To: space at MIT-MC, Pourne at MIT-MC, sf-lovers at MIT-MC

Shortly after the Dean drive was described in Astounding,
John Campbell published a picture of it.  I examined the picture
with a lens and managed to read the brand name of the bathroom
scale used to measure the loss of weight of the machine.
My college roommate, Roland Silver, and I conjectured correctly
that this scale had a "diode" in it that coupled the platform and the
reading device.  So we went to Sears Roebuck in Porter Square, Cambridge
and bought that very scale.

When you stand on it it reads your weight fine, but if you pump your
arms up and down -- just as did the dean machine itself --
then the weight fluctuates a lot -- with the mean weight (and even the maximum)
far below the real weight.

So then Clause Shannon and John Pierce and I wrote a sharp detailed letter
to Campbell about this.

John Campbell didn't print our letter, but he sent me (knowing I was the
instigator) a long letter that I still have here, denouncing
establishment scientists for their reactionary and unimaginative
rigidity and general intolerance.

Suitably chastened, I dropped yhe matter and continued with my
reactionary, establishment-bound studies.

Anyway, this incident jibes with Pournelle's account about
Cambell seeing the machine which "jumped around a lot"
on a bathroom scale.  I checked out all the other scales, too,
and finally found one that reads high when you bounce.  But
these were much less common.  So, possibly, Dean was
hoist by this pitiful petard.  But I maintained that this was
extremely unlikely since, obviously, he was all too familiar
with flakey, vibrating, weighing mechanisms.

  -- marvin

P.S..  I should add that much as we hated him, we loved him
greatly too, and for all he did for all of us.  And same for
G. Harry Stine.

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End of SPACE Digest
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