m.postman@UCLA-Security@sri-unix (12/07/82)
From: m.postman at UCLA-Security (UCLA-LOCUS Mail Handler) ===== POSTMAN output follows ===== Mail-from: OTA@S1-A; 7 Dec 1982 0302-PST Via: su-ai.ARPAnet; Tue Dec 7 03:31:21 1982 Date: 07 Dec 1982 0302-PST From: Ted Anderson <OTA at S1-A> Subject: SPACE Digest V3 #67 To: SPACE@MIT-MC Reply-To: Space-Enthusiasts at MIT-MC SPACE Digest Volume 3 : Issue 67 Today's Topics: Forbidden Planet explosion ; 2001 flaws Re: images from Voyager... Misconceptions 2010: Oddesy Two Burning Oxygen Asteroid mining ---------------------------------------------------------------------- Date: 5 Dec 82 22:32:26-PST (Sun) To: space at Mit-Mc From: harpo!ihnp4!ihuxr!lew at Ucb-C70 Subject: Forbidden Planet explosion ; 2001 flaws "Forbidden Planet" had a good planet explosion effect at the end. To start with, the explosion was viewed from a great enough distance that the planet appeared initially point-like. The explosion itself appeared as a luminous circle which expanded rapidly in radius and then faded (all in silence.) Not beyond criticism, I suppose, but infinitely superior to the firecracker effects in Star Wars. It looked a lot like the upper atmosphere dye explosions which were launched from Virginia in the sixties. Remember them? Also, a technical flaw in "2001" is the existence of "star drift" to indicate the stately motion of the "Discovery". I would guess that they knew it was wrong but left it in anyway. "2001" also had billowing gas and dust in the lunar vacuum. Lew Mammel, Jr. ihuxr!lew ------------------------------ Date: 6-Dec-82 14:30:35 PST (Monday) From: Lynn.es at PARC-MAXC Subject: Re: images from Voyager... In-reply-to: Robert Elton Maas's message of 5 December 1982 19:50-EST To: Space-Enthusiasts at MIT-MC cc: REM at MIT-MC, Lynn.es Very creative idea to make parallax measurements, but it needs some more work to be practical. Parallax measurements now are practically useless beyond a few hundred light years, because the measurements get smaller than the noise. The size of the measurements is proportional to baseline (normally the distance across the earth's orbit, by which photographs 6 months apart differ) and proportional to telescope focal length (or image scale). The loss in focal length between our large telescopes (tens of meters) and Voyager (I think a meter or so) loses more than its present distance gains in baseline (about 12 AU instead of 2 that we get with the earth). In fact the loss of radio contact at perhaps 50 to 100 AU will prevent us from ever getting much accuracy gain using Voyager. At least the attitude adjustment gas should not be a factor in Voyager 1, since its electrical camera platform maneuvering mechanism (which does not use the jets) is still working. As for sending out a probe with ion rocket, let's say we can get a light year away in a reasonable time. Now we are talking gains of 30,000 in the baseline. But it will take one heck of a transmitter and antenna to get the data back to us, say a million times more effective than what is on Voyager. And the baseline improvement would barely get a marginal measurement on the nearest galaxy. We would need at least another factor of 1000 to get good distances for the Hubble constant. Now indirectly it would improve measurements by cepheid variable or other means, because they are calibrated by parallax measurements of nearby objects. But this indirectness probably means only a slight increase in cepheid distance accuracy, and still won't help the intervening material problem with it. The large space telescope may be able to get us better parallax measurements by reducing the noise (atmospheric disturbances of the incoming light) rather than increasing the measurement. I would estimate the improvement to be about a factor of 10. /Don Lynn ------------------------------ Date: 6 Dec 82 19:17:28-EST (Mon) From: the soapbox of Gene Spafford <spaf.gatech@UDel-Relay> To: space-enthusiasts at Mit-Mc Subject: Misconceptions marcw @ teklabs asked us for our favorite misconceptions. The only problem is, I don't know which of the things I believe happen to be misconceptions! Maybe they all are.... Could it be that the moon isn't the sun at night, and that the world may not be flat? Perish the thought! Lest anyone think I'm poking fun at Marc, let me just point out that language is so much fun I just couldn't resist. :-)> Spaf ------------------------------ Date: 6 Dec 1982 2054-PST From: Den Lenahan <DLENAHAN at USC-ISIE> Subject: 2010: Oddesy Two To: dvw.agm at MIT-OZ cc: space at MIT-MC Postal-Address: SMC 2811, NPS, Monterey, Ca 93940. Phone: (Home) 408-633-5161 I wasn't too impressed with 2010. It answers some of the questions left open by 2001, but, on the other hand, the open-endedness of 2001 was one of its pluses. I was going to say that the conversations in 2010 sounded too much like Mr. Wizard lecturing a Jr. High student. Especially when the other person responds, "I didn't know that!" to something that's almost intuitively obvious to a casual observer, let alone a scientist. But, over dinner tonight, I was reading the review in the January issue of Discover, and they say it even better: "The humans in this spacescape are hard to distinguish from one another; most sound like Clarke carrying on a conversation with himself." If you've read Michner's 'Space' you'll have a feel for Clarke's dialogue. However, if you're really curious to know what happened to David Bowman and the Discovery, this is the only way to find out! ------------------------------ Date: 3 Dec 82 2:29:40-PST (Fri) To: space at Mit-Mc From: decvax!genradbo!mitccc!jmturn at Ucb-C70 Subject: Burning Oxygen Article-I.D.: mitccc.208 In-Reply-To: Article azure.1499 Via: Usenet; 6 Dec 82 21:16-PST "Pure Oxygen burns so nicely" It is more accurate to say that pure oxygen promotes oxidation so nicely (no big surprise there...) The key thing to remember is that a spark in a pure oxygen atmosphere doesn't cause the room to blow up, but if the spark lands on a couch, the couch is going to be awfully likely to combust in quick fashion. The reason you don't smoke when O2 is in use is to prevent your seat/the floor from going up if you drop the bloody thing. Flaming without Oxygen James ------------------------------ Date: 6 Dec 82 13:21:25-PST (Mon) To: space at Mit-Mc From: harpo!floyd!rjs at Ucb-C70 Subject: Asteroid mining Article-I.D.: floyd.914 Via: Usenet; 6 Dec 82 23:12-PST I've heard that one way of making space technology profitable would be to mine metals from the asteroid belt. How can this metal be brought safely to earth? It seems that you would need to bring vast quantities down to be worthwhile, and I've heard that dropping meteorites of respectable size onto the earth is a good way to drastically change the environment for a long time. Of course: mail answers to me and I'll summarize. Robert Snyder floyd!rjs ------------------------------ End of SPACE Digest ******************* ===== MAIL WAS SUCCESSFULLY PROCESSED =====