Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from hogtown.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Sun, 30 Jun 91 01:26:33 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Sun, 30 Jun 91 01:26:26 -0400 (EDT) Subject: SPACE Digest V13 #747 SPACE Digest Volume 13 : Issue 747 Today's Topics: United Space Federation,Inc. Hello! Please Post SEATTLE YELLOW PAGES WANTED Re: Dark matter colonizing other galaxies Re: Amputation How long to planets in other solar systems? Winnebagos Re: Slingshot effect Dark Matter Re: Dark matter Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription requests, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: Fri, 14 Jun 91 18:16 EST From: USF@VAX5.CIT.CORNELL.EDU Subject: United Space Federation,Inc. Hello! Please Post X-Envelope-To: space+@andrew.cmu.edu From: IN%"rhys@cs.uq.oz.au" 13-JUN-1991 22:50:39.94 To: USF@VAX5.CIT.CORNELL.EDU CC: Subj: Letter Received: from uqcspe.cs.uq.oz.au by vax5.cit.cornell.edu; Thu, 13 Jun 91 22:46 EST Received: from solution.cs.uq.oz.au by uqcspe.cs.uq.oz.au id ; Fri, 14 Jun 91 12:46:33 +1000 Date: Fri, 14 Jun 91 12:46:31 +1000 From: rhys@cs.uq.oz.au Subject: Letter To: USF@VAX5.CIT.CORNELL.EDU Message-id: <9106140246.AA17281@client> X-Envelope-to: USF Hello! From: United Space Federation, Inc. Ithaca, N.Y., USA Subject: We are seeking your support in our present efforts to set up an International Space Agency by 1993. At present the USF is setting up an International Executive Committee to further develop the USF. There are also openings for USF Directors and Officers. We are also looking to build a strong E-Mail support group. Dear Space Enthusiast, The United Space Federation, Inc. is now looking for your support in a historic undertaking of great importance. We are endeavoring to set up an International Space Administration that would not compete with national space programs or organizations, but would unite and focus their efforts in one common direction. We are looking for people who would like to participate on our now forming International Executive Committee. You would be involved in the formation and development of this International Space agency and would exchange your ideas with others around the world. You would have both a say and vote in all aspects of this effort and the USF's activities. If this sounds interesting to you, drop us a line and we will contact you in this regards. Also, there are now openings for Directors on the USF's Board of Directors. If you would be interested in this opportunity or would like more information about this, please contact us and we will promptly reply. And lastly, we are looking to build a strong E-Mail support group to allow people who wish to support the USF but do not want to be a Committee Member, Director, or Officer the chance to both participate in the development of the USF and to keep abreast of the USF's activities and accomplishments. We look forward to your reply in these regards. Thank you for your time and support! Sincerely, Rick R. Dobson Executive Director and Founder United Space Federation, Inc. E-Mail Contacts:1) United Space Federation,Inc. International Headquarters Internet: USF@VAX5.CIT.CORNELL.EDU USF@CRNLVAX5.BITNET USF@CORNELLA.CIT.CORNELL.EDU USF@CORNELLA.BITNET 2) European USF Representative Fracios Spiero PhD. ESA/ESTEC European Space Agency Alumni: International Space University Internet: FSPIERO@ESTEC.BITNET 3) Australian USF Representative Rhys Weatherley PhD. Student at University of Queensland, Australia Internet: Rhys@cs.uq.oz.au 4) Canadian USF Representative Argun N. Tekant Computer Systems Analyst/Programmer Internet: Atekant@wimesy.bc.ca 5) United States USF Representative Carol L. Redfield PhD. Southwest Research Institute, Texas, USA Internet: Luckhardt@aivax.datasys.swri.edu United Space Federation, Inc. International Headquarters P.O. Box 4722 Ithaca, New York 14852-4722 In the United States of America An International Civil Space Agency By 1993, An Idea Whose Time Has Come! ------------------------------ Date: 14 Jun 91 23:06:05 GMT From: bu.edu!m2c!wpi.WPI.EDU!mrpaolo@uunet.uu.net (Pawel Mario Szymkiewicz) Subject: SEATTLE YELLOW PAGES WANTED I have an urgent need for the Seattle, Wash. telephone directory, i.e. the famous Yellow Pages (the one from April '91, preferably - I've seen it in my library, but of course can't take it home.) It's free for Washington residents so if you could email me we could arrange for a shipment. Please contact me as soon as possible. (e-mail to mrpaolo@wpi.wpi.edu) -- Paul (electronically known as mrpaolo@wpi.wpi.edu) ------------------------------ Date: 15 Jun 91 03:50:14 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!unixhub!slacvm!doctorj@ucbvax.Berkeley.EDU (Jon J Thaler) Subject: Re: Dark matter In article <10705@suned1.Nswses.Navy.MIL>, lev@slced1.nswses.navy.mil (Lloyd E Vancil) says: >And I was wondering, why cant "dark matter" be planets, rocks, comets, etc My recollection is that the ratios of isotopes produced in the big bang, depends on the density of baryonic matter when the temperature became low enough to allow the heavier isotopes (eg, helium) to survive. Postulating enough normal (baryonic) matter to explain the missing mass would ruin the predictions of these ratios. I don't know enough to evaluate the merits of this argument. Perhaps an expert would like to comment. ------------------------------ Date: Fri, 14 Jun 91 08:15:51 PDT From: fermat!r@la.tis.com (Richard Schroeppel) Subject: colonizing other galaxies Paul F. Dietz writes > > > Ultimately, of course, one has to assume that aliens would actually *want* to colonize the galaxy. That's impossible to know a priori, even in principle, so SETI still makes sense. The colonization idea does hint that we should look for emissions from galactic megacivilizations at cosmological distances, under the assumption that intergalactic colonization will not occur or has not yet had time to get here. What about intergalactic colonization? I looked at the distance to Andromeda, about 2MLy, and said "probably not in my lifetime". [I'm something of a pessimist.] But the nearest other galaxies are the Magellanic clouds, and Snickers. The Magellanic clouds are "only" about 150 KLy away. There may well be intermediate stepping stones: loose stars that have "boiled off" from the Milky Way, or the shell of globular clusters surrounding the galaxy. If the infamous dark matter exists, and is organized into planets near the galaxy (but outside the illuminated part we know about) this might provide a bridge. By the selection argument, if some sub-civilization can cross to nearby galaxies, its members will become the most numerous. How far away is Snickers? There are galaxies much bigger than ours: Big galaxies should have a higher chance (per year) of developing star-colonizing life, so they should be the earliest to be colonized. Finally, there are clusters of (thousands of) galaxies. These may be close enough together that they can be regarded as one unit for colonization purposes. Such clusters should be colonized even more rapidly. Rich Schroeppel Better to extinguish one street lamp, rcs@la.tis.com than to curse the light pollution. ------------------------------ Date: Fri, 14 Jun 91 07:17:43 PDT From: jim@pnet01.cts.com (Jim Bowery) To: crash!space+@andrew.cmu.edu Subject: Re: Amputation I wrote: >2) was damaged because by insisting on everything flying on Shuttle, >JSC ensured Galileo would have to take a trajectory it was never >designed for -- one which damaged it, Henry Spencer writes: >However, the original comment is total nonsense. There was no available >booster that could have launched Galileo on a more direct trajectory. This is exactly my point. If JSC hadn't won the bureaucratic turf war back in the 70's to shut down alternative launch systems (or better yet, if the Shuttle program had been nipped in the bud) would have a system capable of lofting Galileo on the desired trajectory. As you yourself point out, even after only a few years, we are already close (if not there) with a Titan IV/Centaur combo. (That is after a few years of recognizing Shuttle isn't all things to all people.) ----------------------------------------------------------------------------- Jim Bowery 619/295-3164 The Coalition for PO Box 1981 Science and La Jolla, CA 92038 Commerce ----------------------------------------------------------------------------- ------------------------------ Date: 14 Jun 91 20:30:52 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!swrinde!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!watdragon!crocus.waterloo.edu!dmswitzer@ucbvax.Berkeley.EDU Subject: How long to planets in other solar systems? Greetings. I am working on a science fiction novel, and would like to know the following: How long would it take, using present technology, to get to the nearest solar system? How long would it take, using technology 10 years from now (an educated guess, perhaps?)? Do we know anything about the planets in nearby solar systems (any with conditions near Earth?)? Please e-mail any responses. Thanks a lot. Dave ------------------------------ Date: 14 Jun 91 16:45:03 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!caen!spool.mu.edu!cs.umn.edu!sialis!orbit!pnet51!schaper@ucbvax.Berkeley.EDU (S Schaper) Subject: Winnebagos Nick, I worked on the line building those potential death-traps. I assure you that Fred is much, much larger than a Winnebago. Spacelab is about the size of a Winnebago. The individual new shorter modules are about the size of a Winnebago Chieftan. ************************************************************************** Zeitgeist Busters! UUCP: {crash tcnet}!orbit!pnet51!schaper INET: schaper@pnet51.orb.mn.org Aslan is on the move! **************************************************************************** ------------------------------ Date: 15 Jun 91 03:28:40 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!usc!snorkelwacker.mit.edu!bloom-picayune.mit.edu!news@ucbvax.Berkeley.EDU (Matthew T Velazquez) Subject: Re: Slingshot effect In la_carle@sol.brispoly.ac.uk (Les Carleton) writes: >Can you please explain the "slingshot" effect as used on recent >probes. I understand that it increases the velocity of the vehicle by >making passes around the sun. I'm not a physics or Astrophysics major >so it may seem a naiive question. What I don't understand is why the >velocity increases. Surely if a pass of the sun is made, the energy >conservation law will come into play and the vehicle will end up with >the same velocity at its original distance from the sun as it had when >left there (after launch?). It's easier to visualize if you consider flyby of a planet. Of course the planet is moving, so there's your energy source. Patched-conics principles approximate that if you do a Hohmann ellipse to the rendezvous body in the inertial frame, the trajectory is a hyperbola in the frame of the planet. Your visualization that the energy of the vehicle is the same at symmetric points on opposite sides of the hyperbola is correct, but in the PLANET frame. If you exit the rendezvous moving in the same direction as the planet, you gain velocity in that direction IN THE INERTIAL FRAME. Voila! Incidentally, if you exit the rendezvous moving opposite the direction of the planet, you lose inertial velocity. By this means it is possible to remove all Sun-relative velocity from a body, causing it to collide with the Sun, and this was one of the methods a group of students (including me) considered in our evaluation of space-based nuclear waste disposal for a sophmore-level course, Unified Engineering (aka Valley of the Shadow of Death) at MIT. Hope that makes any sense at all:o)# T Velazquez MIT Aero/Astro brndlfly@athena.mit.edu "The art of engineering is knowing when to lie, and by how much." -Ken Meltsner ------------------------------ Date: 12 Jun 91 12:48:08 GMT From: uupsi!cci632!ritcsh!ultb!ritvax.isc.rit.edu!SWD0170@nyu.edu (Scott W. Davis) Subject: Dark Matter Just curious... What is the latest on the search for dark matter? I've heard of all kinds of bizzare theories for this;from brown dwarves to supermassive blackholes to massive neutrinos. Has perhaps the IRAS data confirmed the presense of brown dwarves? Have the WIMP's been found? Or do observations now support the idea of massive black holes in the centers of most galaxies? Comments please... __________________________________________________________________________ Scott W. Davis "YOU study PHYSICS?!!!!" Rochester Institute of Tecnology e-mail in%"swd0170@ritvax.isc.rit.edu" --Horrified RIT undergrad Semper Paratus! --Coast Guard Motto __________________________________________________________________________ ------------------------------ Date: 14 Jun 91 16:24:36 GMT From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!sdd.hp.com!elroy.jpl.nasa.gov!suned1!slced1!lev@ucbvax.Berkeley.EDU (Lloyd E Vancil) Subject: Re: Dark matter In article <1991Jun11.165204.6159@isc.rit.edu> swd0170@ritvax.isc.rit.edu writes: >I was just wondering... > > What's the latest news on astronomy's continuing search for the >nature of dark matter? I've heard all kinds of wild theories;from brown dwarves >to black holes to massive neutrinos. Has perhaps the IRAS data conclusively >revealed the existance of brown dwarves? Have the WIMP's finally been found? >Or are there supermassive black holes at the center of most galaxies? > > Comments please... And I was wondering, why cant "dark matter" be planets, rocks, comets, etc etc? Just a question... -- | suned1!lev@elroy.JPL.Nasa.Gov | * S.T.A.R.S.! . + o | | lev@suned1.nswses.navy.mil | The Revolution has begun! . + | | sun!suntzu!suned1!lev | My Opinions are Mine mine mine hahahah!| ------------------------------ End of SPACE Digest V13 #747 *******************