Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from holmes.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr1/ota/space/space.dl) (->ota+space.digests) ID ; Tue, 23 May 89 03:17:44 -0400 (EDT) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Tue, 23 May 89 03:17:33 -0400 (EDT) Subject: SPACE Digest V9 #453 SPACE Digest Volume 9 : Issue 453 Today's Topics: Ancient asteroid impact Re: New Orbiter Name Announced Re: Magellan & SRB exhaust RE: Space telescope delays Andromeda Strain Re: Giotto Re: Asteroids and Dinosaurs (was Re: asteroid almost hits earth) Re: Asteroids and Dinosaurs (was Re: asteroid almost hits earth) explosive bolts Re: The late NEMESIS Theory Re: Asteroids and Dinosaurs (was Re: asteroid almost hits earth) ---------------------------------------------------------------------- Date: Fri, 19 May 89 15:57:36 EDT From: John Roberts Disclaimer: Opinions expressed are those of the sender and do not reflect NIST policy or agreement. Subject: Ancient asteroid impact >From: eugene@eos.arc.nasa.gov (Eugene Miya) >Subject: Re: asteroid almost hits earth >> Alverz et al extinction theory as plausible. >Luis and Walter (and all the others) still got lots of respect, >but one of the people who came up, Peter Ray, a botanist at Stanford, >I won't just say "He shot holes thru the theory," but he did raise >interesting unanswered questions from the botanical community. I think it's likely that a large object did hit the earth at about this time, but there are a few obvious questions the popular presentations of the model don't seem to address, which involve the weighting that should be used to estimate the relative significance of factors, for calculations of the size of the object involved, etc. Under normal conditions, a sea bed being built up (later to be turned into rock) would consist of inorganic matter washed from the land (clay, sand), biologically produced material from the sea (CaCO3, later to be limestone), and extraterrestrial matter from numerous tiny meteorites (rich in the metals in question). One would expect the ratio of these materials not to vary too much. At the point in time in question, however, the contribution from living organisms (and by inference, the total number of living organisms) drops off dramatically. The layers above and below are mostly limestone, while the layer in question is mostly clay with a trace of apparently extraterrestrial matter. Possible inferences other than the stated model: - Something else killed the organisms, and only clay was left as the major contributor to the buildup. Deposition was much slower, so there was a lot more time for trace extraterrestrial material to appear and concentrate. - An asteroid did hit and kill life, but then during a long recovery period conditions were as described above, so only a portion of the material found is from the original asteroid, meaning that it was smaller than now thought. - The rate of deposition of clay was not constant, and in fact was much higher than usual during this period, skewing the results. (Something that killed the ground cover would probably lead to increased erosion.) These alternate models could be tested to some extent, but reports in the popular press don't say whether this has been done. John Roberts roberts@cmr.icst.nbs.gov ------------------------------ Date: 18 May 89 14:24:36 GMT From: asuvax!anasaz!scott@noao.edu (Scott Gibson) Subject: Re: New Orbiter Name Announced Peter Scott writes: >whether one name will be painted on one side and one on the other, or why on >earth they felt it necessary to use non-American spelling at all... The Endeavour is named for a British sailing vessel of some exploratory reknown (in keeping with NASA's supposed policy of naming shuttles for famous exploring vessels). It seems silly to spell it Endeavor (because we spell the word that way) when the original is clearly called Endeavour. Simply put: If the ship was named Endeavour, the shuttle should be too. Scott ------------------------------ Date: 18 May 89 09:32:38 GMT From: mcvax!ukc!icdoc!syma!andy@uunet.uu.net (Andy Clews) Subject: Re: Magellan & SRB exhaust From article <606@cbnewsl.ATT.COM>, by sw@cbnewsl.ATT.COM (Stuart Warmink): > ..... The worry is that > exhaust particles could damage or dirty the orbiter's windows. Hmmm. Perhaps the orbiter should be fitted with windscreen wipers :-) :-) Thanks for the answers to my queries. I'm impressed with the speed - I get answers from the US within a couple of days of posting in the UK. Cheers! -- Andy Clews, Computing Service, Univ. of Sussex, Brighton BN1 9QN, ENGLAND JANET: andy@syma.sussex.ac.uk BITNET: andy%syma.sussex.ac.uk@uk.ac Voice: +44 273 606755 ext.2129 ------------------------------ Date: Fri, 19 May 89 10:53 EST From: Subject: RE: Space telescope delays Henry Spencer writes: >In article <4325@ucdavis.ucdavis.edu> ccs013@castor.ucdavis.edu (Jason Gabler) > writes: >>After the Challenger explosion I stopped keeping track of all the reasons >>for the delay with the H.S. Telescope. Besides that tragedy, can anyone >>give me the other reasons behind its late arrival. > >A combination of not wanting to fly it on the first post-Challenger mission, >not wanting to fly it until the TDRS network for returning data from it was >relatively complete, and not being able to fly it until after flying a >couple of military missions to shut the USAF up. I also seem to remember a lot of software difficulties, starting right from the time of the Challenger explosion. Included in this is a new software bug that was discovered about 6 months ago, which they are just fixing up right now. For the programmers at the Space Telescope Institute, the Challenger disaster was a godsend, because it gave them the extra years they needed to finish AND clean up their software. And they still expect SDI to work correctly! Hah!! -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Arnold Gill | If you don't complain to those who | Queen's University at Kingston | implemented the problem, you have | gill @ qucdnast.bitnet | no right to complain at all ! | -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- ------------------------------ Date: 20 May 89 03:35:56 GMT From: root@unix.sri.com Subject: Andromeda Strain In the *movie* version it was not an asteroid, it was a space probe. It has been a long time since I saw it, but there was I think the implication of a possibility that the probe was lanched by the military in order to collect extraterrestrial material. Also, It didn't decompose plastics at all. It caused blood to coagulate comletely, which kind of slowed the heart down. In the end it was found that it didn't do well in an oxygen environment. However, all of the high-tech machines broke down, for stupid reasons that the movie maker thought representative of engineering narrow mindedness, and so it took them much too long to figure this out. By the way, I do think it is possible that an extraterrestrial bug could cause problems on earth, although very unlikely. ~rI am thinking that something couldevolve to live in an incredibly harsh and spartan extraterrestrial environment by being able to extract energy from almost any kind of molecule. }iConsider for example, molds and such. They will grow on any kind of decomposing organic matter. They are not in any sense host-specific. Now imagine one that grew much more rapidly in a suitable environment, say inside the lungs. Chris Eliot Umass/Amherst You can post this to the net, but don't expect me to defend any of it. ------------------------------ Date: 20 May 89 03:06:00 GMT From: root@unix.sri.com (Bob Gray) Subject: Re: Giotto In article <1217@jarthur.Claremont.EDU> jokim@jarthur.UUCP (John H. Kim) writes: >I heard some (*gag*) press reports that they were going to recover >Giotto and check out some neat Halley's Comet samples that it got >sandblasted with. Is this true (eventually?) No. ESA currently doesn't have any way of retreiving a satellite. Giotto isn't carrying enough fuel to slow down as it passes the Earth (You can't just put on the brakes you know :->). Giotto relied on the comet dust being ionised by the impact with the first layer of the shield so that the expanding cloud of gas gets stopped by the second layer. And even if samples did survive the impact, there isn' any way for them to be kept cold to preserve the more volatile (and interesting) material. The news yesterday was that Giotto is thought to be about sixty percent operational, and that it still has sufficient fuel reserves to carry out the mission to Grigg-Skellerup. It is not expected to survive this encounter. Bob. ------------------------------ Date: 19 May 89 16:11:10 GMT From: tekbspa!optilink!cramer@lll-winken.llnl.gov (Clayton Cramer) Subject: Re: Asteroids and Dinosaurs (was Re: asteroid almost hits earth) In article <40171@bbn.COM>, ncramer@bbn.com (Nichael Cramer) writes: > In article <1216@irisa.UUCP> saouter@irisa.UUCP (saouter yannick) writes: > >In article <13111@ut-emx.UUCP>, ethan@ut-emx.UUCP (Ethan Tecumseh Vishniac) writes: # ## It is also true that this is not the most dramatic mass extinction in the # ## fossil record. # # # #Such collisions occurs about every 50 000 000 years and I've heard that others # #species have disappeared as suddenly as the dinosaurs did, so earlier # #collisions might be the cause for that, too. # # # #Does anyone knows others example of strange disappearance ? # # I don't remember the numbers (in species/yr) offhand, but I've read # arguements (e.g. by S J Gould) that claim that we are *now* in the midst of # the one of greatest (if not in fact _the_ greatest) of mass extinctions of # all time. # # If I recall right, the numbers work out to ~1 species/100,000 increase in # human population. I've read that the current rate of extinction is about 15 species/century -- which is clearly far lower than ~1 species/100,000 increase in human population. Of course, we still don't know all the species on the planet, and I very much doubt that we notice many that come and go anyway. One of the Paleozoic extinctions involved 99% of all species then alive being killed off. But over what time scale? -- Clayton E. Cramer {pyramid,pixar,tekbspa}!optilink!cramer Assault rifle possession is a victimless crime. ---------------------------------------------------------------------------- Disclaimer? You must be kidding! No company would hold opinions like mine! ------------------------------ Date: 20 May 89 06:36:07 GMT From: bbn.com!ncramer@bbn.com (Nichael Cramer) Subject: Re: Asteroids and Dinosaurs (was Re: asteroid almost hits earth) In article <1493@optilink.UUCP> cramer@optilink.UUCP (Clayton Cramer) writes: >In article <40171@bbn.COM>, ncramer@bbn.com (Nichael Cramer) writes: ># #Does anyone knows others example of strange disappearance ? ># ># I don't remember the numbers (in species/yr) offhand, but I've read ># arguements (e.g. by S J Gould) that claim that we are *now* in the midst of ># the one of greatest (if not in fact _the_ greatest) of mass extinctions of ># all time. ># ># If I recall right, the numbers work out to ~1 species/100,000 increase in ># human population. > >I've read that the current rate of extinction is about 15 species/century -- >which is clearly far lower than ~1 species/100,000 increase in human >population. CLAYTON I checked my source for the above after I got home last night, and he was claiming a loss of 10,000 species/yr but he didn't cite any sources. This does sound very high. But on the other hand, it seems equally difficult to believe we've only lost 13-14 species in all of the 20th century. (I've also seen figures in the 1-10/yr range.) Do you (or anyone else) have specific references for what the actual value of this rate is? Thanks NICHAEL ------------------------------ Date: Sat, 20 May 1989 14:53-EDT From: Dale.Amon@H.GP.CS.CMU.EDU Subject: explosive bolts > Do you think that they could flip the explosive bolts that the shuttle is > held on to the EFT with if an emergency arose? Or would the shuttle be unable > to do something like that? No. SRB SEP any time before SRB burnout is nonsurvivable. The solids would at worst burn the wings off the shuttle and at best simply tear it apart from aerodynamic forces. ------------------------------ Date: 20 May 89 14:26:14 GMT From: cs.utexas.edu!ut-emx!nather@tut.cis.ohio-state.edu (Ed Nather) Subject: Re: The late NEMESIS Theory In article <1568@cfa.cfa.harvard.EDU>, wyatt@cfatst.HARVARD.EDU (Bill Wyatt) writes: > I had to comment on the following exchange. I find Ed's response to be > uninformative (and even snide) despite being mostly factually correct. I thought facts informed. I guess I was wrong. > The `mythical Oort cloud' is on much better theoretical and > observational ground that this denigration would imply. Apparently you know of observational evidence that I don't -- would you please cite it, bearing in mind that the theory was devised to explain the origin of comets, so their presence is not evidence the theory is correct? Theoretical ground does not, of course, constitute evidence. Note that I did not say the theory was wrong, only unproven, and totally lacking in observational evidence other than the known evidence it was devised to explain. It has proved to be unprovable, hence "mythical." I guess I would like it to be correct, since it's plausible, but my gullibility was shattered as a child by an unplanned close encounter with the tooth fairy ... -- Ed Nather Astronomy Dept, U of Texas @ Austin ------------------------------ Date: 20 May 89 22:52:07 GMT From: agate!web-2c.berkeley.edu!c60a-1hb@ucbvax.Berkeley.EDU (The Daimyo) Subject: Re: Asteroids and Dinosaurs (was Re: asteroid almost hits earth) In article <40227@bbn.COM> ncramer@labs-n.bbn.com (Nichael Cramer) writes: >In article <1493@optilink.UUCP> cramer@optilink.UUCP (Clayton Cramer) writes: >>In article <40171@bbn.COM>, ncramer@bbn.com (Nichael Cramer) writes: >># #Does anyone knows others example of strange disappearance ? >># >># I don't remember the numbers (in species/yr) offhand, but I've read >># arguements (e.g. by S J Gould) that claim that we are *now* in the midst of >># the one of greatest (if not in fact _the_ greatest) of mass extinctions of >># all time. >># >># If I recall right, the numbers work out to ~1 species/100,000 increase in >># human population. >> >>I've read that the current rate of extinction is about 15 species/century -- >>which is clearly far lower than ~1 species/100,000 increase in human >>population. > >I checked my source for the above after I got home last night, and he was >claiming a loss of 10,000 species/yr but he didn't cite any sources. This >does sound very high. But on the other hand, it seems equally difficult to >believe we've only lost 13-14 species in all of the 20th century. (I've >also seen figures in the 1-10/yr range.) > >Do you (or anyone else) have specific references for what the actual value >of this rate is? There is a theory that was proposed by the late Dr. Luis Alvarez and Dr. Richard Muller on the topic of mass extinctions. In the geological record there is evidence of mass extinctions at regular intervals thru out earth's history. These extinctions occurred (don't quote me on this, I'm doing it by memory) I think every 300 million years, at a almost frightening regular interval. The extinctions of the dinosaurs was one and about 300 million years later, the extinction of pre-historic mammals another. Before then, the geological record shows extinction after extinction at roughly 300 million year intervals. The theory proposed states that our Sun may have a companion star. For years, astronomers and astrophysicists had assumed that our sun was different from the rest of the stars in the universe in that it was not part of a binary system. This theory states that our sun may have a companion star that at its closest point to the earth (it still looks like a normal star from a telescope at its closest point) crosses thru the comet belt with enough gravitational disturbance to knock about a 300,000 (I think) or so comets out of the cloud into the inner solar system. The odds worked out that one would hit the earth. For more information consult the book "Nemesis: the Death Star" by Dr. Richard Muller. Extinctions on the smaller scale, aka caused by man, continue on this planet in several key places : 1South America 2Africa ...etc. the list goes on. The destruction of the Amazon to make farm land is by far one of the fastest destruction of both animal and plant species in the world. The uniqueness of the Amazon enviroment is such that the plant and animal species that live there cannot be found anywhere in the world. In fact in a recent shuttle picture, the Amazon area was nothing but smoke as the forest is being burned down. In Africa, the desert grows. Man's own folly is to blame for that disaster as well. The interference of well meaning foreigners to help the people has led to the destruction of thousands of acres of land. The digging of wells in areas with lush vegetation was not only not productive but is the direct cause of the growing deserts. Herd animals, wild life, and man flock for miles around just to get to this plentiful source of water. In their rampage, the vegetation is stripped, trees are cut down and tender vegetation trampled. What's left in a matter of months is a wasteland, a addition to already expanding desert. Destruction of trees has had a direct impact on the ecosystem in Africa. In areas where there are trees it rains. In areas where there were trees not long ago, it will rain for a few years more. In areas where trees were cut down a long time ago, there is desert. The ecosystem is destroyed the moment the native habitat is destroyed, and the weather adjusts accordingly. The famine in Africa will continue, probably and sadly, forever, unless the the ecosystem is restored. In the United States, coal burning plants have destroyed forest land on the Eastern Sea Board and all over Eastern Canada. Lakes have so much acid content in them that the water is poisonous. In Europe, a similar situation exists in Germany, where a huge portion of forest land has been labeled as doomed from the acid rain. In Chicago, the marble off the buildings is being dissolved by the acid rain, of which sulfuric acid is a member. When the habitats go, so do the life forms that live within them. Hopefully something can be done to stop this. Soon I hope. Albert Sze-Wei Wang ------------------------------ The Daimyo | c60a-1hb@widow.berkeley.edu | ------------------------------ ------------------------------ End of SPACE Digest V9 #453 *******************