Date: Fri, 14 Aug 92 05:00:07 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #106 To: Space Digest Readers Precedence: bulk Space Digest Fri, 14 Aug 92 Volume 15 : Issue 106 Today's Topics: Beanstalks in Nevada Sky (was Re: Tethers) Energiya's role in Space Station assem Energya and Freedom and Soyuz ACRV handheld astronomy NASA statement on Earth Data System proposals [NTE 92-71] (Forwarded) Parsecs? (3 msgs) Seeding Mars with life SPS feasibility (WAS: SPS fouling astronomy) Tethers Upcoming Delta launches... Weak interactions, biology and the SSC (2 msgs) Why is this on SpaceDigest (or sci.space) Welcome to the Space Digest!! Please send your messages to "space@isu.isunet.edu", and (un)subscription requests of the form "Subscribe Space " to one of these addresses: listserv@uga (BITNET), rice::boyle (SPAN/NSInet), utadnx::utspan::rice::boyle (THENET), or space-REQUEST@isu.isunet.edu (Internet). ---------------------------------------------------------------------- Date: 12 Aug 92 19:33:45 GMT From: Bruce Watson Subject: Beanstalks in Nevada Sky (was Re: Tethers) Newsgroups: sci.space In article <1992Aug11.124107.1@fnalb.fnal.gov+ higgins@fnalb.fnal.gov (Bill Higgins-- Beam Jockey) writes: +In article <63811@cup.portal.com-, Eric_S_Klien@cup.portal.com writes: +- Would it be possible to put something in near orbit over Nevada and +- attach tethers to it so that people could reach the object via +- elevators? I know it wouldn't be easy, but is there a way to pull +- this off? + +Hmm. Interesting question. To first order: No, it's impossible, for two +reasons. + +When you say "orbit," you usually mean "Keplerian orbit," a free body +that stays on its path without applying any thrust. Nothing in a +Keplerian orbit can hover over Nevada, since the plane of its orbit +*must* pass through the center of the Earth. + +It *is* possible for an object in orbit to hover over a spot on the +Equator, if it takes exactly 24 hours to make one revolution AND its ^^^^^^^^ 23 hours and 56 minutes -- Bruce Watson (wats@scicom) Tumbra, Zorkovick; Sparkula zoom krackadomando. ------------------------------ Date: 13 Aug 92 05:27:13 GMT From: Gary Coffman Subject: Energiya's role in Space Station assem Newsgroups: sci.space In article <9208101533.AA15222@ucbvax.Berkeley.EDU> nicho@vnet.ibm.com writes: >In <65516@hydra.gatech.EDU> Matthew DeLuca writes: >>Allen, why won't you understand that there is more involved than simple >>finance here? You can 'save' $3 billion, but you better be happy spending >>that $3 billion on social welfare programs, because it sure as hell won't be >>spent in space. > Without wishing to buy into US politics, I will merely point out >that you are being pretty free with other people's money here. There is >no requirement that any savings be spent elsewhere, as I understand that >the US has a significant budget deficit which could do with a bit of >help. Yes, but the "savings" Allen quotes is 0.1% of the debt and there is absolutely no guarrantee that Congress would apply any such "saving" to reducing the debt. Indeed, Congress has shown a strong tendency to spend every dime it can extort and borrow from the US taxpayer. The space budget is literally less than nickels and dimes in the US budget dollar, which is probably as it should be for such a long term investment. What is dangerous is the attitude that it's all right to kill Shuttle or Fred to save such sums when it's an almost certainty that they would *not* be reprogrammed to other space projects, but instead would be redirected to welfare programs. To anyone willing to look, social welfare programs have been counterproductive in nearly every case. Gary ------------------------------ Date: 12 Aug 92 06:55 PDT From: Mark Goodman Subject: Energya and Freedom and Soyuz ACRV Newsgroups: sci.space Quoting Allen Sherzer: >Come now Mr. DeLuca, your grasping as straws. When fabrication begins >it won't take long to build another. As to killing the project, not >likely give the huge and lasing political support it has received. I am not aware of any huge and lasting support. The House votes have been about 230-180, far from 2-1, and then only because the aerospace industry has already received such a big hit from DoD cuts. There is tremendous opposition to the space station, which is based on the essential question: what good is it? What benefits does it offer the average taxpayer in return for its $1000/taxpayer cost (order of magnitude)? That's a question I certainly can't answer. >First of all, even if I agreed with that, so what? Just because somebody >else will waste money doesn't give us any right to waste. As a taxpayer, >I am rather pissed that NASA wastes so much; I'm also pissed about all the >other waste. All this attitude does is help keep space expensive and prevent >private efforts from taking off. This is, of course, the reason reason Allen is basically correct, in spite of his often "imaginative" arguments. As a taxpayer, I cannot support the Space Station unless NASA does everything it can to reduce its costs. That includes using former Soviet (let's not say CIS -- the Commonwealth of Independent States will soon be a memory) technology where feasible. Frankly, I haven't seen any showstoppers regarding Energiya or Soyuz. >Since these will open the space frontier and produce far more tax income, >it seems a good idea. Allen, if you are refering to the Space Station, a Moon Base, or planetary exploration, my reaction is: Come on, give me a break. If you are refering to investments in near-term space technology (improved ELVs, perhaps SSTO, improved automation and remote control, lightsats, etc.) and R&D on more distant prospects (NASP, etc.), I agree. Which is it? +-----------------------------+-----------------------------+ | Mark W. Goodman | What a terrible thing it is | | mwgoodman@igc.org -- econet | to lose your mind. | | goodman@ksgbbs.harvard.edu | | +-----------------------------+-----------------------------+ ------------------------------ Date: 13 Aug 92 12:35:38 GMT From: sinenmaa@cc.helsinki.fi Subject: handheld astronomy Newsgroups: sci.space GREETINGS all Aliens and Earth's Beings !! Have you run into the Phobos or other Heavenly Objects lately ? You haven't ! Ok, It's good because I was downloaded my program in to the News Group COMP.SOURCES.HP48. Its name is TYKO and v=3.0. And by the help of this program you can easily locate those objects so there are no difficulties to take your bearings in time or space. Some features; 8.5 planets, Moon, Sun, 21 stars and available coordinates; Rising times Visual magnitude Ecliptical (Geo or Helio) Setting # Apparent # Equatorial Color index Geocenric distance Horizon Heliocenric distance Semidiameter Diameter Nutation in everywhere Obliquity of the Ecliptic Equation of Equinox Sidereal times Universal time Ephemeris transit times Perihelion dates Mean anomaly Mean longitude Elongation Phase Calendar Easter Sundayes and ... so on. And the input can be both the Calendar date -- either Gregorian date or Julian date -- and Julian day. For instance; you can put the date January 2. 3456789 and time 12.36 in the form 1264287318.02 (TZ=0, Calendar=Gregorian) and you will get excatly the same results ( the accuracy can be a little questionable ). And all This from your Handheld, you do not need to drag those exhausting, not VERY Personal, Computers with yours when you are e.g. on the lake in rowboat or having lunch with other aliens from Pleiades. I have also some HP48sx pictures, are called GROB-picts, so if you want to see them ... mail please. I compined and converted them into three GIF-picts. PS. The DOC file has been written in VSL so be patient -- pleeez ! The latest version is 3.01, if you got 3.0 please replace it. regards, kati ------------------------------ Date: 13 Aug 92 14:59:57 GMT From: Greg Moore Subject: NASA statement on Earth Data System proposals [NTE 92-71] (Forwarded) Newsgroups: sci.space In article <1992Aug13.043115.27308@news.arc.nasa.gov> yee@trident.arc.nasa.gov (Peter E. Yee) writes: > >NASA STATEMENT ON EARTH DATA SYSTEM PROPOSALS > > NASA today issued the following statement regarding >the Earth Observing System Data and Information System >Core System acquisition: > >NASA CALLS FOR REVISED PROPOSALS FOR THE EARTH OBSERVING >DATA AND INFORMATION SYSTEM CORE SYSTEM ACQUISITION > > [stuff deleted for brevity's sake and Mike's sake] > As prescribed by NASA source selection regulations, >the evaluation of proposals included a "most probable >cost" analysis of each proposal as reflected in the >"best and final offers" submitted by the offerers. >Despite NASA's repeated attempts during the solicitation >and evaluation processes to encourage the submission of >realistic cost estimates, the government's analysis >clearly indicates that the offerers significantly >underestimated the cost of the respective technical >approaches. Accordingly, NASA is unwilling to select an >offerer for further negotiations leading to award of a >contract. > Now, am I reading this right? Every submitter said they could do it for around $X and NASA and the government is saying, oh no... you can't do it for $X, it's a lot more than that! Until you say it will cost more we won't award the bid. It seems to me that if EVERY contractor said they could do it cheaper than the government says it will cost, maybe the contractors know something? After all, I'm sur they are in there to make money, not lose it. I can understand if one company was way low. In that case, sure you probably don't want to go with the lowest bidder. But if EVERY company is way low? Come on. So, please, if I'm misunderstanding this, please let me know why the goverment wants to spend more money? (And no, the answer is not that every company is using Soyuz. :-) > Extensive analysis of the proposed technical >approaches shows that the proposals reflect sound >technical approaches and exhibit a reasonable >understanding of the program to be accomplished. >Whatever the reason for the underestimation of cost, the >end result is unrealistic cost proposals that do not >provide a satisfactory basis >for constructive negotiations. > > NASA has elected, therefore, to offer an additional >opportunity for offerers in the competitive range to >adjust the proposed costs to a more realistic level. In >instructions issued by the Goddard Space Flight Center >on Aug.10, 1992, as an amendment to the solicitation, >NASA has directed the offerers to submit revised cost >proposals. Changes to the previously submitted technical >and business management proposals will not be >considered. > > In addition, Goddard Space Flight Center has >provided the offerers with the provision that will be >used to evaluate the contractor's cost performance >during the contract period. This provision assesses >significant reductions to the award fee if the >contractor fails to manage and control the program in >accordance with the costs proposed. > > Revised cost proposals that realistically reflect >the requirements of the solicitation and the proposed >technical approach are to be submitted by 1 p.m. EDT on >Aug. 31, 1992. By the end of September 1992, NASA >intends to select an offerer for negotiations leading to >contract award. -- <-------------------------------------------------------------------------> Greg d. Moore | Strider@acm.rpi.edu Green Mountain Software | "All that is gold does not glitter." Carpe Diem | ------------------------------ Date: 13 Aug 92 09:00:57 GMT From: Keith Allan Schneider Subject: Parsecs? Newsgroups: sci.space,sci.physics rone@alcor.usc.edu (Ron Echeverri) writes: >In article <1992Aug13.030630.3919@cco.caltech.edu> keith@cco.caltech.edu (Keith Allan Schneider) writes: >>Hmmm... at the distance of one parsec, one astronomical unit subtends an >>angle of one arc second. >Coincidence. Remember, one AU is the distance from the Earth to the Sun... No, THAT, my friend, is the DEFINITION of a parsec... >5150 >look ma, i can nitpick too! :) huh? or not keith ------------------------------ Date: 13 Aug 92 14:36:08 GMT From: Mikko Tsokkinen Subject: Parsecs? Newsgroups: sci.space,sci.physics In article zowie@daedalus.stanford.edu (Craig "Powderkeg" DeForest) writes: > This talk of parsecs and so forth reminds me of my favorite volumetric unit: > the barn megaparsec. > A barn is a unit of atomic cross-section, 10^-20 cm^2. A barn megaparsec is > about 1.6 teaspoons! > -- > Craig DeForest: zowie@banneker.stanford.edu *or* craig@reed.bitnet And from jargon file: attoparsec: n. `atto-' is the standard SI prefix for multiplication by 10^{-18}. A parsec (parallax-second) is 3.26 light-years; an attoparsec is thus 3.26 * 10^{-18} light years, or about 3.1 cm (thus, 1 attoparsec/{microfortnight} equals about 1 inch/sec). This unit is reported to be in use (though probably not very seriously) among hackers in the U.K. See {micro-}. Mit xxxxx -- Save bandwidth and nerves! Use small signature! -- ------------------------------ Date: Thu, 13 Aug 1992 14:41:35 GMT From: Richard Martin Subject: Parsecs? Newsgroups: sci.space In article <10319@sun13.scri.fsu.edu> jac@ds8.scri.fsu.edu (Jim Carr) writes: >In article zowie@daedalus.stanford.edu (Craig "Powderkeg" DeForest) writes: >> >>This talk of parsecs and so forth reminds me of my favorite volumetric unit: >>the barn megaparsec. >> >>A barn is a unit of atomic cross-section, 10^-20 cm^2. A barn megaparsec is >>about 1.6 teaspoons! > >Cute, but I have always preferred the Hubble-barn. Granted, the exact >value of the Hubble constant is not exactly agreed upon, but I like >the fact that if you multiply the size of the universe (one uses the >Hubble length, obviously) by 1 barn you get something like 16 liters. >My notes are scribbled in the back of "Gravitation", which is at work, >but memory says that a Hubble-barn is the volume of a straw that has an >opening the size of the nucleus of silver and reaches to the edge of >the universe. BTW, a barn is 10^{-24} cm^2 -- 1 fm^2 = 10 mb. I don't know about that definition, but I'd like to see the question from this year's SIN (Sir Isaac Newton) Contest put up here. Anybody from Waterloo in a mood to put it up? We were asked to figure out what the conversion from carats/(barn*yard) to metric was...it was sort of cute, and the first I'd ever heard of the barn. Richard. =) Thanks for the interest, and the explanations! ------------------------------ Date: Thu, 13 Aug 92 12:16:05 BST From: amon@elegabalus.cs.qub.ac.uk Subject: Seeding Mars with life Life started in a reducing, not an oxidizing atmosphere. If Mars has primitive life forms, then I would expect it to be anaerobic types unless evolution proceeded fast enough to make it to the photosynthesis/aerobic phase. Even if it did, it's currently reduced state would be a strong argument that such died out. But that does not necessarily mean the primitive ones did as well. The point about energy source is a good one. I would have to see I simply don't know. But it is telling that live bacteria have been retrieved from MILES under the Earth. ------------------------------ Date: 13 Aug 92 07:50:37 GMT From: Gary Coffman Subject: SPS feasibility (WAS: SPS fouling astronomy) Newsgroups: sci.space In article <10AUG199219061012@judy.uh.edu> seds%cspara.decnet@Fedex.Msfc.Nasa.Gov writes: >In article <1992Aug10.004625.23290@dartvax.dartmouth.edu>, Frederick.A.Ringwald@dartmouth.edu (Frederick A. Ringwald) writes... >> >>Again, WHAT reasons? Electric cars do not require SPS for their >>development. > >No but converting a transportation infrastructure that runs on billions of >gallons on Hydrocarbons per year to one of running on Terawatts of electricity >will require a vast increase in electrical production. Where else are you >going to get the energy in a non, polluting manner. The thermal pollution of >SPS is miniscule compared to tradtional technologies. Also the laser is tuned >to a frequency that will not be absorbed by the atmosphere. Let's look at this a bit closer with some ROM estimates. If we have a 1 TW laser beam from the Moon impinging Earth, we add an additional TW to the Earth's heat balance. Normal heat input from the Sun for the Earth is about 140 TW so the additional 1 TW is less than a 1% change. But due to efficiency factors discussed below, actual net heat load would be 3 TW. By contrast, for Earth based solar collection, there is no net increase in heat flux. The energy is striking the planet anyway whether we use it or not. All of the energy eventually radiates back to space after being used since any electrical equipment's energy usage ultimately degrades back to heat. Note also that 1 TW of nuclear generated electricity also increases the heat load on the Earth by 3 TW, just like the laser system. Meanwhile, geothermal generation of 1 TW of electricity increases the heat load of the planet not at all, the heat's already here. So direct Earth based solar capture or geothermal are "free" energy while nuclear and Lunar Laser are sources of additional planetary heat. Plus, nuclear is cheaper than lunar, so if we're going to increase the heat load on the planet, we might as well do it with nuke plants. Now what's happening on the Moon? Gas lasers are very inefficient devices. I don't have CO2 numbers at hand, but He-Ne efficiencies are around 0.1%. Giving an advanced CO2 laser a 10% efficiency is likely generous. Now to convert the IR back to electricity the Earth based receiver is either going to be photovoltaic cells, or some thermal system. In either case, efficiency is under 30%. That means that 34 TW of electricity has to be input to the laser on the Moon to deliver 1 TW at the power receiver busbar on Earth. Now the same efficiency factor is at work on the Moon as on Earth for converting light energy to electricity, so now we're talking around 100 TW of captured solar energy on the Moon for 1 TW delivered to the busbar on Earth. Note that I am totally neglecting transmission losses through the atmosphere of the laser beam. Now solar energy striking the top of the Earth's atmosphere, or the surface of the Moon, is 1 kW/m^2. So our 1 TW delivered to the busbar on Earth requires a solar collector area of 1E14 square meters on the Moon. That requires a square 10,000 km on a side, or about 6,000 miles on a side. Sorry gentlemen, the Moon isn't that big. Now if we discard the laser, the Moonbase with it's 6000 mile on a side collector, and simply use the same collector field we were going to use for the laser on Earth, we still gather in 1E10 watts, or 10 GW, and we haven't spent an improbable fortune on the Moon. Note that if we assume 100% laser efficiency, we are still talking about a collector field on the Moon of 1E13 square meters, or a square 3200 km on a side. Still too big. A Lunar collector array would be in darkness 2 weeks out of 4, so storage for two weeks would be required on Earth. For an Earth based array, only 8 to 12 hours of storage would be required for a single site. Since all of Earth uses, or wishes to use, power, multiple sites around the globe make sense to reduce transmission losses. Therefore, at least half of Earth's capture arrays would be in daylight at any given moment. That's at least 7 times better than the Loony Laser. >>> All development of solar tech in the U.S. is carried out by SDIO and they >>> just got their throat cut by congress critters pushing bread and circuses >>> at the expense of the future. >> >>Did you say all? This is news to me. >> >Too bad you don't read the news. There is some work being done by Sharp of >Japan on BSFR enhanced silicon cells. They are the only ones outside of SDIO >doing any meaningful work. Here is a list of the developments and the sponsors > >AlGaAs/CuInSe2 thin film tandem cells [Boeing Defense & Space & Kopin Corp] >GaAs/Ge tandem cells [TRW] >Amorphus (sp) silicon cells [sponsored by Larry Labs] > >There is no other development except a little by TI that I read about recently. >The first two above are high efficiency cells (over 22% with Boeing up to 37% >for the concentrators and 26% on Planar) For more information here I suggest >you read my and my partner's paper on the SEDSAT 1 advanced power system >technology demonstration satellite from last year's Small Sat Conference. I'm sure SERI, EPRI, and Arco, just to name three *US* solar research activities, will be amazed to learn that only Star Wars is doing research on solar energy. SoCal Edison seems to think solar generated electricity is profitable *now* on Earth since they're building a plant. Luz was *almost* profitable at today's peaking prices. Most of the necessary research has already been done, everybody is just sitting back waiting for the price of fossil fuels to rise a bit before making large commitments to *proven* solar technologies. Photovoltaic cells are not the *best* way to use solar energy, and likely never will be for large scale power. But solar *thermal* is workable *today* in certain cases. >>> No we say that we must finally open up the last frontier to development. No >>> single technology or service from space will justify the expense BUT, taken >>> together, the development of the resources of the solar system, whether it >>> be solar energy from space, materials from the Moon, asteroids, and other >>> planets will raise the planetary standard of living to a height that will >>> make today look like the abode of dirt dwellers. So we lose money on every sale, but we make it up in volume? Baahaaahahahahah. >>What does this mean? It has a religious ring to it. Energy might work >>(the point of this thread is to find out), but why should we want to >>import bulk material from space to Earth? Few extraterrestrial ores >>match the quality of those found on Earth, save for iron-nickel >>asteroids, and there's already plenty of steel in landfills. Even if >>you could import diamonds from the Moon, gold from the asteroids, or >>star sapphires from Mars, could you beat the transportation costs? >>Lunar chromium doesn't seem inviting. He3 remains speculative, much >>more so than SPS. And there is NO market for lunar oxygen on Earth. >>There might be one in space, but this seems like a circular argument: >>there isn't, if there's no *other* reason to go into space. > >This is a flame and meant to be a flame. If you are so stupid that you do not >know what this means why don't you pull your head out of the sand and read the >papers. The Rio summit endorsed only ONE space technology and that was laser >power beaming from the moon. In case you have not read we are running out of >almost all of the easily obtainable minerals here on Earth. Don't quote me >your stupid statistics about percentages in the earth's crust. i know them >as well as you. What you do not seem to see is that to get at those percentages >we would have to pollute the world to an extrem extent just to keep up with >preseent growth in the second world, not to mention the development of the >third world's standard of living. They want cars and computers and bridges >just like you in your comfortable American world. There is a great big >world out there, wake up to it. To say that the political posturing in Rio was due to a lot of people with their head up their ass would be understatement. As Paul Dietz has shown at length, we are not running out of *any* material that we need for advanced civilization with the exception of fossil fuels. And there are ample replacements for them. The Earth is a closed system except for energy, and even there natural sources are sufficient for a population ten times the present size *indefinitely*. We have to work smarter, not harder, to utilize those resources well. Raping the planet depends solely on our stupidity, or lack thereof, space based materials won't make a significant difference unless we stupidly continue to be wastrels, and if we do, they're not going to help long anyway. >>> This will allow the >>> Ethopians, our perennial starving masses to irrigate there land and finally >>> grow enough food to be taken off the planetary welfare roll >> >>This assumes an end to the civil war there, which is largely an ethnic >>conflict. If you can get these people to stop hating each other and >>peacefully coexist, more power to you. > >Abraham Maslow in his text on psychology identified a heirarchy of wants and >needs. Formost among them is food and shelter. That is the underlying cause >of the war in Ethopia at this moment. The struggle just happens to be >tribaly not ethnically. Eritrian separtist movement is a tribal movement and >so are most of the rest in Africa. Food comes before race and you protect your >family (tribe) first. I think you might want to take a closer look at the underlying causes of the Ethiopian civil war. It's not lack of food or shelter, it's politics at it's most base, like most wars. Like the people of Bosnia, Ethiopians are quite capable of feeding and housing themselves when they aren't being bombed and shelled off their lands. The current drought is part of a cycle that has repeated for thousands of years. In peacetime the people have coped with this by storing food from the good years to carry them through the bad. The war has destroyed those traditional practices, and prevented the humanitarian aid that is rotting on the docks from being delivered to the people. THIS IS NOT A RESOURCE ISSUE. >The SPS will help those who want to be helped. It can be used to rasie our >standared of living without the destructiveness of raping the resources of the >Earth. I propose that it is wise in your own conceit people like yourself that >throughout history have played the role of opposition to the future by >ridiculing the Columbus's, and Wrights and Goddards and VonBrauns of the world. > >Part of religion is passion and yes I have a passion for the exploration and >development of space, not for the sake of that exploration and development >as and end in and of it self, but for the betterment of the lives of us >all here on earth. I sure as heck have not seen your name associated with >anything doing that. > >I don't usually go this orbital on a post like that but somtimes the arrogance >and presumption of the poster just begs for it. Sorry Dennis, I support space exploration and space exploitation too, but I am realistic enough to know it won't make a material difference here on Earth. Like Columbus' "discovery" of the New World, the riches ultimately fall to the inhabitants of the New World, not those left behind in the Old World. So it is with space. People living in space will be the primary beneficiaries of space activity. Earth can attempt to play Hudson Bay Company, but eventually Earth has to manage by itself. I don't have a problem with that as a justification for supporting space. "To boldly go..." is sufficient reason to support space activities. The human race, wherever they may be, will be the beneficiaries of that process, not Earthlings. Gary ------------------------------ Date: 12 Aug 92 17:42:24 GMT From: Mark Evans Subject: Tethers Newsgroups: sci.space Eric_S_Klien@cup.portal.com writes: : Would it be possible to put something in near orbit over Nevada and : attach tethers to it so that people could reach the object via : elevators? I know it wouldn't be easy, but is there a way to pull : this off? read 'The fountains of paradise' bye Clake. The only way you can get something to orbit above point of the earth's surface is to have it in geo-sync orbit. Thus, the point you have your satellite above must be on the equator. (if you want it to be over pointelse where on the globe, then it is not in orbit and must run thrusters virtually continuiously to stay in position) Try replacing Nevada with Kenya and you might get it to work. -- ------------------------------------------------------------------------- Mark Evans |evansmp@uhura.aston.ac.uk +(44) 21 565 1979 (Home) |evansmp@cs.aston.ac.uk +(44) 21 359 6531 x4039 (Office) | ------------------------------ Date: 13 Aug 92 13:19:53 GMT From: Dean Adams Subject: Upcoming Delta launches... Newsgroups: sci.space > SPACE CALENDAR > July 29, 1992 > > August 1992 > 20 - GE Satcom C4 Delta Launch Does anyone know the time/launch window for this flight? Without it, finding the satellite coverage would be very difficult... Anyone with info please post or email! ------------------------------ Date: 13 Aug 92 10:35:24 GMT From: Magnus Olsson Subject: Weak interactions, biology and the SSC Newsgroups: sci.space Since it has been mentioned several times in the ongoing SSC debate/flamewar in this newsgroup, I thought I'd just summarize one possible (very hypothetical) way the SSC results could be important to biologists: It is a well-known fact that most biological molecules not only have a distinct "handedness" (asymmetry under mirror reflection), but also that all living organisms share the same handedness (all proteins are built exclusively of the L-forms of amino acids, for example). It is also a well-known fact that the electromagnetic force responsible for chemical reactions is parity invariant, i.e. it don't distinguish between left and right. (it should be pointed out that this means it has no *intrinsic* handedness - of course an asymmetric molecule can distinguish between left and right, but then it's due to the spatial asymmetry of the molecule and not to any fundamental reasons). This is normally explained by the fact that all life has a common ancestor that by pure chance happened to have a certain handedness. However, why did all "right-handed" life in that case become extinct? A recent attempt to explain this is the following: The elctromagnetic force is not the only one acting on molecules. There is also the weak force, which is - as the name says - extremely weak. Up to now it has been treated as totally negligible in chemistry. However, the weak force *does* distinguish between left and right. If, for example, the nucleus of an atom interacts with an electron by exchanging a Z boson, the process has different probabilites depending on the direction of the electron's spin. This could, in principle, give atoms a very weak handedness. The idea is that this handedness of atoms would make reactions involving, say, L-amino acids (very) slightly more favourable than those involving R-amino acids. This would over geological time scales give "left-handed" life an advantage over right-handed life. So where does the SSC enter? Well, the argument is that to understand the possible chemical effects, we ought to understand the weak interaction better than today. The SSC will explore the high-energy behaviour of he weak interaction in ways impossible today (for example, one would liek to observe the four-Z-vertex). However, whether this has any relevance to chemistry and biology is doubtful in the extreme - the influence of weak interactions on atomic physics and possibly chemistry would of course be a low-energy phenomenon, and as far as we know, the low-energy behaviour of the weak interaction is well understood from earlier experiments. Magnus Olsson | \e+ /_ Dept. of Theoretical Physics | \ Z / q University of Lund, Sweden | >----< Internet: magnus@thep.lu.se | / \===== g Bitnet: THEPMO@SELDC52 | /e- \q ------------------------------ Date: 13 Aug 92 12:18:31 GMT From: Magnus Olsson Subject: Weak interactions, biology and the SSC Newsgroups: sci.space In article <1992Aug13.103524.4357@pollux.lu.se> I write: >Since it has been mentioned several times in the ongoing SSC >debate/flamewar in this newsgroup Sorry, but I managed to goof up and post it to the wrong newsgrup - it should of course have gone to sci.physics, not to sci.space. Sorry for wasting your bandwidth (and this accursed NNTP server won't let me cancel my own articles...) Magnus Olsson | \e+ /_ Dept. of Theoretical Physics | \ Z / q University of Lund, Sweden | >----< Internet: magnus@thep.lu.se | / \===== g Bitnet: THEPMO@SELDC52 | /e- \q ------------------------------ Date: Thu, 13 Aug 92 12:07:06 BST From: amon@elegabalus.cs.qub.ac.uk Subject: Why is this on SpaceDigest (or sci.space) I really don't see the reason for the massive list of cross postings. If you are going to relate this to how societies approach space, or the formation of extraterrestrial politico-economics systems, fine. But this seems more like a straight poly-sci argument. Be more selective in your cross-posting. ------------------------------ End of Space Digest Volume 15 : Issue 106 ------------------------------