Date: Mon, 7 Sep 92 05:01:59 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V15 #174 To: Space Digest Readers Precedence: bulk Space Digest Mon, 7 Sep 92 Volume 15 : Issue 174 Today's Topics: Airiane Launch Viewing Astro/Space Frequently Seen Acronyms Is NASA really planning to Terraform Mars? Is nasa really planning to waste money making a habitable planet? mission badges for Apollo and STS Relativity 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: 7 Sep 92 05:10:01 GMT From: waterman@titan.ksc.nasa.gov Subject: Airiane Launch Viewing Newsgroups: sci.space Sep 7, 1992 0010 EST Someone posted a while back that all the Airiane launches could be picked up on satelite. Does anyone know which satelite and transponder it might be on? _________________________________ Bob Waterman [Aqua] waterman@titan.ksc.nasa.gov ------------------------------ Date: 7 Sep 92 05:00:39 GMT From: Mark Bradford Subject: Astro/Space Frequently Seen Acronyms Newsgroups: sci.astro,sci.space,sci.space.shuttle,news.answers Archive-name: space/acronyms Edition: 7 Acronym List for sci.astro, sci.space, and sci.space.shuttle: Edition 7, 1992 Aug 27 Last posted: 1992 Aug 6 This list is offered as a reference for translating commonly appearing acronyms in the space-related newsgroups. If I forgot or botched your favorite acronym, please let me know! Also, if there's an acronym *not* on this list that confuses you, drop me a line, and if I can figure it out, I'll add it to the list. Note that this is intended to be a reference for *frequently seen* acronyms, and is most emphatically *not* encyclopedic. If I incorporated every acronym I ever saw, I'd soon run out of disk space! :-) The list will be posted at regular intervals, every 30 days. All comments regarding it are welcome; I'm reachable as bradfrd2@ncar.ucar.edu. Note that this just tells what the acronyms stand for -- you're on your own for figuring out what they *mean*! Note also that the total number of acronyms in use far exceeds what I can list; special-purpose acronyms that are essentially always explained as they're introduced are omitted. Further, some acronyms stand for more than one thing; as of Edition 3 of the list, these acronyms appear on multiple lines, unless they're simply different ways of referring to the same thing. Thanks to everybody who's sent suggestions since the first version of the list, and especially to Garrett A. Wollman (wollman@griffin.uvm.edu), who is maintaining an independent list, somewhat more verbose in character than mine, and to Daniel Fischer (dfi@specklec.mpifr-bonn.mpg.de), who is maintaining a truly HUGE list (535 at last count) of acronyms and terms, mostly in German (which I read, fortunately). Special Bonus! At the end of this posting, you will find a perl program written by none other than Larry Wall, whose purpose is to scramble the acronym list in an entertaining fashion. Thanks, Larry! A&A: Astronomy and Astrophysics AAO: Anglo-Australian Observatory AAS: American Astronomical Society AAVSO: American Association of Variable Star Observers ACE: Advanced Composition Explorer ACRV: Assured Crew Return Vehicle (or) Astronaut Crew Rescue Vehicle ADFRF: Ames-Dryden Flight Research Facility (was DFRF) (NASA) AGN: Active Galactic Nucleus AGU: American Geophysical Union AIAA: American Institute of Aeronautics and Astronautics AIPS: Astronomical Image Processing System AJ: Astronomical Journal ALEXIS: Array of Low Energy X-ray Imaging Sensors ALPO: Association of Lunar and Planetary Observers ALS: Advanced Launch System ANSI: American National Standards Institute AOA: Abort Once Around (Shuttle abort plan) AOCS: Attitude and Orbit Control System Ap.J: Astrophysical Journal APM: Attached Pressurized Module (a.k.a. Columbus) APU: Auxiliary Power Unit ARC: Ames Research Center (NASA) ARTEMIS: Advanced Relay TEchnology MISsion ASA: Astronomical Society of the Atlantic ASI: Agenzia Spaziale Italiano ASRM: Advanced Solid Rocket Motor ATDRS: Advanced Tracking and Data Relay Satellite ATLAS: Atmospheric Laboratory for Applications and Science ATM: Amateur Telescope Maker ATO: Abort To Orbit (Shuttle abort plan) AU: Astronomical Unit AURA: Association of Universities for Research in Astronomy AW&ST: Aviation Week and Space Technology (a.k.a. AvLeak) AXAF: Advanced X-ray Astrophysics Facility BATSE: Burst And Transient Source Experiment (on CGRO) BBXRT: Broad-Band X-Ray Telescope (ASTRO package) BEM: Bug-Eyed Monster BH: Black Hole BIMA: Berkeley Illinois Maryland Array BNSC: British National Space Centre BTW: By The Way C&T: Communications & Tracking CCAFS: Cape Canaveral Air Force Station CCD: Charge-Coupled Device CCDS: Centers for the Commercial Development of Space CD-ROM: Compact Disk Read-Only Memory CFA: Center For Astrophysics CFC: ChloroFluoroCarbon CFF: Columbus Free Flyer CFHT: Canada-France-Hawaii Telescope CGRO: (Arthur Holley) Compton Gamma Ray Observatory (was GRO) CHARA: Center for High Angular Resolution Astronomy CIRRIS: Cryogenic InfraRed Radiance Instrument for Shuttle CIT: Circumstellar Imaging Telescope CM: Command Module (Apollo spacecraft) CMCC: Central Mission Control Centre (ESA) CNES: Centre National d'Etude Spatiales CNO: Carbon-Nitrogen-Oxygen CNSR: Comet Nucleus Sample Return COBE: COsmic Background Explorer COMPTEL: COMPton TELescope (on CGRO) COSTAR: Corrective Optics Space Telescope Axial Replacement CRAF: Comet Rendezvous / Asteroid Flyby CRRES: Combined Release / Radiation Effects Satellite CSM: Command and Service Module (Apollo spacecraft) CSTC: Consolidated Satellite Test Center (USAF) CTIO: Cerro Tololo Interamerican Observatory DCX: Delta Clipper eXperimental DDCU: DC-to-DC Converter Unit DFRF: Dryden Flight Research Facility (now ADFRF) DMSP: Defense Meteorological Satellite Program DOD: Department Of Defense (sometimes DoD) DOE: Department Of Energy DOT: Department Of Transportation DSCS: Defense Satellite Communications System DSN: Deep Space Network DSP: Defense Support Program (USAF/NRO) EAFB: Edwards Air Force Base ECS: Environmental Control System EDO: Extended Duration Orbiter EGRET: Energetic Gamma Ray Experiment Telescope (on CGRO) EJASA: Electronic Journal of the Astronomical Society of the Atlantic ELV: Expendable Launch Vehicle EMU: Extravehicular Mobility Unit EOS: Earth Observing System ERS: Earth Resources Satellite (as in ERS-1) ESA: European Space Agency ESO: European Southern Observatory ET: (Shuttle) External Tank ETLA: Extended Three Letter Acronym ETR: Eastern Test Range EUV: Extreme UltraViolet EUVE: Extreme UltraViolet Explorer EVA: ExtraVehicular Activity FAQ: Frequently Asked Questions FAST: Fast Auroral SnapshoT explorer FFT: Fast Fourier Transform FGS: Fine Guidance Sensors (on HST) FHST: Fixed Head Star Trackers (on HST) FIR: Far InfraRed FITS: Flexible Image Transport System FOC: Faint Object Camera (on HST) FOS: Faint Object Spectrograph (on HST) FRR: Flight-Readiness Review FTP: File Transfer Protocol FTS: Flight Telerobotic Servicer FUSE: Far Ultraviolet Spectroscopic Explorer FWHM: Full Width at Half Maximum FYI: For Your Information GAS: Get-Away Special GBT: Green Bank Telescope GCVS: General Catalog of Variable Stars GEM: Giotto Extended Mission GEO: Geosynchronous Earth Orbit GDS: Great Dark Spot GHRS: Goddard High Resolution Spectrograph (on HST) GIF: Graphics Interchange Format GLOMR: Global Low-Orbiting Message Relay GMC: Giant Molecular Cloud GMRT: Giant Meter-wave Radio Telescope GMT: Greenwich Mean Time (also called UT) GOES: Geostationary Orbiting Environmental Satellite GOX: Gaseous OXygen GPC: General Purpose Computer GPS: Global Positioning System GRO: Gamma Ray Observatory (now CGRO) GRS: Gamma Ray Spectrometer (on Mars Observer) GRS: Great Red Spot GSC: Guide Star Catalog (for HST) GSFC: Goddard Space Flight Center (NASA) GTO: Geostationary Transfer Orbit HAO: High Altitude Observatory HD: Henry Draper catalog entry HEAO: High Energy Astronomical Observatory HeRA: Hermes Robotic Arm HF: High Frequency HGA: High Gain Antenna HLC: Heavy Lift Capability HLV: Heavy Lift Vehicle HMC: Halley Multicolor Camera (on Giotto) HR: Hertzsprung-Russell (diagram) HRI: High Resolution Imager (on ROSAT) HSP: High Speed Photometer (on HST) HST: Hubble Space Telescope HUT: Hopkins Ultraviolet Telescope (ASTRO package) HV: High Voltage IAPPP: International Amateur/Professional Photoelectric Photometry IAU: International Astronomical Union IAUC: IAU Circular ICE: International Cometary Explorer IDA: International Dark-sky Association IDL: Interactive Data Language IGM: InterGalactic Medium IGY: International Geophysical Year IMHO: In My Humble Opinion IOTA: Infrared-Optical Telescope Array IOTA: International Occultation Timing Association IPS: Inertial Pointing System IR: InfraRed IRAF: Image Reduction and Analysis Facility IRAS: InfraRed Astronomical Satellite ISAS: Institute of Space and Astronautical Science (Japan) ISM: InterStellar Medium ISO: Infrared Space Observatory ISO: International Standards Organization ISPM: International Solar Polar Mission (now Ulysses) ISY: International Space Year IUE: International Ultraviolet Explorer IUS: Inertial Upper Stage JEM: Japanese Experiment Module (for SSF) JGR: Journal of Geophysical Research JILA: Joint Institute for Laboratory Astrophysics JPL: Jet Propulsion Laboratory JSC: Johnson Space Center (NASA) KAO: Kuiper Airborne Observatory KPNO: Kitt Peak National Observatory KSC: Kennedy Space Center (NASA) KTB: Cretaceous-Tertiary Boundary (from German) LANL: Los Alamos National Laboratory LaRC: Langley Research Center (NASA) LDEF: Long Duration Exposure Facility LEM: Lunar Excursion Module (a.k.a. LM) (Apollo spacecraft) LEO: Low Earth Orbit LeRC: Lewis Research Center (NASA) LEST: Large Earth-based Solar Telescope LFSA: List of Frequently Seen Acronyms (!) LGA: Low Gain Antenna LGM: Little Green Men LH: Liquid Hydrogen (also LH2 or LHX) LLNL: Lawrence-Livermore National Laboratory LM: Lunar Module (a.k.a. LEM) (Apollo spacecraft) LMC: Large Magellanic Cloud LN2: Liquid N2 (Nitrogen) LOX: Liquid OXygen LRB: Liquid Rocket Booster LSR: Local Standard of Rest LTP: Lunar Transient Phenomenon MB: Manned Base MCC: Mission Control Center MECO: Main Engine CutOff MMH: MonoMethyl Hydrazine MMT: Multiple Mirror Telescope MMU: Manned Maneuvering Unit MNRAS: Monthly Notices of the Royal Astronomical Society MOC: Mars Observer Camera (on Mars Observer) MOL: Manned Orbiting Laboratory MOLA: Mars Observer Laser Altimeter (on Mars Observer) MOMV: Manned Orbital Maneuvering Vehicle MOTV: Manned Orbital Transfer Vehicle MPC: Minor Planets Circular MRSR: Mars Rover and Sample Return MRSRM: Mars Rover and Sample Return Mission MSFC: (George C.) Marshall Space Flight Center (NASA) MTC: Man Tended Capability NACA: National Advisory Committee on Aeronautics (became NASA) NASA: National Aeronautics and Space Administration NASDA: NAtional Space Development Agency (Japan) NASM: National Air and Space Museum NASP: National AeroSpace Plane NBS: National Bureau of Standards (now NIST) NDV: NASP Derived Vehicle NERVA: Nuclear Engine for Rocket Vehicle Application NGC: New General Catalog NICMOS: Near Infrared Camera / Multi Object Spectrometer (HST upgrade) NIMS: Near-Infrared Mapping Spectrometer (on Galileo) NIR: Near InfraRed NIST: National Institute for Standards and Technology (was NBS) NLDP: National Launch Development Program NOAA: National Oceanic and Atmospheric Administration NOAO: National Optical Astronomy Observatories NRAO: National Radio Astronomy Observatory NRO: National Reconnaissance Office NS: Neutron Star NSA: National Security Agency NSF: National Science Foundation NSO: National Solar Observatory NSSDC: National Space Science Data Center NTR: Nuclear Thermal Rocket(ry) NTT: New Technology Telescope OAO: Orbiting Astronomical Observatory OCST: Office of Commercial Space Transportation OMB: Office of Management and Budget OMS: Orbital Maneuvering System OPF: Orbiter Processing Facility ORFEUS: Orbiting and Retrievable Far and Extreme Ultraviolet Spectrometer OSC: Orbital Sciences Corporation OSCAR: Orbiting Satellite Carrying Amateur Radio OSSA: Office of Space Science and Applications OSSE: Oriented Scintillation Spectrometer Experiment (on CGRO) OTA: Optical Telescope Assembly (on HST) OTHB: Over The Horizon Backscatter OTV: Orbital Transfer Vehicle OV: Orbital Vehicle PAM: Payload Assist Module PAM-D: Payload Assist Module, Delta-class PI: Principal Investigator PLSS: Portable Life Support System PM: Pressurized Module PMC: Permanently Manned Capability PMIRR: Pressure Modulated InfraRed Radiometer (on Mars Observer) PMT: PhotoMultiplier Tube PSF: Point Spread Function PSR: PulSaR PV: Photovoltaic PVO: Pioneer Venus Orbiter QSO: Quasi-Stellar Object RCI: Rodent Cage Interface (for SLS mission) RCS: Reaction Control System REM: Rat Enclosure Module (for SLS mission) RF: Radio Frequency RFI: Radio Frequency Interference RIACS: Research Institute for Advanced Computer Science RMS: Remote Manipulator System RNGC: Revised New General Catalog ROSAT: ROentgen SATellite ROUS: Rodents Of Unusual Size (I don't believe they exist) RSN: Real Soon Now RTG: Radioisotope Thermoelectric Generator RTLS: Return To Launch Site (Shuttle abort plan) SAA: South Atlantic Anomaly SAGA: Solar Array Gain Augmentation (for HST) SAMPEX: Solar Anomalous and Magnetospheric Particle EXplorer SAO: Smithsonian Astrophysical Observatory SAR: Search And Rescue SAR: Synthetic Aperture Radar SARA: Satellite pour Astronomie Radio Amateur SAREX: Search and Rescue Exercise SAREX: Shuttle Amateur Radio Experiment SAS: Space Activity Suit SAS: Space Adaptation Syndrome SAT: Synthetic Aperture Telescope S/C: SpaceCraft SCA: Shuttle Carrier Aircraft SCT: Schmidt-Cassegrain Telescope SDI: Strategic Defense Initiative SDIO: Strategic Defense Initiative Organization SEI: Space Exploration Initiative SEST: Swedish-European Submillimeter Telescope SETI: Search for ExtraTerrestrial Intelligence SID: Sudden Ionospheric Disturbance SIR: Shuttle Imaging Radar SIRTF: Space (formerly Shuttle) InfraRed Telescope Facility SL: SpaceLab SLAR: Side-Looking Airborne Radar SLC: Space Launch Complex SLS: Space(lab) Life Sciences SMC: Small Magellanic Cloud SME: Solar Mesosphere Explorer SMEX: SMall EXplorers SMM: Solar Maximum Mission SN: SuperNova (e.g., SN1987A) SNR: Signal to Noise Ratio SNR: SuperNova Remnant SNU: Solar Neutrino Units SOFIA: Stratospheric Observatory For Infrared Astronomy SOHO: SOlar Heliospheric Observatory SPAN: Space Physics and Analysis Network SPDM: Special Purpose Dextrous Manipulator SPOT: Systeme Probatoire pour l'Observation de la Terre SPS: Solar Power Satellite SRB: Solid Rocket Booster SRM: Solid Rocket Motor SSF: Space Station Fred (er, Freedom) SSI: Solid-State Imager (on Galileo) SSI: Space Studies Institut SSME: Space Shuttle Main Engine SSPF: Space Station Processing Facility SSRMS: Space Station Remote Manipulator System SST: Spectroscopic Survey Telescope SST: SuperSonic Transport SSTO: Single Stage To Orbit STIS: Space Telescope Imaging Spectrometer (to replace FOC and GHRS) STS: Shuttle Transport System (or) Space Transportation System STScI: Space Telescope Science Institute SWAS: Submillimeter Wave Astronomy Satellite SWF: ShortWave Fading TAL: Transatlantic Abort Landing (Shuttle abort plan) TAU: Thousand Astronomical Unit (mission) TCS: Thermal Control System TDRS: Tracking and Data Relay Satellite TDRSS: Tracking and Data Relay Satellite System TES: Thermal Emission Spectrometer (on Mars Observer) TIROS: Television InfraRed Observation Satellite TLA: Three Letter Acronym TOMS: Total Ozone Mapping Spectrometer TPS: Thermal Protection System TSS: Tethered Satellite System UARS: Upper Atmosphere Research Satellite UBM: Unpressurized Berthing Mechanism UDMH: Unsymmetrical DiMethyl Hydrazine UFO: Unidentified Flying Object UGC: Uppsala General Catalog UHF: Ultra High Frequency UIT: Ultraviolet Imaging Telescope (Astro package) UKST: United Kingdom Schmidt Telescope USAF: United States Air Force USMP: United States Microgravity Payload UT: Universal Time (a.k.a. GMT, UTC, or Zulu Time) UTC: Coordinated Universal Time (a.k.a. UT) UV: UltraViolet UVS: UltraViolet Spectrometer VAB: Vehicle Assembly Building (formerly Vertical Assembly Building) VAFB: Vandenberg Air Force Base VEEGA: Venus-Earth-Earth Gravity Assist (Galileo flight path) VHF: Very High Frequency VLA: Very Large Array VLBA: Very Long Baseline Array VLBI: Very Long Baseline Interferometry VLF: Very Low Frequency VLT: Very Large Telescope VMS: Vertical Motion Simulator VOIR: Venus Orbiting Imaging Radar (superseded by VRM) VPF: Vertical Processing Facility VRM: Venus Radar Mapper (now called Magellan) WD: White Dwarf WFPC: Wide Field / Planetary Camera (on HST) WFPCII: Replacement for WFPC WIYN: Wisconsin / Indiana / Yale / NOAO telescope WSMR: White Sands Missile Range WTR: Western Test Range WUPPE: Wisconsin Ultraviolet PhotoPolarimter Experiment (Astro package) XMM: X-ray Multi Mirror XUV: eXtreme UltraViolet YSO: Young Stellar Object #!/usr/bin/perl # 'alt', An Acronym Scrambling Program, by Larry Wall $THRESHOLD = 2; srand; while (<>) { next unless /^([A-Z]\S+): */; $key = $1; $acro{$key} = $'; @words = split(/\W+/,$'); unshift(@words,$key); $off = 0; foreach $word (@words) { next unless $word =~ /^[A-Z]/; *w = $&; vec($w{$word}, $off++ % 6, 1) = 1; } } foreach $letter (A .. Z) { *w = $letter; @w = keys %w; if (@w < $THRESHOLD) { @d = `egrep '^$letter' /usr/dict/words`; chop @d; push(@w, @d); } } foreach $key (sort keys %acro) { $off = 0; $acro = $acro{$key}; $acro =~ s/((([A-Z])[A-Z]*)[a-z]*)/ &pick($3, $2, $1, ++$off) || $& /eg; print "$key: $acro"; } sub pick { local($letter, $prefix, $oldword, $off) = @_; $i = 0; if (length($prefix) > 1 && index($key,$prefix) < 0) { if ($prefix eq $oldword) { $prefix = ''; } else { $prefix = $letter; } } if (length($prefix) > 1) { local(*w) = substr($prefix,0,1); do { $word = $w[rand @w]; } until $word ne $oldword && $word =~ /^$prefix/i || ++$i > 30; $word =~ s/^$prefix/$prefix/i; $word; } elsif (length($prefix) == 1) { local(*w) = $prefix; do { $word = $w[rand @w]; } until $word ne $oldword && vec($w{$word}, $off, 1) || ++$i > 10; $word = "\u\L$word" if $word =~ tr/a-z/A-Z/; $word; } else { local(*w) = substr($oldword,0,1); do { $word = $w[rand @w]; } until $word ne $oldword && $word =~ tr/a-z/A-Z/ == 0 || ++$i > 30; $word; } } -- Mark Bradford (bradfrd2@ncar.ucar.edu) <> To err is human, to moo bovine. "It's an ill wind that gathers no moss." ------------------------------ Date: 7 Sep 92 04:46:18 GMT From: Alan Barclay Subject: Is NASA really planning to Terraform Mars? Newsgroups: sci.space barry@chezmoto.ai.mit.edu (Barry Kort) writes: >A colleague of mine, who claims to be knowledgeable in such matters >tells me: > A fairly large team , is planning the terraforming > of Mars, which involves destroying the planet as we know it. > Mars will be rasied 20 degrees C. And with minimal study of > that planet it becomes clear what chain of events will occur. > After this chain Mars will be 'polluted' with earth-based > micro-organisms and rugged plant life. >Can anyone confirm, deny, or refute the above, or otherwise >elaborate on NASA's plans with respect to Mars? The answer, I suspect, is no. This rumour probably started from an incomplete reading of an article that appeared in _Discover_ September 1992, vol 13, Number 9, pages 70-75 called "Mars in Earth's Image" The article begins by describing how poor the prospect of funding even a manned visit to mars is. Then discusses a recent paper called: "Making Mars Habitable." Christopher McKay, Owen Toon, and James Kasting _Nature_, August 8, 1991. Discover says McKay and Toon are from NASA's Ames Research Center. Discover outlines the project: using chlorofluorocarbons released from Mar's soil to boost the greenhouse effect, bioengineering plants to release oxygen from CO2 at an accellerated rate. They figure it might only take a thousand years or so. Discover never portrays the project as more than a what-if. I doubt McKay et al did either. The terraforming of Mars will probably not become an environmental issue for another century or two, when some group actually has the resources to consider doing it. Maybe you want to start a UN lobby for ethical use of extra-terristrial resources (I'm not being sarcastic, I have a suspicion there already is such a body.) This is the value of speculative research. Alan ------------------------------ Date: Sun, 6 Sep 92 22:55:04 -0500 From: pgf@srl01.cacs.usl.edu (Phil G. Fraering) Subject: Is nasa really planning to waste money making a habitable planet? \two days ago I read an article on the topic of Mars in the german /magazine 'GEO'; they talked about some of the planned missions to \our neighbour planet and mentioned that there were still some /dreamers at NASA that actually intended to transform Mars. \I'd say, forget about that. Even a manned mission to Mars would cost /*at least* 500 billion dollars (according to a NASA researcher). \Terraforming is a nice SF idea and sounds like an easy thing to /do, but IMHO we don't know enough about the involved systems \to even think about changing a planet. It's stupid, will cost /too much (NASA will not be given the money for 'Big Tickets' in the \next years) and belongs to SF. So do computers. They were in SF long before IC's came along... I hope the heck you don't think the $500 billion is an accurate figure; it probably isn't. Heck, one of the people looking at terraforming Mars is considering doing it as a matter of course during one of his ~70 billion dollar manned missions, or so I've heard... more later when I have a terminal that works. -- Phil Fraering pgf@srl0x.cacs.usl.edu where the x is a number from 1-5. Phone: 318/365-5418 SnailMail: 2408 Blue Haven Dr., New Iberia, La. 70560 If seven maids with seven brooms swept for half a year, do you think, the Walrus asked, that they could make it clear? I doubt it, said the Carpenter, and shed a bitter tear. --------- "NOAH!" \ \ Lewis Carrol "Yes lord?" > Bill Cosby, The Story of Noah "HOW LONG CAN YOU TREAD WATER?"/ ------------------------------ Date: Mon, 7 Sep 1992 03:10:23 GMT From: Ray Soo Subject: mission badges for Apollo and STS Newsgroups: sci.space,sci.space.shuttle can one buy replicas of mission badges for the Apollo and Shuttle missions? If so , where? email replies to ray@exicom.oz.au thanks in advance, ray ------------------------------ Date: 7 Sep 92 04:40:24 GMT From: Alan Barclay Subject: Relativity Newsgroups: sci.space #4300029 from John Roberts I always thought I had a good handle on the basics of relativity. Can you have a look at this for me, and tell me what you think? A Thought experiment: Star A is four light years from star B. A spaceship leaves earth and accelerates to .9 C and ceases acceleration when it passes Star A. An observer inside the moving frame notes the length of subjective time passing. When the ship passes star B, the observer inside the frame has only experienced 1.95 subjective years. For him, he traversed four light years in only 1.95 years. A subjective speed of 2.05 C. ---->---->---->---->---->.9C *A *B __ T = d/v -> T = 4ly/0.9C = 4.44 yrs ________________ Tsubjective = T x \/ (1-(v*v/c*c)) = 4.44 yrs x 0.44 = 1.95 yrs Vsubj = d/Tsubj = 4ly/1.95yrs = 2.05 ly/yr However, if he were to use instruments to determine his velocity relative to the frame of reference, his velocity would remain .9 C. The only flaw I can see in this is if my observer's velocity somehow changes the timing of his observations of incidence with Star A or B. A recent SF book used relativistic mass to produce black holes. i.e. accelerate a spaceship until it's massive enough to collapse into a singularity. Something seems missing in this equation. Could it happen? Not knowing the more complex math of relativity, I have no way of proving it to myself. But I wonder if time dilation due to velocity (and the gravitation itself?) would put the singularity at the end of an asymptotic curve, like v=1.0C, completely unachievable. You may do SF a great service by whacking this SF writer upside the head if he's wrong. Alan ------------------------------ End of Space Digest Volume 15 : Issue 174 ------------------------------