Date: Sun, 21 Mar 93 05:09:17 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #347 To: Space Digest Readers Precedence: bulk Space Digest Sun, 21 Mar 93 Volume 16 : Issue 347 Today's Topics: *** CRESCENT MOON: May Be (Low Probability) Evening Tue 23 MARCH 1993 *** Clueless Szaboisms (Was Re: plans, and absence thereof) (2 msgs) How to cool Venus Just a little tap (was Re: Galileo HGA) Predicting gravity wave quantization & Cosmic Noise (3 msgs) SSTO: A Spaceship for the rest of us Why use AC at 20kHz for SSF Power? 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: Sat, 20 Mar 1993 21:02:35 GMT From: Mohib N Durrani Subject: *** CRESCENT MOON: May Be (Low Probability) Evening Tue 23 MARCH 1993 *** Newsgroups: sci.astro,sci.physics,sci.space Bismillah hir-Rahman nir-Rahim ( I begin with the name of ALLAH, the Most Beneficent, the Most Merciful ) THE MUSLIM STUDENTS' ASSOCIATION (MSA) of COLUMBIA UNIVERSITY 102 Earl Hall, Columbia University, NEW YORK, N.Y. 10027 SUBJECT: CRESCENT MOON: FIRST VISIBILITY (every lunar month) ************************************************************** NEXT CRESCENT MOON (visible), HILAL: Tue 23 MAR 1993, evening. The first world-wide sightings MAY (LOW PROBABILITY in West Coast) be in USA/Canada on the evening of Tue 23 Mar 1993 then, after the International Date Line, most of the northern hemisphere will sight the Crescent on the evening of Wed 24 Mar 1993. EID-ul-ADHA and SHAWWAL, the 10th. Islamic Month in 1413 AH, MAY (LOW PROBABILITY) start on the day of Wed 24 Mar 1993, for USA/Canada, inshallah, (IF there is CONFIRMED SIGHTING on evening of Tue 23 Mar 1993); IF NOT Eid for USA/Canada will be on the day of Thu 25 Mar 1993, (HIGH PROBABILITY is for Thu 25 Mar 1993) along with most of the Northern Hemisphere. For most of the Northern Hemisphere, West of USA/Canada EID-ul-ADHA will be on the day of Thu 25 Mar, inshallah, BASED ON THE CRITERIA OF VISUAL SIGHTING OF THE CRESCENT MOON (HILAL). It is IMPOSSIBLE for the Crescent Moon to be visible on the evening of Tue 23 Mar 1993, anywhere east of the Americas. EID-ul-ADHA CANNOT be on day of Wed 24 Mar 1993, for any place East of USA/Canada. **************************************************************************** Please note that the Islamic dates start from Sundown of a previous day. **************************************************************************** In addition to the postings in sci.astro, sci.physics, sci.space, see also postings in soc.culture.african, ..arabic, ..bangladesh, ..pakistan, ..turkish, soc.religion.islam for the significance of EID-UL-FITR. (*) Hilal (crescent) sightings would be in the evenings, at least 10 minutes after sunset, usually before 20 minutes, and upto 40 to 90 minutes after sunset; near and along the sun's path. ********************************************************************** * WORLD RECORD: "THE YOUNGEST NAKED-EYE CRESCENT MOON SIGHTING" * * "BADAT & AL-THANI SIGHTING": 13 hrs 24 min after New Moon Phase * * Friday 5 May 1989 from Houston, Texas, USA * * Ref: Royal Astronomical Society of Canada, Vol 83/3, Pages 34-36 * * Newsletter/Bulletin, June 1989 * ********************************************************************** We are conducting research/survey on the recorded WORLD-WIDE first sightings of the "CRESCENT MOON, FIRST VISIBILITY" in the evenings, for every lunar month. Some TECHNICAL INFO. is at the end. PHOTOGRAPHS / SLIDES ARE MOST WELCOME since they are very helpful in the research. Please also pass on the request to your friends who are interested in astronomy/physics and to your local amateur astronomy associations. We would very much like to hear from you. Please respond either by email or by letter. The survey results are to enhance the present ATMOSPHERIC MODEL and fine tune some parameters regarding SCATTERING/VISION. When reporting actual Crescent-Hilal sightings, (even if you do not see it) PLEASE INCLUDE THE FOLLOWING: HILAL was visible to naked eye?......... Hilal sighted in binoculars?........ EXACT TIMES: Complete Sunset at......... Hilal First Visible....... End...... HEIGHT (Degrees): Hilal highest......... Hilal lowest (faded/set)............ Hilal to LEFT of SUN (Degrees) ......... Hilal to RIGHT of SUN (Degs) ....... ORIENTATION: Ends of Hilal Curve: Start at......'O Clock:End at.....'O Clock (Right is 3'O Clock:Bottom is 6'O Clock:Left is 9'O Clock:Top is 12'O Clock) WEATHER condition: Rel.Humidity......... Temperature..... Pressure........... Sky near western horizon: Clear?........ Hazy?........... Cloudy?............ OBSERVER: Age.... Eyesight: Glasses?.... Far sighted?.... Near sighted?...... Name....................... Date........ Location............................ Thanks. Email to: mnd@cunixb.cc.columbia.edu (Dr.Mohib.N.Durrani) Mail: Dr.Mohib.N.Durrani Islamic Amateur Astronomers Association (Research Division) 601 West 113 Street, Suite 11-K Columbia University NEW YORK, N.Y. 10025 United States of America **************************************************************************** Some ORBITAL details for the SUN and MOON: Lunation No.: 869 NEW MOON (not crescent visible moon): 1993 Mar 23d 07h 14m UT (Universal Time), Tuesday. (Universal Time, i.e. mean solar time on the meridian of Greenwich) EQUATORIAL coords.(at 0h UT) ECLIPTIC coords.(at 0h UT) Date Sun Sun MOON MOON Sun MOON MOON MOON MAR R.A. Decl. R.A. Decl. Long. Long. Lat. true Elong '93 Alpha Delta Alpha Delta Lambda Lambda Beta from Sun hr deg hr deg deg deg deg deg *23 Tu 22.30 -10.58 21.81 -08.31 332.47 326.51 4.64 W 8 24 We 22.36 -10.23 22.55 -03.84 333.47 338.41 4.93 E 7 25 Th 22.42 -09.86 23.27 +00.74 334.48 350.41 5.00 E 22 * Sighting Information provided on (*) Date(s) **************************************************************************** 1993 MARCH 23 (Tue) evening Event times are approximate 1413 SHAWAL (10th Islamic Month) Civil - clock - Standard times (nearest) (+N,-S) (+E) Zone SUN MOON AGE at MOON-SUN Unaided-Eye CITY LAT LONG -UT SET SET Sunset Alt/Az SIGHTING *********** deg deg h h m h m h m DegDeg ********** MAKKAH-S.Arab 21.4 39.8 +3 18 33 18 45 8 19 4 5 IMPOSSIBLE DAR SALAM-Tnz -6.8 39.2 +3 18 33 18 33 8 19 1 6 IMPOSSIBLE % MOSCOW - USSR 55.8 37.6 +3 18 49 19 26 8 35 6 2 IMPOSSIBLE % ISTANBUL-Turk 41.0 28.9 +2 18 21 18 45 9 07 5 3 IMPOSSIBLE CAIRO - Egypt 30.1 31.3 +2 18 08 18 25 8 54 5 4 IMPOSSIBLE KHARTOUM-Sudn 15.5 32.6 +2 18 01 18 11 8 47 3 5 IMPOSSIBLE @CAPETOWN-S.Af -33.8 18.6 +2 18 53 18 41 9 39 -2 6 IMPOSSIBLE LAGOS-Nigeria 6.5 3.4 +1 18 57 19 07 10 43 3 6 IMPOSSIBLE ALGIERS-Algra 36.8 3.0 +0 18 02 18 28 10 48 6 3 IMPOSSIBLE % GREENWICH-Engl 51.5 0.0 +0 18 18 18 57 11 04 7 2 IMPOSSIBLE DAKAR-Senegal 14.7 -17.5 +0 19 21 19 38 12 07 5 5 IMPOSSIBLE %@RIO DeJENEIRO -22.9 -43.2 -3 18 01 18 01 13 47 1 8 IMPOSSIBLE PARAMARIBO-Suri 5.9 -55.2 -3 18 51 19 08 14 37 5 6 IMPOSSIBLE @BUNOS ARESarg -34.7 -58.4 -3 19 00 18 54 14 46 0 8 IMPOSSIBLE % LIMA-Peru S.A -12.4 -77.0 -5 18 17 18 27 16 03 3 8 IMPOSSIBLE (#) = May be visible on Previous Evening, with Difficulty. (@) = May NOT be visible even on Next Evening. % (add 1 hr to event time, during summer DAYLIGHT SAVING TIME, from nearly early April to nearly end of October) **************************************************************************** It is IMPOSSIBLE for the Crescent Moon to be visible on the evening of Tue 23 Mar 1993, anywhere east of the Americas. EID-ul-FITR CANNOT be on Wed 24 MAR 1993 for any place East of USA/Canada. **************************************************************************** 1993 MARCH 23 (Tue) evening Event times are approximate 1413 SHAWAL (10th Islamic Month) Civil - clock - Standard times (nearest) (+N,-S) (+E) Zone SUN MOON AGE at MOON-SUN Unaided-Eye CITY LAT LONG -UT SET SET Sunset Alt/Az SIGHTING *********** deg deg h h m h m h m DegDeg ********** % HALIFAX -CNDA 44.6 -63.6 -4 18 31 19 13 15 17 8 2 DIFFICULT % NEW YORK -USA 40.8 -74.0 -5 18 11 18 52 15 57 8 2 DIFFICULT % MIAMI - USA 25.8 -80.2 -5 18 33 19 05 16 19 8 4 DIFFICULT % CHICAGO - USA 41.2 -87.6 -6 18 06 18 49 16 52 9 2 PROBABLE % DALLAS - USA 32.8 -96.8 -6 18 41 19 19 17 27 9 3 PROBABLE % DENVER - USA 39.7 -105.0 -7 18 15 19 00 18 01 9 2 PROBABLE % SAN DIEGO-USA 32.7 -117.1 -8 18 02 18 43 18 48 9 3 PROBABLE % SAN FRANCISCO 37.7 -122.4 -8 18 24 19 10 19 10 10 2 PROBABLE % VANCOUVER-CND 49.3 -123.1 -8 18 30 19 28 19 16 10 0 PROBABLE % ANCHORAGE-Als 61.1 -150.0 -9 19 23 20 47 21 09 10 -2 PROBABLE % HONOLULU -Hwi 21.3 -157.5-10 18 42 19 21 21 28 10 5 PROBABLE (#) = May be visible on Previous Evening, with Difficulty. (@) = May NOT be visible even on Next Evening. % (add 1 hr to event time, during summer DAYLIGHT SAVING TIME, from nearly early April to nearly end of October) The HILAL (Crescent) SIGHTING COMMITTEE for USA-Canada has decided that when the CRESCENT is VISIBLE - in the evening - anywhere from Halifax, New York, Miami, San Diego, San Francisco, to Vancouver, then in the USA-Canada, the next ISLAMIC MONTH STARTS from SUNSET of THAT DATE. The DAY that is shared (Islamic and Gregorian) is the NEXT Gregorian date. (INCREASE date one day, if crossing EAST TO WEST) ##################### INTERNATIONAL DATE LINE ###################### (DECREASE date one day, if crossing WEST TO EAST) 1993 MARCH 23 (Tue) evening Event times are approximate 1413 SHAWAL (10th Islamic Month) Civil - clock - Standard times (nearest) (+N,-S) (+E) Zone SUN MOON AGE at MOON-SUN Unaided-Eye CITY LAT LONG -UT SET SET Sunset Alt/Az SIGHTING *********** deg deg h h m h m h m DegDeg ********** %@SYDNEY-Austra -33.9 151.2+10 18 03 17 40 0 49 -4 3 IMPOSSIBLE TOKYO - Japan 35.7 139.7 +9 17 55 17 59 1 41 2 5 IMPOSSIBLE % PEKING -China 39.9 116.4 +8 18 29 18 39 3 15 3 4 IMPOSSIBLE JAKARTA-Indon -6.3 106.9 +7 18 02 17 55 3 48 -1 5 IMPOSSIBLE DHAKA -B.Desh 23.8 90.3 +6 18 11 18 17 4 57 2 5 IMPOSSIBLE AGRA - India 27.2 77.9 +5 18 01 18 11 5 47 3 5 IMPOSSIBLE PESHAWAR -Pak 33.6 71.4 +5 18 28 18 42 6 14 4 4 IMPOSSIBLE BUKHARA -Uzbk 39.6 64.6 +4 17 56 18 14 6 42 4 4 IMPOSSIBLE TEHRAN - Iran 35.7 51.4 +3 17 48 18 06 7 34 4 4 IMPOSSIBLE (#) = May be visible on Previous Evening, with Difficulty. (@) = May NOT be visible even on Next Evening. % (add 1 hr to event time, during summer DAYLIGHT SAVING TIME, from nearly early April to nearly end of October) **************************************************************************** Please note that the Islamic dates start from Sundown of a previous day. **************************************************************************** **************************************************************************** Ref: ASTRONOMICAL PHENOMENA (Yearly) Nautical Almanac Office, Wash. DC. **************************************************************************** ISLAMIC GREGORIAN MOON - MOON - MOON - MOON - MOON Sun - EARTH YEAR. YEAR. NEW MOON MOON-PERIGEE MOON-APOGEE MONTHS LUNA. (NOT visible) (nearest) (farthest) NO. (All times are in UT = Universal Time) 1413 *1992* d h m d h d h d h 1 MUHARAM 860 JUN 30 12 18 JUL 2 01 JUN 19 22 JUN 21 03 Solstice 2 SAFR 861 JUL 29 19 35 JUL 30 08 JUL 17 11 3 RABI-I 862 AUG 28 02 42 AUG 27 18 AUG 13 16 4 RABI-II 863 SEP 26 10 40 SEP 25 03 SEP 9 19 SEP 22 19 Equinox 5 JUMA-I 864 OCT 25 20 34 OCT 23 05 OCT 7 06 6 JUMA-II 865 NOV 24 09 11 NOV 19 00 NOV 3 23 7 RAJAB 866 DEC 24 00 43 DEC 13 21 DEC 1 20 DEC 21 15 Solstice DEC 29 17 1413 *1993* d h m d h d h d h 8 SHABAN 867 JAN 22 18 27 JAN 10 12 JAN 26 10 JAN 4 03 Perihelon 9 RAMADAN 868 FEB 21 13 05 FEB 7 20 FEB 22 18 *10 SHAWWAL 869 MAR 23 07 14 MAR 8 09 MAR 21 19 MAR 20 15 Equinox 11 ZulQADA 870 APR 21 23 49 APR 5 19 APR 18 05 12 ZulHAJJ 871 MAY 21 14 06 MAY 4 00 MAY 15 22 MAY 31 11 ISLAMIC GREGORIAN MOON - MOON - MOON - MOON - MOON Sun - EARTH YEAR. YEAR. NEW MOON MOON-PERIGEE MOON-APOGEE MONTHS LUNA. (NOT visible) (nearest) (farthest) NO. (All times are in UT = Universal Time) 1414 *1993* d h m d h d h d h 1 MUHARAM 872 JUN 20 01 52 JUN 25 17 JUN 12 16 JUN 21 09 Solstice 2 SAFR 873 JUL 19 11 24 JUL 22 08 JUL 10 11 JUL 4 22 Apihelion 3 RABI-I 874 AUG 17 19 28 AUG 19 07 AUG 7 04 4 RABI-II 875 SEP 16 03 10 SEP 16 15 SEP 3 17 SEP 23 00 Equinox 5 JUMA-I 876 OCT 15 11 36 OCT 15 02 SEP 30 21 6 JUMA-II 877 NOV 13 21 34 NOV 12 12 OCT 28 00 7 RAJAB 878 DEC 13 09 27 DEC 10 14 NOV 24 13 DEC 21 20 Solstice DEC 22 08 1414 *1994* d h m d h d h d h 8 SHABAN 879 JAN 11 23 10 JAN 6 01 JAN 19 05 JAN 4 Perihelion 9 RAMADAN 880 FEB 10 14 30 JAN 31 04 FEB 16 02 10 SHAWWAL 881 MAR 12 07 05 FEB 27 22 MAR 15 17 MAR 20 Equinox 11 ZulQADA 882 APR 11 00 17 MAR 28 06 APR 12 00 12 ZulHAJJ 883 MAY 10 17 07 APR 25 17 MAY 9 02 MAY 24 03 1415 *1994* d h m d h d h d h 1 MUHARAM 872 JUN 9 08 26 JUN 21 07 JUN 5 13 JUN 21 Solstice **************************************************************************** Equinox = Earth has Equal Daylight and Darkness (Mar 21 & Sept 23) Solstice = Sun apparantly Stationary in Declination (Maximum of Summer: June 21 & Min. of Winter: Dec 22) Perihelion = Earth Closest to Sun (Sun moving FASTEST in sky: Jan 3) Aphelion = Earth Farthest from Sun (Sun moving SLOWEST in sky: Jul 6) Perigee = Moon Closest to Earth (Moon moving FASTEST in sky) Apogee = Moon Farthest from Earth (Moon moving SLOWEST in sky) **************************************************************************** **************************************************************************** APPROXIMATIONS TO DIRECTION OF KA'BA (MAKKAH Saudi Arabia) In most places of the UNITED STATES of AMERICA, an APPROXIMATION to the direction of KA'BA, to determine the DIRECTION OF SALAT (PRAYERS), can be obtained by noting the direction of your SHADOW near the time of SUNSET. The direction in which your shadow goes is usually a little north of east DURING WINTER. This is the direction in which salat can be performed, as an approximation. This direction of the shadow changes during the different months of the year but is a good approximation when there is no magnetic compass to determine the exact direction. During summer, the shadow goes south of east and hence we would have to turn further north from the shadow, ie. further to the left of the evening shadow. For locations in the West of America the direction is even further North from the shadow, ie. even further to the left of the shadow. **************************************************************************** Copyright Dr.M.N.Durrani, 1987 - 1993 Permission to copy for free distribution is granted to all, please do give credit and reference. Thanks. For further information, please feel free to contact: Mail: Dr.Mohib.N.Durrani Islamic Amateur Astronomers Association (Research Division) 601 West 113 Street, Suite 11-K Columbia University NEW YORK, N.Y. 10025 United States of America Email to: mnd@cunixb.cc.columbia.edu (Mohib.N.Durrani) ***************************** End of Document ****************************** Look For The CRESCENT MOON ( HILAL ), --- >>> ) It Is One Of THE MOST BEAUTIFUL OF CREATIONS; ---- >>>> ) Then Offer An INTENSE PRAYER To The ONE CREATOR, ---- >>>> ) All Sincere DEVOTIONS Are Surely ACCEPTED. --- >>> ) ------------------------------ Date: Sat, 20 Mar 1993 21:34:39 GMT From: "Allen W. Sherzer" Subject: Clueless Szaboisms (Was Re: plans, and absence thereof) Newsgroups: sci.space,talk.politics.space In article <1ofb2bINN87r@access.digex.com> prb@access.digex.com (Pat) writes: >Second any contracts they get at UAH, first come >through a NASA center, with it's overhead 30% according to allen, The 'Center Wrap' isn't an overhead charge (I wouldn't mind if it was). It is simply a chunk the center takes and uses to fund whatever the center manager wants to fund. It doesn't go to overhead. Allen -- +---------------------------------------------------------------------------+ | Allen W. Sherzer | "A great man is one who does nothing but leaves | | aws@iti.org | nothing undone" | +----------------------88 DAYS TO FIRST FLIGHT OF DCX-----------------------+ ------------------------------ Date: 20 Mar 1993 19:06:37 -0500 From: Pat Subject: Clueless Szaboisms (Was Re: plans, and absence thereof) Newsgroups: sci.space,talk.politics.space In article <1993Mar20.213439.8967@iti.org> aws@iti.org (Allen W. Sherzer) writes: >In article <1ofb2bINN87r@access.digex.com> prb@access.digex.com (Pat) writes: | |>Second any contracts they get at UAH, first come |>through a NASA center, with it's overhead 30% according to allen, | |The 'Center Wrap' isn't an overhead charge (I wouldn't mind if it was). |It is simply a chunk the center takes and uses to fund whatever the >center manager wants to fund. It doesn't go to overhead. > What is the difference between taking 30% for overhead, and taking 30% for the directors pet projects? ------------------------------ From: Nick Szabo Subject: How to cool Venus Newsgroups: sci.space,rec.arts.sf.science References: <93077.010501GRV101@psuvm.psu.edu> <1993Mar18.082941.10534@nic.funet.fi> Date: Sat, 20 Mar 1993 12:38:42 GMT Lines: 48 Sender: news@CRABAPPLE.SRV.CS.CMU.EDU Source-Info: Sender is really isu@VACATION.VENARI.CS.CMU.EDU By the time we get around to doing this, we can get gigatons of dust from a Venus-crossing comet (eg P/Encke) and move it a few tens of m/s with native ice propellant to intercept trajectory. Before it strikes Venus disperse it into a wide cloud. If it vaporizes without recondensing into dust, we have to actually capture the dust in low orbit, a tougher proposition. Alternatively, build a bunch of micron-thin metal reflectors out of ore from Mercury and place them so that solar pressure balances against the Sun-Venus inner LaGrange point. This gives us better control than dust, and is more mass-efficient, but requires more sophisticated industrial infrastructure. Dust or mirrors might be used to cool earth; if global warming becomes a problem this could be a big space application in the 21st century. We are already spending $billions per year worldwide in energy conservation efforts, alternate energy & environmental research, etc. to try to head off global warming so this is a big market. [name removed to protect the innocent] >When considering that almost all of the mass of water lies in the >oxygen atoms and thus we get nine times more water by transporting >hydrogen only, it shouldn't be hard to decide. If only space development were this simple. Where, pray tell, are you going to get the hydrogen tanks? Those are a significant fraction of the hydrogen mass, and they're rather difficult to make in space (vs., for example, ice slabs). How are you going to store the hydrogen that close to the sun for months to years without venting most of it to keep it liquid? Exercise: set up a spreadsheet showing tank mass, Isp, processing equipment cost and mass output/mass equipment per year ratio assumptions, etc. and then try to minimize the mass of equipment, tankage, etc. launched from earth. Compare native hydrogen in an earth-launched tank against native ice rocket. Very enlightening. Given a mature space industrial infrastructure (big SPS's for cheap electrolysis, well-shielded H2 tanks from native materials, interplanetary reciprocating mass drivers, etc.), the mass savings by going to hydrogen become more attractive. -- Nick Szabo szabo@techboook.com ------------------------------ Date: 20 Mar 1993 21:35 UT From: Ron Baalke Subject: Just a little tap (was Re: Galileo HGA) Newsgroups: sci.space In article <1ofbm9INN8vl@access.digex.com>, prb@access.digex.com (Pat) writes... > Oh, the galileo engineering team deserves the Edison Prize for >their work in coping with a basically disasterous event. >The DSN improvements and the new coding schemes are terrific, >but I think 30% is a number placed on for PR purposes, not >in any way a real number. The 70% science return number came from the Galileo science team. It was presented by Torrence Johnson, Galileo Project Scientist, at the Gaspra press conference in June 1992. Note that the 70% science return is the minimum number, and will in actuality be higher by the time Galileo arrives at Jupiter. ___ _____ ___ /_ /| /____/ \ /_ /| Ron Baalke | baalke@kelvin.jpl.nasa.gov | | | | __ \ /| | | | Jet Propulsion Lab | ___| | | | |__) |/ | | |__ M/S 525-3684 Telos | Don't ever take a fence /___| | | | ___/ | |/__ /| Pasadena, CA 91109 | down until you know the |_____|/ |_|/ |_____|/ | reason it was put up. ------------------------------ Date: 20 Mar 1993 21:36:49 GMT From: Mark Subject: Predicting gravity wave quantization & Cosmic Noise Newsgroups: sci.space,sci.astro,sci.physics,alt.sci.planetary (From my previos post) >I believe that the universe is closed. That means that all functions are >decomposeable into a series of harmonics with respect to the closed >dimensions. I believe that the metric has components at low frequencies >that are residual from the Big Bang. They will occur as standing waves, so >the idea of wave speed is utterly inappropriate. In article crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes: > Ignoring the fact that you're talking about standing waves of > tremendous spatial extent Duh. > (and ignoring that wavespeed can be perfectly well defined in systems > with standing waves), and ignoring the fact that this has nothing to do with the quoted material nor with the point you apparently seem to be trying to make (whatever it may be)... > your coefficients are changing with time (since you apparently believe > in some sort of 'Bang'). Have you worked out the havoc this is going to > cause with your 'standing waves'? I don't recall owning any coefficients. Yes, most us believe in this "some sort of 'Bang'". We call it the Big Bang. The question is irrelevant. That there are harmonic components with respect to any of the closed dimensions has nothing at all do with the fact that they might vary in amplitude, nor even with the fact that the closed dimensions will vary in size with time. Also, I don't recall owning any 'standing waves'. > What you're asking for is a constant vibration at all > three satellites and the ground station.... I wasn't asking for anything. Besides, whether I was or not is irrelevant. Anyway, the premise of what you're trying to get me to ask for are wrong. Standing waves are not constants in space or time they vary with position and time, just like anything else. The only function constant in position and time is the constant function. Second, "constant vibration" is a contradictory use of words. Third, "constant in space and time" is the meaning of "constant" you intended, because it's the (false) presumption of your question of how two or more objects separated in space can detect something that is constant between them all. Were it not for that confusion, the question wouldn't have even arisen in the first place. ------------------------------ Date: Sat, 20 Mar 1993 22:21:31 GMT From: Cameron Randale Bass Subject: Predicting gravity wave quantization & Cosmic Noise Newsgroups: sci.space,sci.astro,sci.physics,alt.sci.planetary In article <1993Mar20.173142.18410@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes: >In article crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes: >> >> This points to another question that I had if my first two >> were answered. I'll pose it anyway. Let's say a gravitational >> wave comes through and whacks a spacecraft (ripples in space, and >> all that). For simplicity, we'll think of wavefront normal to the >> line connecting the spacecraft and the earth. Presumably the radio >> connection then sees a doppler shift due to the 'oscillation'. >> Why does the oscillation not identically nullify the doppler shift >> all the way back to the receiver owing to the effect of the wave >> on the radio signal? Is that the case, and is that why they're >> using three craft? > >Let's look at it another way. The gravity wave deforms the fabric of >spacetime. This lengthens the path from Earth to the spacecraft as >the wave passes into the beam. This "stretching" of space lengthens >the radio waves, IE lowers their frequency. This will happen to both >the wave going to the spacecraft, and the wave returning from the >spacecraft for a double downward frequency shift. Apart from the observation that it must be roughly an alternating contraction and dilation, the wave packet must be local in some sense (as implied in many of Thorne's ruminations). This is also implicit in the expectation that we will see a triplet structure of doppler shift. And this disturbance rides 'space' (in some sense I'm not prepared to defend) back to the receiver. The RF wavefront does the same. The propagation velocities are the same (or they are thought to be nearly so). Ignoring for the moment the thought that propagation constants in the solar system probably do not take free space values identically, the two waves ride back at the same 'time', along the same path. One 'wave' contains the RF doppler shifted value of the electromagnetic wavepacket from the 'whacking' the spacecraft received. The other is involved in actively changing spatiotemporal properties of the medium. It we take a crest of the gravitational wave as the maximum 'contraction', that would seem to lower the RF wavelength, but it would also seem to cause a temporal distortion that causes clocks to run slow, thereby correcting for the effects of the 'contraction' on the frequency. It seems to me that my difficulty is that the gravitational wave doesn't go away, it tracks the RF signal all the way back and it propagates at the same velocity. Of course, the only way to understand it in detail is going to be for me to sit my rear down and go through it in detail. dale bass ------------------------------ Date: Sat, 20 Mar 1993 23:01:28 GMT From: Cameron Randale Bass Subject: Predicting gravity wave quantization & Cosmic Noise Newsgroups: sci.space,sci.astro,sci.physics,alt.sci.planetary In article <1og2phINNle6@uwm.edu> markh@csd4.csd.uwm.edu (Mark) writes: >(From my previos post) >>I believe that the universe is closed. That means that all functions are >>decomposeable into a series of harmonics with respect to the closed >>dimensions. I believe that the metric has components at low frequencies >>that are residual from the Big Bang. They will occur as standing waves, so >>the idea of wave speed is utterly inappropriate. > >In article crb7q@kelvin.seas.Virginia.EDU (Cameron Randale Bass) writes: >> Ignoring the fact that you're talking about standing waves of >> tremendous spatial extent >Duh. > >> (and ignoring that wavespeed can be perfectly well defined in systems >> with standing waves), >and ignoring the fact that this has nothing to do with the quoted material nor >with the point you apparently seem to be trying to make (whatever it may be)... Well, let's not ignore them then. You've got 'standing waves' that will never have sufficient time to 'cross the universe'. So what's standing? Where are the nodes? Also, you stated that propagation speed was not a useful concept. Wavespeed can be perfectly well defined in systems with standing waves. Also, I've seen all kinds of responses here, but I believe 'duh' has to take the cake. >> your coefficients are changing with time (since you apparently believe >> in some sort of 'Bang'). Have you worked out the havoc this is going to >> cause with your 'standing waves'? > >I don't recall owning any coefficients. However, I do recall you mentioning some. Since no one else did, they're yours. >Yes, most us believe in this "some >sort of 'Bang'". We call it the Big Bang. We do? I prefer 'Horrendous Space KABLOOIE!'. >The question is irrelevant. That there are harmonic components with respect >to any of the closed dimensions has nothing at all do with the fact that they >might vary in amplitude, nor even with the fact that the closed dimensions >will vary in size with time. Also, I don't recall owning any 'standing waves'. The question is quite relevant. How do time-varying Fourier coefficients affect your waves? I'd think that moving the boundaries of the box would have a quite interesting effect. Oh, and by the way, since you mentioned the 'standing waves', they're yours as well. >> What you're asking for is a constant vibration at all >> three satellites and the ground station.... > >I wasn't asking for anything. Besides, whether I was or not is irrelevant. >Anyway, the premise of what you're trying to get me to ask for are wrong. >Standing waves are not constants in space or time they vary with position and >time, just like anything else. The only function constant in position and >time is the constant function. Second, "constant vibration" is a >contradictory use of words. > >Third, "constant in space and time" is the meaning of "constant" you intended, >because it's the (false) presumption of your question of how two or more >objects separated in space can detect something that is constant between them >all. Third, not at all. Lightspeed delays and phase phenomena could possibly be used to detect 'standing waves'. My point was that the effect is likely to be much more difficult to detect. Second, take your leg, put it on the ground, bounce it up and down four hundred times at quarter-second intervals. Note the constant vibration. First, what in the heck does 'standing wave' mean to you? dale bass ------------------------------ Date: Sat, 20 Mar 1993 22:03:25 GMT From: Paul Dietz Subject: SSTO: A Spaceship for the rest of us Newsgroups: sci.space In article <1993Mar20.170616.18088@ke4zv.uucp> gary@ke4zv.UUCP (Gary Coffman) writes: > So we're down to $35,000 dollars for fuel. That sounds too cheap. Certainly > I can't buy welding gas for $0.05 a pound, it's around $0.55 a pound for > compressed gas, I'd assume LOX would be higher and LH higher still, and the > bulk discount shouldn't be *that* big. Where'd you get that number? Actually, there are large economies of scale in oxygen production and distribution. Almost all of the cost of your compressed oxygen cylinder would be in the overhead of the infrastructure for delivering and filling the tank with oxygen, not in the oxygen itself. Ullman's Encyclopedia has a diagram of the price of oxygen vs. rate of demand; it varies by more than an order of magnitude from small scale (compressed gas cylinders) to intermediate scale (LOX tankers) to large scale (dedicated cryogenic or PSA separation plants). Paul F. Dietz dietz@cs.rochester.edu ------------------------------ Date: Sat, 20 Mar 1993 23:12:30 GMT From: Henry Spencer Subject: Why use AC at 20kHz for SSF Power? Newsgroups: sci.space In article steinly@topaz.ucsc.edu (Steinn Sigurdsson) writes: >One of the most frequent complaints here against NASA is that >they don't consider new technologies that might lower costs >in the long run and don't experiment with different concepts. >Yet, when they do and it doesn't work out they are chastised... The flip side of this complaint is equally valid: that NASA all too often insists on reinventing off-the-shelf equipment from scratch just for the sake of "new technology". You need both airliners and X-planes, and you need to have a clear idea of the difference between them. You don't commit X-planes to flying twice daily from New York to L.A., and you don't try major new experiments on your airliners (not unless it's something trivial like a new type of paint, which isn't going to affect the usability of the airliner if it doesn't work). NASA does indeed need to consider new technologies and experiment with new ways of doing things... but *not* on spacecraft with major operational missions to fly! How many new, untried concepts would you accept in the construction of your house? -- All work is one man's work. | Henry Spencer @ U of Toronto Zoology - Kipling | henry@zoo.toronto.edu utzoo!henry ------------------------------ End of Space Digest Volume 16 : Issue 347 ------------------------------