Date: Fri, 28 May 93 14:23:51 From: Space Digest maintainer Reply-To: Space-request@isu.isunet.edu Subject: Space Digest V16 #642 To: Space Digest Readers Precedence: bulk Space Digest Fri, 28 May 93 Volume 16 : Issue 642 Today's Topics: Another spectral class mnemonic Detecting planets in other system Free seismology textbook on CD-ROM (2 msgs) Hey Ken! You awake? You exist? (LEO Cost; Return cost) How do I convert Galactic Longitude & Latitude to 3D system? Kepler's dream of space travel Launch Vehicle Permits Microlensing searches (was "detecting planets in other systems") Minds in Space Moon Base Privatizing scientific terminology Space Raffles? Tom Wolfe's THE RIGHT STUFF - Truth or Fiction? Voyager Discovers the First Direct Evidence of the Heliopause (3 msgs) 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: 27 May 93 23:44:49 GMT From: Tom Zych Subject: Another spectral class mnemonic Newsgroups: sci.space,sci.astro Obviously Brainy Astronomer Finds Galaxies Keep Moving, Revealing New Science -- Tom Zych tbz1823@hertz.njit.edu ------------------------------ Date: 28 May 1993 05:07:22 GMT From: Joe Elso Subject: Detecting planets in other system Newsgroups: sci.space,sci.astro In article <1993May26.184001.16542@cs.ucf.edu>, clarke@acme.ucf.edu (Thomas Clarke) writes: > In a recent issue of Science there is a discussion of a project > to look for MACHOs (Massive Compact Halo Objects - things like > planets, brown dwarfs, or even black holes in the galactic halo > that might account for some of the missing mass). The scheme for > detecting MACHOs is to look for a micro-gravitational lensing event > as the MACHO passes in front of a distant star. To make the > statistics workable they have put together a 64 million (!!!) pixel > CCD which will be mounted on an otherwise little used 50-odd inch > worn-out telescope. The CCD will then stare at the large Magellenic > Cloud (LMC) to look for microlensing events. They expect a > jupiter-sized object to enhance a stares brightness for a day or two, > a week or two for dwarfs, and possibly months for a black hole. > There is no "will" & "will be" about it - the MACHO project is going strong right now. They have analysed 10% of the data and found 1 probable event & 2 possibles (plus 28,000 variables!!). The data handling required is mighty impressive - they take an exposure every 5 minutes, all night, every night (weather etc permitting :-) ). -- =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- Joe Elso CSLab, Research School of Physical Sci. & Eng. joe@trust.anu.edu.au Australian National University (249 0446) =-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- "No matter what your cause, it's a lost cause if we don't control human numbers" - Paul Ehrlich ------------------------------ Date: 28 May 1993 05:46:50 GMT From: Jon Claerbout Subject: Free seismology textbook on CD-ROM Newsgroups: sci.astro,sci.bio,sci.math,sci.math.stat,sci.med,sci.space,sci.engr,sci.physics,sci.geo.meteorology,sci.math.num-analysis,sci.engr.mech,sci.image.processing Free seismology textbook on CD-ROM for UNIX computers with X11. Includes two PhD theses and nifty electronic document software. Does not work on PC, MS-DOS, or MacIntosh. Many bugs fixed since our 1991 edition Mail your request on your institutional letterhead to Jon Claerbout Geophysics Department Stanford University Stanford, CA 94305-2215 USA details below +-+-+-+-+-+-+-+-+-+-+- = +-+-+-+-+-+-+-+-+-+-+- Seismology on CD-ROM Disk SEP-CD-4 produced at Stanford University includes \item ``Earth soundings analysis: processing versus inversion'', \\ a {\bf textbook} by Jon F. Claerbout, \item ``Imaging by the wavefront propagation method'', \\ a doctoral {\bf dissertation} by Lin Zhang \item ``Elastic modeling and migration'', \\ a doctoral {\bf dissertation} by Carlos Cunha Filho \item Documents and {\bf software} by students and former students at the Stanford Exploration Project (SEP) and software gleaned from the internet that enable you to build electronic documents, You need a CD-ROM drive and a UNIX workstation with X11 and Fortran. Our disk includes binaries for IBM RS-6000, Hewlett-Packard 700 series, Sun 4 (not Solaris 2), and DEC 3100. In many branches of engineering and science there is a substantial computational element. Seismology is one of these. In taking up computational problems we should abandon books, journals, and reports and replace them with electronic documents that can be used to recreate any print document, including its figures, from its underlying data and computations. Today, few published results are reproducible in any practical sense. To verify them requires almost as much effort as it took to create them originally. After a time, authors are often unable to reproduce their own results! It is time to plunge into a new era. These electronic documents contain everything needed to rebuild themselves; data, programs, graphics libraries, text, and word processor. This software, gathered and prepared at the Stanford Exploration Project, is presented in a way to encourage you to prepare reproducible electronic documents. {\bf Interactivity.} Where a figure caption contains a pushbutton (word in a box), you can press the button to interact with the figure. Most figure captions contain pushbuttons. Some of these pushbuttons launch fun interactive programs. {\bf Reproducibility.} Each figure caption is followed by an [R] or an [NR] which denotes Reproducible or Not Reproducible. You can press a button to ``burn'' any reproducible figure, and another to rebuild it according to your own specifications, including any changes you may have made to the parameters, programs, or data. Some people see reproducibility of research as a troublesome ethical issue. We see it as an everpresent, irritating practical concern. We are annoyed when we cannot easily reproduce our own work. Some of us are irritated when other professors publish grandiloquent papers whose conclusions require too much time to confirm. And we are further frustrated when new students cannot reproduce (in a year) the work of other recently graduated students. Although each student prepares a doctoral dissertation that should enable others to reproduce that work, the reality is that paper documents are outdated; they no longer fulfill the role they did a generation ago when data consisted of photographs and pencil marks on a piece of paper---when theory was several pages of Greek symbols. Paper no longer serves us well. Our data now resides in a computer, and our theory is embodied in computer programs. Many libraries overflow and they cannot afford the materials they want. At a million characters per book, over 600 books could be on a CD-ROM with a retail cost below 2 cents per book. We do not have 600 books so we filled our CD-ROM with the accumulated shared software library of many current and former students. We added many valuable, publicly available programs including fortran extenders and programs for composition and typesetting. We added seismograms. And, most importantly, we glued it together with ``shell scripts'' and ``makefiles'' that enable us and others to reproduce all our work. We call this a ``{\bf living document}.'' Our experience shows that it is only slightly more difficult to give birth to a ``living'' document than a ``dead'' one. The major hurdles in preparing a doctoral dissertation, research monograph or textbook are these: (1) mastering the subject matter itself, (2) writing the ancillary technical programs, (3) using a text editor and word processing system, and (4) writing the command scripts that run the programs to make the illustrations. The difference between preparing a ``live'' document and a ``dead'' one, lies in the command scripts. Will they be run once and then forgotten, or will they be attached to the figure-caption pushbutton? Authors who wish to communicate will produce live documents. Authors who merely wish to advertise their scholarship without really sharing it will continue to produce dead ones. The increase in effort for the authors is minuscule---once they learn how to organize their work properly and to ``file'' it electronically. When you look beneath the surface of these documents you will find everything you need to make your own living documents. And you can freely copy it from our disk. At the beginning of the computer revolution, I gave young students the advice: ``Learn how to type.'' With the mass-storage revolution now underway, and with a \$10 CD-ROM able to hold all the keystrokes you can type in a lifetime, I now advise everyone: ``Learn how to file.'' Jon F. Claerbout and Martin Karrenbach ------------------------------ Date: Fri, 28 May 1993 07:37:44 GMT From: Jack Sarfatti Subject: Free seismology textbook on CD-ROM Newsgroups: sci.astro,sci.bio,sci.math,sci.math.stat,sci.med,sci.space,sci.engr,sci.physics,sci.geo.meteorology,sci.math.num-analysis,sci.engr.mech,sci.image.processing Indeed you are correct. Right now I am using authorware to make a simple introductory physics course with calculus suitable for bright high school, community college, US Navy PACE, and first year college levels. It's a lot of fun. I am using Feynman's Lectures on Physics as my guide. But there will be plenty of problems for students to work on interactively. I am also using MATH CAD 4.0 and I have MATHEMATICA if I need it. I also will be using 3D modeling program and Corel Draw. I am making rapid progress and should be quite expert and efficient in a few months. It's all straight stuff - non of my "crazy" ideas on faster than light and backward in time quantum connection communication computing and telepathic consciousness etc in this. That will be in my CD ROM edition of my old best selling book SPACETIME AND BEYOND. ------------------------------ Date: 28 May 93 03:56:21 GMT From: Lynne K Wahl Subject: Hey Ken! You awake? You exist? (LEO Cost; Return cost) Newsgroups: sci.space [a whole bunch of stuff deleted] >Exactly! Not vehicles -- *payload*! The vehicle *is not* payload. >------------------------------------------------------------------------------ >Fred.McCall@dseg.ti.com - I don't speak for others and they don't speak for me. Well, there is a minor technical point. The vehicle delivered to orbit has portions that are not payload, but are still "usefull". The shuttle has the External Tank, and the Saturn has the (second? third?) stage. Both of these are capable of being adapted with airlocks into *BIG* living quarters (AKA Skylab) or melted down and re-manufactured in orbit like a deposit can. (wonder what the deposit would be :) There are some problems that would have to be overcome like draining propellents, drilling the airlock holes, and tacking the outside insulation down (on the ET). -- --Lynn Wahl lwahl@matt.ksu.ksu.edu | The meek will inherit the Kansas State University Student | earth, the rest of us are Soil Conservation Service Computer Specialist | going to the stars. ----* ------------------------------ Date: 28 May 93 05:28:05 GMT From: Morgoth the Mad Subject: How do I convert Galactic Longitude & Latitude to 3D system? Newsgroups: sci.space In article <1993May27.194344.26697@spectrum.xerox.com>, mcapron@wbst845e.xerox.com (Mike Capron) writes: > > I am starting a science fiction FRP campaign and would like to generate star > maps from actual stars in the galaxy. > > I have David Mar's starmapping program which generates maps from a > 3 dimensional coordinate system. I also have the Yale Bright Star > Catalog (and a bunch of similar things) from around the net. I thought > this would be sufficient; I appear to have been wrong. > > The problem is that the star catalogs all seem to give star position in > terms of two angles. Galactic Latitude is the number of degrees north > of the Galactic Equator (90 to 0 to -90) and Galactic Longitude is the > number of degrees east along the disk made by the equator (although I'm > not sure where 0 degrees is). The catalogs also have right ascention and > declination, which is a similar system, but centered on the Earth. > > Don't the intersection of these two angles leave you with a line? Don't > you also need to know distance from the center to convert to a 3D coordinate > system? Am I misreading the catalogs? Help! > > Thanks in advance, > Mike Capron > mcapron@wbst845e.xerox.com > > > PS: If I successfully create a conversion program, I will submit it to the > FRP archives. Can anyone on this sub email him and help?? I know its a gaming question (god forbid), but it is a legitamate question for sci.space!?? == Michael Adams, nsmca@acad3.alaska.edu -- I'm not high, just jacked ------------------------------ Date: Wed, 26 May 1993 17:59:16 GMT From: George Bendo Subject: Kepler's dream of space travel Newsgroups: sci.physics,sci.space In article <1993May26.041100.17721@galois.mit.edu> jbaez@riesz.mit.edu (John C. Baez) writes: >I will describe it more when I have read it all, but for now I just >CAN'T resist giving you all this little puzzle. To WHOM did Kepler >write a letter in 1610 saying: > >Who would have believed that a huge ocean could be crossed more >peacefully and safely than the narrow expanse of the Adriatic, the Baltic >Sea or the English Channel? Provide ship or sails adapted to the >heavenly breezes, and there will be some who will not fear even that >void.... So, for those who come shortly to establish this journey, let >us establish the astronomy.... > Is the answer Galileo? I understand that Kepler and Galileo did write frequently to each other about each other's research George Bendo -- | George Bendo | "The best laid schemes o' mice an' men | | New Mexico Tech | Gang aft a-gley." | | salem@nmt.edu | - Robert Burns, "To a Mouse" | ------------------------------ Date: 27 May 93 21:30:45 GMT From: Mark Johnson Subject: Launch Vehicle Permits Newsgroups: sci.space henry@zoo.toronto.edu (Henry Spencer) writes: >Transportation, which is part of the Dept. of Transport. I'm told >they can be reached at (202)366-2929, although I haven't tried myself. >Anything that is capable of going above 100km needs an OCST permit. Below >that, I think they bow out and it's mostly the FAA that has to be kept happy. >(The OCST minima are stated in more complex terms, but 100km is what they >boil down to, I'm told.) Actually, the criteria are even worse; OCST has jurisdiction over anything with a thrust time > 15 seconds. Yup, this means that the high power non- professional rocket guys had to get a waiver from OCST for this summer's LDRS rocket launch, here in Kansas. :-( -- Mark Johnson USnail: NCR Peripheral Products Division E-mail: Mark.Johnson@WichitaKS.NCR.COM 3718 N. Rock Rd. Voice: (316) 636-8189 [V+ 654-8189] Wichita, KS 67226 [Non-business email: 76670.1775@compuserve.com] ------------------------------ Date: Thu, 27 May 1993 15:49:56 GMT From: Stupendous Man Subject: Microlensing searches (was "detecting planets in other systems") Newsgroups: sci.space,sci.astro In article <1993May26.215600.28549@sfu.ca> Leigh Palmer writes: >In article <1993May26.184001.16542@cs.ucf.edu> Thomas Clarke, Thomas Clarke, talking of the MACHO project (who are looking for microlensing events by staring at the Magellanic Clouds), says > The point, of this is that maybe the same detector will inadvertantly > succeed in detecting planets. It would be ironic if the first > detection of a Jupiter-sized planet were in the LMC! Actually, in order to produce a microlensing event, I believe that a Jupiter-sized lensing object would have to be in the halo of our own galaxy, not in the LMC itself. I don't think that the MACHO search is sensitive enough to detect the millimag variation caused by a planetary occultation, as we've been discussing lately. Leigh Palmer says >If I had a machine like that I'd point it into the center of the Galaxy. Which is exactly what the OGLE group is doing. The OGLE (Optical Gravitation Lensing Experiment) project is similar to the MACHO search, in that it is designed to detect gravitation microlensing (for details, read the article by Udalski et al., Acta Astronomica, 42, 253 (1992)). Instead of looking at the LMC as a source of stars-to-be-lensed, however, the OGLE group is looking at the bulge of our own galaxy. They hope to see microlensing events due to foreground objects in and near the disk of our galaxy passing in front of more distant bulge stars. The OGLE group consists of a contingent from Warsaw University, and the Carnegie Institute; they are using the 1-meter Swope telescope at Las Campanas with a 2048x2048 CCD, so their data acquisition rate is quite a bit smaller than the MACHO group's. They work in I and V, allocating most of the time to I. Last year, they got about 50 good nights, from April through August 1992. The number of stars with photometric errors < 0.1 mag detected were (adding up all the stars in different fields) about 150,000! As Leigh mentioned, they find MANY variable stars; Bohdan Paczynski, who's been following the project very closely, has a big poster on his door which shows about 50 beautiful light curves of various types of variable stars, which is, of course, a tiny fraction of the total number. So far, no microlensing events, but the total amount of information one COULD find in the database is enormous. The MACHO project will tell us a heck of a lot about the properties of the LMC (including distance), and the OGLE project a heck of a lot about the bulge and disk of our own galaxy. But it's going to take years for people to sort through all the data and pick out the useful bits. Graduate students who are looking for thesis topics, take note! -- ----- Michael Richmond "This is the heart that broke my finger." richmond@astro.princeton.edu ------------------------------ Date: 28 May 1993 08:04:29 GMT From: Diaspar Virtual Reality Network Subject: Minds in Space Newsgroups: sci.space June 23, 1993 Event called "Minds in Space" The Diaspar Virtual reality Network, Verde Software and the Electronic Cafe in Santa Monica, California will be sponsoring an e an event on June 23, 1993 called "Minds in Space" from 7:30 pm to 9:30 pm. The content and nubmer of people presenting information about space is still "up in the air" and undergoing planning. Thislooks like it should be a worthwhilke event to attend. And, if you have something worthwhile to say and can do it effectively in person in 5 to 10 minutes, let me know and I will see if it can be included. My goal is for many people to share info about space. There will probably be video-phone links to Phoenix and to Albuquerque so that some presenters will share their information wit hthe main group in Santa Monica. As I know more I will post it. And, as a side note, I will get those DC-X stereoscopic .gifs done soon. I have had zero time and just got back from speaking at the Meckler VR con- ference. All who emailed me have not been forgotten. And, we will get those .gifs up on an ftp site as soon as they are ready. So, in summary: 1. Minds in Space on June 23, 1993 (7:30 pm to 9:30 pm) 2. If you wish to be a part of this., let me know. (we could even use some to transcribe info for the nets, there will be live connection to Diaspar that evening, which is tel-netable) 3. I will get those steroscopic .gifs out soon. David Mitchell Diaspar ------------------------------ Date: Fri, 28 May 1993 03:44:36 GMT From: Henry Spencer Subject: Moon Base Newsgroups: sci.space In article <1993May27.231201.552@njitgw.njit.edu> tbz1823@hertz.njit.edu (Tom Zych) writes: >However, I did have the impression that moonquakes are fairly >common. Anyone know if this is true? ... I think you've been reading pre-Apollo science fiction. :-) The Moon is amazingly quiet seismically. It's just completely dead. The seismic background is so low that before the Apollo seismometer network was shut down, the folks running it claimed to be able to hear the impact of a basketball-sized meteorite anywhere on the Moon. (In fact, as a seismic network it was a bit of a bust after Apollo stopped slamming rocket stages into the Moon; there just wasn't much internal to hear. But it made a dandy large-meteorite detector, with a collecting area 3000km across.) -- SVR4 resembles a high-speed collision | Henry Spencer @ U of Toronto Zoology between SVR3 and SunOS. - Dick Dunn | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 28 May 1993 00:12:46 GMT From: Pawel Moskalik Subject: Privatizing scientific terminology Newsgroups: sci.space,sci.astro Isn't it enough that we already have "Toyota Profesor of Physics" ??? This is no joke, I have met a scientist with such title ..... Pawel Moskalik ------------------------------ Date: Fri, 28 May 1993 03:53:26 GMT From: Henry Spencer Subject: Space Raffles? Newsgroups: sci.space In article <1u39giINNne5@jumbo.read.tasc.com> lapadula@snowwhite.Read.TASC.COM (David B. Lapadula) writes: >I think I recall reading/hearing about some sort of Soviet venture where they >tried to sell raffle tickets, with the lucky winner getting to go to MIR, or >something like that. I recall that it was done w/a US partner. > >Did the whole thing turn out to be a sham? Misunderstanding between the >Soviets (Russians?) and the US partners? Or what? There were some (brief) misunderstandings along the way. But it was a completely legitimate project: some US entrepreneurs set it up, and got a signed-and-sealed contract with Glavkosmos to supply the launch. Much of the financing was to come from sponsorship, actually, not from the ticket sales. Then somebody in the local DA's office who hadn't read the fine print jumped to conclusions and decided it was illegal (it wasn't), and by the time he figured out his mistake, he was in too deep to back out. If they'd been big and well-financed, they could have survived the legal harassment, but they weren't. -- SVR4 resembles a high-speed collision | Henry Spencer @ U of Toronto Zoology between SVR3 and SunOS. - Dick Dunn | henry@zoo.toronto.edu utzoo!henry ------------------------------ Date: 28 May 1993 00:10:55 GMT From: Claudio Oliveira Egalon Subject: Tom Wolfe's THE RIGHT STUFF - Truth or Fiction? Newsgroups: sci.space,sci.space.shuttle,rec.arts.books Kennith Johnson writes > Let me ask you this. If you were writing a book about your > experiences as the wife of Gus Grissom, would YOU mention the > fact that you might have considered slashing your wrists? I > wouldn't. Neither me... By the way do you know any other reference that would confirm or not what Tom Wolfe had written in his book about the above incident? The point that I was trying to make was whether Tom Wolfe had described the incident accurately or not after all, the original question was whether the THE RIGHT STUFF was Truth or Fiction... > Why does it matter so much whether or not Gus (it's spelled with > one 's', by the way) Grissom (with an 'm') was surprised at the way > his wife reacted? It matters so much because if he did not describe this incident accurately, he might had carried out other inaccuracies to other parts of his book. BTW thank you for correcting my spelling. C.O.Egalon@larc.nasa.gov Claudio Oliveira Egalon ------------------------------ Date: 27 May 1993 20:12:40 -0700 From: Julie Bixby Subject: Voyager Discovers the First Direct Evidence of the Heliopause Newsgroups: sci.space,sci.astro,alt.sci.planetary I'm confused. I though one of the Pioneer probes had already discovered the heliopause a few years ago. -- Julie Bixby Internet: markb@cccd.edu Engage Romulan .sig cloaking device.... ------------------------------ Date: 28 May 93 04:34:13 GMT From: Jeff Bulf Subject: Voyager Discovers the First Direct Evidence of the Heliopause Newsgroups: sci.space,sci.astro,alt.sci.planetary In article <1u3vv8$2d4@spock.dis.cccd.edu>, markb@spock.dis.cccd.edu (Julie Bixby) writes: |> I'm confused. I though one of the Pioneer probes had already discovered |> the heliopause a few years ago. I'm sure somebody who is still at NASA can answer this better than I, but here goes anyway... Pioneers 10 & 11 did go beyond Pluto first and are still on their way out there looking for that heliopause. But each of the four spacecraft (2 poineers and 2 voyagers) is headed in a different direction. I believe one of the Voyagers is on the trajectory nearest the close part of the heliopause. What you remember is probably a NASA puff piece (excuse me: press release) about Pioneer being on its way to find the heliopause. True, but not the same thing. More detatiled info from Ames or JPL would certainly be welcome. -- ___ __| __ \ | | | dr memory | | / jbulf@kpc.com | ___ \ | | | Pluto? Gawrsh, Mickey! ____| ______/ ------------------------------ Date: Fri, 28 May 1993 05:12:32 GMT From: Tim Schneider Subject: Voyager Discovers the First Direct Evidence of the Heliopause Newsgroups: sci.space,sci.astro,alt.sci.planetary In article <26MAY199316020920@kelvin.jpl.nasa.gov> baalke@kelvin.jpl.nasa.gov (Ron Baalke) writes: >Paula Cleggett-Haleim >Headquarters, Washington, D.C. May 26, 1993 >(Phone: 202/358-0883) > >Mary A. Hardin >Jet Propulsion Laboratory, Pasadena, Calif. >(Phone: 818/354-5011) > >RELEASE: 93-099 > >VOYAGER SPACECRAFT FIND CLUE TO ANOTHER SOLAR SYSTEM MYSTERY > > ... STUFF DELETED ... >watts. However, these radio signals are at such low frequencies, >only 2 to 3 kilohertz, that they can't be detected from Earth." This is very interesting stuff. However this point is somewhat unclear to me. Could someone please elucidate? > ... MORE STUFF DELETED ... Ron Baalke | baalke@kelvin.jpl.nasa.gov Thanks in advance... Timothy Schneider schneid@stokes.atmos.colostate.edu ------------------------------ From: Tom Zych Newsgroups: sci.space Subject: Re: Moon Base Summary: Lunar observatories Message-Id: <1993May27.231201.552@njitgw.njit.edu> Date: 27 May 93 23:12:01 GMT References: <24610@mindlink.bc.ca> <1993May24.163728.14499@ke4zv.uucp> Sender: "Tom Zych"@hertz.njit.edu Organization: New Jersey Institute of Technology, Newark, N.J. Lines: 29 Nntp-Posting-Host: hertz.njit.edu Source-Info: Sender is really news@CRABAPPLE.SRV.CS.CMU.EDU Source-Info: Sender is really isu@VACATION.VENARI.CS.CMU.EDU In article stephens@geod.emr.ca (Dave Stephenson) writes: >gary@ke4zv.uucp (Gary Coffman) writes: >>[Summary: Farside radio observatory for shielding from Earth's noise; >>Optical observatory no good due to mining & blasting.] >Wrong about optical observatories. Optical interferometers could be built >on the Moon, as it is a stable structure to optical wavelenght dimensions. >An array of interferometric telescopes on the Moon could image Earth-like >planets around near-by stars. This could not be done on the moving plates >of the Earth, or in space. Mining and blasting would not be a problem as long as such operations were confined to areas more than a few hundred miles away, I think. I haven't heard of astronomers here having problems with it, or am I simply displaying my ignorance? However, I did have the impression that moonquakes are fairly common. Anyone know if this is true? This would render any blasting insignificant. The shielding argument would also apply, I suspect, to another set of wavelengths. IR imaging devices would be more easily kept cool on the moon than in open space; use them during the dark semi-lunar, and keep the liquid He underground during the bright. Probably simpler than whatever insulation IRAS used against the constant solar heat. -- Tom Zych tbz1823@hertz.njit.edu ------------------------------ End of Space Digest Volume 16 : Issue 642 ------------------------------