Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from beak.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Thu, 19 Apr 90 01:36:01 -0400 (EDT) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Thu, 19 Apr 90 01:35:21 -0400 (EDT) Subject: SPACE Digest V11 #283 SPACE Digest Volume 11 : Issue 283 Today's Topics: Re: space tomatoes Interstellar Radio Communications Re: Discovery's Spin in 2010 (Was Re: Artificial gravity) Re: Arecibo (sp?) message Re: Fermi Paradox Re: Earthbound Asteroid.....trying again! Re: NASA Headline News for 04/13/90 (Forwarded) Re: Apollo 13, STS-1, Vostok 1 anniversaries Re: Earthbound Asteroid.....trying again! ---------------------------------------------------------------------- Date: 18 Apr 90 14:57:40 GMT From: pasteur!helios.ee.lbl.gov!hellgate.utah.edu!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!watdragon!watyew!jdnicoll@ucbvax.Berkeley.EDU (Brian or James) Subject: Re: space tomatoes Aren't tomatos related to plants like Deadly Nightshade? I wonder how they came to be regarded as a foodstuff, since I know that as recently as the 18th century people assumed they were as deadly as their relatives. Probably some poor bastard starving to death and deciding to end his misery fast [There's a plant from the Amazon that's safe after cooking causes its toxins to break down that was discovered by a starving explorer making a similar decision. He didn't care for a cold last meal, so he cooked it before eating. I think its what tapioca's made from, but I wouldn't swear tp it]. JDN ------------------------------ Date: 18 Apr 90 14:48:01 GMT From: pasteur!helios.ee.lbl.gov!hellgate.utah.edu!cs.utexas.edu!news-server.csri.toronto.edu!utgpu!watserv1!watdragon!watyew!jdnicoll@ucbvax.Berkeley.EDU (Brian or James) Subject: Interstellar Radio Communications Most of the discussion I've seen assumes that that communication we're trying to 'eavesdrop' is only by chance detectable by us. If you are trying to spot other technological cultures, it gets a lot easier if they are trying to be heard [I have this mental image of forty million civilisations listening carefully to the radio bands while trying to be perfectly silent themselves]. While it is probably true that older cultures could be using 'exotic' means of communication that we, in our technologically primitive and intellectually fallen state, cannot imagine, there's not much point in trying to listen for means of communication that are currently inconceivable to us :). If you assume [and I realise that there is no binding reason to do so] that there might be a culture which *wants* to be heard from, the EMR is a good choice to listen to, since it seems likely to be used for communication for at least some point in a technological culture's history. It's like the wheel; a likely although not inevitable tool for sapients to discover, and if you want to be heard, it's a good guess at a communications technology that's likely for most technological cultures to be aware of. Now, the *motives* for a culture to broadcast to other cultures are open to question, and while currently, humans find it hard to justify any activity that lasts longer than a decade [Let's hear it for the Harvard Business School of thought!], even we lowly primates have had projects which took lifetimes to finish [cathedrals in Europe, for example], so it doesn't seem unreasonable to speculate about another species having activities that last multiple centuries or millenia. As someone else pointed out, even though broadcasting in all directions is inefficient, there are groups, like Voice of America or Radio Moscow that have motives for doing so. I hope this doesn't mean that most detected SETI signals are things like 'Quantification of Angel Packing in a Infinitesimal Volume' :) I wonder if there other ways of detecting ETIs at range. We have had an impact on our planet's atmosphere, but I have no idea if that kind of thing is detectable given *big* telescopes [100 km mirrors out beyond pluto, :) ] or obvious that humans caused the change. It could be that life forms like plants are much easier to spot than other high tech species [Any world with lots of O2 in its atmosphere has got to have something constantly replacing the oxygen]. Back in the '70s, there was speculation that a nuclear war is detectable for ~50ish LY, but that's not the kind of technique that is useful for long term detection of signals. I suppose in a few decades, we could do things like dumping a megatonne of rare elements [like Plutonium] into the sun and hope that if any ETI notices the weird emission lines in Sol's spectrum, they don't just create a model of stellar evolution that includes a class of 'stars that really should not have plutonium emission lines but do anyway'. Back when they found LGM 1, and after they realised that it looked much more like a natural source than a technologically produced signal, someone commented that, while pulsars are a stupid way to try and communicate, he knew of no binding reason why high tech types couldn't also be stupid. JDN ------------------------------ Date: 18 Apr 90 16:22:40 GMT From: ames.arc.nasa.gov!mike@ames.arc.nasa.gov (Mike Smithwick) Subject: Re: Discovery's Spin in 2010 (Was Re: Artificial gravity) In article <3104@calvin.cs.mcgill.ca> msdos@calvin.cs.mcgill.ca (Mark SOKOLOWSKI) writes: <>One thing that has always impressed me about 2001 was the lack of <>sound in the outer-space (ie outside of spacecraft) shots; no <>Star Wars-like deep, low freq rumble of powerful thrust engines. <>Any other such movies with silent space? Even Alien, with "in space <>no one can hear you scream", you could hear the engines from "outside". < simpkins@manta.nosc.mil.UUCP (Michael A. Simpkins) writes: >Exactly what image did they choose to send to these far off worlds? It was a crude bitmap picture plus some binary data; I don't have details on hand. -- With features like this, | Henry Spencer at U of Toronto Zoology who needs bugs? | uunet!attcan!utzoo!henry henry@zoo.toronto.edu ------------------------------ Date: 18 Apr 90 05:59:18 GMT From: hoptoad!tim@ucbvax.Berkeley.EDU (Tim Maroney) Subject: Re: Fermi Paradox In article <1990Apr17.174219.20795@utzoo.uucp> henry@utzoo.uucp (Henry Spencer) writes: >We can guess at >our own capabilities a hundred years from now, but most of the guesses will >probably be wrong. A thousand years out, even guessing is silly. A race >that has had a technological civilization for a million years would >probably be capable of doing many things we are certain are impossible. Very much so. And one point that often seems to be missed in discussions of the Fermi problem is that an advanced, starfaring civilization may simply be so different from us as to be incomprehensible, while we would be beneath its notice. When was the last time you tried to make contact with a colony of ants? When was the last time you did make contact with an ant colony and the ant colony came away with any clear impression of what had happened? It seems inevitable that within a thousand years, our own nature as a species will have changed greatly -- through genetic engineering as well as through the integration of artificial and biological neural networks. I simply can't see how this could *not* be true within a millenium if we continue to develop, and a century or two seems like a more realistic estimate. Now consider that a mere four-digit difference between species in technological age is unlikely on these scales, and that the minimum difference we could reasonably expect would be tens or hundreds of thousands of years. What common ground would we have with a species that, for instance, had the combined intelligence of the entire human race in each individual, and each individual seamlessly integrated into a whole (to name just one possibility)? There seems to be a sort of Star Trek assumption that we are going to be just the same as we are now, but tooling around in starships instead of airplanes. No way. Nietzsche was right about one thing -- we stand at the brink of our replacement by a new species, a species we can barely begin to comprehend. That being the case, the idea of "contact" between ourselves and such a highly developed species seems a bit silly. -- Tim Maroney, Mac Software Consultant, sun!hoptoad!tim, tim@toad.com "There are no Famous People on the net. Only some of us with bigger mouths than others." -- Dan'l Danehy-Oakes, The Roach ------------------------------ Date: 18 Apr 90 10:34:10 GMT From: zaphod.mps.ohio-state.edu!samsung!munnari.oz.au!uhccux!tholen@tut.cis.ohio-state.edu (David Tholen) Subject: Re: Earthbound Asteroid.....trying again! In article <28411@ut-emx.UUCP>, grads@ut-emx.UUCP (Feulner ... Matt Feulner) writes: > In article <6122@rayssdb.ssd.ray.com> bea@rayssdb.ssd.ray.com (Brian E. Alber) writes: > > > 5.) Why didn't we see it coming? > > We weren't looking. Ah, but we were! The problem, as I mentioned in my previous followup, was that the asteroid was coming at us from the daytime side, and the search projects work at night when the sky is dark enough to allow such faint objects to be seen. Forgive me for stating the obvious. Of course, the people searching for these objects don't have exclusive access to the telescope, and there is always the possibility of bad weather wiping out an entire telescope run, so other similar close approaching asteroids could manage to zip on by without us noticing. But don't get the mistaken impression that nobody was looking. There are multiple Earth-approaching asteroid search projects going on around the world. It just so happens that the most productive one of the bunch is the one going on at Palomar (Eleanor Helin and Gene+Carolyn Shoemaker). Dave Tholen Institute for Astronomy, University of Hawaii ------------------------------ Date: 17 Apr 90 18:41:17 GMT From: mtndew!friedl@uunet.uu.net (Steve Friedl) Subject: Re: NASA Headline News for 04/13/90 (Forwarded) In article <47304@ames.arc.nasa.gov>, yee@trident.arc.nasa.gov (Peter E. Yee) writes: > NASA engineers announced a successful test of an advanced Space > Shuttle main engine today. It was the 19th test firing in the > Marshall Test Bed facility in the West Test Area. The facility is > used to study and evaluate new engine technology. Does this mean that they will throttle the engines to (say) 110% rather than the 104% that they do now? Steve -- Stephen J. Friedl, KA8CMY / Software Consultant / Tustin, CA / 3B2-kind-of-guy +1 714 544 6561 voice / friedl@vsi.com / {uunet,attmail}!mtndew!friedl "The UNIX PC 3B1: 75% of the power of a VAX-11/780" - Technology Resource Ctr ------------------------------ Date: 17 Apr 90 18:57:40 GMT From: rochester!rit!cci632!dvh@rutgers.edu (David Hallidy) Subject: Re: Apollo 13, STS-1, Vostok 1 anniversaries In article <3085@calvin.cs.mcgill.ca>, msdos@quiche.cs.mcgill.ca (Mark SOKOLOWSKI) writes: > >anniversaries observed at this time of year. April 13, 1990 will be the > >twentieth anniversary of the explosion which crippled the Apollo 13 > >service module, which would have stranded astronauts Lovell, Swigert, > >and Haise in space had it not been for their resourcefulness and that > >of the ground support crew. It was the last time BC (before Challenger) > > The three guys burned alive in a 2,000 degrees C inferno were White, the > first american to have walked in space, Shaffee, a rookie, and Grissom, a > Gemini astronaut. The way they died was stupid, with one of the three (he > was hard to identify at autopsy and I don't remember the name) trying to > open the access tunnel up to the last second and doing about 1/3 of all > the needed procedures to accomplish this task... Mark- Boy, are you confused! The original posting referred to the APOLLO-13 near-disaster, which happened on the way to the Moon, when a tank in the Service Module exploded, causing them to have to limp around the Moon and back to Earth, using the Oxygen on board the Lunar Lander and an ingenious fabrication of some sort using Lithium Hydroxide, which was on board, to give them the Oxygen they needed for the return. Lovell, Swigert and Haise WERE the astronauts on that mission. Jim Lovell was also on the APOLLO-8 mission around the Moon at Christmas time in 1968. You are confusing this with "APOLLO 1", the name given to the first APOLLO test vehicle in which Ed White (a Gemini astronaut and, as you mentioned first American to walk in space) Gus Grissom (SECOND American IN space, and Gemini astronaut), and Roger CHAFFEE (rookie) were killed in the fire on January 27, 1967. There- I feel better. Dave H. ------------------------------ Date: 18 Apr 90 10:23:17 GMT From: uhccux!tholen@ames.arc.nasa.gov (David Tholen) Subject: Re: Earthbound Asteroid.....trying again! In article <13544@thorin.cs.unc.edu>, leech@homer.cs.unc.edu (Jonathan Leech) writes: > In article <6122@rayssdb.ssd.ray.com> bea@rayssdb.ssd.ray.com (Brian E. Alber) writes: > >I had heard that sometime last year or the year before that a large asteroid > >or some other LARGE (I mean really BIG) object nearly hit the Earth. It > >supposedly came within 250,000 miles and scientists (astronomers?) here on > >Earth only knew of its existence after it had passed us. > > > >Questions: > > > > 1.) Is there any truth to this? > > Yes. I vaguely recall (almost certainly wrong, but someone will > correct me, I'm sure) that the asteroid was designated 1989XA. Glad to oblige. The asteroid's designation was 1989 FC. That means it was the third (C) new asteroid to be reported during the sixth (F) half-month of 1989 (namely late March). (Now you know how asteroid designations work, although for completeness I should mention that the letter 'I' is skipped to avoid confusion with 'J', and because there isn't a 25th half-month in a year, you won't find asteroid designations that have 'Z' as the first letter. If more than 25 new asteroids are sighted in any one half-month period, the alphabet is started over with a digit appended. For example, FA, FB, FC, ... FY, FZ, FA1, FB1, ... FZ1, FA2, and so on.) > > > 2.) When did this happen (where is it documented)? > > Check recent issues of _Astronomical Journal_. There's probably > an article on it out by now. Or look in Science Citation Index under > 'Asteroids,' 'Earth-Crossing,' and 'Apollo Objects'. None in the Astronomical Journal that I'm aware of. Initial reports appeared in the IAU Circulars. Additional astrometry and orbit solutions appeared in the Minor Planet Circulars. Discovery was on March 31 by Holt and Thomas; close approach was on March 23 (see IAU Circular 4767, dated 1989 April 7). > > > 3.) How large was it? > > Several km is typical for an earth-crosser, I don't know about > this one. What we really know is how bright the object was. That means it could either be a small object that reflects light well, or a large object that reflects light poorly. Because we don't know the reflectivity of the surface, we don't know the size. However, we can use the extremes of reflectivity measured for other asteroids to give us a range of sizes for 1989 FC. 4 percent reflectivity leads to a diameter of about 500 meters, while 40 percent reflectivity leads to a diameter of about 150 meters. The largest Earth-crossing asteroid is about 10 kilometers in diameter. > > > 4.) What would have happened if it hit? > > Nuclear winter without the nuclear, but far worse than anything > the TTAPS crowd came up with. If it was an ocean strike, vast > quantities of water would be vaporized, increasing the Earth's albedo > and perhaps setting off an ice age. A land strike would be like a > multiteraton H-bomb. There is a not-so-controversial anymore theory > suggesting that an event like this killed the dinosaurs and other > major historical extinction events were also due to cometary impacts. > There's a good deal of geophysical evidence to support this. If the asteroid really was at the small end of the size possibilities (150 meters), it would have made a mess but almost certainly would not have caused global destruction. At the large end (500 meters), we're getting close to the size of event that is theorized to have killed off the dinosaurs (something in the 1 kilometer or larger size). > > If you can get to the NY museum of natural history, they have a > rather lurid artists conception of what would happen if the Barringer > meterorite (that made the km-diameter Meteor Crater in Arizona) would > do if it hit lower Manhattan. Eliminate it, essentially. That object > is tiny compared to an Earth-crosser which can actually be observed. > > > 5.) Why didn't we see it coming? > > Because it's very hard to see tiny objects that are far away, > especially when they're approaching nearly head-on. Also because it > takes time to analyze plates, detect potential asteroids, and compute > their orbits. Quite simple. The asteroid approached the Earth on the outbound leg of its orbit, which means that it came at us from the daytime side. Such objects are looked for only at night, which means we didn't see it until after the close approach. > > > 6.) How often do things this big come our way? > > Fairly often, even on a human time scale. However, they don't hit > very often (thankfully). The previous record holder for close approach was 1937 UB (unofficially named Hermes), which -- you figured it out -- occurred in 1937. Hermes is substantially bigger than 1989 FC. Rather coincidentally, we had another close approach in 1989. That object has the designation 1989 PB (second reported asteroid in the first half of August), and close approach occurred in late August. This object received about as much press coverage as 1989 FC in some areas (like here in Honolulu). A big difference is that 1989 PB approached Earth while on the inbound leg of its orbit, thus we saw it coming before close approach. I for one was able to quickly borrow some telescope time to perform some observations of this object just prior to the close approach. Additionally, radar was bounced off the asteroid by Steve Ostro (JPL). He is submitting a paper to Science magazine about his observations within the next few days. I expect it to appear in about two months. Let's not forget the Tunguska event of 1908. Still a healthy debate about what that object really was, but it obviously wasn't as big as 1989 FC. All in all, these objects come whizzing by rather often. > > > 7.) etc... > > Get Gehrels, _Asteroids_ (U. of Az. Press). A good collection > of important papers in the area, though gradually becoming obsolete. > Read up on Apollo-type asteroids in general (refers to a class of > orbits that cross the Earth's orbit). "Asteroids" is a good book, but rather out of date (1979 copyright, corresponding to the year in which a conference of the same name was held). A similar conference was held in Tucson in 1988 to review the advances made in the field in the last 9 years, and the resulting book, "Asteroids II", is now available from the University of Arizona Press (editors: Binzel, Gehrels, and Matthews). A relavant chapter is "Physical Properties of Aten, Apollo and Amor Asteroids", by McFadden, Tholen, and Veeder. Dave Tholen Institute for Astronomy, University of Hawaii ------------------------------ End of SPACE Digest V11 #283 *******************