SETI Re: A moon's significance in life?

Larry Klaes (
Mon, 21 Jun 1999 12:54:57 -0400

>X-Sender: >X-Mailer: QUALCOMM Windows Eudora Light Version 3.0.6 (32) >Date: Fri, 18 Jun 1999 15:03:13 -0500 >Reply-To: History of Astronomy Discussion Group <HASTRO-L@WVNVM.WVNET.EDU> >Sender: History of Astronomy Discussion Group <HASTRO-L@WVNVM.WVNET.EDU> >From: Wilds <Wilds@NETWORKSPLUS.NET> >Subject: Re: A moon's significance in life? >To: HASTRO-L@WVNVM.WVNET.EDU > >At 05:22 PM 6/17/99 -0400, you wrote: >>>Date: Thu, 17 Jun 1999 17:07:19 -0400 >>>From: "Cecchini, Ron" <Ron.Cecchini@GSC.GTE.Com> >>>Subject: SETI A moon's significance in E.T.I. ? >>>To: Sagan <>, SETI <> >>>X-Mailer: Internet Mail Service (5.5.2448.0) >>>Sender: >>> >>> >>>i don't know if Larry already forwarded something about this, but anyway. >>> >>>Seems like some faulty reasoning in the below... >>> >>>----------------------------------------------------- >>> >>>>From New Scientist, 19 June 1999 >>> >>>WHY DOES THE MOON look the same size as the Sun in the sky? This >>>coincidence, >>>which makes the spectacle of total eclipses possible, has been crying out >>>for >>>an explanation. Now an astronomer in Seattle has proposed one. If he's >>>right, >>>there is a surprising connection between the conditions required for a total >>>eclipse and for the emergence of intelligent life. > >This is just the kind of "science" that is ruining the credibility of the >profession (what little is left in the public view). I was taught that >sciece is "observable and repeatable." It is nice to have ideas about >"coincidences", but this is not science. Many of us have worked very hard >to deal with the numbers and experiments that are required to do quality >science. The public view of science, at this point, is so eroded through >the use of unsubstantiated "coincidence" that I fear the scientific >community is facing an ever greater deterioration of public financial >support for science programs simply through its increasing unreliability. >So much of what we call science today is not observable and repeatable and, >therefore, not science, that we stand to delude ourselves in the extreme. >What ever happened to science by the numbers? > >>>The coincidence in the apparent sizes of the Moon and the Sun occurs >>>because the Sun, though 400 times bigger than the Moon, is also 400 times >>>farther away. In fact, the Moon sometimes looks a shade bigger than the >>>Sun, which is essential for a "perfect eclipse" when the sky is dark enough >>>for you to see the Sun's faint outer atmosphere, or corona. > >In fact, the moon also sometimes looks a shade smaller causing and Annular >Eclipse. > >>>Because tidal effects cause the Moon to slowly recede from the Earth, >>>perfect eclipses have been visible only for about 150 million years and >>>will continue for only another 150 million years, about 5 per cent of the >>>current age of the Earth. Furthermore, Earth is the only planet in our >>>Solar System where a perfect eclipse is visible, although there are 64 >>>other moons. >>> >>>So are we just extraordinarily lucky? Guillermo Gonzalez of the University >>>of Washington in Seattle thinks not. He points out that our distance from >>>the Sun, and hence its apparent size, is a necessary condition for us to be >>>here. "If we were a little nearer or farther from the Sun, the Earth would >>>be too hot or too cold and so uninhabitable," says Gonzalez. >>> >>>At the same time our existence depends on an unusually large moon since its >>>pull stops the Earth wobbling around too much on its axis and causing wild >>>and catastrophic swings in climate like those on Mars. Our Moon, which is >>>unusually large compared to those in almost all other planet-moon systems, >>>probably formed from molten material blasted from the Earth during the >>>impact of a giant body more than 4 billion years ago. >>> >>>In the current issue of Astronomy & Geophysics (vol 40, p 3.18), Gonzalez >>>points out that the way the Moon formed means it started off very close to >>>the Earth and has taken several billion years to move far enough away until >>>it precisely covers the Sun during an eclipse. "The timescale is very >>>similar to that of the appearance of intelligent life," he says. "It is >>>therefore not such a big coincidence that we are around at the time when it >>>is possible to see total eclipses." >>> >>>Gonzalez's explanation has generated much interest among astronomers, >>>though most remain cautious. "The timescale argument of Gonzalez needs >>>more checking," says John Barrow of the University of Sussex. >>> >>>If Gonzalez is right, then all extraterrestrials, wherever they are, are >>>likely to live on planets like ours that experience total eclipses. But >>>since an unusually large Moon is rare, he says, this suggests that both >>>ETs and total eclipses are very rare indeed. > >The "coincidence" of the Earth/Moon systems certainly begs an answer, but >it is not one that science is going to answer anytime soon. Thank You! > > >------ >"...indeed the business of the universe is to make such a fool of you that >you will know yourself for one, and so begin to be wise!" Quote of Mr. >Raven(The Librarian, The Sexton or Adam) from Lilith, by George MacDonald. > >Richard and Tatyana Wilds >7328 SW 23rd Terrace >Topeka, Kansas 66614-6060 USA >(785)478-1868 Home > >E-mail: > >Observatory Director, > Kansas Flint Hills Observatory Complex > A Tech > 629 SE Quincy, Suite 204 > Topeka, Kansas 66603-3927 USA > www: > >Research Coordinator, > Heartland Astronomical Research Team--HART > P.O. Box 3938 > Topeka, Kansas 66604-6938 USA > WWW: > >Writer for Grazing Occultation Services, > International Occultation Timing Association--IOTA > 2760 SW Jewell Ave > Topeka, Kansas 66611-1614 USA > E-Mail: > WWW: > >American Astronomical Society > WWW: > Planetary Sciences Division > WWW: > Historical Astronomy Division > WWW: >

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