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Groups > rec.arts.sf.written > #450712
| From | Don Kuenz <g@crcomp.net> |
|---|---|
| Newsgroups | rec.arts.sf.written |
| Subject | Re: Young People Read Old SFF: Nightfall by Isaac Asimov |
| Date | 2016-09-04 00:38 +0000 |
| Organization | A noiseless patient Spider |
| Message-ID | <20160903b@crcomp.net> (permalink) |
| References | (8 earlier) <robertaw-B43616.22162701092016@news.individual.net> <9804364b-7edb-4e15-a46d-b93e009bdf47@googlegroups.com> <20160902c@crcomp.net> <XnsA677E6946FCBBmelchizedek@216.166.97.131> <slrnnsl21m.1gr.newsposter@andor.dropbear.id.au> |
Paul Colquhoun <newsposter@andor.dropbear.id.au> wrote:
> On Fri, 02 Sep 2016 21:39:50 -0500, Cryptoengineer <treifamily@gmail.com> wrote:
> | Don Kuenz <g@crcomp.net> wrote in news:20160902c@crcomp.net:
> |
> |>
> |> TB <tsbrueni@dcn.davis.ca.us> wrote:
> |>> If our Moon was seven times larger than it is, how long would a solar
> |>> eclipse last?
> |>
> |> That's a good, interesting question, as are your other questions.
> |> Unfortunately, my knowledge of celestial mechanics is just about nil.
> |
> | The length of 'normal' solar eclipses can range up to just over 7
> | minutes. If everything else was equal, a 7x larger Moon could
> | allow an eclipse up to 49 minutes. That's totality, not the partial
> | covering at start and end.
>
>
> I think it would be longer than that.
>
> Say the apparent width of the Sun is 'S',
> and the apparent width of the Moon is 'M'
>
> If S = M then the total eclipse period would be zero, as the leading
> edge of the sun would appear on one side just as the trailing edge
> dissapreaed on the other.
>
> If M = S + X, then the period of totality is the time it takes the moon
> to move distance X.
>
> Now X isn't that big, and it varies a bit since sometimes we get annular
> eclipses where X is actually negative. Call it 5% of S.
>
> So the moon traveling 1/20 * S takes 7 the minutes of totality.
>
> If M was suddenly 7 * S, traveling the extra 6 * S would take
> 20 * 6 * 7 = 840 minutes = 14 hours.
>
> Making X be 10% gives a more manageable 7 hours.
>
>
> Of course, all this assumes that a 7 times larger moon still takes a
> month to orbit the earth. However, now that the moon is 25 times as
> massive as the earth, it will be the earth orbiting the moon, and if the
> distance is the same, the orbital period will be much shorter, and thus
> the period of totality will be much shorter.
>
> According to http://www.calctool.org/CALC/phys/astronomy/planet_orbit
> the orbital period would be ~5.38 days, so ~5.2 times faster, giving
> a totality period of 1.3 to 2.6 hours (depending on the 5% or 10%
> assumptions for X above).
Thank you Paul for your very informative post. Allow me to change tack
away from the story and into natural philosophy.
S ~ M during a solar eclipse when the Sun, Earth, and Moon align to
become a precision optical instrument that provides a teachable moment
to curious people. The Sun's corona, for instance, remains visible,
which enabled people to discover spectral lines.
It's my understanding that the teachable moment requires an optical
alignment with at least a 10% or greater precision. Increase or
decrease the the Moon's diameter by 10% and no coronal spectral lines
are visible. Increase or decrease the Sun's diameter by 10% and again,
no visible corona. Increase or decrease the distance from the Earth to
the Sun, and no corona. And so on and so forth.
Thank you,
--
Don Kuenz KB7RPU
I have always read that the world, both land and water, was
spherical, as the authority and researches of Ptolemy and all the others
who have written on the subject demonstrate and prove, as do the
eclipses of the moon and other experiments that are made from east to
west, and the elevation of the North Star from north to south.
- Columbus
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Young People Read Old SFF: Nightfall by Isaac Asimov jdnicoll@panix.com (James Nicoll) - 2016-08-31 19:59 +0000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Lynn McGuire <lynnmcguire5@gmail.com> - 2016-08-31 15:54 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov news{@bestley.co.uk (Mark Bestley) - 2016-08-31 22:43 +0100
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Lynn McGuire <lynnmcguire5@gmail.com> - 2016-08-31 18:30 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-08-31 19:00 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Greg Goss <gossg@gossg.org> - 2016-09-01 03:10 -0600
Re: Young People Read Old SFF: Nightfall by Isaac Asimov jdnicoll@panix.com (James Nicoll) - 2016-09-01 13:41 +0000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov jdnicoll@panix.com (James Nicoll) - 2016-09-01 03:58 +0000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Lynn McGuire <lynnmcguire5@gmail.com> - 2016-09-01 12:37 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov ted@loft.tnolan.com (Ted Nolan <tednolan>) - 2016-09-01 18:07 +0000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-01 11:34 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Lynn McGuire <lynnmcguire5@gmail.com> - 2016-09-01 15:15 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov tsbrueni@gmail.com - 2016-09-01 13:48 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov "Michael F. Stemper" <michael.stemper@gmail.com> - 2016-09-01 16:24 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-01 15:45 -0600
Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-01 15:47 -0600
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-02 00:40 +0000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov tsbrueni@gmail.com - 2016-09-01 18:18 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-01 20:20 -0600
Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-01 19:46 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-01 21:09 -0600
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Dimensional Traveler <dtravel@sonic.net> - 2016-09-01 20:47 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-02 03:13 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-02 03:25 +0000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov hamish.laws@gmail.com - 2016-09-01 20:48 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-02 04:34 +0000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Robert Woodward <robertaw@drizzle.com> - 2016-09-01 22:16 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-02 07:32 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-02 07:33 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-03 00:22 +0000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-02 21:39 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov "Brian M. Scott" <b.scott@csuohio.edu> - 2016-09-02 22:57 -0400
Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-02 21:28 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Sjouke Burry <burrynulnulfour@ppllaanneett.nnll> - 2016-09-03 05:33 +0200
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-02 23:39 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-02 21:25 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Paul Colquhoun <newsposter@andor.dropbear.id.au> - 2016-09-03 18:22 +1000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-03 10:10 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-04 00:38 +0000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov tsbrueni@gmail.com - 2016-09-03 20:23 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov "J. Clarke" <j.clarke.873638@gmail.com> - 2016-09-03 08:31 -0400
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-03 10:14 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-03 08:25 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-03 08:31 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-02 16:21 +0000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-02 10:39 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-02 13:17 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Jaimie Vandenbergh <jaimie@sometimes.sessile.org> - 2016-09-02 23:03 +0100
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-02 17:54 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-03 00:03 +0000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-02 21:35 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov tsbrueni@gmail.com - 2016-09-02 16:08 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov David DeLaney <daviddelaney@earthlink.net> - 2016-09-02 21:16 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov 103134.3516@compuserve.com - 2016-09-07 12:56 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Robert Carnegie <rja.carnegie@excite.com> - 2016-09-07 19:05 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov "Brian M. Scott" <b.scott@csuohio.edu> - 2016-09-07 22:21 -0400
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-08 04:53 +0000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Jaimie Vandenbergh <jaimie@sometimes.sessile.org> - 2016-09-09 00:12 +0100
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Dimensional Traveler <dtravel@sonic.net> - 2016-09-08 17:00 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Greg Goss <gossg@gossg.org> - 2016-09-08 22:36 -0600
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Jaimie Vandenbergh <jaimie@sometimes.sessile.org> - 2016-09-09 08:34 +0100
Re: Young People Read Old SFF: Nightfall by Isaac Asimov David DeLaney <daviddelaney@earthlink.net> - 2016-09-09 04:41 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov tsbrueni@gmail.com - 2016-09-09 03:31 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Jaimie Vandenbergh <jaimie@sometimes.sessile.org> - 2016-09-09 16:36 +0100
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Peter Trei <petertrei@gmail.com> - 2016-09-09 09:11 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Joe Bernstein <joe@sfbooks.com> - 2016-09-09 09:45 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-09 09:52 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-09 11:18 -0600
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-09 10:29 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Peter Trei <petertrei@gmail.com> - 2016-09-09 12:17 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Peter Trei <petertrei@gmail.com> - 2016-09-09 12:20 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov scott@slp53.sl.home (Scott Lurndal) - 2016-09-09 19:59 +0000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-09 14:14 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-09 14:44 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-09 15:35 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-09 16:00 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-09 14:34 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Robert Carnegie <rja.carnegie@excite.com> - 2016-09-09 19:19 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-10 04:40 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov "J. Clarke" <j.clarke.873638@gmail.com> - 2016-09-10 08:21 -0400
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-10 07:09 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov "J. Clarke" <j.clarke.873638@gmail.com> - 2016-09-10 10:49 -0400
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Dimensional Traveler <dtravel@sonic.net> - 2016-09-10 08:19 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov "J. Clarke" <j.clarke.873638@gmail.com> - 2016-09-10 12:27 -0400
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Greg Goss <gossg@gossg.org> - 2016-09-10 10:47 -0600
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-10 12:49 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov "J. Clarke" <j.clarke.873638@gmail.com> - 2016-09-10 17:15 -0400
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Dimensional Traveler <dtravel@sonic.net> - 2016-09-10 14:20 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-10 10:29 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov "J. Clarke" <j.clarke.873638@gmail.com> - 2016-09-10 12:47 -0400
Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-10 10:55 -0600
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-10 12:51 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov "J. Clarke" <j.clarke.873638@gmail.com> - 2016-09-10 17:18 -0400
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-11 05:45 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Don Kuenz <g@crcomp.net> - 2016-09-12 00:06 +0000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Robert Carnegie <rja.carnegie@excite.com> - 2016-09-10 11:22 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-10 10:33 -0600
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-09 14:33 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Kevrob <kevrob@my-deja.com> - 2016-09-09 15:13 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-09 16:00 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-09 16:08 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Cryptoengineer <treifamily@gmail.com> - 2016-09-10 10:36 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-09 16:06 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-09 16:10 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov "Brian M. Scott" <b.scott@csuohio.edu> - 2016-09-10 12:49 -0400
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Charles Bishop <ctbishop@earthlink.net> - 2016-09-10 14:43 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov "Brian M. Scott" <b.scott@csuohio.edu> - 2016-09-10 17:57 -0400
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Tom Kratman <tomkratman@gmail.com> - 2016-09-10 20:20 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-10 20:27 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Tom Kratman <tomkratman@gmail.com> - 2016-09-11 19:51 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-11 21:16 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Tom Kratman <tomkratman@gmail.com> - 2016-09-12 18:08 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-12 19:40 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Tom Kratman <tomkratman@gmail.com> - 2016-09-14 17:31 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov TB <tsbrueni@dcn.davis.ca.us> - 2016-09-14 18:16 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Gutless Umbrella Carrying Sissy <taustinca@gmail.com> - 2016-09-14 22:26 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-11 05:38 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Greg Goss <gossg@gossg.org> - 2016-09-12 21:55 -0600
Re: Young People Read Old SFF: Nightfall by Isaac Asimov 103134.3516@compuserve.com - 2016-09-16 12:06 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-11 05:30 -0700
Re: Young People Read Old SFF: Nightfall by Isaac Asimov David Johnston <Davidjohnston29@yahoo.com> - 2016-09-02 00:12 -0600
Re: Young People Read Old SFF: Nightfall by Isaac Asimov David DeLaney <daviddelaney@earthlink.net> - 2016-09-02 08:53 -0500
Re: Young People Read Old SFF: Nightfall by Isaac Asimov jdnicoll@panix.com (James Nicoll) - 2016-09-02 01:33 +0000
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Greg Goss <gossg@gossg.org> - 2016-09-01 21:53 -0600
Re: Young People Read Old SFF: Nightfall by Isaac Asimov wdstarr@panix.com (William December Starr) - 2016-09-01 20:11 -0400
Re: Young People Read Old SFF: Nightfall by Isaac Asimov Quadibloc <jsavard@ecn.ab.ca> - 2016-09-02 07:50 -0700
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