[FRIAM] Sunset and Sunrise
Steve Smith
sasmyth at swcp.com
Thu Dec 31 23:43:30 EST 2020
and this https://www.timeanddate.com/astronomy/solar-analemma.html
provides some visual intuition, but the text doesn't quite lead *me* to
a succinct explanation. I could ramble on speculatively but the main
thing I take away from this is that the *axis* of the analemma reflects
the tilt of the earth axis relative to our orbit of the sun... and the
eccentricity of our orbit yields the sqew of the analemma away from an
ellipse. I suspect these geometric arguments are buried in Roger's
albebraic description of same.
> https://www.herts.ac.uk/about-us/media-centre/news/2020/longest-known-exposure-photograph-ever-captured-using-a-beer-can
> <https://www.herts.ac.uk/about-us/media-centre/news/2020/longest-known-exposure-photograph-ever-captured-using-a-beer-can>
>
>
> Science progresses by grad students forgetting what they're doing and
> leaving their experiments running after they leave school?
>
> I was going to explain your rise/set/length paradox, but my
> explanation got confused in my head. But you can do it
> yourself. https://www.esrl.noaa.gov/gmd/grad/solcalc/solareqns.PDF
> <https://www.esrl.noaa.gov/gmd/grad/solcalc/solareqns.PDF> contains
> the formulae for computing the time of sunrise and sunset given the
> date, longitude, and latitude. It's less than two pages of text and
> they're in Boulder so they even mention Mountain Standard Time at one
> point. Hundreds of thousands of years of human worrying about when
> the sun will rise and when it will set, all boiled down to 11 equations.
>
> -- rec --
>
>
> On Wed, Dec 30, 2020 at 12:38 AM <thompnickson2 at gmail.com
> <mailto:thompnickson2 at gmail.com>> wrote:
>
> Yes. I see. Nifty. But it repeats the assertion that the tilting
> of the earth also has to do with it. Could it be that the fact
> that the earth is not quite a sphere be playing a role, in which
> case the tilting on the axis would make a difference? Where are
> all our knowitall nerds when we need them. (};-)]
>
> N
>
> Nicholas Thompson
>
> Emeritus Professor of Ethology and Psychology
>
> Clark University
>
> ThompNickSon2 at gmail.com <mailto:ThompNickSon2 at gmail.com>
>
> https://wordpress.clarku.edu/nthompson/
> <https://wordpress.clarku.edu/nthompson/>
>
>
>
>
>
> *From:* Friam <friam-bounces at redfish.com
> <mailto:friam-bounces at redfish.com>> *On Behalf Of *Frank Wimberly
> *Sent:* Tuesday, December 29, 2020 9:27 PM
> *To:* The Friday Morning Applied Complexity Coffee Group
> <friam at redfish.com <mailto:friam at redfish.com>>
> *Subject:* Re: [FRIAM] Sunset and Sunrise
>
>
>
> Try this one, Nick. It sounds like what you're saying:
>
>
>
> http://wxguys.ssec.wisc.edu/2019/12/16/solarday/
> <http://wxguys.ssec.wisc.edu/2019/12/16/solarday/>
>
> ---
> Frank C. Wimberly
> 140 Calle Ojo Feliz,
> Santa Fe, NM 87505
>
> 505 670-9918
> Santa Fe, NM
>
>
>
> On Tue, Dec 29, 2020, 8:18 PM <thompnickson2 at gmail.com
> <mailto:thompnickson2 at gmail.com>> wrote:
>
> Frank,
>
>
>
> Andl notice another thing. The sentence is, on its face,
> nonsense. The tilting of the orbit has nothing to do with its
> elliptical shape.
>
>
>
> I have tried to figure out the answer to this question for
> years and the only explanation that I have come up with is
> that during the period from early December to early January,
> the days stay roughly the same length but noon moves. It has
> to do with the analemma
> <https://www.space.com/3304-earth-closest-sun-dead-winter.html#:~:text=The%20noontime%20position%20of%20the%20Sun%20in%20the,line%20running%20through%20the%20analemma%20is%20the%20meridian.>.
> Notice that the day-to-day path of the highest sun is moving
> parallel to the horizon and perpendicular to the meridian
> during that period. If you think of that moment as “noon”,
> noon is moving. But why the analemma? Your guess is as good
> as mine.
>
>
>
> Have you noticed that the rising full moon is moving rapidly
> up the horizon. By march it will be rising in the NE.
>
>
>
>
>
>
>
> Nicholas Thompson
>
> Emeritus Professor of Ethology and Psychology
>
> Clark University
>
> ThompNickSon2 at gmail.com <mailto:ThompNickSon2 at gmail.com>
>
> https://wordpress.clarku.edu/nthompson/
> <https://wordpress.clarku.edu/nthompson/>
>
>
>
>
>
> *From:* Friam <friam-bounces at redfish.com
> <mailto:friam-bounces at redfish.com>> *On Behalf Of *Frank Wimberly
> *Sent:* Tuesday, December 29, 2020 8:48 PM
> *To:* The Friday Morning Applied Complexity Coffee Group
> <friam at redfish.com <mailto:friam at redfish.com>>
> *Subject:* [FRIAM] Sunset and Sunrise
>
>
>
> This topic came up at a recent meeting. The word "main" makes
> me wonder what the other reasons are.
>
>
>
> The main reasons for the *earliest* sunset to occur in early
> December and the *latest sunrise* to occur in January are the
> fact that Earth's axis is tilted (23.5°) and Earth's orbit
> around the sun is *not* a perfect circle shape.
>
>
>
> --
>
> Frank Wimberly
> 140 Calle Ojo Feliz
> Santa Fe, NM 87505
> 505 670-9918
>
>
>
> Research: https://www.researchgate.net/profile/Frank_Wimberly2
> <https://www.researchgate.net/profile/Frank_Wimberly2>
>
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