[HN Gopher] Sunset Geometry (2016)
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Sunset Geometry (2016)
Author : Tomte
Score : 70 points
Date : 2025-03-15 13:32 UTC (9 hours ago)
(HTM) web link (www.shapeoperator.com)
(TXT) w3m dump (www.shapeoperator.com)
| rhelz wrote:
| Bravo. A very nice article comparing and contrasting standard
| trig methods and geometric algebra methods.
|
| And as a bonus, it compares both with Dr. Wildberger's Rational
| Trigonometry. (Side note: I've known a few Australian
| mathematicians who embrace some very non-standard methods in
| mathematics, and I think it's great. We need people to shake up
| our thinking bout Math every once in a while.)
|
| A very nice piece for some relaxing weekend recreational math.
| brothrock wrote:
| awesome article. Do you know how to access the other articles in
| the series that are linked (dead) in the first paragraph? Would
| be great to read if still available.
| showmexyz wrote:
| https://web.archive.org/web/20160325085811/http://orfe.princ...
| https://web.archive.org/web/20160508114924/http://orfe.princ...
| https://web.archive.org/web/20170809073230/http://orfe.princ...
| incognito124 wrote:
| A list of urls from the beginning of post that don't seem to work
| anymore:
|
| * Measuring the Earth's Diameter from a Sunset Photo:
| https://vanderbei.princeton.edu/tex/sunset/ms.pdf
|
| * The Earth is Not Flat:
| https://vanderbei.princeton.edu/tex/sunset/34-39.OPN.1108two...
|
| * Sunset: https://vanderbei.princeton.edu/tex/sunset/sunset.pdf
|
| * The Earth is Not Flat: An Analysis of a Sunset Photo:
| https://vanderbei.princeton.edu/tex/talks/sunset/sunsetTalk_...
| antonkar wrote:
| One year of Sun movement captured in a single long exposed photo:
| https://wesely.org/2019/flughafen-tempelhof-berlin-1-7-2008-...
|
| I wonder how 14 bln years of Sun movement will look if you stand
| somewhere on the equator?
| incognito124 wrote:
| Something doesn't sit right with me. I would expect that the
| semicircle would be reflected nonlinearly. That would imply the
| reflection is not a true circle. Am I wrong?
| sparky_z wrote:
| I'm also a little skeptical with this approach, as it's not
| taking into account the curvature of light through the
| atmosphere. In reality, when the photo was taken, the sun was
| already fully below the horizon. It just looks like it isn't
| because the atmosphere is bending the light a little ways
| around the earth. (As a rule of thumb, the amount of bending is
| coincidentally nearly equal to the apparent size of the sun's
| disc, so as soon as the bottom edge appears to touch the
| horizon, that's the moment it has actually fully dropped below
| the horizon, and would be totally obscured if the light were
| travelling in the straight line paths assumed by this article.)
| lisper wrote:
| The flat-earth community is actually kind of fascinating. Someone
| recently paid to fly some flat-earthers down to Antarctica to
| witness the 24-hour sun which is impossible under most flat-earth
| models [1]. The trip was extensively documented, and one of the
| flat-earthers who made the trip actually changed their position.
| The result, predictably, was that this person was ostracized from
| the community. The intellectual backflips that the flat-earth
| community are making to try to debunk this experiment is
| simultaneously fun and disturbing to watch.
|
| The easiest way to debunk the flat-earth model is simply to
| observe that that 1) the sun sets below the horizon and 2) this
| happens at different times in different locations. On a flat
| earth, if the sun is seen at the horizon in one location it has
| to be seen at the horizon everywhere.
|
| ---
|
| [1] https://www.the-final-experiment.com/
| samstave wrote:
| This is great!
|
| I posted the following the other day -- and if you like this post
| and the maths involved - you will really enjoy Randall Carlson's
| Sacred Geometry lecture whereby he talks about all the Ancient
| Sacred Geometry and how it was used to measure the earth, moon,
| sun, stars and Earth's precession -- and how it all relates down
| to the measurements from the Human Body - whereby the 12-inch
| foot comes from, Cubits, etc.
|
| ---
|
| >Speaking of "feet" as a measurement - Randall Carlson has an
| AMAZING video[0] on the source of the 12 inch foot.
|
| >And how its all related to the measurement of the precession of
| the earth. And yes - its specifically how to measure things in
| space. And its all from Sacred Geometry.
|
| [0] https://www.youtube.com/watch?v=R7oyZGW99os
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