Re: [Phys-L] Earths tilt

[Brian Whatcott <betwys1@sbcglobal.net>]

 Keith,The angle of refraction at the visual horizon is about 29 minutes. This why you may expect to be in perpetual twilight at both the Boreal and Austral high latitudes, ifthere were no axial tilt. Jim's question was: "If the earth wasn’t tilted, would the sun rise due east everywhere or would it change due to latitude? " ~ to which the picky answer is "no sunrise everywhere"Brian    On Thursday, October 28, 2021, 12:05:26 PM CDT, Prof. Keith S. Taber via Phys-l <phys-l@mail.phys-l.org> wrote:  
 
 I would say it would technically change - but perhaps not enough to 
easily notice?

About 10↑4 ratio of distance to sun to distance between observation 
points: tan of angle circa 0.001 - so less than a minute of arc 
difference in the angle of view from the two poles?

Keith


On 28/10/2021 17:32, Brian Whatcott wrote:

>     
>     - im cibulka via Phys-l <phys-l@mail.phys-l.org>UnsubscribeTo:phys-l@mail.phys-l.orgCc:jim cibulkaThu, Oct 28 at 11:05 AMHi all!
>     
> If the earth wasn’t tilted, would the sun rise due east everywhere or would it change due to latitude?
>     
> Wish I could change this on stellarium!
>     
> Thanks!
>     
> Jim Cibulka
> Kirkwood mo
>     - ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> You may have noticed that Dawn takes longer in high latitudes. In this case, the circumpolar regions would not grow completely dark at all due to atmospheric refraction, hence the Sun would always appear to have some fraction of itsdisk visible on the horizon.Brian
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https://science-education-research.com



Dr. Keith S. Taber
Emeritus Professor of Science Education
University of Cambridge
http://www.educ.cam.ac.uk/staff/taber.html


Some recent postings include

The heart-stopping queen: An analogy for a paralysing poison. 
<https://science-education-research.com/the-heart-stopping-queen/>

What COVID really likes. Researching viral preferences. 
<https://science-education-research.com/what-covid-really-likes/>

Of mostly natural origin. Is your shampoo of natural, unnatural, or 
supernatural origin? 
<“https://science-education-research.com/of-mostly-natural-origin/”;>

Not a great experiment…What was wrong with The Loneliness Experiment? 
<“https://science-education-research.com/not-a-great-experiment/”;>

We didn’t start the fire (it was the virus). A simile for viral 
infection. 
<“https://science-education-research.com/we-didnt-start-the-fire-it-was-the-virus/”;>





Recently published scholarship:

*Taber, K. S. (2019). Experimental research into teaching innovations: 
responding to methodological and ethical challenges. *
/Studies in Science Education./ doi:10.1080/03057267.2019.1658058

*/The Nature of the Chemical Concept/*/: Re-constructing Chemical 
Knowledge in Teaching and Learning/
Royal Society of Chemistry, 
https://pubs.rsc.org/en/content/ebook/978-1-78262-460-8

*Taber, K. S. (2021). The Challenge to Educational Reforms during a 
Global Emergency: The Case of Progressive Science Education./C.E.P.S. 
Journal/, 11 (Special issue), 1-21. doi:doi: 10.26529/cepsj.1109*
Recent publications primarily for teachers:

*/Foundations for Teaching Chemistry/*/: Chemical knowledge for teaching/
Routledge, ISBN: 9780815377740

*/MasterClass in Science Education/*/: Transforming Teaching and Learning/
Bloomsbury Academic, ISBN: 9781474289412


Editor-in-Chief: */RSC Advances in Chemistry Education Series/*
Royal Society of Chemistry Book Series
Proposals for Advances in Chemistry Education volumes (edited or 
monograph) are invited. Scholarly books on all aspects of chemistry 
education are being considered for publication in the series ( 
https://science-education-research.com/advances-in-chemistry-education/ )




*ECLIPSE - /Exploring Conceptual Learning, Integration and Progression 
in Science Education/*
https://science-education-research.com/projects/eclipse/



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