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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Sun goes round Earth, or something like that...
From: Brad Morris
Date: 2014 Feb 16, 23:02 -0500
From: Brad Morris
Date: 2014 Feb 16, 23:02 -0500
Lu
There's nothing to be sorry about. You came to the same conclusion that I did. But I believe your answer to be more complete, its an N body solution, as all of the bodies in the solar system need be solved simultaneously. So Ceres as well needs to be considered.
Most of the answers are coached from the question. Neither orbits around the other, contrary to the question. The system actually rotates about the common center of mass. So given the choices provided by the question, none are correct!
I just got there first. Whoop dee doo. And you independently got there second. Fair game!
Brad
On Feb 16, 2014 10:00 PM, "Lu Abel" <luabel@ymail.com> wrote:
Yeah, sorry, posted my reply before I read yours...
From: Brad Morris <bradley.r.morris---.com>
To: luabel{at}ymail.com
Sent: Sunday, February 16, 2014 6:21 PM
Subject: [NavList] Re: Sun goes round Earth, or something like that...
LuLooks like you and I agreeBradOn Feb 16, 2014 9:12 PM, "Lu Abel" <lu{at}abelhome.net> wrote:
Oh, and let's not forget that neither the earth rotates about the sun nor the sun rotates about the earth, but they both actually rotate about their common center of mass (n-body complications ignored).
On 2/16/2014 2:11 PM, Frank Reed wrote:
There have been a couple of messages talking about a recent survey suggesting that 25% of Americans do not know that the Earth revolves around the Sun. Shocking! Or maybe not. Undoubtedly, a lot of this has to do with testing dynamics. Some people just get anxious when they're asked anything remotely academic. Some think it's fun to game the results (in other words, they intentionally answer wrong). Some are dyslexic. And yes, for many, it's just one of those things that they are aware of, and could probably get right if asked with a little gentle coaching, but they might well answer wrong on the first pass. There's a whole lot going on here beyond a simple measure of intelligence or knowledge.The link that Gary posted earlier from the Telegraph, a UK newspaper, reminded me of a famous fictional British character who freely admitted that he did not know that the Earth revolves around the Sun. Indeed, it came up again in a very enjoyable recent BBC adaptation of the character starring Benedict Cumberbatch. This literary character was not exactly created as a dullard or even an 'idiot savant'. Can you name him?? His excuse was that the information is utterly useless to him. And he's right. Grade school astronomy has almost no practical value whatsoever, except (perhaps!) to celestial navigators and a few other narrow sects. This particular litmus test does not measure scientific knowledge or reason as much as scientific "literacy" or exposure. It's something that everyone has certainly learned at some point in their lives. But such information fades to childhood trivia if nothing reinforces it over a person's lifetime. For many people the names of the eight (or nine) planets have no more value than the names of the eight (or nine) reindeer pulling Santa's sleigh. Both are cultural trivia from childhood...Finally, a little physics: we all understand that motion is relative, right? If I run past you at 10 mph, then it's the same as if you run past me at 10 mph (in a specific, profound sense) despite the fact that common sense readily tells us who's running and who's not. We learn to set aside common sense and accept this principle of relativity of motion. Ok, then... what about the Earth's motion at 30 km/sec around the Sun? Can't we say that it's just the same as the Sun revolving around the Earth since all motion is relative?? The answer is 'no' because the premise is wrong. It's not true that ALL motion is relative. Nonetheless, it certainly complicates matters!-FER----------------------------------------------------------------
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