Wikipedia coyly suggests that some notions and views kept circulating (apparently since Adam and Eve) until finally Kepler, of all people, ... etc. I find this hard to believe. Please elucidate.

  • $\begingroup$ I wouldn't have thought it's anything to do with Kepler (aside from the fact he didn't speak English anyway). If someone uses the word "orbit" (or a cognate Latin word) to erroneously describe the path of the Sun around the Earth, then is that using it in the modern sense or not? $\endgroup$ Nov 24 '15 at 13:49
  • $\begingroup$ Me neither. Dumas didn't speak a word of English either, and yet we know about the Musketeers and "all for one." As for the other thing: you tell me. What did the geocentrics call that path? $\endgroup$
    – Ricky
    Nov 24 '15 at 14:11
  • $\begingroup$ I don't know what they called it, but even if I did know that still wouldn't tell me what you meant by "in the modern sense" and so I still wouldn't know how to answer your question :-) Cipherbot's answer quotes some really confusing punctuation, but I think it says that "orbit" was used in classical Latin in the astronomical sense, and I believe that being a translation of Avicenna that would refer to geocentrism, so was that "the modern sense" or not? $\endgroup$ Nov 24 '15 at 14:24
  • $\begingroup$ But maybe the quote CipherBot found means that it was used in that Latin translation in the meaning of "eye-socket". Avicenna wrote on both medicine and astronomy, so we can't just use general knowledge to resolve the ambiguous punctuation ;-) $\endgroup$ Nov 24 '15 at 14:28
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    $\begingroup$ I have absolutely no idea what the question body is trying to say. What notions and views? Until finally Kepler... what? I have no idea what you’re getting at. Are you talking about people believing orbits were circular until Kepler determined that elliptical orbits fit the observations much better? And if that’s what you’re talking about, what does that have to do with the title question? Are you questioning whether Kepler was the first to see orbits as elliptical? Your “modern sense” of orbit, given in comments, suggests that is not the question. $\endgroup$
    – KRyan
    Nov 24 '15 at 16:28

Searching for the definition in dictionary.com you can find this under the word origin and history section:

Late 14c., "the eye socket," from Old French orbite or directly from Medieval Latin orbita, transferred use of Latin orbita "wheel track, beaten path, rut, course, orbit Astronomical sense first recorded 1690s in English; it was in classical Latin, revived in Gerard of Cremona's translation of Avicenna.

I believe that this is what you are looking for.

  • $\begingroup$ John Milton in the 1670s Paradise Lost uses the word "orb" obviously in the meaning of planets' orbits around the Sun. "...his ponderous shield Ethereal temper, massy, large and round, Behind him cast; the broad circumference Hung on his shoulders like the Moon, whose Orb Through Optic Glass the Tuscan Artist views" With reference to Galileo. I think "orbit" is a pre-Ptolemaic figure of speech, the meaning of which since has changed with the science. $\endgroup$
    – LocalFluff
    Nov 24 '15 at 10:52
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    $\begingroup$ Could be that "orb" then referred to the body itself being round, not necessarily its movement. Orb is 3D, orbit is 2D. But roundness was very popular in astrology before Kepler. Note "orbicular", that is a word in the English language! According to authoritative writers. "The cumbrous Elements, Earth, Flood, Aire, Fire, And this Ethereal quintessence of Heav’n Flew upward, spirited with various forms, That rowld orbicular, and turnd to Starrs" $\endgroup$
    – LocalFluff
    Nov 24 '15 at 11:07
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    $\begingroup$ @LocalFluff Yes, from that quote it certainly sounds like Milton did indeed mean orb (because the moon is a sphere,) not orbit. Also, the moon doesn't orbit the sun. :) (At least not directly.) $\endgroup$
    – reirab
    Nov 24 '15 at 20:43

The word orbit could refer to three latin words : orbis, which means "ring", orbitus, which describes et circular shape, and orbita, which describes the track of a wheel.

As you can see, the meanings of this word are quite old. It is therefore hard to tell the first time it was used to describe a celestial body's round trajectory. But the word itself comes from latin.


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