Talk:Aryabhata's relativity principle

Accuracy dispute
I see nothing in the text presented that demonstrates that Aryabhata was aware of or enunciating a principle of relativity. Instead, his insight involves frames of reference only. The requirement that the laws of physics be the same in all frames is missing from the quoted parts of Aryabhata's work. As-is Aryabhata could just as easily be identifying a prefered reference frame for describing physical phenomena (in this case a non-rotating reference frame) as anything else. --EMS | Talk 21:42, 6 November 2006 (UTC)
 * Do you have any references to support your POV? MarcAurel 04:12, 10 November 2006 (UTC)
 * Do you have any reference other than that arXiv.org paper that supports your POV? Preprint server posts do not meet the standards of WP:RS.  Instead, publication in a peer-reviewed journal is needed.
 * Overall, I have a lot of reservatins about this article. The text is copied almost wholesale from the arXiv article, potentially violating the article's copyright.  The Sanskrit text is not accessible to the average reader and therefore useless here.  The POV is apparently held by only a few historians of physics.  Worst of all is what I wrote above:  Aryabhata does not explicitly enunciate the principle of relativity!  Instead it is inferred from his writings!  I have news for you:  Even in Newtonian physics, a non-rotating reference frame is preferred over a rotating reference frame.  I see no evidence outside of the author's assertion that Aryabhata was aware of the principle of relativity, and personally I suspect that the author does not understand what the principle of relativity really is.  We could just as easily ascribe the principle of relativity to Copernicus, who had to make observations similar to those of Aryabhata in construcing his helioocentric theory.  Yet in reality Copernicus made the Sun's frame of reference preferred.  It was not until Galileo forumlated the real principle of relativity that the idea of the same laws of physics holding true in all places and states of motion was finally put forward. --EMS | Talk 05:16, 10 November 2006 (UTC)

Use of the word "stationary"
The killer to the idea that Aryabhata was aware of the principle of relativity is the use of the word "stationary". Aryabhata identifies the shore as being stationary, and treats its motion for the person on the boat as an appearance. Under the actual principle of relativity, it makes no difference whether the boat or the shore is treated as being "stationary" and the other as "moving". Similarly, Aryabhata declares that the stars are "stationary" in describing how they come to rise and set.

I don't want to take too much away from Aryabhata, as he correctly infered that the Earth is rotating using much the same logic as Copernicus used 1000 years later. My complaint is that Aryabhata fell far short of achieving what Galileo did when he discovered the actual principle of relativity. --EMS | Talk 15:25, 16 November 2006 (UTC)

On "stationary"
You don't quickly arrive at a definitive judgment based on one word, without knowing the context in which it was used and how it was used by others who followed him. The idea of different worlds in motion with similar laws (obvioiusly not equivalent to modern relativity but a relativity principle nevertheless) also occurs in Yoga Vasishtha.MarcAurel 03:47, 22 November 2006 (UTC)


 * Mr ems57fcva. You are projecting your POV without sufficient knowledge of this subject. Here're two early references that speak of Aryabhata's relativity:


 * "The Aryabhatiya of Aryabhata, An Ancient Indian Work on Mathematics and Astronomy by Walter Eugene Clark: Review author[s]: M. J. Babb, Journal of the American Oriental Society, Vol. 51, No. 1 (Mar., 1931), pp. 51-52


 * See also, the Shukla and Sarma translation of Aryabhatiya, published by the Indian National Science Academy, 1976.


 * Early commentaries on the Aryabhatiya (Aryabhata's book) clearly indicate that his understanding was in terms of the same laws applying to objects that were in relative motion, as is evident from the above two references.MarcAurel 03:42, 22 November 2006 (UTC)


 * I think that I can just as easily accuse you of a lack of knowledge of the subject, albeit with the subject being the principle of relativity. I find it to be a total travesty to see the term "relativity" being used in this context.  I repeat the there is nothing in Aryabhata's writings that Copernicus did not also glean, yet there is no "Copernican theory of relativity".  (This is not to put Aryabhata down, as he figured out that the Earth was moving with respect to the Sun and rotating on its axis 1,000 year before Copernicus did the same.  That is truly an achievement, and it is a shame that it got lost instead of built upon.)
 * I say that we should give Aryabhata his due, but not more. He was obviosuly way ahead of his time in many ways, but he did not achieve the insights of Galileo.  In one way, that is the next step, but it is a major step, and I see no evidence in what you have presented so far that Aryabhata achieved it.  Indeed, your comments in the AfD that this is "obvioiusly not equivalent to modern relativity" does much to impeach the implicit claim that Aryabhata was aware of the principle of relativity.
 * I also am very unimpressed by your suddenly citing two new reference that supposedly bolster your case. If these references were so important, why did you not present them earlier?  I also would like to know what evidence they present that Aryabhata knew of the principle of relativity. --EMS | Talk 04:53, 22 November 2006 (UTC)

based on the Parakh preprint, which attempts to make the case that Aryabhata was aware of the equivalent of Galileo's principle, the actual description (which we quote in full) shows that A. was aware of the concepts of absolute and relative velocity, which is already notable for the 5th century. I see no indication of any sort that he was making Galileo's crucial observation that the laws of physics are the same in each frame of reference. Simply none. The interpretation of the 'provector wind' as an apparent force is entirely within the eye of the beholder. We could state that Parakh speculates as much, if Parakh was published anywhere and not just a pdf found on the internet. We have a much clearer indication of this realization in Lucretius' "free falling atoms", and yet I've never heard of a "Lucretian relativity principle". A. appears to describe the relative rotation of Earth and the celestial sphere, without indicating that it is actually the Earth that is rotating (which would in fact violate the relativity principle, in a relativistic spirit, it doesn't matter which rotates around which), and contemplating the effect seen by observers at the equator compared to those further north. No evidence has been shown that A. thought of the "provector wind" as anything else as "whatever force it is that keeps this rotation going" (there is certainly no reference to inertia). dab (&#5839;) 11:14, 22 November 2006 (UTC)

I've misunderstood this: the pravaha vayu is not a term introduced by Aryabhata, it is rather the traditional term he seeks to debunk. The important bit are the acalani bhani, the motionless stars that only appear to be "blown across the sky". This may well indicate that "A. recognized the Earth rotates around its axis", but it precludes that he formulated anything like a principle of relativity: He is saying that in fact the Earth is moving, and in fact the stars are immobile, which is so to speak the exact opposite of relativity which states that neither is 'in fact' moving, and all that can be said is that they are moving with respect to one another. So I suggest we rephrase this thing to the effect that A. likely recognized Earth rotation without talking of 'relativity'. dab (&#5839;) 11:42, 22 November 2006 (UTC)


 * You hit the nail on the head with that second posting. A. recoginized that the Earth rotates, but in that context treated the Sun/stars reference frame as preferred.  A. definately was advanced for his time, and understood how the same phenomena can look different from different viewpoints.  He still had not ferreted the relativity principle however. --EMS | Talk 16:06, 22 November 2006 (UTC)
 * I realize you said this above already. I was trying to look at the Sanskrit as this occurred to me. So, the title of this article is definitely mistaken, or at least implies a certain point of view, so that it should by all means be moved, preferably merged with the main article, I think this is clear now. I don't care too much about actual deletion, since it does no harm to have this title hang around as a redirect. dab (&#5839;) 18:14, 22 November 2006 (UTC)
 * I'd prefer that the term "relativity" not be associated with Aryabhata at all. As I wrote in the AfD, there is no need to exagerate A.'s accomplishments.  However, your proposal would work as a fallback position. --EMS | Talk 18:42, 22 November 2006 (UTC)

Parakh and RS
the Parakh preprint, which the translation and transcription are taken from, is dubitable and borderline as WP:RS. The Devanagari appears garbled, I didn't look at it all, but looking for the term translated as "provector wind", I found that ' should almost certainly read ' (seriously, pravaherg?). What is the point of stuffing fancy looking but garbled Devanagari strings into articles? It renders badly on most browsers, and errors stay in them forever, because nobody bothers checking them, they are just cool 'foreign squiggles' after all; at least use transliteration. The text should be tagged as unverified until somebody consulted some respectable edition. dab (&#5839;) 10:59, 22 November 2006 (UTC)