ivylove Posted July 12, 2017 Posted July 12, 2017 Huygens refers to Roemer's measurement of the velocity of light since Roemer is accredited as the first to measure the velocity of light but Roemer did not observe a time delay during the interval FG or KL; consequently, Roemer's measurement of the velocity of light was negative. Can anyone explain what is going on?
mathematic Posted July 12, 2017 Posted July 12, 2017 Could you give a reference for this information?
ivylove Posted July 12, 2017 Author Posted July 12, 2017 page 276.................... Roemer, Ole. A Presentation Concerning the Propagation of Light is Determined. French Academy of Science. 1676.
Mordred Posted July 12, 2017 Posted July 12, 2017 (edited) Roemer measured a finite speed of light from observations of Jupiter using numerous eclipses. Huygen accepted Roemers work as essentially fact and developed the wave theory of light. Assuming I recall correctly its been sometime since I last heard those two names mentioned. Edited July 12, 2017 by Mordred
Tim88 Posted July 12, 2017 Posted July 12, 2017 Maybe this: "The time difference between an immersion seen from point F and the next immersion seen from point G [..] no difference is observed at all, from which Rømer concludes that the speed of light must be very much greater than one Earth-diameter per second." - https://en.wikipedia.org/wiki/R%C3%B8mer%27s_determination_of_the_speed_of_light#Order_of_magnitude -> "Démonstration touchant le mouvement de la lumière trouvé par M. Römer de l’Académie Royale des Sciences" (PDF), Journal des Sçavans: 233–36, 1676. (in French) At first sight, that section in Wikipedia seems to summarize it rather well.
ivylove Posted July 12, 2017 Author Posted July 12, 2017 (edited) Roemer (1678) is stating that he did not obtain the time required in measuring the velocity of light nor are there any calculation regarding the velocity of light in his paper; therefore, do you agree that Roemer did not measure the velocity of light? __________________________________________________________________________________________________ Huygens uses the earth orbital diameter KL to measure the velocity of light but after the earth propagates to the position L after six months the dark side of the earth (night) is not facing Jupiter; consequently, do you not agree that it is physically not possible to measure the velocity of light using Huygens' method? Edited July 13, 2017 by ivylove
Tim88 Posted July 13, 2017 Posted July 13, 2017 Roemer (1678) is stating that he did not obtain the time required in measuring the velocity of light nor are there any calculation regarding the velocity of light in his paper; therefore, do you agree that Roemer did not measure the velocity of light? [..] I don't know Roemer 1678. According to the anonymous French summary, of which, as you saw, Wikipedia gives an English summary, Roemer obtained a first estimation of the velocity of light from the approx. 10 min. error between observations in August and November, when one doesn't account for the speed of light. Thus, roughly, 1/4 of Earth orbit around the Sun corresponds to about 10 min. I don't fully follow the explanation, but the concept is straightforward. As illustration, suppose for simplicity (maybe it's written somewhere but I don't see it) that the 10 min. error corresponds to F->H. Then the difference in distance is approx. the distance of Earth-Sun, or 150 million km. That gives 250'000 km/s. Huygens uses the earth orbital diameter KL to measure the velocity of light but after the earth propagates to the position L after six months the dark side of the earth (night) is not facing Jupiter; consequently, do you not agree that it is physically not possible to measure the velocity of light using Huygens' method? I don't understand... and I don't have the drawing. Do you have a link to the paper by Huygens?
ivylove Posted July 20, 2017 Author Posted July 20, 2017 (edited) http://www.gutenberg.org/files/14725/14725-h/14725-h.htm press OK then--------> read on line Edited July 20, 2017 by ivylove
Strange Posted July 21, 2017 Posted July 21, 2017 Huygens uses the earth orbital diameter KL to measure the velocity of light but after the earth propagates to the position L after six months the dark side of the earth (night) is not facing Jupiter; consequently, do you not agree that it is physically not possible to measure the velocity of light using Huygens' method? This image, I assume: http://www.gutenberg.org/files/14725/14725-h/14725-h.htm#Page_8 Are you saying that you think Jupiter is only visible for 6 months of the year? You seem to be ignoring the fact that the Earth rotates on its axis.
ivylove Posted July 21, 2017 Author Posted July 21, 2017 (edited) At the position of L the dark side of the earth is not facing Jupiter (Huygens' figure is found by searching Huygens--Gutenberg); consequently, only during the day when the earth is at the position L, after a six month time interval, is the earth facing Jupiter since the earth's orbital diameter KL is used by Huygens to measure the velocity of light. Normally astronomers view the stellar universe during the night since the intensity of the sun prevents the formation of the image of a star or of a planet such as Jupiter and Io a moon of Jupiter. One should try it an take a telescope an attempt to view Jupiter or Io during the day an it would not be possible to view these entities because of the intensity of the Sun. At position K, Jupiter is at its initial position that Huygens is describing with K and after a six month time interval we can assume that Jupiter only moves a small distance of its orbit since a year of Jupiter is equivalent to 11 earth years (transformation of time based on the different orbital times); therefore, after the earth propagates to the position L described by Huygens the person observing Jupiter would have to be viewing Jupiter during the day but as I have described earlier one cannot use a astronomic telescope during the day which proves Huygens' measurement of the velocity of light is physically invalid. I hope that this has been informative to you for your future endeavors into astronomer which I highly recommend. Edited July 21, 2017 by ivylove -1
Strange Posted July 21, 2017 Posted July 21, 2017 At the position of L the dark side of the earth is not facing Jupiter The Earth rotates you ignorant troll. (Huygens' figure is found by search Huygens--Gutenberg); I provided the link that you are too lazy/stupid to post. consequently, only during the day when the earth is at the position L is the earth facing Jupiter. It rotates. Moron. More than once a year. Jesus Wept, you are dumber than a bag of spanners. I hope that this has been informative to you Well, I have learnt that there is no lower limit to IQ or ignorance. So thanks for that.
beecee Posted July 21, 2017 Posted July 21, 2017 (edited) I hope that this has been informative to you for your future endeavors into astronomer which I highly recommend. In actual fact, and certainly closer to the truth, it is you that needs to study astronomy/cosmology from reputable sources, and approach it without your now obvious agenda. You also seem to have that trollish, habit of ignoring all information that others have given you, and continue on with your ranting baseless, nonsensical crusade against science. Edited July 21, 2017 by beecee
ivylove Posted July 28, 2017 Author Posted July 28, 2017 (edited) Jupiter is in opposition on May 9, 2018 and on October 9 2018 after the earth propagates the distance of the earth's orbital diameter in a six month time period Jupiter does not appear in the night sky (http://www.seasky.org/ goto "site map" --> calendar of events). Edited July 28, 2017 by ivylove
Strange Posted July 28, 2017 Posted July 28, 2017 27 minutes ago, ivylove said: Jupiter is in opposition on May 9, 2018 and on October 9 2018 after the earth propagates the distance of the earth's orbital diameter in a six month time period Jupiter does not appear in the night sky (http://www.seasky.org/ goto "site map" --> calendar of events). There is no such link as "Calendar of events". I assume the reason you don't post anything that supports your claim is because you appear to be wrong. Jupiter is visible pretty much every month: http://www.nakedeyeplanets.com/visibility.htm
ivylove Posted July 28, 2017 Author Posted July 28, 2017 The earth's moon is visible pretty much nearly every month of the earth year.
hypervalent_iodine Posted July 29, 2017 Posted July 29, 2017 ! Moderator Note Strange, you've been active here long enough to know that we don't tolerate members insulting other members. Please tone it down. This thread doesn't seem to be going anywhere productive, however. Ivylove, your continued ignoring of the basic science being presented to you leads me to conclude you aren't actually interested in honest discussion. As such, I am closing this. 1
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