My apologies if this is too naive a question. I keep wondering what steered people away from assuming the new moon to be an eclipse and hence go on to figure the angular difference in the orbital planes. I'm trying to understand the hypothesis and the observations regarding the same.

The search on this question just results in the explanation of the angular differences in the orbital planes. I'm curious how through observations, the scientists concluded the new new moon is not the earth's shadow on the moon?

Through simple home-made experiments, are there ways to identify the relative positions of the earth, sun and moon? Like shadow experiments for e.g.

  • $\begingroup$ if you look at the phases of the moon, which take a month to go from full moon to full moon again, while the moon goes around the earth once, you see easily, that if it were an eclipse, everything from full moon to new moon wold happen in one night instead of one month, the rest of the month would be full moon, So as soon as you belief, that the moon circles around the earth, you don't have to be very clever to see that it can not be an eclipse, how would you otherwise explain the form of half-moon or 3/4 moon. Maybe you just take a broad flashlight an direkt ist in a baseball, and look from d $\endgroup$
    – trula
    Apr 20, 2020 at 17:27
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    $\begingroup$ The shape of the Earth's shadow on the Moon is noticeably different to the usual lunar phases. The ancient Greeks wrote about that. You can see an example here: mreclipse.com/LEphoto/TLE1992/image/TLE1992matrix2w.JPG $\endgroup$
    – PM 2Ring
    Apr 20, 2020 at 18:12
  • $\begingroup$ I would say Galileo concluded this when he observed the moons of Jupiter and Other planets. solarsystem.nasa.gov/news/307/… $\endgroup$ Apr 21, 2020 at 20:51
  • $\begingroup$ @PM2Ring do you have a reference for the ancient Greek document(s)? $\endgroup$ Apr 22, 2020 at 12:09

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I don't think any scientist seriously thought that moon phases (in particular new moon) is caused be Earth's shadow. One can often see moon crescent and sun at the same time. It is clear that there is no Earth between them. I think people understand this, way before they understand that eclipses caused by Earth's shadow. There is no Earth between Moon and Sun


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