Ancient Greek Astronomy

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2017-10-11に共有

How the ancient Greeks understood the universe; what they got right and what they got wrong. How Aristotle understood the Earth was round by observing lunar eclipses; how Aristarchus of Samos used these results to work out the relative sizes of Earth, the Sun, and Moon, how Eratosthenes of Cyrene measured Earth's circumference, and how Hipparchus of Nicaea determined created the first catalog of stars and discovered Earth's 26,000 year axial precession, Finally, we take a look at Claudius Ptolemy's collection of works in the Almagest, and how he came up with a system of epicycles to explain planets' retrograde motion.
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コメント (21)

@cheekiblin690 1年前

Early astronomy sounds more challenging than it does now due to a lot of reliance on assumptions, even Eratosthenes had to assume the distance between Alexandria and Seyene. Ptolemy's idea of epicycles and the difference around Earth to explain retrograde motion was very interesting, and definitely a thinker in his free time!
@ggzyt_livitup3898 4年前

Yay! Progress!!!!
@Astronomynatureandmusic 4年前

What a wonderful video. Your calm voice, the relaxed pace, accompanied by clear, carefully selected and to-the-point visuals. A real story teller if you ask me.
@Rustyzip53 5年前

I'm going through your older videos and find them interesting and valuable. A while back I took Coursera class on astro-archaeology. This professor claimed the shafts in the Great Pyramid of Khufu could not be ventilation shafts because vertical ones would sufficed and have been easier to make. He also claimed that the south facing shafts pointed to the stars in Orion's belt and Sirius. His conclusion was that the shafts were to "direct symbolically the Pharaoh to his proper destinations in the sky."
@therestinghornet6906 3年前

This was such a fun video, I hope you still make videos like these, I learned a lot
@nonridiculousadjective6597 5年前

Great video ! I used information in this video as schema for part of my "year work" and of course I included your video in links.
@retrogrademotionpictures4985 5年前

Excellent video. Great explanations of the concepts involved.
@faramund9865 11ヶ月前

Dude this video is great. Wish there was more of this.
@ghostfifth 5年前

I fell in love with you at around 1:40 with that flat earth joke
@remali26 5年前

Great video!!! Well done sir, well done!
@feynstein1004 5年前

Lovely explanations. I think Hipparchus' and Aristarchus' calculations of the distance and size of the sun and moon would've been even more awesome. It shows that we didn't just come up with the knowledge we have today and just how effective math, in this case trigonometry, is.
@ayyappanramasamy3080 4年前

Thank you. Nice Information
@randomdude7812 5年前

Aristotle's haircut is dope. Hhaha Thanks for video. Your video was shown in our class this morning. Just doing a review
@Chamorristaxd 6年前

awesome video, thanks
@sm6756 3年前

Great great summary video
@RinoLovreglio 1年前

Beautiful work
@Chase_baker_1996 3年前

I absolutely love this stuff
@glenngaseby4077 5年前

jeez this helped me so much. thanks
@elizabethmacharia9786 4年前

I am working on interpreting this to spanish, for personal use, and its kicking my ass. Thanks for the video.
@borabirkardesler4952 3年前

Wasn’t it Eudoxus of Knidus, almost 4 centuries before who proposed an explanation to retrograde motion ?