Ancient Greek Astronomy

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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[Astronomynatureandmusic]

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.

[Rustyzip]

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."

[faramund]

Dude this video is great. Wish there was more of this.

[therestinghornet]

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

[cheekiblin]

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!

[ghostfifth]

I fell in love with you at around 1:40 with that flat earth joke

[retrogrademotionpictures]

Excellent video. Great explanations of the concepts involved.

[nonridiculousadjective]

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.

[paulatreides]

Eratosthenes was one hell of a genius .

[randomdude]

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

[feynstein]

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.

[remali]

Great video!!! Well done sir, well done!

[beaganat]

Based on the video, state the important contributions of ancient philosophers in ancient astronomy and how do we utilize them in our day to day basis?

[borabirkardesler]

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

[vikaskatiyar]

I have liked the video now & watch it later because undobtly ancient technology was great.

[elizabethmacharia]

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

[Mythologos]

The idea that anyone today believes that the earth is flat is also BS.

[alexstevensen]

Imagine if the star parralax thing was visible the whole history would have been different.

[thesickbeat]

How does it follow that if stars move a little bit that the earth is a spinning top that wobbles?

[markwhein]

Erastosthenes of Cyrene wasn’t the first to calculate the earths circumference, not even close