Precession causing perihelion to happen later | Cosmology & Astronomy | Khan Academy
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Clarifying the effect of axial precession on the calendar and the date of perihelion and aphelion. Created by Sal Khan. Watch the next lesson: https://www.khanacademy.org/science/cosmology-and-astronomy/earth-history-topic/earth-title-topic/v/what-causes-precession-and-other-orbital-changes?utm_source=YT&utm_medium=Desc&utm_campaign=cosmologystronomy Missed the previous lesson? https://www.khanacademy.org/science/cosmology-and-astronomy/earth-history-topic/earth-title-topic/v/milankovitch-cycles-precession-and-obliquity?utm_source=YT&utm_medium=Desc&utm_campaign=cosmologystronomy Cosmology & Astronomy on Khan Academy: The Earth is huge, but it is tiny compared to the Sun (which is super huge). But the Sun is tiny compared to the solar system which is tiny compared to the distance to the next star. Oh, did we mention that there are over 100 billion stars in our galaxy (which is about 100,000 light years in diameter) which is one of hundreds of billions of galaxies in just the observable universe (which might be infinite for all we know). Don't feel small. We find it liberating. Your everyday human stresses are nothing compared to this enormity that we are a part of. Enjoy the fact that we get to be part of this vastness! About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content. For free. For everyone. Forever. #YouCanLearnAnything Subscribe to Khan Academy’s Cosmology & Astronomy channel: https://www.youtube.com/channel/UChNPnEkW8LYZ5Rwi8_A2-DA?sub_confirmation=1 Subscribe to Khan Academy: https://www.youtube.com/subscription_center?add_user=khanacademy
Comments
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Playing with concepts but getting the details all wrong. Dec 22 will NOT be the same in 1800 years - without a change to the calendar. The days do not just disappear. A modification will be needed to keep the calendar solstice days accurate to the visible solstice days. The Gregorian calendar does not automatically adjust to keep them in sync.
Also, there is no proof of precession - it's all theoretical. In actual fact, the earth's axis exhibits a logarithmic sine curve recovery from an initial value of 26.5 degrees at an event 4330 years ago (as of 2016) which has almost reached stability. -
I finally understand precession! FINALLY
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smart guy...
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Absolutely wonderful! A model of clarity. Thank you so much. BTW How can anyone dislike this material?
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Doesn't the earth actually orbit in the shape similar to a spirograph (or a flat Bohr's model atom picture)?
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Really good Clarifying point. i got the same wrong idea. thanks.. by the way great work with Khan Academy.
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OK, you've explained what axial precession and obliquity are, but why does it happen? I'd also like this to head into our moons dynamics and global warming.
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