Why Are Planetary Orbits Elliptical?

Planetary orbits are elliptical because gravitational interaction over time changes the delicate balance of mass, velocity and distance from the star which otherwise keeps planetary orbit circular.
For a very long time, from Ptolemy to the age of Copernicus, it was widely believed and accepted that planets in our Solar System revolved in a perfectly circular path. Because the circle was presumed to be an ideal shape for planetary bodies to orbit. But then in the seventeenth century in his seminal book Astronomia Nova, Johannes Kepler rebutted this very idea. He put forth his own theory pertaining to planetary motion. He theorized that planetary bodies orbit in an elliptical path with the Sun sitting at one of the foci of that ellipse. In this video we will try to understand what makes these planetary orbits elliptical.

References:

#science #funfacts #ellipticalorbits

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[amenhussain]

Imagine school teachers teaching us topics things like the way this video did, this one video helped literally learn about the ellipse and much in just 5 mins, this channel deserves more subscribers!!

[millicentsmallpenny]

All the planetary orbit paths are basically visual circles
Here I list the eccentricity and the percentage which the minor axis is of the major. I list them from least elliptical to most elliptical
Ven 0.0068 99.998%
Nep 0.0086 99.996
Earth 0.0167 99.986
Uran 0.0472 99.889
Jup 0.0484 99.883
Sat 0.0541 99.854
Mar 0.0934 99.563
Merc 0.2056 97.864
Plu 0.2488 96.855%

So one can see that (even in the case of the most elliptical), no planetary orbit path is really a visual ellipse

[jaybharat]

I always wondered y it is soo... finally understand it.Brilliant explaination and good animation. Thank u!

[Jipoze]

This is simply an outstanding video for conveying very complex theories cohesively and clearly . Thank you so much for putting this up.

[MDTaufiqueTaj-rprq]

This video is really helpful for me and clear my all doubts in this topic

[andyveh]

At 1:39 when you first show the shapes of the planets' orbits: while the orbits of Mars and Mercury have the largest eccentricities, their shapes are still so circular that indeed they should not show as apparent ovals in your diagram. Their orbits are still so very near-circular that we cannot tell.

[drttt]

BRILLIANT VIDEO I HAVE NEVER FOCUSED ON SOMETHING SO MUCH!

[mohanpathak]

'Back in my days, there were more planets' : That's so cool!

[copernicus]

This is the best explanation in the entire internet. I subscribed.

[valse_]

"Things are getting messier now"
-underrated, educated dad joke

[MrGaborseres]

Thank you 👍 😊 this 65 year old child loved this basic explanation 👍👍👍👍👍

[Aman-yigy]

This is such a beautiful video. Thanks channel!

[orktv]

This video is very unelucidating, if not outright misinforming. The question is "why aren't planetary orbits circular" when many (such as Earth) actually are very close to it. It then asks where that tiny deviation comes from, and neglects to mention that elliptical orbits are just as stable as circular ones—in fact this is blatantly contradicted as is said that orbits would be circular if not for interactions. Nature doesn't have a natural preference for circles and the question is more interesting the other way around ("why are they circles at all?"); the answer is that they evolved from rotating dust clouds to the protoplanetary disk to planets. This evolution also explains why our planets "stood the test of time": each planet swept out the dust of its own orbit, and therefore they would space out, and wouldn't intersect unless some great collision event from outside altered their courses. The video also doesn't explain why orbits are elliptical and not, say, egg-shaped, or a closed shape at all, which is a really interesting physical theory but about which the description gives a gibberish explanation of "gravitational interaction over time".

Even before Kepler it was long known that planets do not move in perfectly circular orbits. Astronomers have tried to salvage this by adding circles upon circles; so-called epicycles. It was not the Catholic Church who promoted this vision, as is suggested in the animations, but was in fact the scientific consesus of the time, and great astronomers like Tycho Brahe and even Nikolaus Copernicus relied on them. In fact, Kepler wouldn't have had any correspondence Rome at all, seeing that he was a devout Protestant. The Church's problem lay with heliocentricity, not with subtle orbital shapes.

Lastly, the scale of eccentricities at 1:10 is strongly exaggerated, for instance "e = 0.25" seems closer to 0.40 (and the path Haley's comet is not eccentric enough), at 3:10 there is a typo "Oribital velocity, " and the planets at 4:20 are animated with constant velocity when elliptical orbits have strongly fluctuating velocities. It's also not true that a planet in parabolic orbit escapes from the gravitational influence of the star.

[mohanpathak]

Such a neat, beautiful video! Thanks for creating it!

[smalin]

The way I think about elliptical orbits is this: if celestial bodies only interacted by gravity and could pass through each other, then if two of them were attracted and were moving on paths directly toward each other, when they got close, they'd oscillate along a straight path. However, celestial bodies can't pass through each other, so if they are headed straight at each other, they collide, and either break apart of form a single body. Therefore, orbits can only happen when bodies are on trajectories that aren't directly at each other. Orbits have both a circular component and an a linear component, and these add up to an ellipse.

[pratyushpattanaik]

Outstanding video, really helped me a lot for clarifying my wonders!

[nightRanger]

Wow so much necessary information in this one video.

[goldenera]

i am more confused than before after watching this video. what is the reason for elliptical orbits? why is that equilibrium of mass velocity not there?

[padmapriya]

This video made me understand the concept more clearly. Thank you

[RimjhimSaha]

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