Newtons three-body problem explained - Fabio Pacucci
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Date: 2020-08-22
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Comments and reviews: 10
Phillip
This video's explanation of chaos in the N-body problem is completely wrong. The N-body problem has sufficient equations of motion to completely define the problem for any number of bodies. The trick they mention about considering relative motion just simplifies the algebra a little by choosing a convenient coordinate system. The unpredictability of the orbits comes from the equations of motion being fundamentally chaotic; NOT having insufficient equations to fully define the problem. I think the creators may have conflated a problem not having an analytic solution (a solution exists, but we can't write it down using simple function, versus the problem not being well posed (which the Newtonian N-Body problem is.
This is such a fundamental error that TED-Ed should be embarrassed and is clear evidence an actual physicist didn't review this video's content.
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This video's explanation of chaos in the N-body problem is completely wrong. The N-body problem has sufficient equations of motion to completely define the problem for any number of bodies. The trick they mention about considering relative motion just simplifies the algebra a little by choosing a convenient coordinate system. The unpredictability of the orbits comes from the equations of motion being fundamentally chaotic; NOT having insufficient equations to fully define the problem. I think the creators may have conflated a problem not having an analytic solution (a solution exists, but we can't write it down using simple function, versus the problem not being well posed (which the Newtonian N-Body problem is.
This is such a fundamental error that TED-Ed should be embarrassed and is clear evidence an actual physicist didn't review this video's content.
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Donald
No you cannot predict any n-body systems in the future with more powerful computers. You are just predicting the orbits of planets in our solar system not controlled by gravity because they are planar related. There is no planar gravity and therefore a two body system is unpredictable unless it is constrained as planar. No planet has fallen into the sun not from their velocity but because of repulsion. Systems appear chaotic from simulations with rounding errors such as the 1 mm case. Do the planets orbit to within 1 mm? Certainly not. That is idiocy. They orbit in a constrained path that is self correcting. Because of that, our solar system is very stable.
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No you cannot predict any n-body systems in the future with more powerful computers. You are just predicting the orbits of planets in our solar system not controlled by gravity because they are planar related. There is no planar gravity and therefore a two body system is unpredictable unless it is constrained as planar. No planet has fallen into the sun not from their velocity but because of repulsion. Systems appear chaotic from simulations with rounding errors such as the 1 mm case. Do the planets orbit to within 1 mm? Certainly not. That is idiocy. They orbit in a constrained path that is self correcting. Because of that, our solar system is very stable.
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Yu
Highly recommended the book three-body problem that is mentioned in this video. I read the Chinese version first a couple years ago, and it's just fascinating, especially the second of the series, which unveils a theatrical formulation (a. k. a. Dark Forest) of the interactions between civilizations in the universe. Although it's a sci-fi, most of what described in this series actually have scientific basis are within reasonable possibility.
Anyway, the English version translated by Ken Liu is great in term of quality, still highly recommended if you can't read the original version in Chinese.
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Highly recommended the book three-body problem that is mentioned in this video. I read the Chinese version first a couple years ago, and it's just fascinating, especially the second of the series, which unveils a theatrical formulation (a. k. a. Dark Forest) of the interactions between civilizations in the universe. Although it's a sci-fi, most of what described in this series actually have scientific basis are within reasonable possibility.
Anyway, the English version translated by Ken Liu is great in term of quality, still highly recommended if you can't read the original version in Chinese.
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Andrew
A lot of theoretical physics and astrology works to give us an idea of the immesity of our universe, whether intentionally or unintentionally. This is the first time in a while where a lesson teaches me how obscenely chaotic the universe can be on a macro scale. It's weirdly hopeful because the immensity of the universe is not something we can overcome by understanding the universe (unless wormholes are feasible) but the chaos of it is and shows a path for science that leads far, far into the future if we're smart enough to make it there.
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A lot of theoretical physics and astrology works to give us an idea of the immesity of our universe, whether intentionally or unintentionally. This is the first time in a while where a lesson teaches me how obscenely chaotic the universe can be on a macro scale. It's weirdly hopeful because the immensity of the universe is not something we can overcome by understanding the universe (unless wormholes are feasible) but the chaos of it is and shows a path for science that leads far, far into the future if we're smart enough to make it there.
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samuelrj
What the heck is with earth's orbit at 0: 51? Earth doesn't orbit in a circle next to the sun, it orbits around the sun. And what's with the orbits at 1: 23 and 2: 30 and 3: 02 and 4: 21. An educational video about orbital mechanics isn't very educational if most of the visuals are inaccurate and misleading. I'm sure the video took a lot of time and effort, but why not take a little more time to make it accurate?
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What the heck is with earth's orbit at 0: 51? Earth doesn't orbit in a circle next to the sun, it orbits around the sun. And what's with the orbits at 1: 23 and 2: 30 and 3: 02 and 4: 21. An educational video about orbital mechanics isn't very educational if most of the visuals are inaccurate and misleading. I'm sure the video took a lot of time and effort, but why not take a little more time to make it accurate?
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Francopolo
There's an incredible trilogy of books written by cixin liu, translated into English. The first book of the series is called the three body problem, and is an amazing sci fi book packed full of interesting but very realistic concepts based on modern or near future technology, and implements ideas from big general relativity and quantum mechanics excellently.
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There's an incredible trilogy of books written by cixin liu, translated into English. The first book of the series is called the three body problem, and is an amazing sci fi book packed full of interesting but very realistic concepts based on modern or near future technology, and implements ideas from big general relativity and quantum mechanics excellently.
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qwato
Good video and informative but the researcher forgot to mention that there is a periodicity even in chaos. What does it means if an N-body system is perturbed? It will get back to its stability even when there is chaos. how else would there be existing solar systems if there would be an unregulated chaos from the smallest perturbation?
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Good video and informative but the researcher forgot to mention that there is a periodicity even in chaos. What does it means if an N-body system is perturbed? It will get back to its stability even when there is chaos. how else would there be existing solar systems if there would be an unregulated chaos from the smallest perturbation?
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Lauren
If anyone would like to know why this approach does not work, then please contact me. I am able to explain what the researchers are doing wrong.
L. Dove
Arbiter - Universal Law
ldoveozemail. com. au
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If anyone would like to know why this approach does not work, then please contact me. I am able to explain what the researchers are doing wrong.
L. Dove
Arbiter - Universal Law
ldoveozemail. com. au
reply
Mr
Every time I try to explain to my friend that the earth isnt flat the sun isnt a planet the universe isnt a hologram jfk cheated the elections and the trees arent made by the government I go here
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Every time I try to explain to my friend that the earth isnt flat the sun isnt a planet the universe isnt a hologram jfk cheated the elections and the trees arent made by the government I go here
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Yiffox
or god created it a short time ago. this would also eliminate the need for dark matter that stars seem to have same velocity in galaxy, rather than slower in middle and slowest on extremes.
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or god created it a short time ago. this would also eliminate the need for dark matter that stars seem to have same velocity in galaxy, rather than slower in middle and slowest on extremes.
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