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It's it possible for three planets to exist together in a braid like formation around their common central orbit. If it is then he would the night sky's constellations and important navigational stars, zodiac signs etc. change their position as the year progresses. Also how different would the night sky look as seen from any one planet. Any pictures would be if great help The planets I am thinking are mostly like earth in nature.

Assume each planet's common orbit (the centre of the braid) to be same as earth orbiting a star similar to our sun

I have read the other question is it possible to have three or more planets in a stable orbit together. But what I am curious about is the night sky from one of the planets' veiwpoint

Sorry I am unable to link the question which this has been cited duplicate of due to being on a smartphone and not a PC

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marked as duplicate by Hohmannfan, Thucydides, PipperChip, Brythan, AndyD273 Aug 15 '16 at 3:11

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

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By "a braid like formation around their common central orbit" I presume you're thinking of the way that Earth and the Moon have orbits that are both always concave towards the Sun, but cross over, and trying to generalise that to three planets?

You can't have three bodies of similar mass in a stable orbit like that. The configuration is unstable, and the slightest outside influence will have unpredictable effects on their orbits, probably ending up with two of them colliding. This is known as the "three-body problem."

The situation you probably could manage would be a planet somewhat larger than Earth, a main moon, and a smaller body in one of the Earth-Moon Trojan points that was large enough to be visible to the naked eye. It couldn't large enough to show much of a disc, but its motion would be obviously the same as the moon, leading or trailing it by sixty degrees. The only obvious difference in the night sky would be the Trojan moon.

Even if your three Earths situation were possible, it would not make any obvious difference to the constellations and stars used for navigation. They're made up of stars, not planets, and those stars are at such great distances that the more complicated motions of the planets would not affect the naked-eye positions of the stars. The constellations and signs of the zodiac are human inventions, and don't correspond to anything physical.

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    $\begingroup$ Scott Manley has a video on a few n-body Universe Sandbox² presets that demonstrate exactly this effect. $\endgroup$ – Jonathan Dickinson Aug 15 '16 at 7:57
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Perhaps not planets, but satellites of a larger dark-body planetoid.

John Dallman's answer is great, but as valuable as a "no" answer in the right place is, it's also fun to see what we have to do to make it a "yes." We have plenty of planets in our own solar system that maintain multiple satellites in a stable orbit, and the movement of these satellites around their respective host planets could be described as braid-like. If you replace the planet in any of these systems with an identically-massed dark-body (maybe a black hole shielded from accreting matter and exuding Hawking radiation, maybe just some unexplained "exotic matter", maybe an artificial gravitation source), it might appear at first blush that you have three or more planets orbiting one another in the way you suggest.

One fun thing about this, though, is that our history of astronomy would be utterly impossible in this planetary configuration. What would Kepler do if he looked up and saw what you describe? Run screaming back to Ptolemaic astronomy, most likely.

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  • $\begingroup$ A planet mass black hole will be of lower "temperature" than the cmb. Hawking radiation will be negligible. The black hole will be 1-2cm in size. $\endgroup$ – Donald Hobson Aug 14 '16 at 17:37
  • $\begingroup$ Fair enough, @DonaldHobson! I was also thinking that gravitational lensing might be noticeable even with the naked eye if the black hole (or other small, strong gravitator) eclipsed one of the neighboring "planets"/satellites. I'm just not imaginative to say how the ancient mind would react to that kind of thing. $\endgroup$ – SudoSedWinifred Aug 14 '16 at 21:10
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    $\begingroup$ An ingenuous solution. The three moons would be orbiting a common centre of mass, albeit an invisible one. It's easy to adjust the mass of the black hole to whatever is necessary for three earth-mass satellites. This is better than a braided planets scenario. From any one planet, they would see the other planets dancing and whirling in the sky. With short term changes in their zodiac on an almost daily basis. Good for navigation & timekeeping too. One up from me. $\endgroup$ – a4android Aug 15 '16 at 2:18

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