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Or one with three planet sharing the same orbit, perfectly spaced!
by hef19898 3y ago
Or one with three planet sharing the same orbit, perfectly spaced!
- marcosdumay 3y agoWell, perfectly spaced is the only way 3 planets can share the same orbit. And if we go for a gas giant and two small planets, there are probably many of those out there. We almost got one such trio.
- hinkley 3y agoPerfectly spaced is not a stable orbit. https://en.wikipedia.org/wiki/Lagrange_point https://en.wikipedia.org/wiki/Lagrange_point You want L4 and L5 for that.
- zeroonetwothree 3y agoThat applies to a small body with two large ones, not three similarly sized planets.
- hinkley 3y agoAh, you are correct. Is there any statically stable shared orbit for planets though? The first wobble and they start accelerating toward each other don't they?
- Retric 3y agoL4 and L5 are unstable unless there is an extreme, as in many orders of magnitude, difference in the masses involved. At equal mass the separation increases until they are all equidistant from each other assuming a completely circular orbit.
- deleted 3y ago[deleted]
- pavel_lishin 3y agoTell that to Janus & Epimetheus: https://en.wikipedia.org/wiki/Janus_(moon) https://en.wikipedia.org/wiki/Janus_(moon)
- bloopernova 3y ago3 planets orbiting a common barycentre would be very cool. I think something like that was mentioned in the Peter F Hamilton "Night's Dawn" trilogy of sci-fi books.
- pavel_lishin 3y agoLarry Niven's Known Space features a series of planets orbiting a common center like that; it's a grand engineer project, and a lifeboat of sorts.
- Zanni 3y agoA pentagonal form of a Klemperer rosette (first thing I thought of also): https://en.wikipedia.org/wiki/Klemperer_rosette https://en.wikipedia.org/wiki/Klemperer_rosette
- TeMPOraL 3y agoOr a planet with 13 moons evenly-spaced on the same orbit? C.f. Ilus IV / New Terra in The Expanse.
- hef19898 3y agoI just wonder so, if there are multiple planets in equal distance between them, would we be able to tell the difference between three planets and one on a fast orbit?
- TeMPOraL 3y agoThat sounds like aliasing issue in signals; we should be able to distinguish between them as long as we sample more often than half the actual orbital period (i.e. with a sampling frequency larger than the Nyquist frequency). https://en.wikipedia.org/wiki/Nyquist_frequency https://en.wikipedia.org/wiki/Nyquist_frequency
- hef19898 3y agoAnother question, is there something like a max. rotation speed for a planet in a certain distance to a sun of a certain size? Edit as a general response: Question answered, multiple times, thank you! Also, there my basic physics knowledge resurfaces, thank you for that as well!
- TeMPOraL 3y agoYes, but that would be dictated by how fast can it spin before shattering into pieces. So mostly gravity/composition thing, I'd imagine. Many things in solar systems are (postulated to) derive from the rotation of the protoplanetary disk, via conservation of angular momentum - however, planets can also get spun up or down after forming by e.g. collisions with other objects, including extra-system objects.
- hef19898 3y agoJust realized, I meant orbit speed and not rotation aeound the planets axis. Shouldn't write in parallel to meetings... Your answer was very interesting so, thank you!
- rob74 3y agoNot convinced until they find a Dyson sphere...
- sirsinsalot 3y agoIf aliens have vacuum cleaners, I hope they're better than ours tbh.
- hef19898 3y agoMandatory mention of Spaceballs incoming... I just don't want the reverse function on my home vacuum.
- TeMPOraL 3y agoIDK, I miss those old vacuums that could run in reverse - they're perfect for building hovercrafts for kids. Make a big disk, punch the vacuum cleaner's pipe through it, put a blanket over the whole thing, add a chair on top. Turn power on, you have a hovercraft. A staple of city science fairs where I live.
- hef19898 3y agoTHAT is a great idea! Would one of those leave blowers work? Ideally a battery powered one?
- JKCalhoun 3y agoThey built a ring world in order to harness enough solar power to continue and sustain their proof of work economy. Alas, when even that was not enough their world collapsed and the successors to their race returned to the trees.
- NoMoreNicksLeft 3y agoDyson spheres are probably really rare. It's just bad strategy, everyone within your galaxy knows you're there pretty much immediately when a star just up and disappears one day. Granted, the non-K2s just stare in awe maybe, but the other K2s will fuck your shit up. Can't exactly pack it up and run either, not with a medium-sized star in your suitcase.
- mapt 3y agoThis is dynamically unstable; Any miniscule imperfection ends up being magnified by the forces involved. The angular momentum of the system is conserved, but resonances build chaotically and are likely to eventually concentrate enough in a smaller body to throw it off past escape velocity. Spaced-out resonant triplets of bodies in the same plane are often dynamically stable - an imperfect ratio is damped by various orbital forces until it approximates a perfect ratio.
- SamBam 3y agoThat's why it would require alien technology to keep it perfect. Why they'd do this, though, would be a mystery.
- fullstackchris 3y agoseems like it'd be a primitive way (in one way, obviously not in the tech sense) of displaying power