# Donut-shaped planet
**URL:** https://boards.straightdope.com/t/donut-shaped-planet/961249
**Category:** In My Humble Opinion
**Created:** [March 17, 2022, 3:42pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249 "2022-03-17T15:42:02Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)
#### Post date: [March 17, 2022, 3:42pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/1 "2022-03-17T15:42:02Z")
Apparently, according to physics, a [donut-shaped planet](https://www.discovery.com/science/donut-shaped-planet) is possible. Given that the universe (if not infinite) is really, really big, does that mean that one does exist somewhere?
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### Author:  [@pjd](https://boards.straightdope.com/u/pjd)
#### Post date: [March 17, 2022, 3:49pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/2 "2022-03-17T15:49:42Z")
No, it means that one _could_ exist somewhere.
Anyway - that site is not available in my country !?!?!?
And it’s a food site … what are you trying to do to me ?!
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### Author:  [@panache45](https://boards.straightdope.com/u/panache45)
#### Post date: [March 17, 2022, 3:54pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/3 "2022-03-17T15:54:37Z")
> [@Lucas\_Jackson](#):
>
> Given that the universe (if not infinite) is really, really big, does that mean that one does exist somewhere?
Where do people get the idea that in an infinite universe, ALL things MUST exist? That’s stupid.
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### Author:  [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)
#### Post date: [March 17, 2022, 3:57pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/4 "2022-03-17T15:57:57Z")
Saturn’s rings seem fairly stable. Maybe they’ll collapse into a donut?
But yeah, if the odds are 1 in 1,000,000 then 1 in 1,000,000 planets will be a donut on average. There are liable to be so many planets in the universe that regardless of whether the big number there is 1,000,000 or 1,000,000,000,000,000, it’s probably still small enough for there to still be an amazing number of donuts floating around.
One current estimate for the total number of planets that we expect to be able to discover is around 10,000,000,000,000,000,000,000,000:
[How Many Planets In The Universe? | by Ethan Siegel | Starts With A Bang! | Medium](https://medium.com/starts-with-a-bang/how-many-planets-in-the-universe-9153a05bd0d5#:~:text=For%20those%20of%20you%20who,planets%20that%20are%20orbiting%20stars).
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### Author:  [@Knowed\_Out](https://boards.straightdope.com/u/Knowed_Out)
#### Post date: [March 17, 2022, 3:59pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/5 "2022-03-17T15:59:07Z")
The article said that it would have to be a rapidly rotating planet, like a merry-go-round out of control. In addition, gravity would be weakest at the equator, so whatever’s there would be flying off the ground. Not a place to retire to.
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### Author:  [@kenobi\_65](https://boards.straightdope.com/u/kenobi_65)
#### Post date: [March 17, 2022, 3:59pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/6 "2022-03-17T15:59:15Z")
As that article notes:
> [@](#):
>
> A planet in the shape of a donut, or toroid, as it’s called in mathematics, [could technically exist](http://io9.gizmodo.com/what-would-the-earth-be-like-if-it-was-the-shape-of-a-d-1515700296), but it would have to jump some steep physics hurdles to get there. Planets are round because gravity pulls inward. To keep the hole, or hub, at the center of a toroid planet from collapsing, you’d need an equal outward force. Centrifugal force (the force you feel when a spinning merry-go-round nearly sends you flying) could do the trick, but it would mean that the planet would have to rotate at an extremely high rate. That would most likely make a day on a donut-shaped planet last just a few hours.
So, hypothetically possible, but not easy to accomplish. There’s lots of good reasons why planetary bodies tend towards a spheroid shape.
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### Author:  [@pjd](https://boards.straightdope.com/u/pjd)
#### Post date: [March 17, 2022, 4:01pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/7 "2022-03-17T16:01:20Z")
Well this is weird.
I now see the url is for [discovery.com](http://discovery.com), but when i click it,
i get a page saying “this site is not available in your country” - but the
address in the address bar says [foodnetwork.com](http://foodnetwork.com)
I blame that bastard putin.
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### Author:  [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)
#### Post date: [March 17, 2022, 4:02pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/8 "2022-03-17T16:02:31Z")
> [@Knowed\_Out](#):
>
> The article said that it would have to be a rapidly rotating planet, like a merry-go-round out of control. In addition, gravity would be weakest at the equator, so whatever’s there would be flying off the ground. Not a place to retire to.
I’m not sure that you would experience the spinning except as a gravitation-like force. Your balance would naturally orient you to be upright and the land around you would be stable. You might notice the sun moving across the sky several times a day but that wouldn’t be enough to make you dizzy, by any sense.
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### Author:  [@John\_DiFool](https://boards.straightdope.com/u/John_DiFool)
#### Post date: [March 17, 2022, 4:03pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/9 "2022-03-17T16:03:12Z")
> [@pjd](#):
>
> Anyway - that site is not available in my country !?!?!?
> And it’s a food site … what are you trying to do to me ?!
Whoosh? The Discovery site is a well-known one, and isn’t a “food” site.
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### Author:  [@Elmer\_J.Fudd](https://boards.straightdope.com/u/Elmer_J.Fudd)
#### Post date: [March 17, 2022, 4:06pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/10 "2022-03-17T16:06:50Z")
Well, this guy would say probability is impossible without prior examples.
[https://www.askamathematician.com/2012/12/q-in-an-infinite-universe-does-everything-thats-possible-have-to-happen-somewhere/](https://www.askamathematician.com/2012/12/q-in-an-infinite-universe-does-everything-thats-possible-have-to-happen-somewhere/)
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### Author:  [@AlsoNamedBort](https://boards.straightdope.com/u/AlsoNamedBort)
#### Post date: [March 17, 2022, 4:11pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/11 "2022-03-17T16:11:02Z")
> [@pjd](#):
>
> I now see the url is for [discovery.com](http://discovery.com), but when i click it,
> i get a page saying “this site is not available in your country” - but the
> address in the address bar says [foodnetwork.com](http://foodnetwork.com)
Discovery, Inc. owns Food Network. They probably have any 404 error redirect to one site.
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### Author:  [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)
#### Post date: [March 17, 2022, 4:12pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/12 "2022-03-17T16:12:49Z")
We have a lot of examples of various space junk - gas clouds, asteroid belts, spherical planets, black holes, etc. A donut isn’t in that but any simulator that we build needs to be able to handle a fairly wide variety of physical interactions.
I wouldn’t expect our predictions on donut manifestation to be exactly accurate but I’d be surprised if our current technology was more than two orders of magnitude away from the real answer. (IANAPhysicist)
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### Author:  [@pulykamell](https://boards.straightdope.com/u/pulykamell)
#### Post date: [March 17, 2022, 4:14pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/13 "2022-03-17T16:14:30Z")
> [@panache45](#):
>
> Where do people get the idea that in an infinite universe, ALL things MUST exist? That’s stupid.
But that is not what is being said.
Wikipedia’s article on toroidal planets does state:
> The odds of any toroidal planet forming might be infinitesimally small yet nonzero; allowing for an [infinite universe](https://en.wikipedia.org/wiki/Universe#Size_and_regions), not only would a ‘donut-shaped planet’ [almost certainly](https://en.wikipedia.org/wiki/Almost_certain) be bound to occur during the [stelliferous era](https://en.wikipedia.org/wiki/Stelliferous_era), it would occur infinitely often.
That said, is a toroidal planet truly a non-zero probability?
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### Author:  [@kanicbird](https://boards.straightdope.com/u/kanicbird)
#### Post date: [March 17, 2022, 4:34pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/14 "2022-03-17T16:34:11Z")
Isn’t there 2 donut possibilities? The one mentioned, a rapidly rotating planet, but what about a donut around the star? More of a o-ring, but would that be possible?
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### Author:  [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)
#### Post date: [March 17, 2022, 4:39pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/15 "2022-03-17T16:39:39Z")
> [@kanicbird](#):
>
> The one mentioned, a rapidly rotating planet, but what about a donut around the star? More of a o-ring, but would that be possible?
Not remotely. For many reasons.
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### Author:  [@Great\_Antibob](https://boards.straightdope.com/u/Great_Antibob)
#### Post date: [March 17, 2022, 4:39pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/16 "2022-03-17T16:39:46Z")
Seems like there’s two different questions here.
Is it likely a toroidal planet has formed at some point? Sure. It may even be fairly likely (for a given low probability for ‘likely’).
Are there such planets that achieve stability and persist for a while? Probably not.
> [@kanicbird](#):
>
> More of a o-ring, but would that be possible?
Definitely not, for several reasons.
Look up “Ringworld”, which is basically this concept. Lots of websites on the physics of such a thing.
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### Author:  [@k9bfriender](https://boards.straightdope.com/u/k9bfriender)
#### Post date: [March 17, 2022, 4:42pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/17 "2022-03-17T16:42:11Z")
Assuming that it is within a habitable zone of a star, the tidal forces on it would be pretty significant, slowing it until it collapsed into a much more stable spheroid shape.
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### Author:  [@Great\_Antibob](https://boards.straightdope.com/u/Great_Antibob)
#### Post date: [March 17, 2022, 4:45pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/18 "2022-03-17T16:45:56Z")
Exactly. Even if one formed, it’s unlikely to keep its shape for long. And the rotation would be big, meaning more likely to occur near the star than farther away.
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### Author:  [@Sage\_Rat](https://boards.straightdope.com/u/Sage_Rat)
#### Post date: [March 17, 2022, 4:49pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/19 "2022-03-17T16:49:06Z")
I would lean towards the idea that any stable configuration is liable to pop up eventually but the longer and skinnier that something is the less connective power it will have against itself and the more likely that it is to get torn apart by collisions with random junk. You’re most likely going to end up with an asteroid belt rather than a nice, rock-like ring with plants growing on it.
Imagine that you fill a wide and flat cylindrical tank with water and use a mechanism to create a small vortex in the absolute center. You need to dribble a line of oil in to create a perfect, continuous ring that doesn’t collect together into a ball and doesn’t spread out and break up. There’s a certain amount of surface tension and self-adhesion in the oil that you might be able to get a small ring to stay together, somewhere in the middle of the vortex where the centripetal force is keeping the ring from collapsing but the gravitational force is keeping the ring from escaping. But any deeper and it’s going to sink and become an oil ball; any further out and the thin line of oil will break apart and turn into separate blobs.
It’s a very hard balancing act.
Gravity is such a weak force that it really is like trying to get oil to stay together in a long line. It mostly wants to break up and spread freely.
You would need an awesomely clear sky in order for it to happen. Any minor gravitational fluctuations from the surroundings, any roaming comets, etc. could all tear it apart.
Assuming that the universe is randomly generated, we should expect that there are many very quiet and stable regions out there. But the grand majority of everything is of average turbulence and mess, and that’s probably too much for a perfect, thin ring.
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### Author:  [@kanicbird](https://boards.straightdope.com/u/kanicbird)
#### Post date: [March 17, 2022, 4:49pm UTC](https://boards.straightdope.com/t/donut-shaped-planet/961249/20 "2022-03-17T16:49:16Z")
> [@Darren\_Garrison](#):
>
> Not remotely. For many reasons.
OK then what about the star itself? A donut star possible? If so that might be easier to find then such a planet.
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