# Can moons have moons? **URL:** \ **Category:** Factual Questions\ **Created:** [June 11, 2015, 5:44am UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240 "2015-06-11T05:44:14Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Tron](https://avatars.discourse-cdn.com/v4/letter/t/3da27b/32.png) [@Tron](https://boards.straightdope.com/u/Tron)\ **Post date:** [June 11, 2015, 5:44am UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/1 "2015-06-11T05:44:14Z")
Just curious, can moons have moons? Galaxies can have stars, stars can have planets, planets can have moons. Can moons have their own satellites? And if so, can those satellites have their own satellites? What is the physical limitation of such relationships? ---
**Author:** ![Trinopus](https://avatars.discourse-cdn.com/v4/letter/t/2bfe46/32.png) [@Trinopus](https://boards.straightdope.com/u/Trinopus)\ **Post date:** [June 11, 2015, 6:59am UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/2 "2015-06-11T06:59:01Z")
The short answer is yes. But there are limitations. The Earth’s Moon is too close to the Earth to have any stable orbits around it. But if the Moon were ten times as far from the Earth as it is, then it could have moons of its own. (As an analogy, the Sun has planets, and those planets have moons, so second-order orbits are possible.) ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [June 11, 2015, 7:33am UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/3 "2015-06-11T07:33:06Z")
Here’s a detailed answer: [Can Moons Have Moons? - Universe Today](http://www.universetoday.com/109666/can-moons-have-moons/) ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [June 11, 2015, 8:20am UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/4 "2015-06-11T08:20:21Z")
> [@Trinopus](#): > > The Earth’s Moon is too close to the Earth to have any stable orbits around it. But if the Moon were ten times as far from the Earth as it is, then it could have moons of its own. Unfortunately, moving the Moon to 10 times its current distance would put it at 3.8 million kilometers away. Since the Earth’s Hill Sphere is only 1.5 million kilometers out, that would be an unstable orbit for the Moon and it would soon be lost to solar orbit. Orbits around the Moon are always very unstable. This is due to [mascons](http://en.wikipedia.org/wiki/Mass_concentration_(astronomy)) on the Moon which make its gravitational field rather lumpy. Combine that with tidal effects from the Earth and Sun and anything put into Lunar orbit won’t stay there for any great length of time. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [June 11, 2015, 1:16pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/5 "2015-06-11T13:16:48Z")
> [@](#): > > So no, in our Solar System, we don’t know of any moons with moons of their own. In fact, we don’t even have a name for them. What would you suggest? Moonlette ---
**Author:** ![John\_Mace](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_mace/32/185_2.png) [@John\_Mace](https://boards.straightdope.com/u/John_Mace)\ **Post date:** [June 11, 2015, 1:37pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/6 "2015-06-11T13:37:45Z")
How about Secondary Moons? ---
**Author:** ![Lanzy](https://avatars.discourse-cdn.com/v4/letter/l/74df32/32.png) [@Lanzy](https://boards.straightdope.com/u/Lanzy)\ **Post date:** [June 11, 2015, 1:41pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/7 "2015-06-11T13:41:50Z")
We just have to call them “moonies” ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [June 11, 2015, 2:02pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/8 "2015-06-11T14:02:30Z")
> [@Trinopus](#): > > The short answer is yes. But there are limitations. > > The Earth’s Moon is too close to the Earth to have any stable orbits around it. But if the Moon were ten times as far from the Earth as it is, then it could have moons of its own. > > (As an analogy, the Sun has planets, and those planets have moons, so second-order orbits are possible.) Third-order, or higher if our galaxy is rotating around a cluster or supercluster 🙂 ---
**Author:** ![BubbaDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bubbadog/32/333_2.png) [@BubbaDog](https://boards.straightdope.com/u/BubbaDog)\ **Post date:** [June 11, 2015, 2:17pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/9 "2015-06-11T14:17:48Z")
[QUOTE=watchwolf] Moonlette [/QUOTE] [QUOTE=John Mace] How about Secondary Moons? [/QUOTE] [QUOTE=Lanzy] We just have to call them “moonies” [/QUOTE] Nope Earth: 5 letters Moon: 4 letters Moon’s moon: 3 letters - suggestion: Nub Moon’s moon’s moon: 2 letters - suggestion: Ir Moon’s moon’s moon’s moon: 1 letter - suggestion: O Moon’s moon’s moon’s moon’s moon: 0 letters - suggestion: ---
**Author:** ![Amateur\_Barbarian](https://avatars.discourse-cdn.com/v4/letter/a/59ef9b/32.png) [@Amateur\_Barbarian](https://boards.straightdope.com/u/Amateur_Barbarian)\ **Post date:** [June 11, 2015, 3:17pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/10 "2015-06-11T15:17:15Z")
That’s all ridiculous. If you had that many moons in a row, you’d have a moon river. ---
**Author:** ![Ludovic](https://avatars.discourse-cdn.com/v4/letter/l/7ab992/32.png) [@Ludovic](https://boards.straightdope.com/u/Ludovic)\ **Post date:** [June 11, 2015, 3:19pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/11 "2015-06-11T15:19:32Z")
And if they all hit your eye like a big pizza pie, either the pain of the impact or the lovestruckness will render one lachrymose, so it would also be Crimea River. ---
**Author:** ![Dendarii\_Dame](https://avatars.discourse-cdn.com/v4/letter/d/bbce88/32.png) [@Dendarii\_Dame](https://boards.straightdope.com/u/Dendarii_Dame)\ **Post date:** [June 11, 2015, 4:51pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/12 "2015-06-11T16:51:07Z")
Won’t somebody think of the cow jumping over the moon? Maybe a moon’s moon could be a “moo”, in honor of the cow. ---
**Author:** ![sbunny8](https://avatars.discourse-cdn.com/v4/letter/s/c77e96/32.png) [@sbunny8](https://boards.straightdope.com/u/sbunny8)\ **Post date:** [June 11, 2015, 5:21pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/13 "2015-06-11T17:21:33Z")
I suggest “filia”, the Latin word for daughter. Then, if someday we found a rock orbiting a filia orbiting a moon orbiting a planet orbiting a star… we could call that rock a granddaughter, “neptem” in Latin. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [June 11, 2015, 5:30pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/14 "2015-06-11T17:30:36Z")
> [@Amateur\_Barbarian](#): > > That’s all ridiculous. If you had that many moons in a row, you’d have a moon river. But it would be wider than a mile. ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [June 11, 2015, 5:46pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/15 "2015-06-11T17:46:21Z")
> [@BubbaDog](#): > > Nope > Earth: 5 letters > Moon: 4 letters > Moon’s moon: 3 letters - suggestion: Nub > Moon’s moon’s moon: 2 letters - suggestion: Ir > Moon’s moon’s moon’s moon: 1 letter - suggestion: O > Moon’s moon’s moon’s moon’s moon: 0 letters - suggestion: Which six letter name do you want to replace Sun/Sol with? ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [June 11, 2015, 5:49pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/16 "2015-06-11T17:49:13Z")
> [@naita](#): > > Which six letter name do you want to replace Sun/Sol with? Just call it Dat Sun. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [June 11, 2015, 6:09pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/17 "2015-06-11T18:09:48Z")
> [@Exapno\_Mapcase](#): > > Just call it Dat Sun. There is already an automobile by that name. ---
**Author:** ![tonyfop](https://avatars.discourse-cdn.com/v4/letter/t/85f322/32.png) [@tonyfop](https://boards.straightdope.com/u/tonyfop)\ **Post date:** [June 11, 2015, 6:15pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/18 "2015-06-11T18:15:13Z")
So now that yellow thing in the sky is a Nissan? ---
**Author:** ![Balance](https://avatars.discourse-cdn.com/v4/letter/b/ccd318/32.png) [@Balance](https://boards.straightdope.com/u/Balance)\ **Post date:** [June 11, 2015, 6:29pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/19 "2015-06-11T18:29:32Z")
Well, such a secondary satellite would likely be relatively small… “moonimal”. ---
**Author:** ![74westy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/74westy/32/3950_2.png) [@74westy](https://boards.straightdope.com/u/74westy)\ **Post date:** [June 11, 2015, 6:43pm UTC](https://boards.straightdope.com/t/can-moons-have-moons/722240/20 "2015-06-11T18:43:23Z")
> [@naita](#): > > Which six letter name do you want to replace Sun/Sol with? Helios. Duh! [Next page](https://boards.straightdope.com/t/can-moons-have-moons/722240.md?page=2)