# Could our moon have a submoon? **URL:** \ **Category:** Factual Questions\ **Created:** [May 10, 2024, 11:57am UTC](https://boards.straightdope.com/t/could-our-moon-have-a-submoon/1001353 "2024-05-10T11:57:01Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![Love\_Rhombus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/love_rhombus/32/10694_2.png) [@Love\_Rhombus](https://boards.straightdope.com/u/Love_Rhombus)\ **Post date:** [May 10, 2024, 11:57am UTC](https://boards.straightdope.com/t/could-our-moon-have-a-submoon/1001353/1 "2024-05-10T11:57:01Z")
I’m not asking if it does, of course. We’d have noticed by now. But from the little I’ve read a moon would need a stable orbit to “support” a submoon. Does ours qualify? And would it affect Earth? ---
**Author:** ![commasense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/commasense/32/3017_2.png) [@commasense](https://boards.straightdope.com/u/commasense)\ **Post date:** [May 10, 2024, 12:07pm UTC](https://boards.straightdope.com/t/could-our-moon-have-a-submoon/1001353/2 "2024-05-10T12:07:54Z")
A real scientist will be along soon to correct me, but probably not. The three-body-problem is not just a TV show. Here’s Neil deGrasse Tyson explaining it. [![](https://img.youtube.com/vi/6GfIDwwxfsM/maxresdefault.jpg "Neil deGrasse Tyson Explains The Three-Body Problem") ](https://www.youtube.com/watch?v=6GfIDwwxfsM) ---
**Author:** ![Love\_Rhombus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/love_rhombus/32/10694_2.png) [@Love\_Rhombus](https://boards.straightdope.com/u/Love_Rhombus)\ **Post date:** [May 10, 2024, 12:10pm UTC](https://boards.straightdope.com/t/could-our-moon-have-a-submoon/1001353/3 "2024-05-10T12:10:19Z")
Huh, All this time I assumed (for some reason) that the “Three Body Problem” was something about swapping minds. ---
**Author:** ![mbh](https://avatars.discourse-cdn.com/v4/letter/m/a6a055/32.png) [@mbh](https://boards.straightdope.com/u/mbh)\ **Post date:** [May 10, 2024, 12:29pm UTC](https://boards.straightdope.com/t/could-our-moon-have-a-submoon/1001353/4 "2024-05-10T12:29:32Z")
In order for the system to be stable, either: The submoon has to be really tiny, and really close to the moon. Or: The earth has to be really large, and really far away from the moon and submoon. ---
**Author:** ![Der\_Trihs](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/der_trihs/32/233_2.png) [@Der\_Trihs](https://boards.straightdope.com/u/Der_Trihs)\ **Post date:** [May 10, 2024, 12:33pm UTC](https://boards.straightdope.com/t/could-our-moon-have-a-submoon/1001353/5 "2024-05-10T12:33:02Z")
As I understand it, there’s a few fairly stable orbits around the Moon; [it’s where we put probes/satellites](https://www.nasa.gov/general/does-anything-orbit-the-moon-we-asked-a-nasa-technologist/). [However](https://en.wikipedia.org/wiki/Lunar_orbit#Stable_low_orbits) they can’t be very high or the Earth will perturb the orbit, and most low orbits are unstable because the Moon is very “lumpy” with an uneven gravitational field. I expect that you therefore _could_ have a natural “submoon” orbit Luna just as our probes do; but probably not a long-lasting one. ---
**Author:** ![Prof.Pepperwinkle](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/prof.pepperwinkle/32/13627_2.png) [@Prof.Pepperwinkle](https://boards.straightdope.com/u/Prof.Pepperwinkle)\ **Post date:** [May 10, 2024, 12:44pm UTC](https://boards.straightdope.com/t/could-our-moon-have-a-submoon/1001353/6 "2024-05-10T12:44:30Z")
But there are [ghost moons](https://en.wikipedia.org/wiki/Kordylewski_cloud). ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 10, 2024, 3:45pm UTC](https://boards.straightdope.com/t/could-our-moon-have-a-submoon/1001353/7 "2024-05-10T15:45:11Z")
Depends what you classify as a moon. I think it hasn’t been proven that the Apollo 11 ascent module ever crashed back into the moon and could still be orbiting since 1969. Modeling of the orbit strongly indicates the orbit did decay and the module did return to the moon’s surface. On that basis earth has thousands of other moons now, and for some time to come. ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [May 10, 2024, 3:51pm UTC](https://boards.straightdope.com/t/could-our-moon-have-a-submoon/1001353/8 "2024-05-10T15:51:08Z")
As mentioned above, it is possible for _a_ moon to have the right conditions to have a stable submoon, but not _our_ moon because of the mascons. > **[Mystery of Moon's Lumpy Gravity Explained](https://www.space.com/21364-moon-gravity-mascons-mystery.html)** > > A new study of strange concentrations of mass on the moon sheds light on anomalies in the lunar gravitational field. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [May 10, 2024, 4:42pm UTC](https://boards.straightdope.com/t/could-our-moon-have-a-submoon/1001353/9 "2024-05-10T16:42:49Z")
Technically, a sub-moon would be part of a _four_ body problem. The Sun’s gravity is strong enough to play a notable part of the equations. While going from 2 bodies to 3 is the killer step in calculating paths, going from 3 to 4 just piles on the chaos in the equations. ---
**Author:** ![Peter\_Morris](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/peter_morris/32/359_2.png) [@Peter\_Morris](https://boards.straightdope.com/u/Peter_Morris)\ **Post date:** [May 10, 2024, 4:50pm UTC](https://boards.straightdope.com/t/could-our-moon-have-a-submoon/1001353/10 "2024-05-10T16:50:04Z")
previous discussion: > [@Could a moon have a moon of its own?](https://boards.straightdope.com/t/could-a-moon-have-a-moon-of-its-own/963716): > > I think there are no examples in our own Solar System. But suppose we imagine a Jupiter-like gas giant orbiting a faraway star. This has several moons, including an Earth-like ball. Could there be a Luna-like rock orbiting? Is there any reason why it couldn’t happen? Maybe the gravity of the main planet would prevent a stable orbit forming, or something.