🚀 go-pugleaf

In article <1jhaldINNicf@elroy.jpl.nasa.gov> tjt@Jpl.Nasa.Gov (Tim  
Thompson) writes:
>    The Earth's moon is locked by tidal forces, applied over zillions of  
years,
> the result being that one side now always faces the Earth. Very standard  
orbital
> physics. I am quite sure there are other moons in the same fix, but I  
can't
> name any right off the top of my head.
>                                              Tim T.

I thought I was one up on you, about to post that Phobos is also  
rotationally locked, but then I checked the table in Hartmann's 'Moons and  
Planets, 2ed' and got woken up. Tidal locking is much more common than I  
thought!...
Planetary natural satellites with Revolution=Rotation
Earth: Moon
Mars:  Phobos, Deimos
Jupiter: 1979J3 (.29,.30 days), 1979J1 (.294, .29 days), J5 Amalthea,
         1979J2, Io, Europa, Ganymede, Callisto
Saturn:  Mimas, Enceladus, Tethys, Dione (2.737, 2.74),
         Rhea (4.518, 4.52), Titan (15.94, 15.9?), Iapetus

In cases where the two numbers were not exactly the same they are given as  
(revolution period,rotation period).
There are likely more cases, as Uranus and Neptune systems had a lot of ?  
in this 1983 edition which are likely now known. Also it is fairly certain  
that Pluto's moon Charon is locked.
--
Martin Connors         |
Space Research         | martin@space.ualberta.ca  (403) 492-2526
University of Alberta  |