nightbat wrote

Odysseus wrote:

In article .com,
"Double-A" wrote:

When moons revolve around their planet slower than the planet rotates,
angular momentum is transferred from the planet to the moons and they
move further away as the planet slows down. When moons revolve around
a planet faster than a planet rotates, then the planet's rotation will
speed up as the moons move closer. It's all done though the action of
tidal forces.

The Sun rotates faster than the planets revolve, so I would think there
should be some tendency for the planets to move further out, but I
think the effect is small.


Very small indeed. IIANM tidal effects are proportional to the cube of
the distance; that's why the Moon has the dominant influence on our
oceanic tides, despite the much stronger gravity of the Sun. Note that
none of the planets from here outward exhibit any resonance between
their orbital and rotational periods.

The Sun is not a rigid body, and I don't think it's heterogeneous enough
to have anything like the "mascons" that help tie the Earth and Moon, so
it's unclear to me how it would be able to transfer angular momentum to
a planet, even as near as Mercury. I guess the surface rotation around
the bulge at the solar equator would produce the strongest tidal
effects, but these would be weakened by 'competing' rotational rates
from other latitudes & depths, and by turbulent flow.

nightbat

Very very good this Odysseus is being Captain nominated for
cadet status overwhelmingly. Officer Double-A congratulations for always
bringing out the best in loyal science group posters. Please continue
this excellent discussion and Odysseus elevation to preliminary elite
rank nomination duly log noted.

carry on,
the nightbat