# Does rotation on their axis cause winds in gaseous planets?

As far as I know, as planets rotate around their axis, they can influence winds but not cause them (like the Coriolis effect)

However, does this apply only for rocky planets? Do rotation alone in gaseous planets contribute to their winds?

I am asking this because of this question (https://worldbuilding.stackexchange.com/questions/123419/how-can-a-remote-planet-with-little-to-no-sunlight-have-high-wind-speeds) where one answer seems to imply that rotation in gaseous planets is one direct cause of their winds (while in rocky planets it is not). Is this true?

It is not true. What makes wind actually be wind is that it is moving relative to something else. On earth, that something else may be you, but on a gaseous planet the only "something else" is other parts of the atmosphere. And there is nothing about a fluid body rotating in isolation that will apply a differential force in a way that will cause a wind.

One way to think about this is that you can convert to a rotating coordinate system. Then you have the fictitious centrifugal and Coriolis forces. But the centrifugal forces are constant and Coriolis forces require existing motion. There is no force that can generate a wind.

The most common source of wind on a planet like Neptune with little energy from the sun will be good old convection, resulting from the initial heat of all the matter coalescing (in many cases near the end colliding at high speeds) to form the planet. The rotation will absolutely play a role in how that wind flows. (I just found one article that says the wind of Uranus and Neptune are in a pretty thin layer and may be driven by liquids condensing and evaporating, but that's still convection and the ultimate energy source is still the difference between the interior and exterior temperatures of the planet.)

There actually is a way rotation can generate wind-causing energy in a non-isolated planet (like Neptune), and that's tidal heating. Triton creates a bulge on Neptune (two bulges, really), and, as Neptune rotates under its moon, the bulge essentially kneads the planet, which will generate some heat which will be part of the heat budget in Neptunian weather. So maybe I'm hiding a "Yes" at the end of an answer that led with "No", but I think you were talking about rotation by itself, and I still say that cannot create winds.

• Related discussion: physics.stackexchange.com/questions/649173/… Aug 2, 2023 at 0:58
• Thank you. Only one question. In the article you mentioned they say that winds in Neptune are caused by water being condensed and evaporated. But how can water be evaporated if Neptune is so far away from the Sun? @MarkFoskey Aug 2, 2023 at 9:04
• The article said "moisture", which you might interpret to specifically mean water, but I think they are probably talking about other things with lower boiling points. Maybe methane, but I'm not sure. I will say that, deep inside Neptune, it is very hot. But, by the time you get deep enough for water to be liquid, I think the pressure is so great ("above the critical point") so that there's no real distinction between liquid and gas and so you can't have droplets evaporating and condensing. But I'm not sure. Aug 2, 2023 at 11:58

There are two factors that determines why there are strong winds on these gaseous planets:

1. Convection: The gaseous planets emit more heat than they receive from the sun and this internal heat is causing winds to flow in a turbulent convective motion. These systems do not change along the axis of rotation and try to organize themselves into cylinder-shaped columns which is in conflict with the spherical shape of the planet.
2. Lack of Atmospheric Drag: The gaseous planets do not have solid surface. So, there is virtually no surface roughness to act as a drag on winds. Moreover, they are very far from the sun. So, there is less solar energy to impart turbulence to the atmosphere, which also acts as a drag.

The stronger curvature of the inner boundary helps to organize the turbulent convection of these winds but it is noted that they tends to slow down with height as become in contact with the electrically conductive gas region (the planets' atmosphere mainly consists of hydrogen and helium and at some point, the hydrogen molecules are pressed so close together that they form a metallic, electrically conductive state Also, they have a strong magnetic field which prevents wind movement by working as an eddy current brake. This limits the fast jet flows to the outer 10 percent of the planet’s radius). Refer to paper 4 for more details.

You can refer to below links for more indepth discussion.

1. Paula N Wulff et. al., Zonal winds in the gas planets driven by convection above a stably stratified layer, R. Ast. Soc., Volume 517, Issue 4, 2022, DOI: 10.1093/mnras/stac3045
2. Organised Wind Chaos on Jupiter by Johannes Wicht (link)