Are there any types of wind or waves caused and produced only and exclusively by a planet's rotation? Not influenced by the planet's rotation, but produced solely by it?

In the case of waves, are Rossby waves 1 and Kelvin waves 2 examples of this? Like, imagine the Earth as a single planet with no Sun (so no influence by the Sun's heat), no moon (so no tides) and no planetary internal hot core (so no influence by the heat from Earth's internal core). Then assume that somehow water is still liquid and air in its gas form, then, just by Earth's rotation, would there be any waves or wind (even if they would be very subtle)? Would there still be Rossby waves or Kelvin waves for instance? (I found a comment to a question in Quora that indicates that the answer is basically "yes" 3, but no sources are given, so I would like to see if someone could verify that).

Also, I've read that inertial oscillations 4 and low level jets 5 could be examples of this. Any suggestions...?

Finally, if the rogue planet was travelling through a zone with a high amount of dust or gas (e.g. a nebula), could this affect the atmosphere creating some type of winds?

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    $\begingroup$ Would these waves dissipate energy, e.g. by making sploshing noises? Are you constructing the question so that solar, tidal, and geothermal energy sources are unavailable? Are you assuming that such a cold planet has a liquid ocean and/or a fluid atmosphere? I'm not sure these assumptions are consistent with each other, which makes your question hard to answer. $\endgroup$
    – rob
    Jul 4 at 15:26

1 Answer 1


Rotation alone is not sufficient.

A good way to illustrate that, I think, is a type of telescope mirror that is referred to as 'liquid mirror'.

The simplest implementation is a dish filled with mercury, with the dish spinning at a constant angular velocity. When the Mercury is co-rotating with the dish the Mercury comes to rest completely. The shape is very steady, steady enough for the surface of the Mercury to serve as a mirror that is good enough for astronomical observations.

The state of a fluid in uniform rotating motion is called 'solid body rotation'. The fluid is not actually solid, of course, the 'solid' in that expression refers to the property of all the parts of the fluid being motionless with respect to each other.

As the assembly is rotating: the dish doesn't need to have a profile that matches the surface profile of the fluid. Also: it isn't necessary for the dish to have itself a smooth surface; bumps in the surface make no difference; any bumps of the surface of the dish do not transfer to the surface profile of the rotating liquid. The liquid, being a liquid, accomodates any lump and/or depresssion of the surface of the dish.

In the case of a planet: over geologic time scale the body of the Earth's is deformable; the stone is in effect a highly viscous fluid. Over geologic time scale the solid body of a planet will deform, the final shape is the same shape that it would have if the celestial body would consist of a low viscocity fluid.

For instance, there are reconstructions that indicate that when the Earth first formed out of a proto-planetary disk it had a rotation period of about 6 hours. (And the event that formed the Moon happened early.) Ever since interaction with the Moon has been slowing down the Earth's rotation.

We have that the Earth's solid mass is in hydrostatic equilibrium. But even if the solid Earth would not be in hydrostatic equilibrium: the distribution of fluid over the Earth would not be affected by that. The surface of the fluid will still be the equilibrium shape, independent of the shape of the solid Earth

Going back to the example of the Mercury mirror. When the dish is rotating with a uniform velocity: then all of the fluid has the same angular velocity. The fluid at the outer rim has a larger speed, but it is in precise proportion, such that all of the fluid has the same angular velocity.

So: in and of itself shape of a rotating celestial body cannot produce any form of wave pattern, or more generally: in and of itself shape of a rotating celestial body cannot induce any form of motion.

In order for any form of churning to arise some form of energy gradient must be present. In the case of a planet orbiting a Sun there is a larger influx of heat at the equator than at the poles, and that energy gradient leads to convective flows.

  • $\begingroup$ not even if the planet has a particular shape where the fluids would e.g. rotate slower at the equator than near the poles? Wouldn't that create a difference in the rotation velocities throughout the planet, provoking in turn some kinds of wind or liquid currents? @Cleonis $\endgroup$
    – vengaq
    Jul 4 at 19:57
  • $\begingroup$ @vengaq I have expanded my answer $\endgroup$
    – Cleonis
    Jul 5 at 17:16
  • $\begingroup$ I understand. However, here (oceanservice.noaa.gov/facts/rossby-wave.html) it says that Rossby waves are a type of wave produced by rotating liquids in rotating planets. So, how could a wave form only due to the rotation of the planet in this case? @Cleonis $\endgroup$
    – vengaq
    Jul 6 at 12:04
  • $\begingroup$ @vengaq The description on that oceanservice page is so incomplete that in effect it is wrong. (I tried to find accessible intormation about Rossby waves. Stunningly, most instructors do not attempt to explain Rossby waves. Most instructors discuss the equation(s), but not the physics, which I think is poor education practice.) Overall: Rossby wave is about an already formed vorticity, and then that small scale vorticity interacts with the planet's rotation. That is, Rossby waves arise in a process of the planet's rotation affecting an independently formed local vorticity. $\endgroup$
    – Cleonis
    Jul 6 at 19:35
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    $\begingroup$ @vengaq There is an ambiguity in how the verb 'causing' is used. Example: take a bowl. and throw a marble into the bowl, aiming in such a way that the marble is subsequently rolling around, in roughly circular motion. The circular motion is sustained by a combination of two factors: presence of gravity, and the slope of the bowl; the slope of the bowl is redirecting the force of gravity. An author may describe that as: 'the shape of the bowl causes the circular motion'. That is sloppy language; the shape of the bowl sustains the circular motion; the cause was you throwing the marble. $\endgroup$
    – Cleonis
    Jul 7 at 12:55

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