Astronomy - rotation period of planet and wind speeds

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Discussion Overview

The discussion revolves around the relationship between the rotation period of Saturn and the wind speeds at different atmospheric levels. Participants explore how to calculate the rotation period at a higher altitude based on known wind speeds and the rotation period at the equator, focusing on theoretical and mathematical reasoning.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Exploratory

Main Points Raised

  • One participant states that the rotation period of Saturn at the equator is 10 hours and that the equatorial winds blow west to east at 250 m/s, questioning how to relate these to find the rotation period at a higher level in the atmosphere.
  • Another participant suggests considering a balloon in Saturn's atmosphere, indicating that its speed depends on both the planet's rotation and the wind, implying that knowing the speed and circumference would help calculate the time.
  • A further participant expresses confusion about how to determine the balloon's speed, questioning whether it would be the sum of the rotation speed and wind speed at the equator and how this changes with altitude.
  • Another reply clarifies that the balloon's speed is influenced by the surrounding gas, which combines the wind speed and the linear speed of the surface, suggesting that the rotation speed at the surface can be treated as a rigid body motion.

Areas of Agreement / Disagreement

Participants do not reach a consensus on how to calculate the rotation period at higher altitudes, with multiple viewpoints on the relationship between wind speed and rotation speed. The discussion remains unresolved regarding the specific calculations needed.

Contextual Notes

Participants express uncertainty about the assumptions regarding wind speed and its relationship to rotation speed at different atmospheric levels, as well as the dependence on definitions of speed and motion in a gaseous environment.

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Homework Statement



assume that the rotation period of saturn at the equator, very deep in the atmosphere is 10 hrs. higher in the atmosphere, the equatorial winds blow west to east at 250 m/s. What would be the rotation period of this higher level in the atmosphere?
also know - maximum wind speed at equator = 450 m/s (from another source)


Homework Equations





The Attempt at a Solution



I converted the rotation period of 10 hrs into rotation rate using 2pi(saturn's radius)/rotation period to get a value of 10 km/s. Now I am stuck - how do I find the relationship between rotation period/rate and wind speed? And does this relationship stay constant as you go up in the atmosphere? I guess ultimately I want to know is - how do I find the rotation rate/period for the upper level in the atmosphere? Thanks!
 
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Imagine a balloon in the Saturn atmosphere. Its speed depends both on the rotation and wind. What is its speed? Once you know the speed and circumference, calculating the time is a breeze.
 
But how on Earth can I start to go figuring the circumference and speed of the balloon? Would it's speed at the equator deep in the atmosphere be the rotation speed and the wind speed? But as I go up in the atmosphere - since it's speed varies with the rotation and wind, how can I figure out it's speed if I don't know the rotation speed? I am very confused. Any help would be really appreciated. Thanks!
 
Circumference of the planet - you have already used it, so you know how to calculate.

Balloon speed is that of surrounding gas - that is in turn sum of wind and linear speed at the 'surface' (I suppose 10 km/s that you calculated is just this value).

If there will be no wind, you will just calculate speed of the surface treating the planet as a rigid body, so period and radius are enough. Now there is completely independent move of the outermost surface - that either adds or subtracts (depending on the direction) to the speed of the rigid body.
 

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