Escape Speed and Atmospheric Temperatures of Planets: Calculations and Analysis

AI Thread Summary
The discussion focuses on calculating escape speed and atmospheric temperatures for Jupiter and Earth, emphasizing the formula for escape speed as (2GM/R)^(1/2). Participants calculate the root mean square (rms) speed of hydrogen molecules in both atmospheres, finding values of approximately 1,321 m/s for Jupiter and 1,656 m/s for Earth. The conversation highlights that Jupiter retains a high percentage of hydrogen due to its strong gravitational pull, while Earth loses it due to lower escape velocity. Additionally, there is confusion regarding the implications of these calculations for the existence of an oxygen atmosphere on Ceres, with participants seeking clarification on how to approach the problem. Overall, the thread illustrates the complexities of atmospheric science and gravitational effects on different celestial bodies.
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a) Show that the escape speed for a particle to leave the gravitational infuence of a planet is given by (2GM/R)^1/2, where M is the mass of the planet, R is its radius, and G is the gravitational constant.
b) The temperature near the top of Jupiter's multicolored cloud layer is about 140K. The temperature at the top of the Earth's troposphere, at an altitude of about 20km, is about 220k. Calculate the rms speed of huydrogen molecules (h2) in each of these environments. Give your answers in the m/s and as a fraction of the escape speed from the
respective planet.
c) Hydrogen gas is a rare element in the Earth's atm. In the atmosphere of Jupiter, by contrast, 89% of all molecules are H2. Explain why, using your results from the previous part.
d) Ceres is an asteroid with mass equal to .014 times the mass of the moon, a density of 2400kg/m^3 and a surface temp of about 200K. Suppose an astronomer claims to have iscovered an oxygen (O2) atmosphere on the asteroid Ceres. You are asked by a TV news reporter to comment on this claim. What would you say, and how would you support that?

a) I don't fully understand what I have to calculate or demonstrate in this, can someone please break this down for me? Thanks!




b) I need the formula Vrms = sqrt(3RT/M)

M of H2 = 2g/mol = .002kg/mol

Vrms Jupiter = sqrt(3x8.314x140k/.002kg) = 1.321x10^3 m/s
Vrms Earth = sqrt(3x8.314x220k/.002kg)= 1.656x10^3 m/s

I don't quite understand what I have to do to get the fraction of the escape speed relative to the planet.

I suppose use the given formula (2GM/R)^1/2 to calculate each plantes escape and then divide that number by the Vrms of Jupiter and Earth?? What is g, M, and R of jupiter?? Is 9.8m/s the gravitational force at 20km high in the Earth's atmosphere?? Please help!

c) I am guessing this will have to do with the escape velocity of each planet? Maybe Jupiter likes to hang on to it's H2 and Earth let's them go?

d) Lost me again on this one? Thanks for all the help..:confused: :confused: :confused:
 
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Once you've got the rest d) is dead easy zferic. You just plug a) and b) back in.
 
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