Earth's Energy Output Compared to the Sun | Ast HW Help

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Discussion Overview

The discussion revolves around a homework problem comparing the energy output of Earth to that of the Sun. Participants explore concepts related to luminosity, absolute magnitude, and the implications of energy output on these measures.

Discussion Character

  • Homework-related
  • Mathematical reasoning
  • Technical explanation

Main Points Raised

  • One participant poses a question about calculating Earth's total energy output if it produced energy at the same rate as the Sun.
  • Another participant asks for clarification on how absolute magnitude relates to total energy output.
  • A participant explains that absolute magnitude is a measure of luminosity at a distance of 10 parsecs.
  • Further discussion includes the logarithmic nature of absolute magnitude and its relationship to energy output.
  • One participant attempts a calculation involving the mass and luminosity of the Sun and Earth, suggesting a specific energy output value.
  • Another participant corrects the understanding of how absolute magnitude changes with energy output, emphasizing its logarithmic scale.
  • A participant shares their final calculation for absolute magnitude, expressing gratitude for the assistance received.

Areas of Agreement / Disagreement

The discussion includes multiple viewpoints on the relationship between energy output and absolute magnitude, with some participants clarifying concepts while others propose calculations. No consensus is reached on the final values or interpretations.

Contextual Notes

Participants reference specific values for mass and luminosity but do not resolve the implications of these calculations or assumptions made in their reasoning.

Who May Find This Useful

Students or individuals interested in astrophysics, particularly those studying luminosity and energy output comparisons in celestial bodies.

Kiwithepike
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Hey guys, I am new here so i hope this is in the right place. I just need help with a problem.

Suppose the Earth produced as much energy per kilogram each second as the sun does. what would be the total energy output of Earth be? how would the absolute magnitudes compare between the sun and earth
 
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Welcome to PF!

Hi Kiwithepike ! Welcome to PF! :wink:

Tell us what you think, and we'll comment.

How does absolute magnitude depend on total energy? :smile:
 
Its the measure of the absolute magnitude of luminosity at 10pc.
 
ok, and how does that depend on total energy?

eg, if you double the energy, what does that do to the absolute magnitude? :smile:
 
ok think I got it, so if mass(s)= 2.0E30kg L(s)= 3.8E26W, and Mass(E)= 6.0E24kg
then, L(s)/(s)= x/m(e) yields
1.42E21 W?
 
it doubles as well
 
Kiwithepike said:
it doubles as well

No, absolute magnitude is logarithmic … see http://en.wikipedia.org/wiki/Luminosity" for details. :wink:
 
Last edited by a moderator:
so i think i finally got it after some much needed rest,
is this correct. M1-M2=2.5log(L1/L2) =>
4.8-M1=2.5log(3E-6) =>
4.8-M1=-13.8 =>
M1=18.6?

And thank you so much for the help and patience with me!
 

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