Energy from the sun that reaches the earth

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Homework Help Overview

The discussion revolves around calculating the energy from the sun that reaches the Earth, specifically focusing on the energy output of the sun and how it diminishes over distance. The subject area includes concepts from astrophysics and energy transfer.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • The original poster attempts to calculate the energy output of the sun and how much of that energy reaches the Earth's surface. Participants raise questions about necessary values, such as distance and radius, and discuss the concept of energy dispersion over distance.

Discussion Status

The discussion is active, with participants exploring different aspects of the problem. Some guidance has been provided regarding the inverse square law, which describes how energy decreases with distance. There is an ongoing inquiry into the fraction of the solid angle subtended by the Earth relative to the sun.

Contextual Notes

Participants note the importance of specific values, such as the distance from the sun to the Earth and the Earth's radius, which are crucial for the calculations being discussed.

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The sun consumes about 600 million tons of matter per second, How much energy is that? Of this energy how much reaches the surface of the earth


E=mc^2



I solved the first part, but how do I start the second?
 
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Have you been given a value of the distance from the Sun to the Earth, and the diameter of the Earth? They are useful things to know in this context.
 
Yeah I have the distance of and the radius. I know the speed of light. Problem I have is how does energy decrease over a distance with a speed
 
Backup said:
Problem I have is how does energy decrease over a distance with a speed

It's an inverse square law because, assuming the sun radiates equally in all directions, then the same amount of power is being spread out over a sphere of successively larger and larger surface area as the distance from the sun increases. This means that the power received (per unit area) at any location decreases with distance in inverse proportion to the area of that sphere.

http://en.wikipedia.org/wiki/Inverse-square_law
 
What fraction of the solid angle surrounding the sun is subtended by the earth?
 

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