What percentage of the Sun’s energy hits the Earth?

This is a purely geometric-based solution of light emitting from a source and spreading out in all directions and contacting another sphere some distance away. This does not account for any fancy "scientific" stuff that I am no expert at, such as the energy getting absorbed by the Earth’s atmosphere, or other factors that may be at work in this matter.

Here are some other sources I found that address some of the scientific issues of this matter, as well as other mathematical approaches to estimating this value:



  • Step 1

    Surface area of a sphere: A = 4πr^2

    r is the distance of the Earth from the Sun = 92,960,000 miles (92.96 million miles)

    Surface area of the "sphere" formed by this distance:

    Area = 1.09×10 ^ 17 square miles
  • Step 2:

    Cross-sectional area of a sphere: A = πr^2

    r = radius of earth
    r = 3,958.8 miles
    A = 4.92×10 ^ 7 square miles
  • Step 3:

    Divide Area of Earth by Area of Sphere:

    (4.92×10 ^ 7) / ( 1.09×10 ^ 17 )
    = 4.5137615e-10   =  4.5292×10^-10

    For reference, "1 Billionth" is 1e-9, so 4.51e-10 is even less than this…

    Basically, it’s "Less than 1 billionth"

    It could also be stated as 4.5 "10 billionths"

    = 0.00000000045137615  =   0.000000045137615 %

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