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evan9162 said:
Easy
Once we know how bright the sun is in lux directly overhead, we can use that number to figure the lumens (since the sun radiates more or less equally in all directions.
Digging around, I found that bright sunlight is 50K-100K lux. Let's go halvies on that, and say 75K lux.
That answers one of your questions.
Now, lux is defined as lumens per square meter. So, we are measuring 75,000 lumens per square meter at the Earth's surface. All we have to do is find the number of square meters on the surface of a sphere with a radius equal to the Earth's distance from the sun.
The Earth is about 150 million km from the sun (150 billion meters). The formula for the area of a sphere of radius r is 4(pi)r^2.
Thus, the sphere has a surface area of 4(pi)(150x10^9)^2 = 2.83*10^23 square meters.
Multiply that by the lux value from before (75,000 lux = 75,000 lumens/m^2) and we get 2.12x10^28 lumens.
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Yes....but,
Digging around some more, for what is more applicable to us down on earth, and more specifically how we rate incident light from the flashlights we use, for comparison; noon daylight reaching the surface of the earth at the equator(relatively constant throughout the year), after being filtered by the atmosphere we get around only 10,000-12,000 fc(lumens/f-sq'd) and full moon only about 0.02 fc. So turning your Aurora or simliar very high output lights, and shining directly into your eye's is like looking at the sun, you'll go blind!
Keep these 'toys', like a loaded gun, away from children.
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