How many of the suns photons are absorbed by earth?

Answer 1

The sum of these little guys, photons covering all frequencies and covering all the earth (without being reflected or scattered off) is a really, really, really big number. Even over a short period of time. (And the answer would have to be averaged for a number of reasons.) Something like 2 x 10really big number per day would be close.

Answer 2

If you mean as a fraction of the Sun's total power output, here is the relevant calculation from Wikipedia: The angular diameter of the Earth as seen from the Sun is approximately 1/11,700 radians (about 18 arc-seconds), meaning the solid angle of the Earth as seen from the Sun is approximately 1/175,000,000 of a steradian. Thus the Sun emits about 2.2 billion times the amount of radiation that is caught by Earth, in other words about 3.86×1026 watts. If you mean how much actually reaches the ground, here are some numbers I found: Outside of Earth's atmosphere, the intensity of the radiation received by Earth is approximately 1367 watts per square metre; the intensity that reaches the Earth's surface when the Sun is at the zenith is around 1120 watts per square metre. That includes visible light, infrared, etc. Please note that when the Sun is lower, less sunlight (and other radiation) reaches the ground. Also, the intensity received will depend on the altitude.

Answer 3

Very interesting. You can probably look it up somewhere, but let's work it out. The fraction you're looking for would be (the solid angle subtended by the earth as seen from the sun) divided by (4 pi solid radians). The apparent angular size of the earth as seen from the sun, in radians, is tan-1 of (diameter/distance) = tan-1(7,900 / 93,000,000) = tan-1(2.314 x 10-11). (Since it's such a tiny number, we can use the angle itself in place of the (tan-1).) To get the solid angle subtended by the earth's apparent circular face, just use that number for the apparent diameter of the earth. Its area, in square radians, is the 'diameter' angle times (pi). So the fraction we want is (2.314 x pi x 10-11) / (4 pi) = 1.817 x 10-11. As an engineer, I'm required to go one step further and point out that this is 107.4 dB below the sun's total output.

Answer 4

We can calculate this. Earth's radius is about 4 thousand miles, so the surface area presented to the sun is πr2 or about 50 million square miles. Earth orbits at 93 million miles, and the surface of a sphere of that radius is 4πr2 or 108 quadrillion miles (108,000,000,000,000,000). The ratio is about 1/2,000,000,000 or one out of every two billion rays of light. In other words, for every ray of light intercepted by the earth, two billion go streaming off into interstellar space.

Answer 5

only 51 units are obsorbed by the earths surface. 19 units are absorbed by water vapor and clouds, ozone, and dust.

Answer 6

From Wikipedia, article on solar energy: "The Earth receives 174 petawatts (PW) of incoming solar radiation (insolation) at the upper atmosphere." That is 174 x 1015 watts (or joules/second).

Answer 7

It is said that approximately half a billionth of the sun's total energy output reaches the earth. That is exactly sufficient to sustain all life on the planet.

Answer 8

The Sun's total output is about 386 yottawatts

The solar radiation impinging on the Earth delivers about 173 petawatts

yottawatt = (1026 watts)

petawatt = (1015 watts)

Answer 9

50% !