# How many joules of sunlight hit Earth per day? I have looked everywhere and can't find an answer!!

The sun emits about 4*10^26 Watt. The flux of solar energy at the Earth is thus about:

F = 4*10^26 Watt/(4 pi R^2)

where R = 149.6*10^9 meters is the Sun-Earth distance:

F = 1422 Watt/m^2

Multiply this by the intercepting cross section of the Earth, which is pi times the square of the radius of the Earth (and *not* 4 pi times radius squared) to obtain the amount of sunlight in joules that hits the Earth per second.

1422 Watt/m^2 * pi (6378*10^3 m)^2 =

1.82*10^17 Joules/second

There are 24*3600 seconds in a day, so about 1.6*10^22 Joules of sunlight hit the Earth per day.

## To calculate the amount of joules of sunlight hitting the Earth per day, you need to take into account the flux of solar energy at the Earth and the intercepting cross section of the Earth.

1. First, find the flux of solar energy at the Earth by dividing the sun's emitted power (4*10^26 Watt) by 4π times the square of the Sun-Earth distance (149.6*10^9 meters). This gives a value of 1422 Watt/m^2.

2. Next, multiply this flux by the intercepting cross section of the Earth, which is π times the square of the radius of the Earth (6378*10^3 meters). This will give you the amount of sunlight hitting the Earth per second. The calculation is as follows:

1422 Watt/m^2 * π * (6378*10^3 m)^2 = 1.82*10^17 Joules/second.

3. Finally, to find the amount of sunlight hitting the Earth per day, multiply the value obtained in the previous step by the number of seconds in a day (24*3600 seconds). This calculation yields:

1.82*10^17 Joules/second * 24*3600 seconds = 1.6*10^22 Joules/day.

Therefore, approximately 1.6*10^22 joules of sunlight hit the Earth per day.