how much of the sun's energy actually reaches the Earth?
To determine how much of the Sun's energy reaches the Earth, we need to consider a few factors.
First, we need to understand that the Sun emits energy in all directions, not just towards the Earth. This means that the total energy emitted by the Sun is spread out over a large volume.
The energy emitted by the Sun is in the form of electromagnetic radiation, with the majority being in the form of visible light. However, the Earth receives energy not only from the visible spectrum but also from other forms of radiation like ultraviolet (UV) and infrared (IR).
Second, we need to consider the distance between the Sun and the Earth. The Sun is about 93 million miles (150 million kilometers) away from us. Since energy spreads out over an increasing sphere as it travels away from its source, the further we are from the Sun, the more spread out the energy becomes.
Lastly, we need to account for the Earth's atmosphere. When sunlight passes through the Earth's atmosphere, it is scattered, reflected, and absorbed by molecules and particles in the air. This interaction with the atmosphere affects how much of the Sun's energy reaches the Earth's surface.
Taking all these factors into account, roughly 1,368 Watts per square meter is the amount of solar energy that reaches the outer atmosphere of the Earth. However, once it passes through the atmosphere, approximately 1,000 Watts per square meter of solar energy actually reaches the Earth's surface on average.
It's important to note that these figures can vary due to factors like the Earth's tilt, cloud cover, and atmospheric conditions. Measurements are typically taken over an extended period of time and averaged to estimate the amount of solar energy reaching Earth's surface.