What are the three things controlling the amount of solar energy reaching Earth?

The amount of solar energy reaching Earth is primarily controlled by three factors: the Earth's distance from the Sun, which varies due to its elliptical orbit; the Sun's output, which can fluctuate due to solar cycles; and the Earth's atmosphere, which can absorb or reflect solar radiation. Additionally, clouds and aerosols can influence how much solar energy reaches the surface. Together, these factors determine the overall solar radiation received by the planet.