Weather in Space

The Sun

Why is the Sun essential for weather?

Our Sun is the source of almost all of the energy that creates weather on the planet; plate tectonics, the heat within the Earth, tidal effects, radioactive elements, and the effects of gravity from Jupiter and Saturn provides the rest. The majority of the energy—99.98 percent—is from the Sun, however. Although the amount of light, heat, and other energy from the Sun that hits the Earth is equal to only 5 × 10-10 of its total output, this is still the equivalent of burning 700 billion tons of coal every day! It has also been calculated that the energy reaching Earth’s upper atmosphere is equal to 5 million horsepower per square mile. That’s enough to rev up the engines of 7,400 Indianapolis 500 race cars. Planet-wide, that would be about 14.5 billion race cars being powered up daily by the Sun.

If the Sun’s energy on the planet’s surface was constant, it would not affect weather. This is not the case. Because our planet spins, giving us day and night, and tilts, giving us the seasons, the energy is not distributed evenly. Also, clouds and variations in the upper atmosphere affect solar energy levels. The result is that Earth is covered with areas of colder and warmer air, causing air masses to move, which are, in turn, diverted this way and that by variations in geography and the Coriolis effect. This is what gives us the weather.


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