Just saw a post talking about how Europe gets a decent amount of sunlight less than the Americas. Why would this be? I understand the how latitude changes the time of sunrise/sundown but wouldn’t it average out in the end? For example Alaska vs. Hawaii. Hawaii gets close to 12 hrs of sunlight every single day all year. Alaska might get 22 some days in the summer but 2 in the winter? Wouldn’t both places receive the same annual hours of sunlight or am I missing something?
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The Earth isn’t straight, it’s tilted
Depending on the time of the year the Earth is either tilted towards the Sun, or away from the Sun depending on where it is in its orbit.
This changes the amount of surface area of the Earth’s Northern and Southern hemispheres that are exposed to the sun, which translates to longer and shorter days.
If you’re just talking about hours the sun is above the horizon then the high latitudes actually get (very slightly) more sunlight than the tropics. But you really need to consider the angle of the sun for heating, solar power, growing crops, etc.
In the tropics the midday sun can shine vertically down, so a square metre of sunlight heats up a square metre of the earth’s surface. Once you get up to 60° latitude, the same square metre of midday sun is now angled and spreads over 2 square metres of the surface, halving its heating effect. It’s even worse when you consider the even shallower sunlight angles at other times of the day.
You are correct: on an annual basis, anyplace on the should receive exactly the same hours of light as any other. ( This is only true if the globe is a perfect sphere, not being ovoid, nor having mountains and valleys. In practice, the earth is close enough. )
However, the total amount of energy is quite a bit less. Europe is further north, and the angle of the light decreases the energy received in two ways: the sunlight has to go through more atmosphere to get to the surface, and the area that the sunlight hits is larger. ( FWIW, the energy received is proportional to the cosine of the angle between the sunlight and vertical )
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