The Sun is at its farthest from Earth every year, around two weeks after the Summer Solstice. At 6:27 p.m. EDT tonight, the Earth will be over 94.5 million miles (152,098,463 km or 94,510,888 miles) from the Sun, a point known as aphelion. On January 2, the will approach the perihelion, when the Sun is 3.1 million miles closer. Because the orbit is stretched into a slightly extended elliptical, this occurs.
The fact that Earth is closest in the winter and farthest in the summer appears to be backward. However, the distance between the Sun and the Earth has little effect on how much of the Sun’s energy reaches us, which is roughly 1.361 kilowatts per square meter (kW/m2). Because this value fluctuates so little (approximately 3.5 percent every year), scientists refer to it as the solar constant.
The flashlight’s brightness hasn’t changed, but changing the angle at which you shine, changes how concentrated the energy is. During the summer, the Sun spends more time above the horizon, so we are exposed to more direct rays for more extended periods, accumulating more heat. Conversely, less heat is reflected from the surface during those shorter nights, keeping summer months warmer.
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