Whoops, I forgot to mention a recent solar system milestone. Two days ago, the Earth (that’s you and that’s me!) reached aphelion, or the point in our orbit at which we’re the farthest distance away from the Sun. That puts us at approximately (give or take the distance we’ve traveled in the past two days) about 3 million miles farther away from the sun than we are at perihelion.
It also raises a funny question:
Aphelion: Earth is as far away from the sun as it ever gets. So why is it so hot?
This happens every year in early July, which might sound backward. If we’re farthest from the sun, shouldn’t it be cooler?
The answer lies in the fact that the Earth gets closer to and farther away from the Sun, but it’s also tilted.
Our planet spins at an angle — about 23.5 degrees — which means different parts of the globe receive more (or less) sunlight depending on the time of year. In July, the Northern Hemisphere is tilted toward the sun, bringing longer days and higher sun angles that lead to more direct sunlight — all of which produce summer-like heat.
And as this Space.com article details, we’re also moving at our slowest:
Since Kepler’s laws of motion dictate that celestial bodies orbit more slowly when farther from the sun, we are now moving at our slowest pace in orbit, slightly less than 18 miles per second (29 kilometers per second) compared to just over 19 at perihelion.
Given that, today might be a good time to relax, and enjoy the ride.
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