Hemispheric Darkening: Is the Earth trying to freeze us?

Scientists have been observing a historical phenomenon that they say may cause widespread cooling. Cornell professor, Dr. Crowell N., has coined the term hemispherical darkening. Sound ominous right? This phenomenon is an annual reduction in insolation, or the incoming light from the sun, and is reported to affect large areas throughout one half of the globe.


Data from Carraway et al. (2009) shows that decreased insolation causes unwanted drops in temperature and, in some cases, the onset of winter-like storms.I don’t know about you guys but I am not a cold-weather person so I’m not liking the sound of this thing. For those of you that love skiing, snowboarding, and those other sports I freeze doing hemispherical darkening might be right up your alley!

Hemispherical darkening is in full swing in the left and bottom globes. The white dot represents North Carolina.

Hemispherical darkening is in full swing in the left and bottom globes. The white dot represents North Carolina.

So what causes this darkening? The main cause seems to be the Earth itself. Wait, so it’s trying to get darker so it can freeze us? Well Earth doesn’t really have a say in the matter. The phenomenon is a result of the Earth’s position in space (insert Star Trek theme song), specifically the tilt and our orbit around the sun. Earth doesn’t have very good posture, instead we are tilted at about a 23o angle.

Our tilt doesn’t change much, which means that as Earth circles the sun (that takes a year) part of the Earth is tilted towards the sun on one side of the circle and that same part is tilted away from the sun on the opposite side of the circle. Being tilted away from the sun means less light gets to you, hence less insolation which leads to hemispherical darkening and cooling. (Follow the dot on the globe)

Some of you have probably heard this phenomenon called by another name… winter! Yup, hemispherical darkening is a fancy name that I made up for winter. My venture into nomenclature started with me complaining to my Dad about it getting so dark so early in the winter, ugh hemispherical darkening. He laughed and challenged me to make it a believable scientific term. Challenge accepted. I also thought that it could be a lesson on reliable sources. Dr. Crowell N, the Cornell professor, sounds fancy but in reality is my Dad. Same goes for the “data” from Carraway et al. (2009)… that’s me. The science about the Earth’s tilt is correct; it’s what causes our seasons. If we didn’t have a tilt, we wouldn’t have four seasons. Anyways, I hope you found this little joke enjoyable. Sometimes scientific nomenclature can sound like people just picked random letters.

Do you have any favorite weird science names?


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