We made it. From today on, the days will slowly get longer again. For me, the Winter Solstice is a special day because I seem to belong to the group of people who suffer from SAD—Seasonal Affective Disorder, or winter depression. The short days and the resulting lack of light cause the body to reduce the production of serotonin, the “happiness hormone.” In its place, melatonin levels rise in the darkness, signaling that it’s time to sleep, making us feel tired and sluggish. And that’s exactly how I often feel in winter: it’s hard to enjoy the little things, I’m fatigued, overly emotional, and easily annoyed.
Exercise and yoga help. As soon as the sun dares to peek through the clouds, I try to go outside and catch a few rays of sunlight (so don’t be surprised if you see me standing in the snow with my arms wide open and my eyes closed). And because I know this feeling won’t last forever, I try to steer my thoughts in the right direction when they convince me to just stay in bed. But today, I’m grateful that the shortest day of the year is behind us, and I’m looking forward to the sun rising on the horizon (the “real” sunrise here happens around 11 a.m. because that’s when the sun finally manages to rise above the mountain behind our house).
So I decided to look up the things I should remember about the sun (because I learned them in school at some point in the distant past): From the perspective of Earth, the sun seems large and bright because it’s relatively close to us—only about 91 million miles away. Like other stars, the sun radiates energy by converting hydrogen into helium in its core. The temperature at the center of the sun is around 27 million degrees Fahrenheit. As you move away from the core, the sun cools down and on its surface, the temperature is “only” about 15,000 degrees.
Every second, about 600 million tons of hydrogen are converted; in that second, 300,000 tons of the sun’s mass is burned. That sounds like an enormous amount, but the sun is apparently capable of continuing this process for billions of years before it fades. The energy the sun releases is emitted as electromagnetic waves—these include heat rays and light. Only a tiny fraction of them reaches Earth, but that small amount is enough to provide us with warmth and light—and today, it’s enough to make me feel happy and grateful (despite not completely understanding the chemical processes or grasp those numbers)