The Science Behind Stunning Sunsets: Why Aren't They Blue?
Written on
Chapter 1: The Beauty of Sunrises and Sunsets
Recently, I woke up early, as I often do, with coffee in hand and a determination to write. As my favorite playlist played softly in the background, a sense of tranquility enveloped me, amplified by the aroma of freshly brewed coffee. Through my office window, I admired a breathtaking sunrise, where clouds were illuminated in vibrant shades of violet, fuchsia, and coral. It felt as if an extraordinary artist had crafted the morning sky, filling me with gratitude for such beauty.
Often, it's the ordinary phenomena, like sunlight interacting with our atmosphere, that spark profound inspiration. The stunning colors we witness during sunrises and sunsets have a straightforward explanation, which makes them even more enchanting. To comprehend these spectacular displays, we must delve into the concept of 'Rayleigh scattering'—the reason the sky predominantly appears blue.
Chapter 2: Understanding Rayleigh Scattering
As sunlight enters our atmosphere, shorter wavelengths of light are scattered by tiny molecules of nitrogen and oxygen. These shorter wavelengths correspond to the blue and violet spectrum, which are scattered most effectively. However, since humans are less sensitive to violet light, the sky predominantly appears blue.
At sunrise and sunset, the sun's position causes its rays to traverse more of Earth's atmosphere. This increased distance results in greater scattering of blue light, allowing only the longer wavelengths—reds, oranges, and yellows—to reach our eyes. Consequently, we are treated to vivid displays of red, pink, and orange hues.
The first video, Why aren't sunsets blue?, explores the science behind these vibrant colors, providing insight into the atmospheric phenomena that create such beauty.
To illustrate this effect, consider a piece of blue glass. Only the longer wavelengths—orange, red, and yellow—can pass through, while the shorter wavelengths are scattered away.
The atmospheric filtering we experience is responsible for the stunning colors we see. From above, such as from the International Space Station, sunrises would appear bright white instead of the vibrant colors we enjoy on Earth. Moreover, environmental conditions play a significant role: colder, cleaner air leads to sharper, more vibrant colors.
During my time in coastal Scotland, I experienced some of the most intense sunrises imaginable, often attributed to the cold temperatures that limited humidity and pollution levels. Urban settings, while hazy, possess their own charm, as evidenced by the soft, rosy tones found in cityscapes like Paris.
Warm urban sunsets can significantly differ from those in colder, rural areas. Photos by Luca Micheli and Anders Jildén showcase these contrasting scenes.
It's fascinating how such breathtaking moments can be attributed to simple scientific principles. Just another reason to appreciate the beauty of our planet.
For more about my writing and interests, feel free to check out my profile!
The second video, Why is the Sky Blue? Why are Sunsets Red?, further elaborates on the science of atmospheric color phenomena and their impact on our perception of the sky.