From Blue Skies to Red Sunsets: The Science Happening Above Us
🔥 LOOK UP- THERE IS MORE HAPPENING THAN YOU THINK
A bright summer afternoon sky may appear a pleasant shade of blue
but several hours later, the same sky may appear to be tinged with orange, pink or red hues. As night falls, the sky darkens and stars may appear. But is the sky really changing colors? Let's investigate! The story actually begins with something you are very familiar with:
☀️ SUNLIGHT
🌈 SUNLIGHT IS ACTUALLY MORE THAN WHAT MEETS THE EYE
Sunlight, while appearing white to our eyes, actually consists of many different colors. When light is passed through certain materials, different colors may be produced and separated, like in a rainbow. The atmosphere also has an effect on sunlight. When sunlight passes through the atmosphere, it encounters molecules and particles in the air, causing it to scatter.
🔵 SO WHY IS THE SKY BLUE?
The atmosphere contains nitrogen, oxygen and other microscopic molecules which cause sunlight to scatter. The scattering of the light is dependent upon the wavelength of the color. Blue and violet wavelengths of visible light scatter more readily than red ones do. Another factor is the sensitivity of the human eye. Our eyes are more sensitive to blue light than they are to violet light and there is also more blue light than violet light in the visible spectrum of sunlight. Thus, when you look at a blue sky, you are actually seeing the effects of scattered sunlight.
🌅 THEN WHY DOES THE SUNSET TURN RED?
Here's where the story gets particularly interesting. When the sun is high in the sky, the light from the sun has a relatively short distance to travel to reach your eyes. Near sunrise or sunset, the sun is low on the horizon, meaning that the sunlight has a much longer distance to travel through the atmosphere to reach your eyes. As a result of this scattering process, the amount of blue light reaching you may be greatly reduced, allowing the remaining, unscattered light to appear more yellow, orange or red.
☁️ CLOUDS CAN MAKE THE SHOW EVEN MORE SPECIAL
Clouds are also capable of making their own unique contributions to the show. When the sun's rays pass through clouds, water vapor and ice are able to interact with the light in order to reflect and refract it, producing some remarkable effects. As a result of this, we are able to see remarkable golden and crimson hues of orange, pink, red and purple across the sky. The overall effect is contingent upon a number of atmospheric conditions, cloud formations, particles, humidity and the position of the sun, which is why no two sunsets are ever exactly the same.
🌫️ WHAT ABOUT DUST OR AIR POLLUTION?
Minute particles suspended in the atmosphere also have the ability to influence the effect. Dust, smoke, aersols, volcanic grit and other substances may have an influence. A brilliant red or orange sky is not necessarily a certain indicator of a particular type of pollution. Atmospheric effects are complex and many factors play a role in creating the effect.
🌌 WHY IS THE NIGHT SKY DARK?
As soon as the sun goes below the horizon, the atmosphere above your head no longer contains the same amount of sun light as it did during the day. As a result, the sky appears dark and the stars become visible (assuming you are not in a city where artificial light may scatter into the atmosphere, brightening the night sky) .
💡 THE INTERESTING PART
Colors are a reminder that what we observe is not always what we see.
The sun doesn't have to change color for a red sunset to occur- the atmosphere can have an effect on the journey of the light before it reaches our eyes.
❓ QUESTIONS YOU MAY HAVE
Q: Is the sky actually blue?
A: The atmosphere is not actually blue like paint. The blue you are seeing is actually sunlight being scattered by molecules in the atmosphere.
Q: Why isn't the sky always blue?
A: A combination of atmospheric conditions, clouds, particles, the sun's position and other factors can influence the way light reaches our eyes and changes the apparent color of the sky.
Q: Why can sunsets look different every day?
A: The amount and kinds of clouds and particles in the atmosphere vary, influencing the way the sun's light is scattered and transmitted. Conditions can change from day to day.
Q: Why are some sunsets extremely red?
A: Longer travel through the atmosphere and specific particles may remove or scatter more of the shorter wavelengths. This allows more longer wavelength light to reach your eyes. In addition, the sun's position in the sky can also play a role in the intensity of the color.
⭐ KEY TAKEAWAYS
☀️ Sunlight actually contains many colors that can be seen.
🌍 Earth's atmosphere can interact with sunlight.
🔵 Shorter wavelengths of light are scattered the most.
🌅 Sunlight has to travel further through the atmosphere near sunrise and sunset
🟠 This makes it possible for warmer colors to be more visible
☁️ Clouds and particles in the atmosphere have a major influence on the way light is scattered and transmitted in the sky
🤝 AN ETHICAL PERSPECTIVE
Science teaches us a valuable lesson here: seeing isn't always understanding. A beautiful sunset may seem like no big mystery, but there are actually important scientific principles which make it possible. Isn't it great when an inquisitive mind makes seemingly normal things seem so much more interesting?
🏁 CONCLUSION
Next time you look up and see a bright blue sky or witness a brilliant sunset and think how beautiful it is, keep in mind that you are seeing something far more interesting than you might have thought! These interactions are actually a form of experimentation taking place above your head.
The next time you see a blue sky or a brilliant sunset, remember:
It's really a mini science lesson taking place above your head!
📢 CALL TO ACTION
The next time you look at the sky, don't just stop at saying, "What color is it?" Ask yourself,
🧠 "Why does it look that way?"
One question can make an ordinary thing seem extraordinary.
source: NASA - Why Is the Sky Blue?
NASA Science: Why Is the Sky Blue?
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