Shishya: Acharya why is the sky blue?
Acharya: When it comes to existential truths – it’s best to ask ‘how’ than ‘why’. Is it really blue or only humans perceive it as blue?
Shishya: What! Do you mean the animals and birds don’t see the colors as we do? So a cat, a dog, or an eagle don’t see everything as us humans?
Acharya: Well there are studies which have found that the cat would see in blue, gray, and hints of yellow. A dog in shades of blue and yellow. An eagle has a broader spectrum of colors, including ultraviolet vision capabilities.
Now when it comes to humans they can see in shades of red green blue. Now as far as sunlight goes – when it reaches the atmosphere during daylight – it sends the colors in all different directions. Blue scatters more due to its shorter wavelength. So we see it as blue during daylight.
Shishya: And in the evening like during sunset? it looks red and orange, right?
Acharya: At sunset, light’s long journey through the air scatters blue out, leaving warm colors to reach you.
Shishya: I also see the sky as white most of the time why is that?
Acharya: There are a few reasons…
Clouds: Think of clouds as giant white screens, now the sunlight hits them – the light bounces around in all directions and we see it as white.
Airborne Particles: The atmosphere could be filled with water droplets, dust, and pollution particles – these too scatter the sunlight – making the sky appear white or grayish.
Time of Day: Have you noticed early in the morning the sky might be more blue? That’s often due to fewer clouds or fewer particles scattering the light.
At noon, sunlight travels directly through the atmosphere, scattering all colors evenly and making the sky appear white.
At sunset, the sunlight’s angle causes more blue and green light (shorter wavelengths) to scatter away. Only red and orange light (longer wavelengths) reach us directly, creating those beautiful sunset colors
Shishya: Pollution affects the sky color?
Acharya: Ofcourse!
Shishya: Will different seasons have different sky color
Acharya: Yes so it all depends on the angle of the sun and the atmosphere – The seasons that you are talking about the sun’s position changes right – so you will see more blue sky in summers than in winters
Shishya: Is there a place on Earth where the sky is the bluest?
Acharya: The sky in desert regions or mountainous areas like the Himalayas can appear intensely blue.
Shishya: Can the sky have colors other than blue, without including sunrise or sunset?
Acharya: If the atmosphere conditions are unusual it can create unusual or let’s say unique colors. For instance, volcanic eruptions can send ash into the atmosphere and the sky could appear gray or even reddish. Northern and southern lights, or auroras, can also paint the sky with greens, pinks, and purples due to charged particles from the sun interacting with the Earth’s magnetic field.
If the atmosphere conditions are unusual it can create unusual or let’s say unique colors. For instance, volcanic eruptions can send ash into the atmosphere and the sky could appear gray or even reddish. Northern and southern lights, or auroras, can also paint the sky with greens, pinks, and purples due to charged particles from the sun interacting with the Earth’s magnetic field.
Shishya: Wow, the sky is like a canvas that reflects the many facets of our world!
Acharya: Indeed, an interplay between light, matter, and the forces of nature.
Shishya: If blue light scatters the most, why don’t we see a violet sky?
Acharya: Our eyes are simply more sensitive to blue wavelengths than violet ones. Also, the atmosphere absorbs some violet light.
Acharya: If a planet’s atmosphere is filled with different gases and particles, the scattering of light will be different. Some planets like Mars often have a reddish hue in the sky due to dust in the air. So next time you look up at the sky – you remember the play of lights and forces of nature that makes it look the way it does – not just to humans but to all creatures !
