YOUR WEEKLY DOSE OF WOWZERS AND WONDER FROM THE NATURAL WORLD
It’s one of the world’s most common questions, and one that most parents will hear at some point in their parenting adventure. So why are so few of us able to provide a factual answer for our curious kids (myself included)?
As a part of my research for this week’s featured topic, I decided to conduct a random survey to this intriguing question, and I received a number of interesting theories:
Because of reflection from the oceans or Earth’s surface
The sky is really purple, it’s just looks blue because it is so far away
It’s from the sun reflecting off the moisture in the atmosphere
While these are some thoughtful answers, none of them are entirely correct. But here’s the good news: we here at Wowzerful have done the research for you.
The next time this question comes up, you’ll be well prepared to provide a scientific answer, and in turn be the envy of everyone in the room!
In order for us to understand why the sky is blue, we first need to understand a few key elements that come into play.
LIGHT FROM THE SUN
While many of us think of the sun as a big yellow ball in the sky, it’s actually a big white ball.
The white light that comes from the sun is composed of all colours of the rainbow: red, orange, yellow, green, blue, indigo and violet.
The Earth’s atmosphere is mostly made up of gas molecules, with oxygen comprising about 21% and nitrogen about 78%.
The last percent is made up of water molecules, as well as other gases like argon, carbon dioxide and hydrogen. Particles such as dust, pollutants, and pollen round out the mix.
HOW LIGHT TRAVELS
Similar to how energy passes through an ocean, all light energy travels in waves.
Blue, indigo and violet light travels in short choppy waves, while red, orange and yellow light travels in long lazy waves.
Light also travels in a straight path, unless something gets in the way and either reflects it (like a mirror), bends it (like a prism) or scatters it (like particles in the atmosphere).
Still with us?
Now that we have a good understanding of sunlight, our atmosphere, and how light travels, let’s see how they all interact to create that beautiful blue sky we all know and love.
When light comes from the sun, all these light waves of different wavelengths travel through empty space.
Because the blue, indigo and violet light waves are similar in size to the nitrogen and oxygen molecules in our atmosphere, they run into each other and bounce and scatter in all directions,painting our sky in glorious shades of blue.
The red, yellow, and orange lightwaves are larger than the nitrogen and oxygen molecules, so they easily pass through.
This all seems to make sense, but it doesn’t explain why sunsets and sunrises are made up of red, orange and yellow colour tones.
During sunsets and sunrises, when the sun is closer to the horizon, light from the sun has to travel a longer distance and through more of the particle-dense atmosphere to reach our eyes.
This means that the blue, indigo and violet light waves are colliding with even more of those hydrogen and oxygen molecules, which removes more blue light from the sun.
With no more blue light available, the larger red, orange, and yellow lightwaves are the only ones left to illuminate the sky.
And there you have it — the answer to one of nature's most common questions!
The atmosphere is home to an average of almost 150 trillion litres (40 trillion gallons) of water, which is enough to cover our entire planet in 2.5cm (1 inch) of rainwater. While this sounds like a lot, atmospheric water vapour only accounts for 0.001% of all the water on Earth.
In 2013, a skydiver named Felix Baumgartner traveled to the upper level of the stratosphere and jumped from a height of 36.5km (22.7 miles) above Earth’s surface.
The Earth’s atmosphere consists of 5 layers: the troposphere, the stratosphere, mesosphere, ionosphere and exosphere. The exosphere extends more than 9,965km (6,000 miles) into outer space!
Did you know that there are organisms that hang out and live in the air? Bioaerosols are tiny microbial organisms that aren’t able to fly, but can travel long distances by wind, rain, or even a sneeze!
Astrophysicist Neil deGrasse Tyson and his friend Chuck explain why the sky is blue in this funny, entertaining and informative video.
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