Why is the sky blue? The reality explained – as well as its the same for other planets
IT’S a question as old as humanity itself – why is the sky blue? There are many myths and legends surrounding the query, but we’ve got the science behind the phenomenon below. Why is the sky blue? The sky is blue due to the way that light interacts with Earth. As sunlight strikes gas particles […]
IT’S a question as old as humanity itself – why is the sky blue?
There are many myths and legends surrounding the query, but we’ve got the science behind the phenomenon below.
Why is the sky blue?
The sky is blue due to the way that light interacts with Earth.
As sunlight strikes gas particles in the atmosphere, the light separates into all the colours of the rainbow.
Light travels as waves of energy, and these waves are scattered all over the place when the sunlight separates.
The sky is blue because blue light waves scatter more than other colours, according to Nasa.
“Blue is scattered more than other colours because it travels as shorter, smaller waves,” the space agency says.
“This is why we see a blue sky most of the time.”
When the Sun is high in the sky, it appears white: Its true colour.
We see a much redder Sun, however, at sunrise and sunset.
This is because sunlight passes through a thicker layer of our atmosphere, scattering green and blue light as it goes.
Redder light is allowed to pass through and illuminate the clouds in a stunning array of red, orange, and pink.
In terms of proof, we know that the colours of the sky follow a law known Rayleigh scattering, which tells us how light scatters.
Is the sky blue on other planets?
Other planets don’t have an atmosphere like ours and so their skies would look different.
On Mars, for instance, the atmosphere is about one per cent the thickness of Earth’s.
As a result, light wouldn’t scatter as much as it does on our planet.
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According to the Royal Observatory in London: “We might expect Mars to have a very faint blue coloured sky.
“But due to the haze of dust that remains suspended in the air, the daytime sky on Mars appears more yellow.
“This is because the larger dust particles absorb the short wavelength blue light and scatter the remaining colours to give a butterscotch hue over the Martian sky.”
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