A.The sky weighs 5,148 teratonnes, or 5,148,000,000,000,000 tonnes. Mars' atmosphere weighs only 25 teratonnes. The Earth's atmosphere is 78.08% nitrogen.
A.Rayleigh scattering makes the sky blue. The blue part of sunlight has a short wavelength, so it hits air molecules, scatters off them, & you see it more.
Q.Why is the sea blue?
A.The sea is blue because water itself has a slight blue colour that can be seen when the depth is at least 3 metres. It's not the reflection of the sky.
Q.Why do you get a pint glass in the corner of a football match on skysports tv?
A.The Sky Sports Live pint logo is there to catch pub landlords avoiding Sky subscription fees. If there is no glass, they are showing Sky illegally.