Hi ^-^

geologise:

Blue light is scattered more than other wavelengths by the gases in the atmosphere, giving the Earth a blue halo when seen from space.
~ Information via Wikipedia | Photo via NASA

“The atmosphere of Earth is a layer of gases surrounding the planet Earth that is retained by Earth’s gravity. The atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect), and reducing temperature extremes between day and night (the diurnal temperature variation).”