If the sky is blue during the day ... When the Sun is low on the horizon, its light must pass through a thicker layer of the atmosphere. This extended journey scatters the shorter blue and ...

If Earth had no atmosphere like the Moon there would be no scattering, and the sky would remain black, even in daylight ...

T he sky isn't just blue by chance. I t takes all the colors ... Light breaks over the horizon at sunrise, seen in a photo from the International Space Station. O ur modern-day expert ...