Question

Why does earth appear blue green in colour from outer space ?

Answer 1

when the suns light hits the earth’s atmosphere, the light particles slow down and and the blue light bounces between the molecules. this turns the sky blue.

When looking at the earth from the outside think of it like a 1-way mirror, you see the blue oceans only because they are reflecting the blue sky which you cannot see from outer space. (again, like a 1 way mirror).

because 70% of the earth is ocean it appears more blue than anything else.

Answer 2

The way light reflects off air molecules has an effect on the way people see the sky as well as the ocean. When orbiting the Earth, satellites and astronauts see a blue globe due to some of these same properties. The sheer amount of water on Earth makes it appear blue