Question

why does the earth looks blue in satellite image​

Answer 1

The earth looks blue because of its vast expanse of salt war which is the ocean. The ocean covers 72% of earth and thus the colour of blue.

Answer 2

Answer:

As with the Earth's atmosphere, most of the colors of the light spectrum are absorbed by the water. The water radiates the blue in the spectrum, giving it its blue color. If another color were radiated, say red for instance, the Earth would look red from outer space, like Mars.