Behold our mothership

Artists like to depict the Earth as a deep blue planet with richly saturated green or brown continents. From a low orbit, the Earth indeed looks rich and colorful. But from the edge of space onwards, a layer of blue covers the entire planet, desaturated in a manner artists understand as atmospheric perspective.

The air molecules and aerosols in the Earth's atmosphere scatters light of different wavelengths by different amounts. Light with shorter wavelengths (blue end of visible spectrum) gets scattered more than light with longer wavelengths (red), this being the simplified explanation for why the sky is blue.

NASA's Blue Marble 2002. Colorful and beautiful, but not quite what the astronauts saw...?

The most famous photo of the Earth, taken on Dec 7, 1972 by the crew of Apollo 17

Furthermore, most of the ground terrain (especially vegetation) has low albedo which means only a very low percentage of sunlight gets reflected back into space. The oceans would appear black if not for the fact that the water reflects the blue sky. The low albedo of soil and plant life is also the reason why vegetated areas appear very dark from space, and not the bright, beautiful green that we see in the atlas.

Incidentally, the polar ice (being of high albedo) is mostly responsible for reflecting sunlight away from the Earth and reducing global warming by the Sun. But the Arctic ice and Antarctic ice shelves have been melting steadily in recent years, a matter of some concern for environmentalists.

Real photography of the Earth from deep space are few and far between. From them, we can observe that the brightest things visible, along with the blue scattered atmosphere, would be clouds and snow, followed by ice and sand. The "true" colors are not as cheerful as we might like, but we can always take artistic license and put some more hues back into our CG Earth render ^_^


Some of my more presentable rendering attempts (dated 13 Sept 2011, rendered using Houdini) follows:

Naturally, city lights will not appear so bright without either nigh-vision goggles or long exposures, and would be practically impossible in reality, but this kind of "day and night" artistic treatment is always popular ^_^

After rounds of tweaking, I keep coming back to this particular palette, though realistically I should use a deeper shade of blue. For now, this would be the overall look and feel until I come up with something else later...