What is this optical phenomenon, as looked from outer space? I just saw a photo from NASA. This is it. 

This is beautiful. But i am not being able to understand, what are those red and green lines above the earth surface? These cannot be due to Rayleigh scattering of course as there are no particles to do that. 
Moreover, just above the surface of the earth, we see a blue colour( which is very faint ) . Is this due to Rayleigh scattering? 
PS- I can assure you, that these are not photographic effects, so please don’t take it into account. 
 A: This optical phenomenon is called "airglow". A couple of other images, both also taken from the ISS:

(source: nasa.gov)
The blue band just next to the Earth in the second image is caused by Rayleigh scattering, which occurs primarily in the troposphere. The blue band is just barely visible in the first image, which was taken much later at night. This blue band is not airglow. The airglow starts in the stratosphere and continues for hundreds of kilometers up.
You can see airglow from the surface of the Earth. It gets in the way of astronomy, even in the darkest of places. All together, airglow is ten times brighter than is the light from all of the stars in the night sky. Airglow is one of the key motivators for space-based telescopes.


Airglow is, as the name suggests, glowing air. The orangish/yellowish band closest to Earth is sodium glowing at 589nm. The sodium comes from micrometeoroids that disintegrate into tiny particles 80 to 105 kilometers above the surface. Just above is a greenish band caused by excited oxygen atoms glowing at 558nm. Sometimes a thin blue band appears above this greenish band, caused by molecular oxygen glowing at 464 to 467 nm (multiple spectral lines). High above, atomic oxygen glowing at ~630 nm (multiple spectral lines) forms the faint red part of the airglow.

Aside: The images are clickable. Hover your cursor over the images to see a description of the image and of the link.
