Sunset from the International Space Station
			
		
		
			Credit: 
Expedition 23 Crew, 
NASA
		
		
			What are these strange color bands being seen from the International Space Station?
The Sun setting through Earth's atmosphere. 
Pictured above, a sunset captured last month by the ISS's 
Expedition 23 
crew 
shows in vivid detail many layers of the 
Earth's thin atmosphere.
Part of the 
Earth experiencing night 
crosses the bottom of the image.
Above that, 
appearing in deep orange and yellow, is the Earth's 
troposphere, 
which contains 80 percent of the atmosphere by mass and 
almost all of the 
clouds in the sky.
Above the troposphere, seen as a light blue band with white clouds, is the 
stratosphere, part of the Earth's atmosphere where airplanes fly and some hardy bacteria float.
Above the stratosphere, visible as a darker blue bands, are higher and thinner 
atmospheric levels that gradually fade away into the cold dark  
vacuum of 
outer space.
Sunset is not an uncommon 
sight 
for occupants of the 
International Space Station, 
because it can be seen as many as 16 times a day.