The crew of the International Space Station (ISS) sees space in a whole different
light compared to those of us on the ground.
This image by an Expedition 7 crewmember shows what scientists call the limb
of the Earth, at the bottom of the photo, along with the planet's atmosphere.
The colors fade from the dark, mostly unlit surface of the planet into the orange-colored
troposphere, the lowest and most dense portion of the atmosphere.
The troposphere ends abruptly at the tropopause, which appears in the image
as the sharp boundary between orange and blue.
Silvery-blue noctilucent clouds -- visible from Earth's surface but only at
night -- extend far above the Earth's troposphere. This special type of cloud
is illuminated from below due to the extreme angle of the Sun's last shafts
of incoming light. Interestingly, these clouds can be produced by exhaust from
rockets, a recent
study of a space shuttle launch showed.
Then there's a sliver of silver, the setting Moon, in the upper right. The
Moon was full yesterday. The
image was released July 27.
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