24 Apr '11, 10pm

Sunset from the International Space Station.

Astronauts onboard the International Space Station see, on average, 16 sunrises and sunsets during a 24-hour orbital period. Each changeover between day and night is marked by the terminator, a line on Earth's surface separating the sunlit side from the darkness. While the terminator is often conceptualized as a hard boundary—and is frequently presented as such in graphics and visualizations —in reality the edge of light and dark is diffuse due to the scattering of light by the Earth’s atmosphere. This zone of diffuse lighting is experienced as dusk or twilight on the ground; while the Sun is no longer visible, some illumination is still present due to light scattering over the local horizon. The terminator is visible in this panoramic view across central South America, looking towards the northeast. An astronaut shot the photo at approximately 7:37 p.m. local time. Layers...

Full article: http://earthobservatory.nasa.gov/IOTD/view.php?id=50205&s...

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Sunset over Western South America [image] #NASA

earthobservatory.nasa.gov 24 Apr '11, 10pm

Astronauts onboard the International Space Station see, on average, 16 sunrises and sunsets during a 24-hour orbital perio...

Sunset over Western South America: The changeov...

earthobservatory.nasa.gov 24 Apr '11, 10pm

Astronauts onboard the International Space Station see, on average, 16 sunrises and sunsets during a 24-hour orbital perio...

See a sunset over Western South America as the ...

earthobservatory.nasa.gov 25 Apr '11, 1am

Astronauts onboard the International Space Station see, on average, 16 sunrises and sunsets during a 24-hour orbital perio...

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earthobservatory.nasa.gov 22 Apr '11, 10pm

You've seen the pattern in science class when you laid bits of iron around a bar magnet. The invisible force field around ...

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earthobservatory.nasa.gov 04 May '11, 1pm

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