24 Apr '11, 10pm

Sunset over Western South America: The changeover between day and night is marked by the terminator, a line o...

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...

Tweets

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...

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...

Sunset from the International Space Station.

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...

Jizzax Province, Uzbekistan [image] #NASA

earthobservatory.nasa.gov 24 Apr '11, 2am

Uzbekistan is a dry, landlocked country, covered mostly by the sands of the Kyzyl Kum (Qizilqum) Desert. A little over 10 ...

America's Farmers Are Second to None - Renewabl...

renewableenergyworld.com 24 Apr '11, 3pm

There are a lot of special interests looking to profit from American families. Not surprisingly, these are the same compan...

The Endangered Macaws of Central America and South America

The Endangered Macaws of Central America and So...

environmentalgraffiti.com 13 Apr '11, 10am

Macaws belong to seventeen species within six branches of the parrot family, Psittacidae . They are known for their brilli...

Almost 300 Dead After Tornadoes in South: How You Can Help: via @addthis

Almost 300 Dead After Tornadoes in South: How Y...

care2.com 29 Apr '11, 5am

In any building, underground is safest, if possible, but stay as close to walls and if possible in corners as you can. Rem...