NASA: Libya - Sand Dunes - Marzuq Sand Sea - Southwest Libya - An image near to the art - Una imagen cercana al arte

Posted by ricardo marcenaro | Posted in | Posted on 15:09


Open your mind, your heart to other cultures
Abra su mente, su corazón a otras culturas
You will be a better person
Usted será una mejor persona
RM

Sand Dunes, Marzuq Sand Sea, Southwest Libya

Sand Dunes, Marzuq Sand Sea, Southwest Libya

This detailed astronaut photograph, taken from low earth orbit, shows classic large and small sand masses of the central Sahara Desert, where wind is a more powerful land-shaping agent than water. “Draa” dunes (from the Arabic for “arm”) are very large masses of sand, and they appear here as the broad network of yellow-orange sand masses, with smooth-floored, almost sand-free basins between them. These sand masses lie in the western part of Libya’s vast Marzuq Sand Sea (centered at 24.5 degrees north, 12 degrees east). Geologists think that the draa of the Marzuq were probably formed by winds different from the prevailing north-northeast winds of today.
Numerous smaller dunes have developed on the backs of the draa. Three distinct dune types are visible: longitudinal dunes, which are more or less parallel with the north winds; transverse dunes, which are usually more curved and formed at right angles to the wind; and star dunes, in which several linear arms converge towards a single peak.
The upwind sides of the sand masses appear smoother than the downwind side. Wind is moving sand grains almost all the time. This means that the draa and the dunes are all moving as sand is added on the upwind side and blown off the downwind side. Small sand masses move much faster than large sand masses. The draa are almost stationary, but the smaller dunes move relatively quickly across their backs. When the smaller dunes reach the downwind side of the draa, they are obliterated; their sand is blown across the basins as individual grains.
Astronaut photograph ISS018-E-14770 was acquired on December 20, 2008, with a Nikon D2Xs digital camera fitted with a 400 mm lens, and is provided by the ISS Crew Earth Observations experiment and Image Science & Analysis Laboratory, Johnson Space Center. The image was taken by the Expedition 18 crew. The image in this article has been cropped and enhanced to improve contrast. Lens artifacts have been removed. The International Space Station Program supports the laboratory to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by M. Justin Wilkinson, NASA-JSC.
Instrument: 
ISS - Digital Camera
 
 
 http://earthobservatory.nasa.gov/images/imagerecords/36000/36675/ISS018-E-014770_lrg.jpg
 
 
 
http://earthobservatory.nasa.gov/images/imagerecords/36000/36675/ISS018-E-014770_lrg.jpg
NASA: Libya - Sand Dunes - Marzuq Sand Sea - Southwest Libya - An image near to the art - Una imagen cercana al arte



You have an alphabetical guide in the foot of the page in the blog: solitary dog sculptor
In the blog: Solitary Dog Sculptor I, the alphabetical guide is on the right side of the page
Thanks

Usted tiene una guía alfabética al pie de la página en el blog: solitary dog sculptor
En el blog: Solitary Dog Sculptor I, la guia alfabética está en el costado derecho de la página
Gracias




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My blogs are an open house to all cultures, religions and countries. Be a follower if you like it, with this action you are building a new culture of tolerance, open mind and heart for peace, love and human respect.

Thanks :)

Mis blogs son una casa abierta a todas las culturas, religiones y países. Se un seguidor si quieres, con esta acción usted está construyendo una nueva cultura de la tolerancia, la mente y el corazón abiertos para la paz, el amor y el respeto humano.

Gracias :)





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