Placeholder Image

Subtitles section Play video

  • Hi I'm Kelsea Brennan-Wessels and welcome back to Earth from Space

  • on the European Space Agency Web TV.

  • A giant, geological wonder in the Sahara Desert of Mauritania

  • is pictured in this satellite image.

  • Measuring 40 km in diameter the circular Richat structure is one of the geological features

  • that is easier to observe from space than from down on the ground, and has been a familiar

  • landmark to astronauts since the earliest missions.

  • Once thought to be the result of a meteor impact, researchers now believe it was caused

  • by a large dome of molten rock uplifting and, once at the surface, being shaped by wind

  • and water into what we see today. Concentric bands of resistant quartzite rocks

  • form ridges, with valleys of less-resistant rock between them.

  • This image was acquired on 23 November 2010 by the Advanced Visible and Near Infrared

  • Radiometer on Japan's ALOS satellite. The dark area on the left is part of the Adrar

  • plateau of sedimentary rock standing some 200 m above the surrounding desert sands.

  • A large area covered by sand dunes can be seen in the lower-right part of the image,

  • and sand is encroaching on the structure's southern side.

  • Zooming in on the southern side of the bullseye, we can see individual trees and bushes appear

  • as tiny dots. These follow a river-like structure that appears

  • to have been dry when this image was acquired, a few weeks after the rainy season.

  • Some areas to the south and east of the Richat appear to be covered by temporary lakes, which

  • are dry for most of the year.

  • Well that wraps up this edition of Earth from Space.

  • Remember that we broadcasting online every Friday at ten o'clock Central European Summer Time

  • Watch us on our website or through the ESA App on your mobile device

  • From the ESA Web TV studios I'm Kelsey Brennan-Wessels

Hi I'm Kelsea Brennan-Wessels and welcome back to Earth from Space

Subtitles and vocabulary

Click the word to look it up Click the word to find further inforamtion about it