Where In The Universe Challenge #22

By Nancy Atkinson - September 24, 2008 at 4:50 PM UTC | Extragalactic
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It's time once again for this week's Where In The Universe challenge. Take a look at the image above and try to determine where in the universe this image was taken. Give yourself extra points if you can name the spacecraft responsible for taking this image. As always, no peeking below before you make your guess. And comments are welcome if you want to share how well you did!

Make your guess, and then proceed.

This prominent circular feature, known as the Richat Structure, is found on our home planet Earth, in the Sahara Desert. Lots of astronauts have noted it and taken pictures of it because it forms a conspicuous 50-kilometer-wide (30-mile-wide) bullet's-eye on the otherwise rather featureless expanse of the desert. Initially it was thought to be an impact crater, but it is now known to be an eroded

circular anticline

(structural dome) of layered sedimentary rocks.

This image was generated from a Landsat satellite image draped over an elevation model produced by the Shuttle Radar Topography Mission (SRTM), so if you said either a satellite or an astronaut took this image, you can consider yourself correct. The view uses a 6-times vertical exaggeration to greatly enhance topographic expression. To give a scale for this image, the height of the mesa ridge in the back center of the view is about 285 meters (about 935 feet) tall. This is a color enhanced image, using both visible and infrared bands, which helps to differentiate bedrock (browns), sand (yellow, some white), minor vegetation in drainage channels (green), and salty sediments (bluish whites). Some shading of the elevation model was included to further highlight the topographic features.

This is quite a striking image from the old home planet.

See a hi-resolution image here.

Source:

NASA Earth Observatory

Nancy Atkinson

Nancy Atkinson

Nancy Atkinson is a space journalist and author with a passion for telling the stories of people involved in space exploration and astronomy. She is currently retired from daily writing, but worked at Universe Today for 20 years as a writer and editor. She also contributed articles to The Planetary Society, Ad Astra (National Space Society), New Scientist and many other online outlets.

Her 2019 book, "Eight Years to the Moon: The History of the Apollo Missions,” shares the untold stories of engineers and scientists who worked behind the scenes to make the Apollo program so successful, despite the daunting odds against it. Her first book “Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos” (2016) tells the stories of 37 scientists and engineers that work on several current NASA robotic missions to explore the solar system and beyond.

Nancy is also a NASA/JPL Solar System Ambassador, and through this program, she has the opportunity to share her passion of space and astronomy with children and adults through presentations and programs. Nancy's personal website is nancyatkinson.com