{"id":218295,"date":"2025-12-06T09:12:33","date_gmt":"2025-12-06T09:12:33","guid":{"rendered":"https:\/\/www.europesays.com\/ie\/218295\/"},"modified":"2025-12-06T09:12:33","modified_gmt":"2025-12-06T09:12:33","slug":"seeing-a-bulls-eye-in-the-desert","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/ie\/218295\/","title":{"rendered":"Seeing a bull’s-eye in the desert"},"content":{"rendered":"

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The Richat Structure looks like an eye in the Saharan Desert. | Credit: Contains modified Copernicus Sentinel data (2025), processed by ESA<\/p>\n

In the middle of Mauritania’s Sahara Desert, surrounded by an ocean of sand, lies a colossal stone spiral that seems almost too perfect to be natural. From orbit, in a recent image taken by the European Space Agency<\/a>‘s Copernicus Sentinel-2 satellite mission<\/a>, it looks like a target etched into the desert: the Richat Structure, better known as the Eye of the Sahara.<\/a><\/p>\n

What is it?<\/p>\n

The Richat Structure spans around 31 miles (50 km) across, large enough to be a clear landmark for astronauts passing overhead.<\/p>\n

On the ground, its rings are hard to appreciate; dunes, heat haze, and uneven terrain all conspire to hide the full shape. But from space, especially in the images taken by the Copernicus satellite, the structure appears as a set of concentric circles, like ripples frozen in rock.<\/p>\n

For years, its near-perfect circle led scientists to suspect a dramatic origin: a meteorite impact. A formation that round, in the middle of nowhere, had to be a crater<\/a> \u2014 or so it seemed.<\/p>\n

Where is it?<\/p>\n

This image was taken over the Adrar region of northern Mauritania.<\/p>\n

\"A<\/p>\n

A false-color image of the Richat Structure shows its chemical composition. | Credit: Contains modified Copernicus Sentinel data (2025), processed by ESA<\/p>\n

Why is it amazing?<\/p>\n

Further fieldwork and analysis overturned the impact crater<\/a> theory, as researchers found no signs of shocked quartz, melted rock, or other telltale traces of a high-energy collision. Instead, the Richat Structure turned out to be something more subtle and, in many ways, more impressive: a deeply eroded geological dome.<\/p>\n

Millions of years ago, a large bubble of molten rock pushed up beneath the surface, gently doming the overlying sedimentary layers. Over time, wind, water, and sand did what they do best in the Sahara: sandblast and carve away the softer rocks. Harder rocks, like quartzite-rich sandstones, resisted erosion and remained as high ridges, while the softer layers between them were worn into valleys.<\/p>\n

The result is a natural cross-section of Earth’s crust, peeled back in rings. The outer rings mostly consist of more erosion-resistant rock, while the interior exposes older layers that once lay deep underground. Geologists estimate that parts of this structure are at least 100 million years old.<\/p>\n

In the false-color composite images from the Copernicus satellite mission, the story of the landscape becomes much clearer as specific wavelengths of light are combined to highlight different materials and surface features: the tougher quartzite sandstones appear in shades of red and pink, tracing the outer rings and inner ridges; darker patches between these rings mark zones of softer, more eroded rock; and tiny purple specks in the southern part of the structure reveal individual trees and bushes following a dry riverbed that snakes into the Eye. From the vantage point of Earth orbit, the Eye continues to stare back at us: a giant geological bull’s-eye, etched into the Sahara, quietly recording a deep history of Earth written in stone.<\/p>\n

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The image shows the difference in temperature between the top of a hurricane and the bottom.<\/p>\n

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The images reveal the storm’s incredible power and offer vital insights into how such hurricanes form.<\/p>\n

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A powerful geomagnetic storm created a series of brilliant auroras recently for observers across North America.<\/p>\n

Want to learn more?<\/p>\n

You can learn more about Earth-observing satellites<\/a> and the Copernicus program.<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"When you buy through links on our articles, Future and its syndication partners may earn a commission. The…\n","protected":false},"author":2,"featured_media":218296,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[273],"tags":[118170,118171,18,28434,19,17,118169,118166,118167,118168,133,461],"class_list":{"0":"post-218295","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-wildlife","8":"tag-copernicus-satellite","9":"tag-copernicus-sentinel","10":"tag-eire","11":"tag-european-space-agency","12":"tag-ie","13":"tag-ireland","14":"tag-mauritania","15":"tag-richat-structure","16":"tag-saharan-desert","17":"tag-satellite-mission","18":"tag-science","19":"tag-wildlife"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/115671856024536685","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/218295","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=218295"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/218295\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/218296"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=218295"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=218295"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=218295"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}