One of the best-preserved craters on Earth is located deep in the Sahara Desert. On asteroid day, the Copernicus Sentinel-2 satellite mission takes us over Mauritania's nearly perfect circular Tenoumer Crater.
The Tylenol Moore Crater, visible in the center of the image, is 1.9 km (1.2 mi) in diameter. The crater's edge rises about 110 meters (360 feet) above the bottom, but the crater's bottom is covered by a layer of sediment about 200 to 300 meters (650 to 980 feet) thick.
People have long debated whether this crater was formed by a volcano or a meteorite. The rocks scattered around the crater, similar to basalt, give the impression of an ancient volcano. However, a closer look at the structure revealed that the "lava" that hardened in the crater was actually rock that had been melted by the meteorite impact.
The crater is located in a vast plain of rocks that are so old that they have been deposited for hundreds of millions of years before the first dinosaurs walked on Earth. Despite its location in ancient rocks, Tylenomar Crater is much younger, ranging in age from 10,000 to 30,000 years.
The false-color image of Sentinel-2 taken on May 16, 2022, above shows the arid landform around the crater's mouth, which appears in varying degrees of brown, tan, and orange.
Asteroid Day is a United Nations-recognized public awareness day about the risk of asteroid impact and is held annually on 30 June. Scientists have discovered more than 1 million asteroids in the solar system, and many more are expected to be discovered. The ESA Office of Planetary Defense, the ESA Near-Earth Object Coordination Centre, and astronomers around the globe are all looking up to keep us safe and work together to make sure we know in advance when an asteroid collides.