Image of the Day: Mars’ Ancient Water World

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Latest images from the Mars Express of the Schiaparelli impact basin along the Mars equator has allowed ESA astronomers to interpret the dark sediments on the floor of the Schiaparelli basin as evidence for water -– resembling sediments that are deposited by evaporated lakes on Earth.


The entire basin is nearly 300 miles (460 kilometers) wide. The image from the High Resolution Stereo Camera on the European Space Agency's Mars Express spacecraft zeros in on the northwestern rim, which cuts diagonally across this image from the top left to the bottom right. A 26-mile-wide (42-kilometer-wide) crater is embedded in the rim.

The effect of other geological processes can be seen in the image, such as smaller craters created by the fallback of material that was ejected during the initial impact. Some of these were partially flooded and filled with watery deposits. Flows of lava appear to have created smooth plains. The sediments forming the smooth plains in the lower left of the image have been modified by erosion — either by wind, or water, or both — to form sharp contours. In other places, material deposited by the wind forms hills and dunes.

The impact basin is named after the Italian astronomer Giovanni Schiaparelli, famed for his observations of Mars, including an 1877 map of the planet that showed straight dark lines he interpreted as natural water-filled channels called "canali" in Italian -illusions created by the telescope technology of the time.

But the latest images add to ever increasing evidence that Mars had a watery past that helped shape and sculpt the planet we view today.

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