September 2, 2011
Ancient Lake Delta Found On Mars
The European Space Agency (ESA) said on Friday that it has discovered a crater on Mars that was once filled by a lake.
NASA's Mars Global Surveyor spacecraft was first to identify the lake. ESA said this delta structure is characteristic of the presence of a lake in the crater.
The delta is an ancient fan-shaped deposit of dark sediments that is laid down in water, according to the space agency.
The extinct lake is in the 40-mile-diameter Eberswalde crater that formed about 3.7 billion years ago when an asteroid struck the planet.
The rim of the crater is intact only on the right-hand side, while the rest appears only faintly or is not visible at all.
Both Eberswalde crater and Holden crater were on the shortlist of possible landing spots for the NASA's next Mars rover, which will be launched in November.
However, in July, NASA selected Gale crater as the mission's landing site due to its high mineral and structural diversity related to water.
Image Caption: Holden crater is 140 km across, filling the left side of the image, while to the right is the remaining part of Eberswalde crater, with a diameter of about 65 km. They are located in the southern highlands of Mars. North is to the right of the image. The image was acquired by Mars Express at approximately 25°S / 326°E during orbit 7208 on 15 August 2009. The images have a ground resolution of about 22 m per pixel. Credits: ESA/DLR/FU Berlin (G. Neukum)
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