| Holden | |
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Layers in the Martian crater Holden, taken by HiRISE. Click for technical information. |
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| Planet | Mars |
| Diameter | 153.8 |
| Eponym | Edward S. Holden |
Holden is a 140 km wide crater on Mars, located with the southern highlands. It is named after Edward Singleton Holden, an American astronomer, and the founder of the Astronomical Society of the Pacific.
Like Gusev, it is notable for an outlet channel, Uzboi Vallis, that runs into it, and for many features that seem to have been created by flowing water.
The crater's rim is cut with gullies, and at the end of some gullies are fan-shaped deposits of material transported by water. The crater is of great interest to scientists because it has some of the best-exposed lake deposits. One of the layers has been found by the Mars Reconnaissance Orbiter to contain clays.[1] Clays only form in the presence of water. It is believed that great amount of water went through this area; one flow was caused by a body of water larger than Earth's Lake Huron. [2] Holden is an old crater, containing numerous smaller craters, many of which are filled with sediment. The crater's central mountain is also obscured by sediment. Holden Crater is a proposed landing site for NASA's Mars Science Laboratory. Just to the north east of Holden Crater is Eberswalde Crater which contains a large delta.
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Several sites in the Margaritifer Sinus quadrangle have been proposed as areas to send NASA's next major Mars rover, the Mars Science Lab. Holden Crater made the cut to be among the top four. Holden Crater is believed to have once been a lake.
The aim of the Mars Science Laboratory is to search for signs of ancient life. It is hoped that a later mission could then return samples from sites identified as probably containing remains of life. To safely bring the craft down, a 12 mile wide, smooth, flat circle is needed. Geologists hope to examine places where water once ponded.[3] They would like to examine sediment layers.
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