Rahe is a
crater
A crater is a landform consisting of a hole or depression (geology), depression on a planetary surface, usually caused either by an object hitting the surface, or by geological activity on the planet. A crater has classically been described ...
on the planet
Mars
Mars is the fourth planet from the Sun. It is also known as the "Red Planet", because of its orange-red appearance. Mars is a desert-like rocky planet with a tenuous carbon dioxide () atmosphere. At the average surface level the atmosph ...
in the
Tharsis quadrangle
The Tharsis quadrangle is one of a series of 30 list of quadrangles on Mars, quadrangle maps of Mars used by the United States Geological Survey (USGS) Astrogeology Research Program. The Tharsis quadrangle is also referred to as MC-9 (Mars Chart- ...
, positioned at 25.05° north latitude and 262.52° east longitude,
between the volcanoes
Ceraunius Tholus and
Uranius Tholus. It measures approximately 34 kilometers in diameter and was named after Jürgen Rahe, a German-American astronomer and
NASA
The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...
science program director.
Description
The crater has an elongated shape measuring 35 km by 18 km and is the result of an oblique impact. A channel connects Rahe crater to the vicinity of the summit caldera of Ceraunius Tholus, with an interesting fan-shaped deposit at the lower end.
Rahe crater is 1 km deep in places, and was created by a low angle impact which is evident by its elongated shape and ejecta deposit in the shape of a "butterfly".
Rahe is believed to once have held a lake. The lake was formed because heat from the nearby volcano Ceraunius Tholus melted glaciers. Melt water first collected in the caldera of Cerunius Tholus, and then spilled over the caldera rim forming a valley and the lake in Rahe crater. The valley that carried the water was about 200 m wide. A delta formed where the valley entered the crater.
This type of event involving volcanic heat melting glaciers is common in Iceland. Eruptions under glaciers are called
jökulhlaup
A jökulhlaup ( ) (literally "glacial run") is a type of glacial outburst flood. It is an Icelandic term that has been adopted in glaciological terminology in many languages.
It originally referred to the well-known subglacial outburst floo ...
s and average two each century. Studies of climate change show that many low-latitude regions accumulated large amounts of snow when the climate was different.
[Head, J. et al. 2006. Extensive valley glacier deposits in the northern mid-latitudes of Mars: Evidence for Late Amazonian obliquity-driven climate change. Earth Planet. Sci. Lett. 241,663-671.]
Wikirahe.jpg, Rahe crater, as seen by CTX camera (on MRO).
Wikirahedelta.jpg, Delta in Rahe crater, as seen by CTX camera. Note: this is an enlargement from the previous image of Rahe Crater.
See also
*
Climate of Mars
The climate of Mars has been a topic of scientific curiosity for centuries, in part because it is the only terrestrial planet whose surface can be easily directly observed in detail from Earth with help from a telescope.
Although Mars is small ...
*
Geology of Mars
The geology of Mars is the scientific study of the surface, crust, and interior of the planet Mars. It emphasizes the composition, structure, history, and physical processes that shape the planet. It is analogous to the field of terrestrial geo ...
* , minor planet
*
List of craters on Mars
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This is a list of craters on Mars. Impact craters on Mars larger than exist by the hundreds of thousands, but only about one thousand of them have names. Names are assigned by the International Astronomical Union after petitioning ...
References
{{Portal bar, Solar System
Impact craters on Mars
Tharsis quadrangle