Asimov Crater is an
impact crater in the
Noachis quadrangle of
Mars
Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...
, located at 47.0° S and 355.05° W. It is in diameter and was named after
Isaac Asimov
yi, יצחק אזימאװ
, birth_date =
, birth_place = Petrovichi, Russian SFSR
, spouse =
, relatives =
, children = 2
, death_date =
, death_place = Manhattan, New York City, U.S.
, nationality = Russian (1920–1922)Soviet (192 ...
(1920–1992), an American biochemist and writer.
The name was officially adopted on May 4, 2009.
Gullies in Asimov
Asimov contains many gullies.
Martian gullies are small, incised networks of narrow channels and their associated downslope
sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an ...
deposits, found on the planet of Mars. They are named for their resemblance to terrestrial
gullies. First discovered on images from
Mars Global Surveyor, they occur on steep slopes, especially on the walls of craters. Usually, each gully has a
dendritic
Dendrite derives from the Greek word "dendron" meaning ( "tree-like"), and may refer to:
Biology
*Dendrite, a branched projection of a neuron
*Dendrite (non-neuronal), branching projections of certain skin cells and immune cells
Physical
* Dendr ...
alcove at its head, a
fan-shaped apron at its base, and a single thread of incised channel linking the two, giving the whole gully an hourglass shape.
[Malin, M., Edgett, K. 2000. "Evidence for recent groundwater seepage and surface runoff on Mars". ''Science'' 288, 2330–2335.] They are believed to be relatively young because they have few, if any craters.
A subclass of gullies is also found cut into the faces of sand dunes which themselves considered to be quite young.
On the basis of their form, aspects, positions, and location amongst and apparent interaction with features thought to be rich in water ice, many researchers believed that the processes carving the gullies involve liquid water. However, this remains a topic of active research.
As soon as gullies were discovered,
researchers began to image many gullies over and over, looking for possible changes. By 2006, some changes were found. Later, with further analysis it was determined that the changes could have occurred by dry granular flows rather than being driven by flowing water. With continued observations many more changes were found in Gasa Crater and others.
With more repeated observations, still more changes have been found; since the changes occur in the winter and spring, experts tend to believe that gullies were formed from dry ice. Before-and-after images demonstrated the timing of this activity coincided with seasonal carbon-dioxide frost and temperatures that would not have allowed for liquid water. When dry ice frost changes to a gas, it may lubricate dry material to flow especially on steep slopes.
See also
*
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 by ...
References
{{Portal bar, Solar System
Noachis quadrangle
Impact craters on Mars
Isaac Asimov