APOD: Layers of the South Pole of Mars (2018 Jul 31)

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APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by APOD Robot » Tue Jul 31, 2018 4:08 am

Image Layers of the South Pole of Mars

Explanation: What lies beneath the layered south pole of Mars? A recent measurement with ground-penetrating radar from ESA's Mars Express satellite has detected a bright reflection layer consistent with an underground lake of salty water. The reflection comes from about 1.5-km down but covers an area 200-km across. Liquid water evaporates quickly from the surface of Mars, but a briny confined lake, such as implied by the radar reflection, could last much longer and be a candidate to host life such as microbes. Pictured, an infrared, green, and blue image of the south pole of Mars taken by Mars Express in 2012 shows a complex mixture of layers of dirt, frozen carbon dioxide, and frozen water.

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Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by bystander » Tue Jul 31, 2018 4:23 am

Know the quiet place within your heart and touch the rainbow of possibility; be
alive to the gentle breeze of communication, and please stop being such a jerk.
— Garrison Keillor

star strukk

Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by star strukk » Tue Jul 31, 2018 7:08 am

white rhinocerus went extinct on earth in 2015.

111 years after the creature was given a scientific name it went extinct.

it does not make sense questioning existence of life on mars when creatures of the earth are in peril.

even if there is microbial life on mars it does not have any significance in terms of human existence.

the manner of human consumption of the earth's natural resources is an activity which is taking its toll on the well being of the earth.

nasa should recall juno space craft (on mission to jupiter) to earth for terestrial survey: polar ice melt; global warming; extinction of species; oceanic pollution; deforestation; armaggedon . . .

the next leap in human cosmic involvement will invove asteroid mining - excavation of a selected asteroid for mineral. extra terestrial alien of human kind will be needed for this effort. an outcome of such venture will be excavation of a chamber inside a large asteroid (such as 511 davidea) which may be modified for human habitation.

GomeLord

Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by GomeLord » Tue Jul 31, 2018 7:14 am

Interesting image. Might there be a 3D version to ponder? One wonders how thick the sharply defined layers are.

However, the use of the word 'dirt' is not very helpful to an enquiring mind. Would you throw it away [with disgust] into the nearest bin if samples removed from this region were to be somehow brought back? With the current dust storm(s) raging across Mars, might there be perhaps be another more scientific term for 'dirt' for the narrative in the astronomy storybook?

emanueldewitt

Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by emanueldewitt » Tue Jul 31, 2018 8:09 am

Nice photo.
But without any indication of length totally incomprehensible. What are we seeing? 1 m? 1 km? 100 km?
Giving an idea of length/distance in a photo would be a good custom.

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Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by De58te » Tue Jul 31, 2018 10:17 am

emanueldewitt wrote:
Tue Jul 31, 2018 8:09 am
Nice photo.
But without any indication of length totally incomprehensible. What are we seeing? 1 m? 1 km? 100 km?
Giving an idea of length/distance in a photo would be a good custom.
According to the 'image' link, the Southern Mars Cap is around 350 km in diameter.

Roger Venable

Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by Roger Venable » Tue Jul 31, 2018 12:39 pm

The image here is of the residual South Polar Cap, showing most of it, with a shape familiar to students of Mars. Its irregular ovoid shape has dimensions of about 5 degrees by 7 degrees of Martian latitude, and it is offset from the actual South Pole so that the Pole is located on one of its edges. This is not the area in which the subsurface brine was found.
Indeed, a broad area of the South Polar Region was searched with the ground penetrating radar aboard Mars Expresss, and the densest area of reflection (from a depth of about 1500 meters, indicating the top of the brine layer) is centered at latitude 81 degrees south and longitude 193 degrees east. Furthermore, it is only 20 km across. Softer reflections were detected from other South Polar Region areas, but the assertion of a subsurface lake was made primarily for this densest reflection.
In view of this, the APOD today is slightly misleading. The lake is not below the South Polar Cap seen here.

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Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by neufer » Tue Jul 31, 2018 12:43 pm

star strukk wrote:
Tue Jul 31, 2018 7:08 am

white rhinocerus went extinct on earth in 2015.
111 years after the creature was given a scientific name it went extinct.
it does not make sense questioning existence of life on mars when creatures of the earth are in peril.
even if there is microbial life on mars it does not have any significance in terms of human existence.
  • White rhinos were killed off by folks who have absolutely no appreciation
    of science or of modern technological advances (e.g., Viagra).
Art Neuendorffer

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Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by BDanielMayfield » Tue Jul 31, 2018 2:01 pm

APOD Robot wrote:
Tue Jul 31, 2018 4:08 am
Explanation: ... a complex mixture of layers of dirt, frozen carbon dioxide, and [url=https://apod.nasa.gov/apod/ap050720.html]frozen water.
GomeLord wrote:
Tue Jul 31, 2018 7:14 am
Interesting image. Might there be a 3D version to ponder? One wonders how thick the sharply defined layers are.

However, the use of the word 'dirt' is not very helpful to an enquiring mind. Would you throw it away [with disgust] into the nearest bin if samples removed from this region were to be somehow brought back? With the current dust storm(s) raging across Mars, might there be perhaps be another more scientific term for 'dirt' for the narrative in the astronomy storybook?
Dust is the more commonly used term, (equivalently disgusting in many settings), but when dust is on the surface of a world it is ... dirt. Or, in this case, with the CO2 and water mixed in perhaps the more precise wording would be "mud". :lol2:

Bruce, made from "the dust of the earth", which was in turn made from stardust

P.S. The "more scientific term for 'dirt' for the narrative in the astronomy storybook" is "metals". Good old 'dirt' is way more understandable.
Last edited by BDanielMayfield on Tue Jul 31, 2018 3:02 pm, edited 3 times in total.
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Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by Chris Peterson » Tue Jul 31, 2018 2:27 pm

star strukk wrote:
Tue Jul 31, 2018 7:08 am
it does not make sense questioning existence of life on mars when creatures of the earth are in peril.
even if there is microbial life on mars it does not have any significance in terms of human existence.
nasa should recall juno space craft (on mission to jupiter) to earth for terestrial survey: polar ice melt; global warming; extinction of species; oceanic pollution; deforestation; armaggedon . . .
I agree with all your observations about our foolish management of Earth. But it would be foolish, as well, to abandon our scientific exploration of the Universe. It could have profound scientific and social impact to find life, or evidence of past life, on another planet. And our exploration of other planets doesn't impact our exploration of our own. NASA already operates a huge number of Earth observation instruments. And much of that technology has followed from the development of deep space probes.
Chris

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Tszabeau

Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by Tszabeau » Tue Jul 31, 2018 2:38 pm

For some reason... I got a hankerin’ for Tiramasu... or is it Terramasu?

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Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by neufer » Tue Jul 31, 2018 2:52 pm

APOD Robot wrote:
Tue Jul 31, 2018 4:08 am

Explanation: What lies beneath the layered south pole of Mars? A recent measurement with ground-penetrating radar from ESA's Mars Express satellite has detected a bright reflection layer consistent with an underground lake of salty water. The reflection comes from about 1.5-km down but covers an area 200-km across.
Mars Express detects water buried under the south pole of Mars wrote:
<<A particularly bright radar reflection underneath the layered deposits is identified within a 20 km-wide zone.>>
https://en.wikipedia.org/wiki/Lake_Wobegon wrote:
<<Lake Wobegon is a fictional town created by Garrison Keillor to provide the setting for the radio broadcast, Prairie Home Companion. On the show Keillor says the town's name comes from a fictional old Indian word meaning "the place where we waited all day in the rain [for you].">>
Last edited by neufer on Tue Jul 31, 2018 2:59 pm, edited 1 time in total.
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Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by MarkBour » Tue Jul 31, 2018 2:56 pm

star strukk wrote:
Tue Jul 31, 2018 7:08 am
white rhinocerus went extinct on earth in 2015.
111 years after the creature was given a scientific name it went extinct.
...
Not accurate. Only the northern white rhino is (most likely) extinct.
https://en.wikipedia.org/wiki/White_rhinoceros
... The northern white rhinoceros or northern square-lipped rhinoceros (Ceratotherium simum cottoni) is considered Critically Endangered and Possibly Extinct in the Wild. ... the southern white rhinoceros, with an estimated 19,682–21,077 wild-living animals in the year 2015.
Mark Goldfain

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Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by neufer » Tue Jul 31, 2018 3:31 pm

MarkBour wrote:
Tue Jul 31, 2018 2:56 pm
star strukk wrote:
Tue Jul 31, 2018 7:08 am

white rhinocerus went extinct on earth in 2015.
111 years after the creature was given a scientific name it went extinct.
...
Not accurate. Only the northern white rhino is (most likely) extinct.
https://en.wikipedia.org/wiki/Northern_white_rhinoceros wrote:
<<The northern white rhinoceros, or northern square-lipped rhinoceros (Ceratotherium simum cottoni), is one of two subspecies of the white rhinoceros (the other being the southern white rhinoceros). As of 25 July 2018 there were only two known rhinos of this subspecies left, both of which are female; barring the existence of unknown or misclassified male northern white rhinos elsewhere in Africa, this makes the subspecies functionally extinct. The two female rhinos belong to the Dvůr Králové Zoo in the Czech Republic but live in the Ol Pejeta Conservancy in Kenya and are protected round-the-clock by armed guards. In 2015, scientists from the Leibniz Institute for Zoo and Wildlife Research, San Diego Zoo Global, Tiergarten Schönbrunn, and Dvůr Králové Zoo developed a plan to reproduce northern white rhinos using natural gametes of the living rhinos and induced pluripotent stem cells. Subsequently, in the future, it might be possible to specifically mature the cells into specific cells such as neurons and muscle cells, in a similar way in which Katsuhiko Hayashi has grown mice out of simple skin cells. The DNA of a dozen northern white rhinos has been preserved in genetic banks in Berlin and San Diego.>>
Art Neuendorffer

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Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by GoshOGeeOGolly » Tue Jul 31, 2018 4:22 pm

Yet another Galactic fishing hole. Oh, the wondrous opportunity to fly fishermen .. those who fly in spaceships that is.

Catalina

Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by Catalina » Tue Jul 31, 2018 5:03 pm

During which Martian "season" was this photo of the pole taken? Spring, summer, winter, or autumn?

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Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by Chris Peterson » Tue Jul 31, 2018 5:20 pm

Catalina wrote:
Tue Jul 31, 2018 5:03 pm
During which Martian "season" was this photo of the pole taken? Spring, summer, winter, or autumn?
The image was made on 17 December 2012. That was about halfway between the southern spring equinox (29 Sep 2012) and the southern summer solstice (23 Feb 2013). If this image were of Earth's southern pole, it would correspond to early November. Late spring or early summer.
Chris

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Popeye

Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by Popeye » Wed Aug 01, 2018 4:09 pm

Looks like Pluto

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Re: APOD: Layers of the South Pole of Mars (2018 Jul 31)

Post by neufer » Wed Aug 01, 2018 5:37 pm

De58te wrote:
Tue Jul 31, 2018 10:17 am
emanueldewitt wrote:
Tue Jul 31, 2018 8:09 am

What are we seeing? 1 m? 1 km? 100 km?
Giving an idea of length/distance in a photo would be a good custom.
According to the 'image' link, the Southern Mars Cap is around 350 km in diameter.
https://en.wikipedia.org/wiki/Martian_polar_ice_caps wrote:
<<The south polar permanent cap is much smaller than the one in the north. It is 400 km in diameter, as compared to the 1100 km diameter of the northern cap. Part of the ice cap consists of dry ice, solid carbon dioxide. Each winter the ice cap grows by adding 1.5 to 2 meters of dry ice from precipitation from a polar-hood of clouds. In summer, the dry ice sublimates (goes directly from a solid to a gas) into the atmosphere. During each year on Mars as much as a third of Mars' thin carbon dioxide (CO2) atmosphere "freezes out" during the winter in the northern and southern hemispheres. The south polar cap is higher in altitude and colder than the one in the north.

The residual southern ice cap is displaced; that is, it is not centered on the south pole. Studies have shown that the off center cap is caused by much more snow falling on one side than the other. On the western hemisphere side of the south pole a low pressure system forms because the winds are changed by the Hellas Basin. This system produces more snow. On the other side, there is less snow and more frost. Snow tends to reflect more sunlight in the summer, so not much melts or sublimates. Frost, on the other hand has a rougher surface and tends to trap more sunlight, resulting in more sublimation.

Research, published in April 2011, described a large deposit of frozen carbon dioxide near the south pole. Most of this deposit probably enters Mars' atmosphere when the planet's tilt increases. When this occurs, the atmosphere thickens, winds get stronger, and larger areas on the surface can support liquid water. Analysis of data showed that if these deposits were all changed into gas, the atmospheric pressure on Mars would double. There are three layers of these deposits; each is capped with a 30-meter layer of water ice that prevents the CO2 from sublimating into the atmosphere. In sublimation a solid material goes directly into a gas phase. These three layers are linked to periods when the atmosphere collapsed when the climate changed.>>
Popeye wrote:
Wed Aug 01, 2018 4:09 pm
  • Looks like Pluto
https://en.wikipedia.org/wiki/Sputnik_Planitia wrote:
<<The informal name Sputnik Planum was first announced by the New Horizons team on a press conference on 24 July 2015. A planum is a flat region of higher elevation (a plateau). When topographical data was analyzed in early 2016, it became clear that Sputnik is actually a basin, and the informal name was changed to Sputnik Planitia. Sputnik Planitia is presently close to the anti-Charon point on Pluto, a result that has less than a 5% probability of arising by chance. Sputnik Planitia, the western lobe of the "Heart", is a 1,000 km-wide basin of frozen nitrogen and carbon monoxide ices, divided into polygonal cells, which are interpreted as convection cells that carry floating blocks of water ice crust and sublimation pits towards their margins; there are obvious signs of glacial flows both into and out of the basin. It has no craters that were visible to New Horizons, indicating that its surface is less than 10 million years old.

A high seasonal thermal inertia of Pluto's surface is an important driver of deposition of nitrogen ice at low latitudes. These latitudes receive less annual insolation than Pluto's polar regions due to its high obliquity (122.5°). The coldest regions on Pluto, on average, are at 30° N. and S. latitude; early in Pluto's history, ice would tend to accumulate at these latitudes in a runaway process due to the positive feedback association of increased albedo, cooling and further ice deposition (similar to the ice segregation that occurred on Iapetus). Simulations suggest that over a period of about a million years, the runaway process would collect much of the ice into a single cap even in the absence of a preexisting basin.>>
Art Neuendorffer