APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

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APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by APOD Robot » Mon Feb 22, 2016 5:06 am

Image Flying Over Pluto's Moon Charon

Explanation: Given some poetic license, there is now scientific evidence that hell has frozen over. To start, Greek mythology holds that Charon is the ferryman of the underworld. Next, recent analysis of data taken by the robotic New Horizons spacecraft that shot past Charon -- the namesake that is the largest moon of Pluto -- in July now indicates that the cause of the huge chasm that runs across the 1200-km moon was that a huge internal sea froze. And since water expands when it freezes, the already hardened outer crust could not contain it and cracked. To better picture the crack, a fanciful journey over some of Charon's has been digitally created from collected images. The featured video starts by showing the Dark Polar Deposit (dubbed Mordor) near Charon's north pole and then flies over the dwarf-planet-wide canyon. Last, the video shows a much-debated protuberance called Moated Mountain. Understanding the history of Pluto and Charon is helping humanity to better understand both the friendliest and more forbidding places in the early Solar System from which Earth formed and life somehow emerged.

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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by Boomer12k » Mon Feb 22, 2016 8:31 am

Um....should that not be MOON wide canyon???

Also, does not look like a crack...many places have similar features, but don't postulate water freezing beneath them. The Moon for one...Mars for another...

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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by De58te » Mon Feb 22, 2016 11:00 am

Ahh, gotta love astronomers! Wonder why a video from NASA, Johns Hopkins U, and others, gave it a name of 'planet-wide canyon' in the video when Charon isn't a planet? Even the larger Pluto isn't a planet.

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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by runge200 » Mon Feb 22, 2016 12:54 pm

The featured video as an imaginative travel is excellent, impressive and just WOW. Please more of " flying over ".

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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by neufer » Mon Feb 22, 2016 12:55 pm

https://en.wikipedia.org/wiki/Pluto wrote:
<<Pluto & Charon are sometimes considered a binary system because the barycenter of their orbits does not lie within either body. The IAU has not formalized a definition for binary dwarf planets, and Charon is officially classified as a moon of Pluto.>>
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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by Chris Peterson » Mon Feb 22, 2016 2:46 pm

De58te wrote:Ahh, gotta love astronomers! Wonder why a video from NASA, Johns Hopkins U, and others, gave it a name of 'planet-wide canyon' in the video when Charon isn't a planet? Even the larger Pluto isn't a planet.
Formally, Pluto is a "dwarf planet", which also requires it be a planet. Informally, Charon is commonly considered a dwarf planet, as well. So outside a scientific paper, where people would be more strict about observing IAU conventions (although not always), the usage is perfectly reasonable. (One reason a lot of astronomers largely ignore the IAU planet definition is because it doesn't work very well, and it simply doesn't matter, because how the word is used virtually never interferes with understanding.)
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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by heehaw » Mon Feb 22, 2016 3:24 pm

When we have colonies on every orb, it will be so much fun: tourists from Charon visiting their relatives on Mercury and vice versa, and tourists from Titan visiting their relatives on our colonies all over Venus! Won't it be great? Of course, that's a few years from now, but hey, the USA is almost back to being able to put people into orbit without help from our dear friends...

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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by ta152h0 » Mon Feb 22, 2016 10:54 pm

I wonder now if Triton and Pluto are related ? both about equally weird :D
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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by Nitpicker » Tue Feb 23, 2016 12:13 am

heehaw wrote:When we have colonies on every orb, it will be so much fun: tourists from Charon visiting their relatives on Mercury and vice versa, and tourists from Titan visiting their relatives on our colonies all over Venus! Won't it be great? Of course, that's a few years from now, but hey, the USA is almost back to being able to put people into orbit without help from our dear friends...
I suspect that if there are ever human colonies spread throughout the solar system, the political map of Earth will be significantly different from what it is now. Proper nouns like "China", "USA", "Russia", etc, may well have become historical artifacts.

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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by Chris Peterson » Tue Feb 23, 2016 12:18 am

Nitpicker wrote:
heehaw wrote:When we have colonies on every orb, it will be so much fun: tourists from Charon visiting their relatives on Mercury and vice versa, and tourists from Titan visiting their relatives on our colonies all over Venus! Won't it be great? Of course, that's a few years from now, but hey, the USA is almost back to being able to put people into orbit without help from our dear friends...
I suspect that if there are ever human colonies spread throughout the solar system, the political map of Earth will be significantly different from what it is now. Proper nouns like "China", "USA", "Russia", etc, may well have become historical artifacts.
Or the main reason that the colonies will exist is because Earth is no longer habitable. Which also means "China", "USA", "Russia" could be historical artifacts. Unless those are the names of the colonies.

Our technological progress far outpaces our social progress, after all.
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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by neufer » Tue Feb 23, 2016 12:30 am

ta152h0 wrote:
I wonder now if Triton and Pluto are related ?
  • Triton is a nephew of Hades/Pluto.
https://en.wikipedia.org/wiki/Triton_%28mythology%29 wrote:
<<Triton is the son of Poseidon/Neptune and Amphitrite, god and goddess of the sea respectively, and is herald for his father. He is usually represented as a merman, having the upper body of a human and the tail of a fish, "sea-hued", according to Ovid "his shoulders barnacled with sea-shells".>>
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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by MarkBour » Tue Feb 23, 2016 12:44 am

So, the label "dwarf planet" appears to be right. Only the race of dwarves could have excavated such a massive trench. I want to visit it someday, to see what great works they've done in their caves. Do you have any elf planets in this solar system? :D

Seriously, this rift looks comparable to Valles Marineris on Mars. But I like the cooling core theory here, whereas on Mars, it would need to be a different mechanism. Perhaps drying out?
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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by Nitpicker » Tue Feb 23, 2016 2:19 am

Chris Peterson wrote:
Nitpicker wrote:
heehaw wrote:When we have colonies on every orb, it will be so much fun: tourists from Charon visiting their relatives on Mercury and vice versa, and tourists from Titan visiting their relatives on our colonies all over Venus! Won't it be great? Of course, that's a few years from now, but hey, the USA is almost back to being able to put people into orbit without help from our dear friends...
I suspect that if there are ever human colonies spread throughout the solar system, the political map of Earth will be significantly different from what it is now. Proper nouns like "China", "USA", "Russia", etc, may well have become historical artifacts.
Or the main reason that the colonies will exist is because Earth is no longer habitable. Which also means "China", "USA", "Russia" could be historical artifacts. Unless those are the names of the colonies.

Our technological progress far outpaces our social progress, after all.
I reckon if humans can make other parts of the solar system habitable, there will still be humans living on Earth, too. (I can't imagine ex-Earth colonies surviving for long periods, without support from Earth.)

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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by neufer » Tue Feb 23, 2016 2:44 am

MarkBour wrote:
Seriously, this rift looks comparable to Valles Marineris on Mars. But I like the cooling core theory here, whereas on Mars, it would need to be a different mechanism. Perhaps drying out?
https://en.wikipedia.org/wiki/Valles_Marineris wrote: <<There have been many different theories about the formation of Valles Marineris that have changed over the years. Ideas in the 1970s were erosion by water or thermokarst activity, which is the melting of permafrost in glacial climes. Thermokarst activity may contribute, but erosion by water is a problematic mechanism because liquid water cannot exist in most current Martian surface conditions, which typically experience about 1% of Earth’s atmospheric pressure and a temperature range of −125° C to 37° C. However, scientists agree that there was liquid water flowing on the Martian surface in the past. Valles Marineris may have been formed by flowing water at this time. Another hypothesis by McCauley in 1972 was that the canyons formed by withdrawal of subsurface magma. Around 1989 Tanaka and Golombek proposed a theory of formation by tensional fracturing. The most agreed upon theory today is that Valles Marineris was formed by rift faults like the East African Rift, later made bigger by erosion and collapsing of the rift walls.

Because Valles Marineris is thought to be a large rift valley, its formation is closely tied with the formation of the Tharsis Bulge. The Tharsis Bulge was formed from the Noachian to Late Hesperian period of Mars, in three stages. The first stage consisted of a combination of volcanism and isostatic uplift; soon, however, the volcanism loaded the crust to a point at which the crust could no longer support the added weight of Tharsis, leading to widespread graben formation in the elevated regions of Tharsis. Stage two consisted of more volcanism and a loss of isostatic equilibrium; the source regions of the volcanism no longer resided underneath Tharsis, creating a very large load. Finally, the crust failed to hold up Tharsis and radial fractures, like Valles Marineris, formed. Stage three mainly consisted of more volcanism and asteroid impacts. The crust, having already reached its failure point, just stayed in place and younger volcanoes formed. Tharsis volcanism involved very low viscosity magma, forming shield volcanoes similar to those of the Hawaiian Island chain, but, because there is minor or no current active plate tectonics on Mars, the hotspot activity led to very long histories of repeated volcanic eruptions at the same spots, creating some of the largest volcanoes in the solar system, including the biggest, Olympus Mons.

Landslides have left numerous deposits on the floor of Valles Marineris and contributed to widening it. Possible triggers of landslides are quakes caused by tectonic activity or impact events. Both types of events release seismic waves that accelerate the ground at and below the surface. Mars is much less tectonically active than Earth, and Mars-quakes are unlikely to have provided seismic waves of the required magnitude. Most sizable craters on Mars date to the Late Heavy Bombardment, 4.1 to 3.8 billion years ago (the Noachian period), and are older than the landslide deposits in Valles Marineris. However, three craters (including the crater Oudemans) have been identified, on the basis of their proximity and later dates, as ones whose formation may have caused some of the landslides.>>
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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by MarkBour » Tue Feb 23, 2016 4:56 pm

neufer wrote:
MarkBour wrote: Seriously, this rift looks comparable to Valles Marineris on Mars. But I like the cooling core theory here, whereas on Mars, it would need to be a different mechanism. Perhaps drying out?
https://en.wikipedia.org/wiki/Valles_Marineris wrote: ... There have been many different theories about the formation of Valles Marineris that have changed over the years. ...
erosion ... thermokarst ... flowing water ... withdrawal of subsurface magma ... tensional fracturing ... rift faults
... three stages: [1] volcanism and isostatic uplift; [2] more volcanism and a loss of isostatic equilibrium; the crust failed to hold up Tharsis and radial fractures, like Valles Marineris, formed. [3] more volcanism and asteroid impacts.
Interesting. This is all pretty hard for me to follow. But it does look, from an image such as this (just widened the field of yours above), that the shield volcanoes are more than a coincidence to Valles Marineris, so that they share a story.
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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by neufer » Tue Feb 23, 2016 8:16 pm

https://en.wikipedia.org/wiki/Graben wrote: <<In geology, a graben is a depressed block of land bordered by parallel faults. Graben is German for ditch or trench. The plural form is either graben or grabens.

A graben is a valley with a distinct escarpment on each side caused by the displacement of a block of land downward. Graben often occur side-by-side with horsts. Horst and graben structures indicate tensional forces and crustal stretching.

Graben are produced from parallel normal faults, where the displacement of the hanging wall is downward, while that of the footwall is upward. The faults typically dip toward the center of the graben from both sides. Horsts are parallel blocks that remain between graben; the bounding faults of a horst typically dip away from the center line of the horst.

Single or multiple graben can produce a rift valley.>>
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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by heehaw » Fri Feb 26, 2016 11:22 pm

heehaw wrote:When we have colonies on every orb, it will be so much fun: tourists from Charon visiting their relatives on Mercury and vice versa, and tourists from Titan visiting their relatives on our colonies all over Venus! Won't it be great? Of course, that's a few years from now, but hey, the USA is almost back to being able to put people into orbit without help from our dear friends...
My posting was, and deliberately, completely asinine. I am astonished by the mild way it was received! Even Mars, with its minimal water, is completely out of the question for human colonization. End the human space program now, and end it forever! Send in the machines!

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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by geckzilla » Sat Feb 27, 2016 12:21 am

I was thinking the only way Earth would be less habitable than Mars is if it became Venus-like. My initial thoughts were similar to Nitpicker's, but I can imagine a runaway greenhouse effect might do the trick. Failing that, perhaps some kind of biological, chemical, or atomic warfare might also do it. It would take one very long, widespread, and determined war effort to bring Earth to that level of awfulness.
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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by Ann » Sat Feb 27, 2016 4:37 pm

geckzilla wrote:I was thinking the only way Earth would be less habitable than Mars is if it became Venus-like. My initial thoughts were similar to Nitpicker's, but I can imagine a runaway greenhouse effect might do the trick. Failing that, perhaps some kind of biological, chemical, or atomic warfare might also do it. It would take one very long, widespread, and determined war effort to bring Earth to that level of awfulness.
I find it hard to believe that we will ever bring the Earth to the sort of utter catastrophe that will make it easier for humans to survive on Mars than on Earth.

Life has evolved on the Earth for three and a half billion years, and we humans are very, very much a product of that evolution. The Earth is in our blood and in our genes. We owe our existence to the biosphere of the Earth.

But we have no connection to Mars, or to any of the other planets.

I don't see how any of the other planets could ever - or, say, within the next million years - offer us humans better living conditions than the Earth, although I do think it is possible that small groups of humans could establish small colonies on a planet like Mars.

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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by MarkBour » Tue Mar 01, 2016 9:24 pm

heehaw wrote:
heehaw wrote:When we have colonies on every orb, it will be so much fun: tourists from Charon visiting their relatives on Mercury and vice versa, and tourists from Titan visiting their relatives on our colonies all over Venus! Won't it be great? Of course, that's a few years from now, but hey, the USA is almost back to being able to put people into orbit without help from our dear friends...
My posting was, and deliberately, completely asinine. I am astonished by the mild way it was received! Even Mars, with its minimal water, is completely out of the question for human colonization. End the human space program now, and end it forever! Send in the machines!
Now it's getting rather hard to tell which part is in jest and which is serious.
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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by Nitpicker » Tue Mar 01, 2016 11:35 pm

heehaw wrote:
heehaw wrote:When we have colonies on every orb, it will be so much fun: tourists from Charon visiting their relatives on Mercury and vice versa, and tourists from Titan visiting their relatives on our colonies all over Venus! Won't it be great? Of course, that's a few years from now, but hey, the USA is almost back to being able to put people into orbit without help from our dear friends...
My posting was, and deliberately, completely asinine. I am astonished by the mild way it was received! Even Mars, with its minimal water, is completely out of the question for human colonization. End the human space program now, and end it forever! Send in the machines!
Well, we're all very mild-mannered here on The Starship, apart from the occasional machine. :ssmile:

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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by geckzilla » Wed Mar 02, 2016 12:01 am

I get a little spicy sometimes.
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Re: APOD: Flying Over Pluto's Moon Charon (2016 Feb 22)

Post by Nitpicker » Wed Mar 02, 2016 12:09 am

I suppose there was also my initial response to heehaw, where I foretold the end of China, Russia and the USA. Perhaps not me at my most mild.