Pluto's Peaks Are Ice Volcanoes, Scientists Conclude (theguardian.com) 31
Existence of volcanoes makes idea that dwarf planet is inert ball of ice look increasingly improbable. From a report: Strung out in the icy reaches of our solar system, two peaks that tower over the surface of the dwarf planet Pluto have perplexed planetary scientists for years. Some speculated it could be an ice volcano, spewing out not lava but vast quantities of icy slush -- yet no cauldron-like caldera could be seen. Now a full analysis of images and topographical data suggests it is not one ice volcano but a merger of many -- some up to 7,000 metres tall and about 10-150km across. Their discovery has reignited another debate: what could be keeping Pluto warm enough to support volcanic activity? Sitting at the southern edge of a vast heart-shaped ice sheet, these unusual surface features were initially spotted when Nasa's New Horizons spacecraft flew past in July 2015, providing the first close-up images of the icy former planet and its moons.
"We were instantly intrigued by this area because it was so different and striking-looking," said Dr Kelsi Singer, a New Horizons co-investigator and deputy project scientist at Southwest Research Institute in Boulder, Colorado. "There are these giant broad mounds, and then this hummocky-like, undulating texture superimposed on top; and even on top of that there's a smaller bouldery kind of texture." At the time, an ice volcano seemed like the least-weird explanation for these features -- there were no impact craters from asteroids or meteors nearby, suggesting these features had been erased by relatively recent geological events; and no evidence of plate tectonics -- a key contributor to mountain formation on Earth.
"We were instantly intrigued by this area because it was so different and striking-looking," said Dr Kelsi Singer, a New Horizons co-investigator and deputy project scientist at Southwest Research Institute in Boulder, Colorado. "There are these giant broad mounds, and then this hummocky-like, undulating texture superimposed on top; and even on top of that there's a smaller bouldery kind of texture." At the time, an ice volcano seemed like the least-weird explanation for these features -- there were no impact craters from asteroids or meteors nearby, suggesting these features had been erased by relatively recent geological events; and no evidence of plate tectonics -- a key contributor to mountain formation on Earth.
That's unfortunate (Score:1)
I was really hoping they were made of chocolate cakes filled with hot fudge, and a big dollop of vanilla ice cream on top. I haven't been this disappointed since finding out there's no cheese on the moon.
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Sounds like you were planning a visit.
Why So Warm? (Score:2)
[W]hat could be keeping Pluto warm enough to support volcanic activity?
So many to choose from: Aphoom-Zhah, B'gnu-Thun, Cthaat, Cthugha, Ghatanothoa, Janai'ngo, Tulushuggua, Vthyarilops, ... ; but my money's on Zindarak.
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Obviously, Cthulhu. Cthulhu's water is super-heated you just never knew.
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[W]hat could be keeping Pluto warm
Seething rage over having been demoted.
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General Relativity failed a basic test, successfully classifying gravity as a force.
The Germ Theory failed a basic test, successfully articulating how miasma gets us sick.
Give me a fucking break.
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No matter who said anything, you failed to refute the fact that your logic has all the impressiveness of a 4 year old's musing on the nature of the universe.
You have asserted that a classification regime is invalid unless it includes everything included in the previous regime. This line of reasoning implies that no classification can ever be wrong.
So ya, another stupid fucking response from you. Use your fucking head.
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Goofy.
So it's active. (Score:2)
We already knew there was subsurface liquid water, so heat isn't a surprise. But volcanos would suggest a semi-liquid core and maybe functioning plate tectonics. Looking awfully planetish.
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Why does that matter? Diagnostic criteria that fail to do any useful diagnostics are not useful criteria to have.
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If they were, Mars wouldn't be a planet.
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Mars has a liquid core, we know that from the magnetic field. We know it used to have a magnetic field because it held an atmosphere capable of supporting liquid water on the surface. Therefore, by this criterion, it would indeed be a planet.
Diagnostic criteria have to be useful, I think we can agree on that. Where it is, whether it is orbiting something, and what else is on the orbital path do NOT impact the object of interest and therefore are not useful in describing that object, they only describe a rel
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Mars has a liquid core, we know that from the magnetic field. We know it used to have a magnetic field because it held an atmosphere capable of supporting liquid water on the surface. Therefore, by this criterion, it would indeed be a planet.
No, we do not.
Mars, famously, does not have an intrinsic magnetosphere. Hence why we initially assumed its core was solid.
We surmise that the core is at least partially liquid due to bulges in the gravitational field. We are certain there is no convection, though.
There are other explanations for its gravitational anomalies other than a liquid core, however.
Diagnostic criteria have to be useful, I think we can agree on that. Where it is, whether it is orbiting something, and what else is on the orbital path do NOT impact the object of interest and therefore are not useful in describing that object, they only describe a relationship. This can be very useful if you want terms that are about relationships but is not useful if you want terms that are about the object itself.
This might seem reasonable at first glance, however if we continue down this line of reasoning, you will find it impossible to distinguish between sat
Radiation? (Score:2)
Is there a reason that radioactive isotopes in the core isn't considered the obvious default explanation?
Re: Radiation? (Score:2)
This is what I thought but maybe the conclusion is that these radioactive isotopes should lead naturally to plate tectonics. Thus an inconsistency in how we currently view these mechanisms in planetology.
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Is there a reason that radioactive isotopes in the core isn't considered the obvious default explanation?
Probably because there's an even more obvious explanation in the form of tidal heating. Pluto has a moon that's about 1/8th its mass that orbits 12,200 miles away from it. They orbit around a common center of gravity that is outside Pluto's radius. It seems likely that there's some tidal heating going on there.
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Aren't they tidally locked though? Tidal heating stops once locking occurs.
Though I suppose that may have happened fairly recently, geologically speaking, with the heat from it not having all escaped yet.
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Tidal heating can still occur if the moon has an eccentric orbit, but Charon's orbit is pretty circular.
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What I was attempting to say is that being tidally locked by itself won't stop frictional heat. An eccentric orbit on a facially locked moon can still create heat. Even a circular orbit can create heat if it's not aligned at the planet's equator. But the Pluto-Charon system is pretty "stiff" on all 3 counts. Hmmm, perhaps too stiff...
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Though I suppose that may have happened fairly recently, geologically speaking, with the heat from it not having all escaped yet
Good point about the tidal locking. For them to be tidally locked in the first place, tidal forces had to have acted for a long time to sync them up which could have led to current warmth if it ended not too long ago as you pointed out. I suppose whatever event led to the creation of the Pluto-Charon system in the first place could have led to a lot of residual heat as well. There do seem to be a lot of potential causes.
Another thought here on tidal forces though. When two bodies are tidally locked to each
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Good point on the lighter elements - Pluto has a mean density of about 1.9g/cm3 versus Earth's 5.5. Not that there aren't lighter radioactive elements, but they mostly have geologically short half-lives until you start getting up around iron. There are exceptions - Potassium-40 has a billion-year half-life comparable to U-238 or Th-232, but for whatever reason there's not actually much of it around. https://en.wikipedia.org/wiki/... [wikipedia.org]
Most of the heavier elements had probably already settled inwards closer t
Size (Score:2)
Earths moon is bigger than Pluto, a lot bigger. And, Titan is bigger than Mercury, makes you wonder if mercury was ever a moon....
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Mercury at some point had its outer layer(s) blasted off it seems, judging by its density.
Pluto's a planet again? (Score:2)
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The existence of features that we only find on ice ball satellites of gas giants?