If there’s one thing Pluto turned out to have beyond all expectation, it’s geological activity. New Horizons is now showing us what researchers are calling ‘hills of water ice’ floating in a sea of frozen nitrogen, much like icebergs moving through our own Arctic Ocean. The isolated hills are thought to be fragments of the water ice in the surrounding upland regions. Measuring several kilometers across, they are found in Sputnik Planum, a plain within Pluto’s ‘heart.’
Image: The image shows the inset in context next to a larger view that covers most of Pluto’s encounter hemisphere. The inset was obtained by New Horizons’ Multispectral Visible Imaging Camera (MVIC) instrument. North is up; illumination is from the top-left of the image. The image resolution is about 320 meters per pixel. The image measures a little over 500 kilometers long and about 340 kilometers wide. It was obtained at a range of approximately 16,000 kilometers from Pluto, about 12 minutes before New Horizons’ closest approach on July 14, 2015. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.
The hills, according to this JHU/APL news release, are probably upland fragments that are being carried by nitrogen glaciers into the ice plain. When they reach the central cellular terrain of Sputnik Planum, convective motion of the nitrogen ice pushes them to the edges of the cells, where they can be found in groups. Look toward the top of the image for Challenger Colles, where a large number of hills are found in an area roughly 60 by 35 kilometers. Near the boundary with the uplands and away from Sputnik Planum’s cellular terrain, this may be a region where the hills have run aground thanks to the shallowness of the nitrogen ice.
Learning about Pluto’s terrain as New Horizons data continues to stream in, I’m remembering how we used to imagine it. Digging around recently in my collection of old magazines, I uncovered the June, 1935 issue of Astounding Stories, then in the hands of editor F. Orlin Tremaine (this was two years before John Campbell took over). A story by Raymond Z. Gallun caught my eye because of its title: “Blue Haze on Pluto.” You’ll recall that last Monday we took another look at the real blue haze on Pluto as seen by New Horizons.
In Gallun’s story, a stranded astronaut has crashed into a deep crevasse and is forced to trek to a settlement on Pluto, learning as he does about a strange form of life that, in the Plutonian night, “…glimmered like serried hosts of huge gems in whose hearts icy fire of every hue throbbed and cascaded.” All of this in a landscape of “steep crags, part ice, part frozen atmosphere” that could stand in pretty well for parts of Pluto we see today. It’s not a bad tale for its day (our hero is, of course, rescued, with the ‘blue haze’ playing an inadvertent role), but for me its value is in that interesting interplay between the distant thing imagined and the distant thing observed, that generative place where our preconceptions are transformed by the incoming flow of data.
It really does look like they are floating, trapped at the boundaries of convection cells where subduction is occurring.
What about all those tiny, even, “pits” in the lower half of the image. What are they and how are they formed?
Could Pluto become an ocean world way in the future?
http://www.exoclimes.com/topics/the-far-future-of-the-solar-system-pluto-as-an-ocean-planet/
Huh, very interesting :) Even better, I suspect that humanity will have the technology to terraform Pluto or at least hasten its journey to an ocean planet! It would take vast orbital mirrors, nuclear power plants, and probably a great deal of genetically engineering microbial life, but definitely a possibility.
This reminds me of the network science officer’s reply when asked what we should expect to see as Voyager approached the Galilean moons. Essentially he told us to expect something probably not unlike our own moon.
Slowly our candle burns a bit brighter.
“If there’s one thing Pluto turned out to have beyond all expectation, it’s geological activity.”
I wonder. It seems more like weather than geology, depending on whether the energy primarily comes from internal heat and processes rather than solar energy.
Well said Paul. SF readers of the Baby Boom generation have had the experience of living on the cusp of imagination and revelation.
We are both very lucky and very unlucky, the latter because we can sense now what we will never get to see.
Not a unique experience, but in the ‘century of the jackpot’ to misplace a title, that experience of being on the cusp has a greater intensity than ever.
Pluto is not just another chunk of rock, but a remarkable and complex body. To not call it a fully-fledged planet is looking to be increasingly misguided.
If you want the term “planet” to be anything other than arbitrary, then Pluto cannot be a planet. If you want Pluto to be included, the changed definition would have to include at least a dozen other dwarf planets, which would be rather silly.
I fail to see why it would be silly.
Bodies vary in size from dust particles to stars, along some power law. It doesn’t appear to me that “planet” is actually a natural class. And if we decided tomorrow that both Pluto AND Ceres were “planets”, there’d be nothing contradictory about the decision.
It’s just an arbitrary category.
Planet is absolutely a rational class in the sense that any scientific categorization of nature is rational. If you dismiss the planetary category as arbitrary, you must out of principle also dismiss all biological categorization. From your train of thought, one could similarly state that the different between eukaryotes and prokaryotes are wholly arbitrary because after all, they are both cells.
My point is that, yes, Pluto and Ceres and every single object orbiting the sun are indeed planetary by definition. But that term is incredibly broad and covers every single collection of atoms in the solar system. As such, it is utterly useless to use that term in astronomy. Consequently, astronomy has developed myriad categories to better order our understanding of the solar system: there are comets, asteroids, gas giants, moons, meteoroids, planets, dwarf planets, and many more.
There can’t be and so won’t be a definition of planet that isn’t arbitrary. As Neils Bohr so aptly put the matter: “It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we say about nature.” And what we say about ourselves, and so we have this penchant for categorizing things, to eliminate all of the gray and have the piece viewed in patterns of black and white….nice, clean, clear, dividing lines. And so observing the IAU, a study in human psychology rather more than a study of immutable truth.
While I highly value his scientific contributions, Bohr’s philosophy of science is a bit dated.
As for the concept of categorization as an attempt to “eliminate all the gray”, it must be acknowledged that any implication that there are no vaguely discernible blacks and whites to be found also necessarily implies that science as a method of understanding the world and developing knowledge is no better than any other method, like pseudoscience.
In the context of defining what a planet is, astronomers have understood that – following the discover of at least another dozen planetary bodies approximately the same size and mass of Pluto – considering it a planet in the sense that the other eight are planets would be unscientific and confusing. At least the eight planet solar system, however “arbitrary”, is reasonably logical and rational in its composition. Furthermore, your critique of any conception of “planet” as arbitrary leads you down a dangerous path, for what is science if not a method of better understanding the world by way of making distinctions between its many parts? If you consider this “arbitrary” nature of science negative in the sense that it externally appears to be nothing more than humans assigning technically random linguistic and conceptual signifiers to apparently distinct events and objects that exist within the universe following observations of those events and things, then you are taking a stance that is incoherent at best if you desire to value science as a system at all without contradicting yourself.
Note: No hard feelings, feel free to critique my retort as you please. I just love the philosophy of science :)
Pluto may not be a Planet but it has the heart of one : )
I feel in the far distance future alas it will be dismantled for colonies for the great outwards expansion of humanity.
Andrew, everything we’ve visited, including numerous moons, are “remarkable and complex bodies”. This has no connection to planetary status though.
WHAT AN INCREDIBLE WEEK FOR DWARF PLANETS! A frozen nitrogen lake on Pluto, and that CRAZY shape-shifting THING in the middle of Occator crater on CERES!