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NASA's New Horizons Shows Pluto's Moon Charon Is a Strange, New World
MarkWhittington writes: NASA's New Horizons has returned a stunning series of images of Pluto, the dwarf planet that resides on the edge of the solar system, revealing a strange new world of ice mountains and glaciers of frozen nitrogen. NASA also released images of Pluto's largest moon Charon. Scientists expected a plain ball of rock pockmarked with craters, but what they saw was anything but plain and monotonous.
s/life/oil/
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
We can, when you're willing to call Vesta, Ceres, Haumea, Makemake, Eris, Sedna, Sila-Nunam, Varuna, Quaoar, Ocrus, Ixion, and likely hundreds of other objects of similar size to Pluto (yet to be identified, as the Kuiper Belt and scattered disc are large search spaces) planets as well.
In order to retain the use of the word "planet" in a context that is relatively closely related to its historical usage, a line has to be drawn somewhere. It is far more logical to draw that line above Pluto than below it. If you are advocating for every object which is large enough to pull itself into hydrostatic equilibrium by gravity, and is not in orbit around another non-stellar object a planet -- you're going to have upwards of 100 of them, and that's just what we know of right now.
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
The New Horizons team refers to it as a planet. New Horizons head Alan Stern is one of the leading advocates for the reversal of the IAU decision. Pluto and other large KBOs have been referred to many times as planets in peer-reviewed literature since the IAU decision. One of the NASA links in this article itself refers to Pluto as a planet ("At half the diameter of Pluto, Charon is the largest satellite relative to its planet in the solar system."). Large numbers of people in the field - I'd wager a solid majority of planetary scientists (who make up only a small minority of the IAU's membership but really should be the ones making these decisions) - think the IAU seriously screwed up here. There are literally dozens of reasons why it was a screwup - need I go into them?
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Says who?
Some of the models call for a liquid water layer inside Pluto (if that's even a requirement). It has a young surface, younger than Mars; resurfacing** means energy and transport of chemicals between layers. And it's covered in tholins, meaning long-chain organics.
I'm not saying that there's life on (or rather, in) Pluto. Personally, I expect life to be pretty rare in the cosmos. But ruling it out just because it's far from the sun seems quite unreasonable. Look at all of the people oggling the finding of "water" on Mars (a more accurate headline would have been "Scientists find mildly damp rocket fuel on Mars"). Pluto could potentially have a subsurface ocean with organics actively cycling into it.
** - Heck, the best guess right now for what Sputnik Planum is is that it's a giant convecting nitrogen-ice "sea", like having the mantle exposed to the surface. If it truly is convecting then it's dragging down any heavier materials at the edges of its convection cells down into Pluto's (warmer) depths.
Crowd: What do we want? Fry: Fry's dog! Crowd: When do we want it? Fry: Fry's dog!
Right. If you're looking for hydrocarbons, Pluto may not be the best spot. Titan has oceans of liquid natural gas, though.
Seriously dude, do you not have better things to do with your time?
These fucking nutters may suggest otherwise. http://www.theregister.co.uk/2... Jeez, sometimes I wonder what is going on in the brains of some people and can only conclude that the answer is "nothing"
First, the IAU definition:
1. Nomenclature: An "adjective-noun" should always be a subset of "noun". A "dwarf planet" should be no less seen as a type of planet than a "dwarf star" is seen as a type of star.
2. Erroneous foundation: Current research suggests that most planets did not clear their own neighborhoods, and even that their neighborhoods may not always have been where they are. Jupiter, and Saturn to a lesser extent, have cleared most neighborhoods. Mars has 1/300th the Stern-Levison parameter as Neptune, and Neptune has multiple bodies a couple percent of Mars's mass (possibly even larger, we've only detected an estimated 1% of large KBOs) in its "neighborhood". Mars's neighborhood would in no way would be clear if Jupiter did not exist - even Earth's might not be. Should we demote the terrestrial planets as well?
3. Comparative inconsistency: Earth is far more like Ceres and Pluto than it is like Jupiter, yet these very dissimilar groups - gas giants and terrestrial planets - are lumped together as "planets" while dwarfs are excluded.
4. Poor choice of dividing line: While defining objects inherently requires drawing lines between groups, the chosen line has been poorly selected. Achieving a rough hydrostatic equilibrium is a very meaningful dividing line - it means differentiation, mineralization processes, alteration of primordial materials, and so forth. It's also often associated with internal heat and, increasingly as we're realizing, a common association with subsurface fluids. In short, a body in a category of "not having achieved hydrostatic equilibrium" describes a body which one would study to learn about the origins of our solar system, while a body in a category of "having achieved hydrostatic equilibrium" describes a body one would study, for example, to learn more about tectonics, geochemistry, (potentially) biology, etc. By contrast, a dividing line of "clearing its neighborhood" - which doesn't even meet standard #2 - says little about the body itself.
5. Mutability: What an object is declared at can be altered without any of the properties of the object changing simply by its "neighborhood" changing in any of countless ways.
6. Situational inconsistency: An exact copy of Earth (what the vast majority of people would consider the prototype for what a planet should be), identical down to all of the life on its surface, would not be considered a planet if orbiting in the habitable zone of a significantly larger star (harder to clear zone), or a young star (insufficient time to clear), a star without a Jupiter equivalent (no assistance in clearing), or so forth.
Crowd: What do we want? Fry: Fry's dog! Crowd: When do we want it? Fry: Fry's dog!
I wouldn't have any problem calling all of those hundreds of objects planets. Doing so wouldn't necessitate us to force every 6th grader to learn all their names - we can just say ".. Uranus, Neptune, and then a great number of tiny planets further out".
New rule: there's only 8 rivers on Earth, and all others are "dwarf rivers" and don't really count as rivers. In order to retain the use of the word "river" in a context that is relatively closely related to its historical usage when people were primitive tribesmen and only knew of a few rivers in their area, a line has to be drawn somewhere. It is far more logical to draw that line above the Brahmaputra than below it. If you are advocating for every river which is large enough to be too deep and fast flowing to ford a river -- you're going to have upwards of 100000 of them, and that's just what we know of right now.
New rule: there are only organs in the human body, and all others are "dwarf organs" and don't really count as organs. In order to retain the use of the word "organ" in a context that is relatively closely related to its historical usage, a line has to be drawn somewhere. It is far more logical to draw that line above the spleen than below it. If you are advocating for every object which is large enough to have a distinct biological function, and is not a part of another organ an organ -- you're going to have many hundreds if not thousands of them, and that's just what we know of right now.
New rule: there are only 8 elements, and all others are "secondary elements" and don't really count as elements. In order to retain the use of the word "element" in a context that is relatively closely related to its historical usage, a line has to be drawn somewhere. It is far more logical to draw that line above bismuth than below it. If you are advocating for every particle which contains a unique number of protons to be called an element -- you're going to have 118 of them, and that's just what we know of right now.
Shall I keep going?
It is in no way, shape or form scientific to define what something is based on whether schoolchildren can memorize a list of all of them. Time and time again, ancient peoples have created names for things thinking that there's only a small number of them, and later scientists discovered that there's actually a vast diversity of them. Well, guess what, you deal with that and accept that the universe is a fascinating place rather than trying to hide it with definitions that aren't even internally consistent or in alignment with our models of what actually cleared most "neighborhoods" in our solar system (hint: it wasn't planets like Mars).
And you certainly don't do so in opposition to the very perception of the word itself. People look at pictures of Pluto and they see a planet. Because it's a giant chunk of rock orbiting a star - yes, there are bigger ones, but it's still huge, so large that gravity crammed it into a sphere, setting of processes of mineralization, tectonics, and so forth - which more to the point appear to be still active to this day. People turn on Star Trek and when they see the Enterprise arrive at a body like Pluto, they expect to hear Captain Kirk say "Beam me down to the planet", not "Beam me down to this... hmm, Spock, I'm not sure what to call it, could you run a long-range scan to see if it has "cleared its neighborhood"... oh wait, I forgot, "planets" can only be objects in orbit around the sun, there is no name for whatever this thing is!"
Crowd: What do we want? Fry: Fry's dog! Crowd: When do we want it? Fry: Fry's dog!
Can we send a moon to crash into Pluto, making it large enough to be a planet by the new definition? ;-)
== Jez ==
Do you miss Firefox? Try Pale Moon.
These other objects have a name: Dwarf Planets. I will grant that this is moderately confusing, as you would expect anything with "planet" in its name to be a subset of "planets" as a whole, thus I've never cared for this nomenclature. However, it's pretty clear to my eyes that Pluto and Charon are Kuiper Belt Objects, fundamentally unlike the rocky inner planets or the enormous gas and ice giant outer planets. The fact that Pluto turns out to be pretty damn interesting doesn't make it not a KBO. It seems pretty apparent there is a need to distinguish between what are currently deemed planets, and everything else. If you wanted to call the eight current planets "major planets" and everything else just "planets", fine, whatever -- but you seem to be denying that there is any reason to draw the distinction at all. There is. For the most part, planets are visible to the naked eye. Inner planets are small, but close enough (to the sun, and to us) to be bright. The outer planets are large enough to make up for the increased distance. Neptune admittedly requires some optical assistance to spot, but it's so much like its cousin Uranus that it again becomes an argument over where to draw boundaries. Neptune has had a significant effect on the dynamics of the system as a whole. It was discovered because of the perturbations it was causing elsewhere, and likely had a great deal to do with scattering all those KBOs in the first place (as well as capturing one for itself). There is no such claim for Pluto. It is little more than a blob to the HST.
Don't get me wrong, I'm quite pleased we sent a probe there. I'm even more pleased it has returned results that are greatly in excess of expectations. We will find out with the trip past the next KBO whether it's typical. (If the next one is boring, that doesn't really tell us which of the two is typical, but if the next one shows similar signs of resurfacing, it's probably a safe bet that this is the rule rather than the exception.) That still doesn't mean it requires the use of the word "planet".
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
Hmm.
I hate to respond to my own comment, but something just occurred to me.
That was in reference to the fact that the "water streaks" are not "water", but rather deliquescent perchlorate salts that managed to draw enough water out of the atmosphere to create damp streaks on the surface. Perchlorates are most famously used as the oxidizer in a number of rocket fuel mixtures, and seem to be very abundant in the Martian regolith, all over the planet - it makes up about half a percentage of its mass. This is of course bad for the search for life - they make a better hand sanitizer than they do a growth medium.
But could one actually use them for what we use them for on Earth - rocket fuel?
They're readily soluble - many are even deliquescent - and so should be very easy to extract with nothing more than water in a closed loop, consuming little energy (compared to the amount of energy needed to produce oxygen as an oxidizer on Mars). And the oxidizer is the heavier portion of a rocket propellant. Rather than the concept of making Mars return propellant from turning atmospheric CO2 and water-electrolysis hydrogen (or Earth-imported hydrogen**) into methane, and liquefying oxygen as an oxidizer, you could use the easy-to-extract perchlorates as your oxidizer. A clever rover wheel or tread design could scoop up regolith as it crawls, wash it, dry it, and return it in a continuous process.
Calcium perchlorate, for example, is a common Martian perchlorate - Ca(ClO4)2. It burns with hydrogen (14 H2) to produce CaO + Cl2 + 7 H2O. It burns with methane (3,5 CH4) to produce CaO + Cl2 + 3,5 CO2 + 3.5 H2O. In the former case, that's 28 AMU of hydrogen per 239 AMU of calcium perchlorate, or a ratio of 1:8.5. In the latter case, it's 14 AMU of hydrogen per 239 of calcium perchlorate, or a ratio of 1:17 - meaning you need very little hydrogen per unit mass of oxidizer (which is a very good thing!**). LOX/H2 and LOX/CH4 are, by contrast, ratios of 1:4 and 1:8, respectively. Now, using perchlorate as an oxidizer yields a propellant that's not as high ISP as using LOX, of course, but for the first stage (the heavy stage), you don't need a super-high ISP. Calcium perchlorate is 2 1/2 times denser than LOX (a huge advantage in terms of reducing tankage mass), suffers no thermal management issues at practical Martian temperatures, and being a solid rather than a liquid does not slosh. The ISP of the propellent mix can be improved by converting the calcium perchlorate to ammonium perchlorate, at a cost of complexity and additional raw materials (imported hydrogen + local Haber process or imported NH3). If a pure solid rocket is desired rather than a hybrid, methane can be polymerized with heat and catalysts to heavier hydrocarbons that will solidify when allowed to cool to Martian ambient temperatures. This process would further reduce the amount of hydrogen that needs to be imported, as hydrogen gas gets released during polymerization.
Not saying that this is the best of approaches. It's just an approach I haven't heard discussed before as far as locally produced propellants are concerned.
** While most people assume local Martian hydrogen and oxygen from electrolysis of Martian ice, this is far harder than most people assume, and not simply because mining hard materials on another world is so potentially difficult. Our history of experience with electrolysis in space has been fraught with problems (see the ISS for examples), and that's with about as tightly controlled feedstocks as you can get. On Mars you're dealing with not pure water ice, but rather frozen muck. Hence the lower-risk proposals call for using a solid oxide fuel cell to convert CO2 to CO+O2 to get the oxygen and importing the hydrogen.
Crowd: What do we want? Fry: Fry's dog! Crowd: When do we want it? Fry: Fry's dog!
The planet Pluto is a planet because planet is a word, and words are part of language and language is an UNCONTROLLED interchanged between people.
So you're really getting upset by this, but in doing so you're accepting the IAU as an authority on the matter. You could simply continue to call Pluto a planet and it is a planet and nothing has changed about planet Pluto.
See point 19.
Really its not about 'disagreeing' with IAU, its simply that they don't control the language and if their decision doesn't have any traction in the language then tough. Its not worth fretting about it, just keep calling it a planet and its a planet.
Yes, it's stupid, confusing, and the IAU needs to revisit their bad decision even if only for this reason, rather than letting it fester.
You apparently see no problem grouping together the rocky inner planets with the enormous gas and ice giant outer planets. Yet you have a fundamental problem with grouping the rocky inner planets with bodies like Ceres and Pluto that they share far more in common with.
And yes, Pluto and Charon are KBOs. KBOs are an orbital designation, one type among many. Mercury, Venus, Earth and Mars also have an orbital designation, for example - "inner planets". An orbital designation can quite happily sit side by side with a classification of an object based on what its actual physical characteristics are.
You're avoiding the question: why? What's so damned logical about grouping Mars with Jupiter, but not with Ceres or Pluto? And what was "currently deemed planets" included Pluto until the IAU decided to butt in, so that argument buys you nothing. They changed the status quo, they weren't preserving it.
Hydrostatic equilibrium is a highly logical dividing line. It has meaning, unlike whether a neighborhood has been cleared (usually by a larger second party, I should add, not by the planet itself - the IAU definition is built on a foundation that is a lie, that the "8 planets" cleared their own neighborhoods). When a body relaxes into hydrostatic equilibrium, it not only changes shape, but it differentiates and remineralizes. It becomes a fundamentally new type of body, with internal structure, non-primordial minerals, and internal heat flows (even if they - like everything else - eventually die). One studies bodies that are in non-hydrostatic equilibrium to learn about the primordial solar system, while one studies bodies that are in hydrostatic equilibrium to learn about planetary evolution, to search for life, etc. It's a distinct dividing line. Let's not pretend that it's not there. Or that it doesn't need a term to refer to it. Such as the term we've been using this whole damned time - "planet".
Which is why the ancients knew of Uranus and Neptune, right? Oh wait... Sorry, I guess they're not planets!
And again: why don't we just lock all sciences down by what the ancients knew? Sorry, guys, there's only 8 elements - copper, sulfur, tin, gold, antimony, mercury, and lead - everything else is just "earths"! Or maybe we should just stick with the 4 elements? Because that's the whole point of science, after all - rote memorization of things that people in long-extinct societies declared in their ignorance.
"all" is of course a falsehood. For many KBOs, Neptune has little effect. And here's a category for you to ponder while you're at it: the Sednoids. One of the leading theories is that there's a body out there, potentially in the ballpark of the size of the Earth, that's scattering them;
Crowd: What do we want? Fry: Fry's dog! Crowd: When do we want it? Fry: Fry's dog!
You could replace Pluto with an exact copy of Earth, and it still wouldn't be called a planet under the IAU's definition.
Crowd: What do we want? Fry: Fry's dog! Crowd: When do we want it? Fry: Fry's dog!
Not really. We can call Pluto a "planet" and call the asteroids asteroids and call the Kuiper Belt objects Kuiper Belt objects. There's no particular need to go into a frenzy over it. The reality is that there is going to be range of sizes of objects, from "almost suns" down to pebbles, so sweating exactly how you are going to name objects is ridiculous.
An "adjective-noun" should always be a subset of "noun". A "dwarf planet" should be no less seen as a type of planet than a "dwarf star" is seen as a type of star.
Exactly! Dwarf planet, red planet, giant planet... they're all still planets, just with useful and informative adjectives stuck on the front.
Is it just me or did Earth get stuck with possibly the most boring satellite in the entire solar system?
Plutos existance was also predicted by the perturbations it did to the rest of the solar system. Uranus is only visible to the naked eye when it is close to the sun. That is why we "classically" only have 5 planets: Merkur, Venus, Mars, Jupiter and Luna, the Greeks and Babylonians counted Luna as planet and did not figure that earth is one, too. (Yes, the greek already knew that the Earth is a sphere, so)
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
Rest assured, when I talk about the planet Pluto, I always will refer to it as a planet. I probably will even start always prefix "Pluto" with "planet", or even a capital Planet! Just so as I'm used to address a Mr. Smith and a Ms. with a capital title.
I for my part welcome New Horizon at Planet Pluto!
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
Calling those bodies planets, and adding more as we find them, perfectly illustrates to people that science is not dogmatic, not immutable. As we learn, we adopt; and when necessary, we change. It's good that we all learned nine planets as children. What's maybe not so good was that we learned the universe is static...and of course it is not.
I'm sorry, but your opinion seems to be wrong.
WTF? How do you even know all this stuff? Seriously... I hold my doctorate in Applied Mathematics and, honestly, I can barely wrap my head around half of what you said and I'm not even sure the total is half. I'm assuming you're a hobbyist and not some sort of astrophysicist. If you are an astrophysicist, then still, how the hell do you manage to retain that well enough to just nonchalantly type it out on Slashdot?
Don't get me wrong - I'm impressed and you're the reason I come here and have been coming for many years. However, sometimes you freaks amaze me. How do you cram that much into your head without vomiting it up?
"So long and thanks for all the fish."
You'll be unhappy with the gaps : For both bodies, it's very high resolution on one side, very poor resolution on the opposite side, and on the "dark poles" we've got almost nothing at all. They'll be trying to weasel more data out of the dark areas later via "charonshine" and "plutoshine", but don't get your hopes up too much. This was a flyby mission, not an orbiter, unfortunately.
Your best bets for maps as it stands would be over at unmannedspaceflight.com, they've been trying to piece together the datasets as best as possible. They have some maps, but nobody's done anything significant thusfar to try to ferret out topo data via photogrammetry. That should come later, though, and is definitely something to look forward to - these bodies have some very interesting topography, to say the least :)
Crowd: What do we want? Fry: Fry's dog! Crowd: When do we want it? Fry: Fry's dog!
Thank you BOTH for this great discussion. Both of you have made good and interesting points. I've enjoyed it thoroughly and learned a lot!
And I think it is only fitting that I be the final arbiter, as I am a Computer Scientist, and we all know scientists are interchangeable no matter the field. I here-by declare Rei the winner (despite his stores high prices) and Pluto will furthermore be defined as a planet.
-apk
20. The goal of terms in science is to aid our understanding of the universe, not hinder it. For this reason, definitions, particular baseline definitions, need to be simple. I'm not an ornithologist but I have a pretty good idea of what a "bird" is and any 5 year old does as well. Yet I guarantee most if not all ornithologists cannot name all 10,000+ species of birds. In a similar vein, why does it matter if kids can't name all the planets?
Agreed that the IAU is so far off the mark it's not funny considering they are supposed to be a major scientific body. What is needed is a taxonomical approach to astronomical object classification with increasingly complex definitions - and the IAU definition itself could be allowed to one of them.
1. World - a body that is massive enough to enter hydrostatic equilibrium but lacking mass sufficient to undergo nuclear fusion at its core.
2. Planet - a world orbiting a star.
3. Moon - a world orbiting a planet
The above excluded what are now called "rogue planets" from being planets since they aren't orbiting a star, but rogue world isn't too detached. Phobos and Deimos would no longer be considered moons under the above - they are merely satellites.
Moving to the more specific: "Classical Planet" - A planet visible to the naked eye (Mercury, Venus, Mars, Jupiter, Saturn). "Major Planet" - A planet which is the dominant body in it's orbital path, meaning it has more than 99.99% of all mass in the path or other objects in that amount are in tight orbit around it (earth/moon). "Dwarf Planet" - A planet which is not the dominant body in its orbital path.
They do not expire as far as I know. I had an older ID using a non-standard UID and have long since forgotten it so I can understand.
"So long and thanks for all the fish."
"Pluto's existence was also predicted by the perturbations it did to the rest of the solar system" -- but that prediction was proven to be erroneous when the real mass of Pluto was determined. The facts that the prediction was made and Pluto actually existed are pure coincidence.
Order If if you can!
If you have a strange new world for a freakin' moon then you deserve a better title than "senior asteroid" or "rock++".
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
You misspelled Uranus.
Is it just me or is the link to nasa.gov down!?
"Evil man makes you kill me...evil man makes me kill you..even tho..we're just families apart.."
Sure, Charon is a strange new world, but what we really want to know: is it a harsh mistress?
I do call Pluto a planet. What is anyone going to do about it, call the planet police.
According to the cleared the neighborhood part of the definition, Jupiter and Earth (at least) aren't planets either. Jupiter has the trojan and greek asteroids in its orbit, it has not managed to clear them out either. Earth has various asteroids that coorbit the sun, some of them near L4 and L5, and some on weird approaching/retreating orbits. There are also the comets that seem to pass the orbits of most of the planets, those haven't been cleared by even Jupiter.
The definition is a very odd one to use.
Also, wouldn't you expect that a body with life on it should be classified as a planet, even if it is orbiting Jupiter?
APK likes to ask for responses to the same things over and over. Maybe he just likes the responses?
There are only 8 countries on the planet, all the other ones are dwarf countries.
APK likes to ask for responses to the same things over and over. Maybe he just likes the responses?
For the most part, planets are visible to the naked eye.
Such a fascinating statement you've made. Planets do not exist outside the solar system!
"Lack of speed can be overcome. In the worst case by patience." --Znork
Will we have to run hosts files on Pluto though?
APK likes to ask for responses to the same things over and over. Maybe he just likes the responses?
The New Horizons team refers to it as a planet.
It was when they left Earth.
Have gnu, will travel.
I thought we called dwarf rivers streams and creeks?
Analogies are hard.
I had a few semesters of Chemistry a fairly long time ago (Organic, a semester of PhysChem) and I understood it well enough. I guess it's a matter of specialization of knowledge.
It's just an approach I haven't heard discussed before as far as locally produced propellants are concerned.
A fair bet: The number of people who have heard any discussions at all about locally produced propellants on a planet that nobody has ever been to is pretty close to zero.
Ideology: A tool used primarily to avoid the bother of thinking.
We need 3 missions to Pluto, the first mission we send a man around Pluto and back home.
The second mission we send a different man to Charon as practice for the Pluto mission
Let me guess... the third mission gets halfway there, but has to turn around because they run out of fuel.
Ideology: A tool used primarily to avoid the bother of thinking.
I consume a great deal of media. Usually in text but sometimes video. I, pretty much exclusively, watch only educational things like documentaries - real ones and not the stuff you see on cable these days. So, yeah, I mean I've *heard* of this stuff but I can't just repeat it, fully understand it, get the intricacies, or even opine on it. I mean, yeah, I understand the concept of going somewhere, creating fuel with the material there to either further your voyage or return, and all that - at least conceptually. That? What was posted? It's a mix of astrophysics, chemistry, and theory with strange concepts that, when added to the sum total of their posts in this thread, make me highly impressed, confused, and almost a little overwhelmed.
It's okay though, They'll need me to check their maths. *sighs*
"So long and thanks for all the fish."
Extrasolar planets are subject to one rule and one rule only thus far: can we tell they exist? It so happens that Pluto-size objects in Pluto-size orbits are well beyond our current detection capabilities, so there is little reason to invoke any other definition, but the use of the word "planet" inside and outside our own system is admittedly inconsistent. It may and probably will matter at some point, but not yet.
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
I agree that the time spent arguing should be minimized. However, I disagree with the "leave it alone" idea to not arguing. Sometimes getting a definition in place now (and fighting over it) saves a lot of squabbling over what gets included later. There's a reason Eris is called that, you know. Discovery of the existence of another Pluto-size object threw the entire classification scheme into chaos. It can be argued the current definition is vague and arbitrary. That's fine, it is, and it will probably have to be tweaked later. Most notably, the use of "dwarf planet" is confusing. (It would have been better perhaps to elevate the eight big ones to "major planets".) My argument is with the people who want "anything my nostalgia says is a planet" to be the definition of a planet.
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
The reason the IAU doesn't want to tackle extrasolar planets is pretty simple: while we know they exist, and have even imaged a small number of them directly, we really don't know that much about them. Is what we detect typical of the population, or is it an artifact of our detection methods? Do they have moons? Since we can't even pin down their characteristics yet, it doesn't make sense to attempt to make up standards for classifying them yet either. Yet. I'm pretty sure that at the very least, the planet/moon distinction will be carried over to other systems.
The ancients did not know about Uranus (as far as we know, it may have been detected and later forgotten) because it's not visible all the time, making it hard to track without photography. But it is naked-eye visible some of the time. It's also frigging huge, enough so that the orbital dances of Uranus and Neptune have had massive effects on the evolution of the entire system. Any definition of planet that excludes the two ice giants is willfully ignoring their significance. If it turns out there is another Earth-mass object out there substantially directing the evolution of the Sednoids, it would indeed be fair to argue that it too is a planet. It is busy clearing its neighborhood, however slowly.
As for lumping the terrestrial planets and the gas/ice giants under one name, you have a point. If the IAU demanded that they have two different (but short and easily spoken) names, I'd be happy to go with that.
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
Also, wouldn't you expect that a body with life on it should be classified as a planet, even if it is orbiting Jupiter?
Like Pandora? (Fictional, but relevant.)
No. What does life have to do with the definition of a planet or a moon? There's quite a good chance there are life-bearing moons Out There, quite possibly within our own solar system. That has fuckall to do with their physical characteristics or orbital mechanics.
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
There was, in ancient times, an idea of a river. If we consider streams of water flowing in long depressions in the ground, we currently call the larger ones rivers. We don't refer to small creeks as rivers.
There was, in ancient times, an idea of organs. If we consider distinct components of the body, we apply the term "organ" to the ones of roughly the size of the classical organs or larger. We don't usually refer to small glands as organs.
There was in ancient times, an idea of elements. We screwed that one up proper. There's not one of the classical elements that we'd call an element nowadays, and while we have solid (earthlike), liquid (waterlike), and gaseous (airlike) elements at our usual temperatures, we don't have one that's firelike. Instead, what were elements have been mostly redefined as phases of matter. There's no comparison.
There was, in ancient times, an idea of planets, being Mercury, Venus, Mars, Jupiter, and Saturn (and possibly the Sun and Moon). Earth, Uranus, and Neptune fit into this category nicely. Pluto doesn't really, not really having its own near-circular orbit or being nearly as large as the smallest classical planet (Mercury). Pluto was also not considered a planet by the ancients. Since the ancients had no knowledge of Pluto-like objects, we can leave Pluto off without doing any violence to etymology.
"When you have eliminated the unacceptable, whatever is left, however improbable, must be the truthiness" - Holmes
(a.k.a. La Pig). We should send the Enterprise out there to investigate further...
I cannot believe it took this long for someone to post this exact comment. Glad that someone's priorities are straight. But, to be fair, it could be buried under ice and silicate. Charon's a pretty big rock (relatively speaking).
I disagree with a blanket taxonomic separation of planets vs. moons. The fact that an object orbits another object which in turn orbits a star provides as little insight as to the nature of the object as "clearing its orbit" does. For example, Triton is far more similar to KBOs, and therefore should be taxonomically closer to Pluto, than to Earth's Moon. Additionally, if two objects of similar mass and sufficient separation orbit each other, one can not be said to orbit the other as their barycenter is a point between the two objects. Such objects would be considered a double planet rather than a planet and a moon. But whether the barycenter is contained within the volume of one of the objects or not is also just as non-predictive and therefore unscientific. Consider Earth's moon, which is slowly receding from Earth. Eventually it will be far enough away that the barycenter will be outside the volume of Earth, at which point the Earth-Moon system will become a double-planet, though its fundamental nature will remain unchanged. Adding to the absurdity, assuming by that time Earth is not tidally locked to the Moon, there will be a time when the barycenter is right at the surface of the Earth, so as Earth rotates, the Moon will alternate between being a moon and being a planet several times a day as the barycenter passes through mountains and valleys.
Man, how long I was calling that one "make make" instead of "ma kay ma kay"...
English is a bitch that way. Is "read" pronounced "reed" or "red"? Is "lead" pronounced "leed" or "led"? Depends on context. Just ask Sean Bean. (Seen Been? Shawn Bawn?) We need disambiguating accents, dammit -- and to stop retaining spellings intact when rifling through the pockets of other languages for vocabulary.
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
Seems to be a fact missing in my physics books. Any references?
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
It's been well known for a while. The wikipedia article (https://en.wikipedia.org/wiki/Pluto) has some scholarly references and states, "With the new figures added in, the discrepancies, and with them the need for a Planet X, vanished.[55] Today, the majority of scientists agree that Planet X, as Lowell defined it, does not exist.[56] Lowell had made a prediction of Planet X's orbit and position in 1915 that was fairly close to Pluto's actual orbit and its position at that time; Ernest W. Brown concluded soon after Pluto's discovery that this was a coincidence,[57] a view still held today.[55]"
And another popular reference: http://www.space.com/29911-plu..., which states, "Studies eventually showed that Pluto doesn't have the mass necessary to interfere with the orbits of Uranus and Neptune. The errors in calculation that helped lead to its discovery were later attributed to an incorrect mass estimate for Neptune, a value that was refined by NASA's Voyager 2 mission."
Thanx for the summary. Funny what coincidents exist in science!
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.