NASA's Hubble Discovers Another Moon Around Pluto 208
thebchuckster writes "Astronomers using the Hubble Space Telescope discovered a fourth moon orbiting the icy dwarf planet Pluto. The tiny, new satellite – temporarily designated P4 — was uncovered in a Hubble survey searching for rings around the dwarf planet. The new moon is the smallest discovered around Pluto. It has an estimated diameter of 8 to 21 miles (13 to 34 km). By comparison, Charon, Pluto's largest moon, is 648 miles (1,043 km) across, and the other moons, Nix and Hydra, are in the range of 20 to 70 miles in diameter (32 to 113 km)."
Pluto's Moons (Score:2)
Poor Pluto, they can take away your planetary designation but you will always have your moons!
As for Hubble, I am quite happy with its continued usefulness and success. Hopefully it never loses its funding (at least not until there is a suitable replacement).
Re:Pluto's Moons (Score:4, Insightful)
Hubble will eventually degrade in performance just as it has in the past. Gyros and batteries wear out, electronics get glitchy, etc.
Unfortunately, when it starts to happen again, there won't be anything we can do about it. Without the shuttle, another service mission is impossible. And with Hubble's successor (JWST) hanging by a fraying budgetary thread, there likely will be no replacing it with an improved telescope, either.
We as a country have given up on science, unless it makes immediate profits for megacorporations or helps the military kill people more efficiently in foreign lands.
Re:Pluto's Moons (Score:5, Insightful)
Unfortunately, when it starts to happen again, there won't be anything we can do about it. Without the shuttle, another service mission is impossible. And with Hubble's successor (JWST) hanging by a fraying budgetary thread, there likely will be no replacing it with an improved telescope, either.
This has been repeated a number of times, but launching an entirely new Hubble into high orbit (without a shuttle, that is) would be substantially cheaper than maintaining the shuttle program in order to service the existing scope. I hope JWST pulls through, but I don't think NASA should get a blank check from the taxpayers.
We as a country have given up on science, unless it makes immediate profits for megacorporations or helps the military kill people more efficiently in foreign lands.
I'm not a fan of our budget priorities for the last decade, but I can understand why Congress is viewing JWST skeptically. The telescope isn't even supposed to launch until 2017 at the earliest and it's already billions of dollars over budget. Sure, this is a fraction of what we're flushing down the toilet in futile wars, but we're already stuck in those, and they're much more difficult to pull out of than a project that's still in the planning stages.
Except for servicing Hubble - a dubious justification - the shuttle was a terribly inefficient use of money for the science that came out of the program. As far as scientific funding in general is concerned, NASA continues to do great work with remote probes and will be sending another rover to Mars soon. The NIH and NSF managed to avoid major funding cuts in a year when most federal agencies got hit hard, and the DOE Office of Science, which was slated for a huge cut, also survived mostly intact. Speaking as a scientist involved with many of these agencies, I'm thrilled with the outcome.
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We as a country have given up on science, unless it makes immediate profits for megacorporations
I'm not thinking Hubble was manufactured by schoolchildren or launched by a volunteer group.
That's the mystifying part. You'd think there's just as much room for corruption in the aerospace contracting field as the banking field, but apparently fraud is easier in the banking industry. Since they (as in the big bankers) are not going to let us fix the banking system, the solution would seem to be, make the aerospace industry as corrupt, or more corrupt, than the banking industry.
I'm sure we could set up so
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We as a country have given up on science, unless it makes immediate profits for megacorporations or helps the military kill people more efficiently in foreign lands.
What's more disappointing is that the other industrialized countries haven't taken this torch and run with it. Europe has at least 50% more population than the USA, and a larger economy (and it appears, stronger, despite the problems in Greece). While obviously no one country there can match the US in size and economic power, combined they eas
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Remember this when people start talking about "lazy Americans". We're producing nearly as much as 1.5x the number of Europeans are.
US citizens are quick to claim that the US isn't this, or the US isn't that. Fact of the matter is we are still the shit.
We have the highest GDP of any country, we have the highest standard of living, and have the highest rate of scientific advanc
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we have the highest standard of living,
Wrong. Sweden, Norway, and Switzerland consistently lead the standard-of-living rankings worldwide. USA is way down on the list. Having the "highest standard of living" doesn't mean your richest people live the most opulent lifestyles, it means your average people live the safest, most comfortable, and most healthy lifestyles. If you want to compare the rich peoples' lifestyles, then places like Mexico would rank high on the list, since the world's richest man, Carl
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I live in the US too, and it looks like we're falling apart to me with ever more corporate corruption in government.
The US has one of the best-educated populations in the world
You've got to be kidding. Every ranking shows our public education to be near the bottom of industrialized countries. Sure, if you compare our education to Zimbabwe's or Myanmar's, we look pretty good, but that's not saying much.
and one of the least corrupt societies in the world.
You're seriously delusional if you believe that. Aga
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"Gyros and batteries wear out"
That certainly explains the discomfort I felt last night after eating a week-old Greek pita sandwich and a couple of AAs I found in my desk drawer.
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What do you mean alone except for Charon? Did you not even read the title?
Pluto it not a planet (Score:2)
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Actually, it is (along with Eris, Makemake, Ceres, Quaoar and many others, mostly with technical identifiers) properly termed a dwarf planet. Not a planet, a dwarf planet. So the article is actually quite correct.
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Let's lobby for a new standard (Score:5, Funny)
Four moons means it gets to be called a planet.
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not sure who modded you down, but I was thinking the same thing.
I spent my entire childhood thinking pluto was a planet. To me it will always be a planet. Even my 9yo was originally taught it was a planet. Where's the love? Seriously, after 76 years, NOW you're going to choose to call it a 'dwarf planet'? I think not.
If you have enough gravity to have something orbiting you, then you get to be a planet.
There's got to be an 'in soviet russia' joke here, I'm just not sure what it is yet.
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NOW you're going to choose to call it a 'dwarf planet'?
Please. Pluto prefers the term "Gravitationally Challenged Planet"
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Please. Pluto prefers the term "Gravitationally Challenged Planet"
If Pluto wants to make something of it, it knows where to find us. I dare it to come complain about what we call it...
So, if Pluto isn't a planet, then what orbits it can't be moons, right? Moonoids? Moonsters? Moonites? Moonies? Moonenites?
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Satellites (or lack thereof) don't make or break "planet" status.
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See my rule # 4, it was specifically designed for Mercury and Venus, who are both Larger than pluto, yet have no natural orbiting rock.
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You make it too complicated. Here are the criteria:
1. It is not on fire (sun)
2. It has something not man made orbiting it.
3. It was discovered before 1931
4. It's larger than the smallest listed in #2 (this will pick up mercury which otherwise would have failed my tests.
Or, lets make it even easier.
A planet is any one of MVEMJSUNP...
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1. a celestial body orbiting a star or stellar remnant
2. massive enough to be rounded by it's own gravity
3. not massive enough to be in a state of thermonuclear fusion (which would make it a star)
4. has cleared the neighboring region of planetesimals
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The list of planets will be open and ever extending,
Not likely. Eventually its all found. Like arguing we must redefine australia as an island, or else we'll have trillions of "continents" in the ocean. Eventually you find them all. For example, we are not likely to find any new planets within the orbit of Mars.
and there will be an insoluble argument about where you draw the line between planets and asteroids,
Easy Peasy. Does it crush itself under its own mass to an almost spherical shape? Theoretical compression stress at the core due to gravity exceeds stress limit of the rock? Then its a planet. An asteroid is a smaller lump of rock that isn't h
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There's tons of tiny asteroids with their own, even smaller, moons. Are we going to call those planets too? Do we need to have schoolchildren remember the names of hundreds of moon-bearing asteroids, I mean planets?
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Do we need to have schoolchildren remember the names of hundreds of moon-bearing asteroids, I mean planets?
We're already at 53 planets. Whats one more?
http://en.wikipedia.org/wiki/List_of_extrasolar_planets [wikipedia.org]
The good news is the names are pretty easy. Whats the planet orbiting between Kepler-11 B and Kepler-11 D? Oh let me guess it's Kepler-11 C.
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What happens when they find a new planet between them? Rename everything farther away, leading to questions like "did you mean the object named Kepler-11 C before [date], or the object named that after [date]?"
Interstate exit numbers suffered this same issue every time a new exit was built, by the way, which is why they all got renumbered after the corresponding mile ma
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I thought there were still some stupid states that hadn't done that, or are you saying the last holdouts (I'm thinking PA was one) finally changing their exit numbering?
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I thought there were still some stupid states that hadn't done that, or are you saying the last holdouts (I'm thinking PA was one) finally changing their exit numbering?
They haven't changed them here in CT or in nearby NY yet. There are, however gaps in the numbers sometimes...not sure if it's because the exits were removed, planned but never made, or someone didn't know how to count. For example, the first exit on I-95 in CT is exit 2.
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Honestly, I can't imagine why anyone would prefer sequential exit numbering. I don't care how many exits exist between my and my destination, I only care about the absolute distance. Numbering them with mile numbers also makes it easy to calculate how far different exits are from one another (suppose you have two destinations to visit in your trip, one at exit 217 and one at exit 219; that's two miles between them, versus exit 138 and exit 159, where it's 21 miles).
But of course, the biggest benefit is si
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Let's be consistent:
Only satellites that have been pulled into a spherical shape by their mass and have cleared their orbit around the planet should be called "moons". The rest are obviously "dwarf moons".
As for what we should call a satellite that orbits a satellite, I vote for "Zappa".
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Funding (Score:2)
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Four moons means it gets to be called a planet.
Surely that depends on the number of wolves.
Queue the Pluto vs. Planet diatribes (Score:2)
Get over it. We have a better understanding of the Cosmos now without blurry images from a couple pieces of polished glass. Think of it as an advancement in our scientific horizons.
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I assume you mean "if I have consistent standards..." since that seems to be the most common argument.
It boils down to how many planets do you want to have in the solar system. Most honest attempts at a scientific definition that includes Pluto also include a handful of other known bodies. That's fine, 8 planets, 9 planets, 14 planets... who cares right? The problem is that modern theory predicts dozens of Pluto-like bodies in the outer solar system, and having 70+ planets listed is seen as extremely awk
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It boils down to how many planets do you want to have in the solar system. Most honest attempts at a scientific definition that includes Pluto also include a handful of other known bodies. That's fine, 8 planets, 9 planets, 14 planets... who cares right? The problem is that modern theory predicts dozens of Pluto-like bodies in the outer solar system, and having 70+ planets listed is seen as extremely awkward, especially when only a handful of them would be scientifically interesting as individual bodies (as opposed to a class of bodies like the predicted objects in the outer Oort cloud would be).
Fair enough, but why should we want an arbitrary upper bound on the number of planets? Awkwardness isn't really an issue except for elementary school kids memorizing lists; we have these things called "computers" now that are remarkably good at keeping track of large amounts of information. If there are a bunch of planets floating around out there in the dim outer reaches of the Solar System, fine -- we'll get to them we develop the technology to make it possible. And I don't see why they should be any l
Ah, the good old days.... (Score:2)
All this talk about mooning has me wistful for my wild youth.
Bad definition for planet (Score:2)
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If you calculate the ratio of the mass of the object to the mass of all the other objects in the same orbit, there is a vast difference between the planets and the dwarf planets. The eight planets have ratios on the order of 10^4 through 10^6, meaning they are much, much more massive than everything else in their orbit combined. The dwarf planets, including Pluto, all have ratios less than one.
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Thank you! This is the key point that somehow never gets discussed. And of course I never have mod points when I need them.
Pluto (Score:2)
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Don't talk to me about life. Brain the size of a dwarf planet.
Mass relay... (Score:3, Insightful)
I thought there'd be more Mass Effect jokes. Jeeze, people, it's 2011, get over Star Wars!
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Escape Velocity (Score:3)
Using Pluto's density of 2.03 g/cm^3, I compute (at 21 mile diameter) the moon is 4.2e16 kg.
With a 4.2e16 kg mass and 1.7e4 m radius, I compute an escape velocity of 18 m/s, or 40 miles per hour.
So I suspect you could jump really hard and not come back down, assuming I didn't misplace a decimal point.
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New moon... isn't that the name of a teen movie? (Score:2)
vampire movie where the vampires have feelings and stuff... have they released the sequel?
moons! (Score:3)
Earth needs more moons!
We should get some.
Question: (Score:2)
How many moons does it take before something becomes a planet?
[Your mom]
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Astronomers using the Hubble Space Telescope discovered a fourth moon orbiting the icy rock Pluto.
There.. FTFY ;o)
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Depending on how you count, it may be more accurate to say "rocky ice". By volume, Pluto has more ice than rock. (By mass, it is indeed an icy rock.)
Re:Planet (Score:5, Funny)
Astronomers using the Hubble Space Telescope discovered a fourth moon orbiting the icy rocky thing we call Pluto.
There... FTFY :D
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Astronomers using the Hubble Space Telescope discovered a fourth moon orbiting the icy rocky thing we call Pluto.
There... FTFY :D
Astronomers using the Hubble Space Telescope discovered a fourth dwarf moon orbiting the icy dwarf planet Pluto.
There... FTFY :D :D
-Actually, would it be a dwarf moon, or a dwarf-planet moon? Or -in this case- both?
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If you count Pluto as a planet, do you count Eris as a planet? (It's bigger than Pluto.) What about Sedna? (Smaller, but not by a whole lot.)
Wikipedia says Nix and Hydra were discovered in 2005 (also by the Hubble team, apparently) and named in 2006.
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That's interesting, but that then brings up another question. Should you qualify what is or isn't a planet based on it's size, or it's mass?
To a real estate agent, size is pretty important, but I would think that mass would be more important to an astronomer.
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i think the sensible answer is "neither".
Whether you base it around "X" size or "X" mass, the problem is that "X" is inherently non-empirical and subject to change, thus inappropriate as a definition.
The only "mass" related definition that would be empirical would be "Mass large enough to compress it into a sphere." It's empirical enough that you can actually chart it.
Combined with other definitional points such as the ones mentioned in my earlier post, you can have a totally empirical definition of a plan
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Re:Planet (Score:5, Informative)
Pluto and Charon orbit around a non-fixed barycenter that is actually outside of both Pluto and Charon. Pluto/Charon is really a binary Dwarf Planet with 3 moons. Which, honestly, is fucking awesome.
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All orbiting objects orbit around a non-fixed barycenter. The only factors determining if that center is inside or outside one of the planets is the ratio of masses of an object pair, the distance between them and the radius of the more massive object.
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I meant inside a fixed object. (IE, the moons Barycenter is inside the Earth, until such time as it floats far enough away in a few millenia)
Re:Planet (Score:5, Insightful)
Pluto and Charon orbit around a non-fixed barycenter that is actually outside of both Pluto and Charon. Pluto/Charon is really a binary Dwarf Planet with 3 moons. Which, honestly, is fucking awesome.
Absolutely! Further more its physical and orbital characteristics clearly associate it with the recently discovered Kuiper Belt Objects. It is should not be viewed as a "pathetic little planet wannabe" but as the King of the KBOs (Eris would be the Queen).
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(Eris would be the Queen)
Don't tell Charon that. She's been hanging with Pluto a long time. Also, she's an icy bitch.
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If an object orbits a planet, it's a moon, irrespective of shape.
So the space station is a moon? And the hammer they dropped up there? And Saturn's rings are moons too?
I would be good with a definition of moon that requires a spherical shape and long-term stable orbits. That would exclude Mars' satellites, which is fine with me. They're just captured asteroids in decaying orbits.
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Sure it does. They're just large groups of moons. Just as an asteroid belt is a large group of asteroids, and the Kuiper belt is a large group of comets.
Re:Planet (Score:4, Interesting)
Yep. I'm pretty comfortable with the idea that our star holds on to more than nine planets. I also think the idea that Pluto isn't a planet is ridiculous, and that any definition that ends up that way is by definition, busted.
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But if you stop counting Pluto as a planet, and then you discover another Kuiper Belt object that's not only bigger than Eris but as big or bigger than Mercury, do you make it a planet, or do you take Mercury off the list?
Right now, the IAU definition of planet is deliberately limited to our own solar system, just so it doesn't apply to situations extra-solar astronomers have actually already found, or are very likely to find in the next few years (How do you determine wh
extra-solar astronomers ? (Score:2)
"Right now, the IAU definition of planet is deliberately limited to our own solar system, just so it doesn't apply to situations extra-solar astronomers have actually already found,"
AFAIK "extra-solar astronomers" are not members of the IAU and are probably not aware that the IAU even exists. Maybe when the news of Pluto's demotion reaches them (which will take a while since there don't seem to be any habitable planets within a few LY of the sun) they could send the IAU a message about it. Of course all ali
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Not only that, but as a definition it is empirical and not subjective, like the various "size" based definitions are.
Planet: Any body which has all of the following properties:
1. It's mass has compressed it into a spherical shape.
2. It's primary orbit is around a star
3. It has cleared it's orbit of all other bodies that aren't satellites of itself, Lagrange point bodies, or "twin" satellites of similar mass that it stably co-orbits with where the co-orbital point exists outside either body.
Note the las
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> 3. It has cleared it's orbit of all other bodies that aren't satellites of itself, Lagrange point bodies, or "twin" satellites of similar mass that it stably co-orbits with where the co-orbital point exists outside either body.
Wouldn't this definition preclude a Kemplerer Rosette? Sure, they don't occur in nature, and are in fact quite unstable without active stationkeeping, but if you put (to pick a number at random) 5 Earth-sized planets equally spaced in the same orbit, be kinda silly to declare th
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You missed the "Stable" part of the definition. Any body not in a stable orbit, regardless of size, would not be considered a "planet".
Yes, it may seem silly, but a randomly wandering body, regardless of size, shouldn't be called a planet. I think "Planetoid" or "dark body" would be more accurate, although we may need to come up with a new word.
However the size alone should not be the definitional point as size-based parameters are constantly subject to revision, and are thus unreliable.
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The trick there is, whatever we declare the worlds of an artificial rosette to be, what they are is whatever the transhuman species that made them calls them. Trust me - you don't want to get into an argument with people who can shoot you with a gun that causes your grandparents to have a 50 year string of bad luck, precluding you ever being born. Whether they call them "planets", "properly sorted and indexed lebensraum", or "the big round closets where I keep all my stuff when I'm back in this brane", we'd
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I include it as it not only allows BOTH Pluto and Charon to be counted as planets, but also takes into account any new extra-solar co-orbiters we may discover in the future.
Except that they haven't in fact cleared their orbit of all other bodies that aren't satellites - with the discovery of the Kuiper Belt, Pluto started looking a lot more like Ceres than it did like Mercury.
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Haven't they? I was under the impression that they orbited near the edge of the Kuiper belt, but that their orbit was actually clear of other Kuiper belt objects.
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On that point, Pluto is more of a planet than Mercury.
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Well, Mercury certainly COULD hold an atmosphere, but it's orbit is so close to Sol that the solar wind strips it.
If Pluto were closer it wouldn't have an atmosphere either. That's why the "outside the solar wind stripping influence" part of the definitional point.
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Your definition comes very close to having the moon declared a planet. Although at present the barycenter is below the surface of the Earth, the moon is constantly moving away from the Earth. The day will come when, by your definition, the moon will suddenly and instantly be elevated to planet-hood even though nothing obvious has changed.
Not that that makes your definition wrong of course, just pointing it out.
The argument of what is and isn't a planet is older than people realize; Isaac Asimov suggested
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Your definition comes very close to having the moon declared a planet. Although at present the barycenter is below the surface of the Earth, the moon is constantly moving away from the Earth. The day will come when, by your definition, the moon will suddenly and instantly be elevated to planet-hood even though nothing obvious has changed.
Not that that makes your definition wrong of course, just pointing it out.
Excellent point. However I would hasten to point out that I included several other definitional points that must all be met to call a body a planet. Certainly point number 4 about having enough gravitational force to hold onto an atmosphere would prevent Luna from being classified as a new planet as it escapes Earth's grasp.
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It amounts to people having a holy war over where blue ends and purple begins. It's arbitrary. They needed a definition and it was generally felt that a definition that kept the number of planets to a reasonable number was in everyone's interest. The reason the definition was changed was because modern theory predicts dozens or even hundreds of Pluto-like objects in the outer solar system, which was thought to be an unreasonable number of bodies to be labeled as planets.
IMO, what they should have done wa
I bet a German answers this (Score:2)
I really hope you aren't a coder on anything that matters.
See, you've left the case where something is exactly the same size as Pluto undefined.
Still, what are the odds of it happening? Can anyone name anything that could be on a dwarflist of things potentially the exact same size as Pluto?
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Re:Planet (Score:4, Informative)
What we need is a MORE confusing system of naming! (Score:2)
Let's make it even more confusing.
We shall now call an object in solar orbit, a Solar Orbiting Object. Size will be a secondary classification, with descriptive terms like Large (LaSOO), Medium (MeSOO) and Small (SmaSOO). If it is the object has cleared its orbit, it is the primary object of that orbit, so we have Primary (Pri) and Shared (Sha). Under this system, Pluto is a ShaSmaSOO and Jupiter is a PriLaSOO.
For the objects that orbit a SOO, it is a SOOOO, a Solar Orbiting Object Orbiting Object. Prim
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But the point is, the number of satellites should have nothing to do with whether a body is classified as a planet or not, because it's not logically connected to the classification. It's pretty intuitive that two planets of the same size could gobble up different numbers of smaller satellites on a pretty much random basis. We don't want to make a random factor paramount in defining something.
That bit about clearing orbits in the standard definition the IAU now uses... Isn't that an es
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Um, didn't you check the first post?
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We'll find out when Pluto is suddenly replaced by an asteroid field, or when this new moon suddenly disappears.
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Rebel Scum! (Score:2)
Pluto is really just the debris remains of the Rebel Base Alderann.
Never again will these terrorists plague our fair and just empire!
Why are we still moving towards it?! (Score:2)
"Why are we still moving towards it?!" screeched Luke, pubescently.
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It's a bit like the tides, Mister O'Reilly.