Pluto defines a Planet as being a Planet!

[jakethesnake]

Science has always been about the debate, consensus and politics within the scientific community! Politics has always been and always will be apart of the scientific community and, this is in part due to the fact that a lot of scientists and in this case astronomers have worked their whole lives trying to prove a theory and/or belief. Also, a doctoral theses and/or someone’s funding is not wiped out easily as being worthless without a fight. That is the firm line in the proverbial sand of science, the standard and, that line should always be there. <br /><br />On the other hand there is always the caveat of going against the “in crowd” of any scientific community and that can make for a very unsuccessful scientist or a very successful scientist if he or she prevails.<br /><br />Its debates such as what is going on here which are driven by the enthusiasts i.e. us and those who notice us. What a time to live in, just imagine how limited our voices were just 20 years ago!<br /> <div class="Discussion_UserSignature"> <strong></strong> </div>

 

[arkady]

Directed to noone in particular:<br /><br />What Pluto is or isn't is not really a very relevant consideration in this matter. The idea was to come up with a practical definition, since we realized that we had no such.<br /><br />Now, I get your point with simply defining Pluto as the minimum size of a planet, however I'm not qualified to say if it's practical or not. That should be the topic of this post, and while a lot of posts in the thread lives up to this, I'm getting slightly annoyed with all the fuzz about Pluto. (not just this thread) <br /><br />I might not be very knowledgable when it comes to astronomy, but from a philosophical standpoint the Pluto discussion often has me banging my head against the table. Who cares if Pluto is a planet or not, aslong as the definition is the most practical for whatever purpose it will be used. <div class="Discussion_UserSignature"> "<font color="#0000ff"><em>The choice is the Universe, or nothing</em> ... </font>" - H.G Wells </div>

 

[adman69]

I believe that what Pluto is or is not really is the crux of the matter. The long needed definition of a planet is secondary. Pluto has been a planet for decades and it should remain as such due to it's significance in the astronomical world for it's time. Let the new (un)definition pertain to the objects discovered hereafter. All the live by the IAU word, die-hards need to understand the importance of protecting the status of the decades defined solar system. I would rather have 40 planets than take one away.

 

[wonky]

In the end, I think this whole arguement centers around one thing--in general, people are resistant to change. Perhaps this is more fitting for a psych forum than this one, but it's a perfect example.

 

[jakethesnake]

A light year = 5,878,482,164,161 miles X 2 = 11,756,964,328,322 miles or about 11.8 Trillion Miles.<br /><br />So 2 light years = 11.8 Trillion miles<br /><br />The out edge of our solar system or the edge of the heliosphere is guessed to be about 100 AU or 9,295,580,700 miles or 9.3 billion miles from our sun. I think you’re off by about 1265 times the actual distance to the edge of our solar system.<br /><br />Although this is besides the point consider me from the state of Missouri the “show me state” so, “SHOW ME” where’s the proverbial beef! Only one celestial body is know to be larger than Pluto and that’s UB313 or informally known as Xena.<br /> <div class="Discussion_UserSignature"> <strong></strong> </div>

 

[MeteorWayne]

I believe he was referring to the gravitational "sphere" of influence of the sun.<br />Since, AFAIK, the Alpha Centauri (A,B, Proxima) system has ~ 2 solar masses, a better estimate might be ~ 1.5 light years in that direction, and 2 or more light years in other directions. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[jakethesnake]

I didn't think of that and you’re probably right, thanks.<br /><br />At least it was fun calculating the values.<br /><br />Do you know what defines the end of the solar system or is this something the IAU has to define also? <div class="Discussion_UserSignature"> <strong></strong> </div>

 

[MeteorWayne]

I don't think there's any hard and fast definition.<br />The heliopause is where the solar wind yields and it becomes interstellar space. This is affected by our motion through the galaxy, and interstellar gas and dust density.<br />The gravitation influence varies in different directions as well<br /><br />I imagine there are other definitions you could use.<br /><br />But we may be getting a little off topic for this thread.<br /><br />Maybe start a new one with this question, so we can all take a shot at definitions? <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[MeteorWayne]

<i>"The costs in terms of changing texts will be enormous. $10's of millions at least. Will the IAU fund that? "</i><br /><br />Astronomy textbooks are obsolete in details before they are printed. From writing to printing to purchase is years.<br /><br />That's what happens when you live in a time of discovery. <br /><br />Asteroid #20000 Varuna was discovered in 2000<br />Asteroid #50000 Quaoar was discovered in 2002<br />Asteroid #90482 Orcus was discovered in 2004<br /><br />Edit 9/8/06 {The Minor Planet Centre has now given numbers to Pluto (134340) and 2003 UB313 (136199)}<br /><br />Jupiter moons: 1997-16, 2001-28, Current 68+<br />Saturn moons: 1997-18, 2001-30, Current 47+<br />Uranus moons: 1997-15, 2001-21, Current 27+<br />Neptune moons: 1997-8, 2001-8,, Current 13+<br />For TNO's:<br /><br />Pluto: 1997-1, 2001-1, Current 3<br />Other small solar system objects' moons:<br />1997 3? Current nearly 100?<br /><br />This argument is a straw man. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[jakethesnake]

Wayne, and by the way that happens to be my real name so you have a little added weight in my book, although I still don’t agree with you. I have read your latest post “Pluto Perspectives- Part 3 - Inclination” which was well done as were the prior two and an interesting grouping of categories to try and prove your point.<br /><br />Only one celestial body has been discovered orbiting our sun that is not a moon and which is known to be larger than Pluto - UB313 “Xena”. Even though science is constantly changing I think reducing the planet count is a little more subtenant than the discovery of some asteroids and moons so, I would definitely say that the IAU’s demotion of Pluto’s status is defiantly a costly one.<br /><br />I have a question for you:<br /><br />What would you call a celestial object with the same planer inclination and eccentric orbit as Pluto located in the kuiper belt but with a mass and size of Mercury?<br /><br />And if the answer is a “planet” then how important is all the statistics you have present in your posts?<br /><br />Don’t take it the wrong way it’s just a question. <br /> <div class="Discussion_UserSignature"> <strong></strong> </div>

 

[MeteorWayne]

Jake (or Wayne <img src="/images/icons/smile.gif" /> )<br />We don't have to agree, this is all discussion fodder.<br />For that reason, I can't take it the wrong way!<br /><br /><i>" I have a question for you: <br />What would you call a celestial object with the same planer inclination and eccentric orbit as Pluto located in the kuiper belt but with a mass and size of Mercury? " </i><br /><br />Well, the answer off the top of my head would be a Plutino. At least one of which is "dwarf" or "minor" planet. <img src="/images/icons/wink.gif" /><br /><br />However, these Pluto Perspectives are designed not only to reinforce my own feelings, but to critically examine the data. To be honest, I don't know how it will turn out, or I didn't before I started. As I've gone along, I have some ideas, but the intention is to see where the data leads.<br /><br />Part 4, which is almost done, will add more weight to my position , I think. We'll see.<br /><br />A great question! I may just add such a hypothetical planet to the analysis to find out where it would fall in the lists. Since you defined the parameters, I'll call it "Jake". I don't know how that will turn out!<br /><br />Thanx for another thoughtful response.<br /><br />Wayne<br /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[jakethesnake]

Newfound Object Further Blurs Planet Definition<br /><br />CHXR 73 B<br /><br />Is it a planet or a star?<br /><br />Kevin Luhman of Pennsylvania State University, leader of the international team that discovered “CHXR 73 B” said that the “IAU definition was never meant to be applied to other solar systems” Luhman told SPACE.com. "It was just for our solar system."<br /><br />If this is true then the new IAU classification of planets comes into question in a big way wouldn't you say?<br /><br />Please check out this article and let me know what you think:<br /><br />http://www.space.com/scienceastronomy/060907_chrx73b.html<br /><br /> <br /> <div class="Discussion_UserSignature"> <strong></strong> </div>

 

[MeteorWayne]

IMO, this is an object around another star.<br /><br />The IAU definition specifically applies to objects around Our<font color="orange"> Sun</font><br /><br />We know much more about our solar system than the diversity present in other stellar systems.<br /><br />I'd say we shouldn't even touch the subject of how to classify other systems for a decade, and if the waylaid budgets don't get restored, it may take much longer to learn enough. As I've stated elsewhere, we live in a time when knowledge of the solar system, galaxy, and universe is increasing by the millisecond.<br />Yes, even the solar system, which could throw "a spanner in the works" as far as the current planetary definition.<br /><br />Other systems? Who knows if this definition is specific (or arbitrary <img src="/images/icons/smile.gif" /> ) enough to apply.<br /><br />In any case, to the bottom line, that is not relevant to the Pluto question, since last time I checked, Pluto was an important part of the solar system. <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[JonClarke]

In principle the boundary between planet and star is very simple, the ability to sustain thermonuclear reactions. of course the ability to determine this is pratice may be difficult in borderline cases. I believe that some place the limit as low as 8 Jupiter masses and others at 13. Varying deutrium contents in the super-Jupiters/mini brown dwarves will also effect the mass at which fusion will occur. This variability is to be expected and is acceptable.<br /><br />But this is different to the IAU planet definition issue which is unworkable, ignores cultural history, planetary history, and any planetary systems other than our own. Remember the whole definition was highjacked in a pustch by the dynamicists after the vast majority of astronomers had gone home.<br /><br />Jon <div class="Discussion_UserSignature"> <p><em>Whether we become a multi-planet species with unlimited horizons, or are forever confined to Earth will be decided in the twenty-first century amid the vast plains, rugged canyons and lofty mountains of Mars</em>  Arthur Clarke</p> </div>

 

[wonky]

Here's an interesting article about when the asteroids were first discovered. It's a little long, but it's worth reading if you've got the time. It mirrors the arguement about Pluto today.<br /><br />http://aa.usno.navy.mil/hilton/AsteroidHistory/minorplanets.html<br /><br />Here's the best quote from the article:<br />The acceptance of the first four asteroids was so matter-of-fact that introductory texts such as First Steps to Astronomy and Geography (1828) lists the planets as, "Eleven: Mercury, Venus, the Earth, Mars, Vesta, Juno, Ceres, Pallas, Jupiter, Saturn, and Herschel." Herschel was an alternate name for Uranus (after its discoverer) used in Britain until the 1850's.

 

[jakethesnake]

I believe that this latest article highlights the profound lack of knowledge of what a planet is and by what this article asserts it’s very relevant to the Pluto question! It is very clear that astronomers today are finding too many a “spanner in the works" to come up with any solid planetary definition.<br /><br />I understand that in science that sometimes it is necessary to (arbitrarily) categorize what is not well understood to break up the monotony of analysis as I do on a daily basis but, here in lies the hasty mistake of the IAU.<br /><br />Wayne I posed a question to you that I believe narrowed this problem down and my question to you was:<br /><br />“What would you call a celestial object with the same planer inclination and eccentric orbit as Pluto located in the kuiper belt but with a mass and size of Mercury?”<br /><br />Your response was:<br /><br />“Well, the answer off the top of my head would be a Plutino. At least one of which is "dwarf" or "minor" planet.”<br /><br />With that interpretation I can only surmise that to you size and mass are not part of the mix so let’s see if that is actually the case.<br /><br />Here is a more refined question that gets to the crux of what I have been saying all along:<br /><br />If a celestial object with the same planer inclination and eccentric orbit as Pluto was found in the kuiper belt what mass and size would that object have to be so that you would classified it as a “Planet”?<br /> <div class="Discussion_UserSignature"> <strong></strong> </div>

 

[MeteorWayne]

Jake,<br />Let me work on adding planet "Jake" to my lists before I answer that. I want to see wher it falls before I speculate further.<br />As I said, Plutino was only off the top of my head.<br />I don't always trust what falls off there <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> <p><font color="#000080"><em><font color="#000000">But the Krell forgot one thing John. Monsters. Monsters from the Id.</font></em> </font></p><p><font color="#000080">I really, really, really, really miss the "first unread post" function</font><font color="#000080"> </font></p> </div>

 

[alokmohan]

Pluto is dead Lets prepare for future.Before Pluto's demotion, countless school children remembered the solar system's planetary progression with the popular mnemonic, or memory aid, "My Very Educated Mother Just Served Us Nine Pizzas."<br /><br />Now that the International Astronomical Union voted to reclassify Pluto as a dwarf planet, we need a replacement.<br /><br />Astronomy is looking for creative and unique suggestions. To win, you'll need to create something more of a variation than "My Very Exhausted Mother Just Served Us Nothing."<br /><br />The Astronomy staff will pick the winners. This is from astronomy magazine.Hpe you contact astronomy magazine web and get the prize.<br /><br /> <br />

 

[rhodan]

<i>"My Very Exhausted Mother Just Served Us Nothing."</i><br /><br /><img src="/images/icons/smile.gif" /> <br /><br />

 

[jakethesnake]

This question is to all who would like to take a stab at it.<br /><br />If a celestial object with the same planer inclination and eccentric orbit as Pluto was found in the kuiper belt what mass and size would that object have to be to classify it as a “Planet"?<br /><br />Very interested in your answers!<br /> <div class="Discussion_UserSignature"> <strong></strong> </div>

 

[kheider]

<font color="orange">>“What would you call a celestial object with the same planer inclination and eccentric orbit<br /> />as Pluto located in the kuiper belt but with a mass and size of Mercury?"</font><br /><br />Inclination and eccentricity are not necessarily that important. What really matters is <b>ORBITAL DOMINANCE</b>. Since Mercury is only 0.055 Earth masses, I would call it a Dwarf Planet IF Mercury were orbiting where Pluto is.<br /><br />Pluto is very small being only 0.0023 Earth masses. Mercury is 23 times more massive than Pluto. If we find an object the size and mass of Mars (0.11 Earth masses) orbiting out in the Kuiper Belt, we will have to revisit some of these questions of what exactly defines orbital dominance.<br /><br />Often in life, location does count.<br /><br />What makes one 1700 square foot home in a good neighborhood worth more $$$ than the same home (with the same up keep) in the ghetto? Location!<br /><br />What makes Titan, Triton, and our Moon not Planets? Location!<br /><br /><font color="orange">>If a celestial object with the same planer inclination and eccentric orbit as Pluto was found in the kuiper belt<br /> />what mass and size would that object have to be so that you would classified it as a “Planet”?</font><br /><br />Good question. I have MY answer! But the real question is, "What would the professional astronomical community call a Planet?"<br /><br />Defining a border-line Planet is difficult. But surely Pluto is too small to dominate his region (30AU-50AU) that is full of very similar sized brothers.<br /><br />According to Steven Soter's Arcticle at "<b>What is a planet?</b>"<br /><br />If we were to magically upgrade Pluto (0.0023 Earth mass) to a 0.16 Earth masses (more massive than Mars) it would probably be considered a planet, because one of it's 'Planetary Discriminants would be 0.0001' which is much more in line with the other P

 

[shawking]

A different idea for the definition of a planet:<br /><br />A body is a planet if it:<br /><br />1. Orbits a star : eliminates moons.<br /><br />2. Is not undergoing nuclear fusion: eliminates stars.<br /><br />3. Is in hydrostatic eqilibrium: eliminates small asteroids, comets, etc.<br /><br />4. Is differentiated chemically by depth: eliminates brown dwarfs, and, implicitly, exotic objects not made of atoms or molecules.<br /><br />5. Is differentiated thermally by depth, and is projected to be so for a majority of the lifetime of its star: eliminates objects that may fulfill all the other requirements, but nevertheless are not large enough to have a core that is kept hot by the conversion of kinetic energy left over from the body's formation.<br /><br />-----------------------------<br /><br />6. If a body fits requirements 1-5 for planetary status, but has a satellite such that the barycenter of the body and satellite is outside either body, then the system is defined as a binary planet, even if the satellite does not fit requirements 1-5: Remember when Charon was going to be called a planet? That was stupid. This clause eliminates a scenario like that.<br /><br />Requirements 1-4 are probably not controversial. I added #5 because often the intuitive objection to Pluto's planetary status has been that it really isn't in the same category as something like Mercury or Earth, much less Jupiter. A planet, goes the intuition, should be a full-sized world which creates its own conditions that are substantially different from those of the surrounding space. Requirement 5 seemed like a good way to accomodate this intuition in a relatively rigorous and scientifically useful way.<br /><br />(I'm not sure if it's even known whether Pluto, Ceres, or UB 313 are thermally differentiated by depth. I'm guessing not. But does someone actually know?)<br /><br />I also tried to come up with a definition that would work for classifying extrasolar objects (hence #4, 6). As it is right now, we don't have

 

[wonky]

Well, I've been researching Ceres (see my other thread.) As far as I understand, Ceres is differentiated chemically but not thrermally.

 

[wonky]

IMHO all the screaming started because the class "dwarf planet" is considered "not a REAL planet."<br /><br />I think the best solution is to keep the dwarf planet category, but tweak the definitions a bit, and say that the dwarf planets are freakin' planets. That's how the general public will understand it anyway. <br /><br />Average Joe is saying, "Oh, a dwarf planet? That's just a really small planet."

 

[Philotas]

<font color="yellow">Good question. I have MY answer! But the real question is, "What would the professional astronomical community call a Planet?"</font><br /><br />What puzzles me is why astronomers got so much to do with the planetary defintion; since it's really the geologist's field. Most science done at a planetary object is geology, not orbital measurements. Yet orbit counts so much when defining? <div class="Discussion_UserSignature"> </div>