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As children, everyone is taught the traditional order of the nine planets in the solar system. However, as we learn more about our neighboring planets— and space in general— this may have to be changed. Between and beyond Neptune and Pluto, thousands of small, somewhat planet-like objects have been found. These have been shown to occupy three distinct areas: the Kuiper belt, the scattered disc, and the Oort cloud. The discoveries have so far had two major implications:
First, there are several possible ‘tenth planet’ contenders out there – objects roughly the same size as Pluto and not unreasonably far away. The major examples are Quaoar, Sedna, and “Xena”, all discovered since 2002. Several smaller, unnamed ones have been found also, and surely will not be the last.
Second— perhaps conversely— the categorization of Pluto as a planet has come to be disputed. In fact, many astronomers argue that if Pluto had been discovered only in the last few years, it would not be labelled a planet at all.
The definition of “planet” is contentious and, considering how many things are possible in space, may be somewhat arbitrary in the first place. However, there are several signs that Pluto may be better considered a “Kuiper belt object” than a full-fledged planet. Among the nine current planets, Pluto proves to be the single anomaly in a number of ways— most obviously in size, or maybe lack thereof— but it is strikingly similar to some of its new-found neighboring objects.
History is partially to blame for the controversy. When it was first found in 1930 by young American astronomer Clyde Tombaugh, Pluto was believed to be larger than Earth – in fact, 400 times what we now know its size to be. Fueled by a national wave of patriotism at the discovery, Pluto entered the history books as the first planet discovered by an American. Through the 20th century, any attempts at labelling Pluto as anything less significant was met with outrage by proud astronomers and scientists in the U.S. When British astronomer Brian Marsden suggested at a 1980 conference that Pluto be deemed a mere asteroid, the Americans reportedly almost threw him into a swimming pool.
Pluto did, though, turn out to be problematically tiny. Its equatorial diameter of roughly 1485 miles (2390 km) makes it smaller even than its new-found neighbor “Xena”. It is also smaller even than some of the moons in the solar system, Earth’s included. This would be less of an issue if Pluto were one of the roughly similarly-sized inner planets – but it is out beyond the ‘gas giants’ and in a region of space that is rapidly becoming known for its relatively high concentrations of small objects.
Also, while the orbits of the first eight current planets lie in a plane, Pluto’s orbit is tilted by 17º relative to them. Its orbit also much more elliptical than the others’, so much so that it actually overlaps with Neptune’s orbit. During certain periods of Pluto’s orbit, it is nearer to the sun than Neptune is. Most recently this happened between 1979 and 1999, and will occur again starting in the year 2227.
Then there’s the issue of Pluto’s relationship with its three moons. Two— Nix and Hydra— are so tiny that they weren’t found until 2005. The largest, Charon, is strikingly large for a moon: its diameter is almost half of Pluto’s.
Because of this, Charon has an unusual amount of gravitational influence over Pluto; Charon does not actually orbit Pluto at all. Instead, Pluto and all three moons orbit the common point between Pluto and Charon – their center of mass or barycenter. No other objects in the solar system do this. It is unclear, then, whether Charon can be strictly labelled a moon – or, for that matter, Pluto a planet. For a while, some astronomers took to referring to Pluto and Charon as ‘double planets’ or ‘sister planets’. Neither of the terms ever caught on, though— and the recent discovery of Nix and Hydra does nothing to help clear up the situation. (Does that make them quadruplets now?)
It is looking increasingly likely, then, that Pluto is probably better categorized as a mere Kuiper belt object than a planet. The decision may come in September, when astronomers, historians, scientists, and teachers are hoping to formalize a definition for ‘planet’ once and for all. Could Pluto be demoted? It has been a long time since Tombaugh first identified it, and there is very little left of the fierce American pride that kept Pluto very securely a planet for the first few decades after its discovery.
And such a reclassification has actually been done before. Ceres, the largest asteroid and the first to be discovered, was considered a planet from its accidental discovery in 1801 until about 1850. What caused astronomers to change their minds was simply the discovery of more asteroids— a lot more. With the recent similar discoveries of the many trans-Neptunian objects, Pluto’s claim to planethood is looking more and more dubious. Whatever it is, Pluto will be studied in detail for the first time in 2015, with the arrival of NASA’s New Horizons, launched in January 2006.
Distinguishing between a ‘planet’ and a ‘Kuiper belt object’ may be nothing more than pickiness at the moment, but the need for a firm definition for ‘planet’ may become more pronounced as we look farther beyond our solar system. As of June 2006, over 200 extrasolar planets have been found, and we have few ways of knowing what sorts of astronomical objects are still out there. Agreed-upon classifications, therefore, will only become more crucial as we gradually explore and catalogue the universe around us.
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Hmm… If the term “planet” is so contentious, why does it even matter what we call it? Can’t we just call Pluto and all the other objects with near-closed orbits “solar satellites” and be done with it?
The only Planet I care about is a nice little Blue and Green one. I still have a soft spot for pluto, though. Its a charming little thing,
Hey second in line again! WOOHOO!
Ahem, it seems to me that objects with moons have at least that going for them in terms of planetary recognition, even if their interorbital patterns are unusual. Also, if the 17 degree orbital tilt is a factor, I’d like to know if there are any asteroid belts that exhibit the same feature. I mean, I know there are asteroids everywhere, but maybe there are actual asteroid belts that are at all sorts of tangents and degrees from the usual orbits exhibited by our greater known planets.
Also, what do these “Quaoar,” “Sedna” and “Xena” look like, anyway? What properties do they exhibit?
And me being an 18-year old, I may not be at the proper age for remembering this, but I seem to recall something about a “Planet X”??
Actually, hehe…. I just looked it up. And there was a Times article about it in 1982… maybe some stuff about it lingered until the early 1990’s and into my bedtime stories… but it may be worth checking out:
http://xfacts.com/x2.htm
buckyboy314 said: “Hmm… If the term “planet” is so contentious, why does it even matter what we call it? Can’t we just call Pluto and all the other objects with near-closed orbits “solar satellites” and be done with it?”
Good point, however, I don’t think that people will be completely satisfied until everthing is clearly classified, and officially defined. People just have to know everything as a fact. It’s inevitable.
Haha, second in line, I guess not. But I do have one more topic to bring up, and I apologize if this will be considered as a waste of comment space, but how are the new damninteresting writing smaples (hehe) turning out? Not to sound impatient, but can we expect an update on those soon?
So, i wonder what the implications would be for that wacky world of astrology?
As far as i understand, the introduction of pluto was pretty much just added in without too much impact in the first place.
Bah. Let’s just rename it Yuggoth and be done with it.
I had the opportunity to attend a lecture given by Clyde Tombaugh back around 1980… it was fascinating to listen to his account of how Pluto was discovered. I also read an account on Randy Cassingham’s site about how when they first conceived of the idea to send a probe to Pluto, the project director at JPL actually called Clyde up on the phone and asked for permission to send a craft to “his” planet!
I don’t think that the inclination of Pluto’s orbit is all that unexpected (or has any bearing on the being a planet argument – I favor keeping Pluto as a planet solely for sentimental and historical reasons), as there have been a lot of harsh collisions in our solar system that happened eons ago, but we can still see the evidence. Uranus’ moon Miranda was shattered by an intense impact, and while the pieces came back together it looks like a shattered vase that was put back together with krazy glue… there are cracks radiating out from the impact crater and circling the moon. Uranus itself was struck by at least one object, (no crater, the planet is a gas giant) and we can tell because the axis of it’s orbit (the imaginary line passing through the planet’s north and south poles that it rotates around) is 98 degrees off from the plane of it’s orbit (Earth is off by 23 degrees). There are periods of time that the north or south pole of Uranus is actually pointed at us.
There is also a widely credited theory that the Earth’s moon is actually debris that was flung into orbit and clumped together after the Earth was struck by an object about the size of Mars… the composition of the moon is the same as the top couple of miles of the Earth’s crust (minus the organic material), but it contains none of the Earth elements found only in the Earth’s core.
Dang, I should have made that last paragraph a story suggestion… feel free to treat it that way, guys.
rhea_sun said: “So, i wonder what the implications would be for that wacky world of astrology?
As far as i understand, the introduction of pluto was pretty much just added in without too much impact in the first place.”
Did you hear about the Russian astrologer that actually tried to file a suit against NASA for sending a probe to crash into a comet to learn about it’s make-up? She claimed that it threw off the accuracy of all her readings and adversely affected her livelyhood. The Russian government said she couldn’t sue NASA and dismissed her suit.
The signs of the Zodiac are the constellations that lie in the stripe of the sky that the moon, sun and planets traverse (called the plane of the eliptic). One of the reasons that no astronomers have any respect for ass-trologers is that there are actually 13 constellations along that line, but the 12 signs/12 months parity they want caused them to completely disregard the constellation of Ophiuchus, the serpent bearer (during the summer it rises just before scorpius.)
“As children, everyone is taught the traditional order of the nine planets in the solar system.”
…hmmm let’s see, My Very Efficient Mother Just Served Us Nine Pickles. Or what it stood for… Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.
Still works for me. Don’t screw with it unless you add something that will still make sense. Kids have enough problems in school already…don’t make it any worse. Sit down…Shut up…and hold on for the ride.
Last year, when Xena was discovered, I blogged about this very issue. In my opinion, for what it’s worth, I think Luna should be the benchmark for planetary distinction. If a body is larger then our moon, and not in orbit around a larger non-solar body(ie the moons of Jupiter or Saturn) then it is a planet. If not, then it is an asteroid, or planetessimal, or whatever. I did not know, however, about Nix and Hydra. It is sounding more and more like Pluto was once a much larger body that got smashed to bits.
cspariah said: “Bah. Let’s just rename it Yuggoth and be done with it.”
Yes, there’s definitely something Lovecraftian about Pluto. And I like the idea of Xena and Yuggoth battling it out for the right to be #9.
Just a point of clarification. I believe that ALL “planets” with “moons” orbit around their common center of mass. The difference comes about when the mass of the “planet” is so much greater than its “moons”, that center of mass lies within the planet.
No, rename it Rupert! So, what the similarity between Earth and Jupiter? Well, not much really… apart from we call them planets. Its all a bit arbitrary anyways
Stop arguing! Don’t you realize he has FEELINGS? You’re going to give poor Pluto a complex!
another viewpoint said: “”As children, everyone is taught the traditional order of the nine planets in the solar system.”
…hmmm let’s see, My Very Efficient Mother Just Served Us Nine Pickles. Or what it stood for… Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto.
Still works for me. Don’t screw with it unless you add something that will still make sense. Kids have enough problems in school already…don’t make it any worse. Sit down…Shut up…and hold on for the ride.”
i would have to disagree and think that we should make the educating of our children as hard as possible. Many other countries laugh at the way our children are educated. We have an incredibly poor education system.
Marius said: “Last year, when Xena was discovered, I blogged about this very issue. In my opinion, for what it’s worth, I think Luna should be the benchmark for planetary distinction. If a body is larger then our moon, and not in orbit around a larger non-solar body(ie the moons of Jupiter or Saturn) then it is a planet. If not, then it is an asteroid, or planetessimal, or whatever. I did not know, however, about Nix and Hydra. It is sounding more and more like Pluto was once a much larger body that got smashed to bits.”
why exactly should we use our moon as the measuring stick for planet size? Does not seem logical that we should measure everything in relation to what we have… Extraterrestrial Americanism indeed (and yes I am american)
Some scientists have proposed to add a new category (“planetoid”) to better distinguish Pluto, Xena etc. from the other space bodies roaming out there. It’s not a moon, it’s not a large rock, neither is it an asteroid. IMO the proposal is a good idea, but I’m not sure if it got the attention of the major Space Agencies.
There’s a card game called Space Shuffle (by Playroom Entertainment), which involves placing the planets in order. Amoung the usual nine, guess who appears? Sedna. Presumably the game makers required an extra planet so there could be a round number, or some similar reason. It’s interesting that Sedna was chosen, when eg Xena appears to have more going for in the planet status contest (it is larger). At the time the game was made, Xena was still just known as 2003 UB313, so it just goes to show that if planet status is determined by general societal opinion, a catchy, memorable, pronounceable name is far more effective at infiltrating popular culture than a cold scientific label, and actual scientific considerations are largely irrelevant.
I actually sent in a letter very similar to the above to New Scientist magazine, and they published it along with a cartoon of someone reading a newspaper with the headline “Exciting New Planet Discovered” and the reader saying to another person “It’s only 10cm across, but it’s called Elvis.”
1c3d0g said: “Some scientists have proposed to add a new category (“planetoid”) to better distinguish Pluto, Xena etc. from the other space bodies roaming out there. It’s not a moon, it’s not a large rock, neither is it an asteroid. IMO the proposal is a good idea, but I’m not sure if it got the attention of the major Space Agencies.”
Be careful of what you wish for…for after such astronomical bodies such as asteroids and planetoids,
…comes hemorrhoids. Strange objects from another galaxy that are forever circling Uranus.
(sorry people…couldn’t help it…besides, it beats the heck out concentrating on work today!)
Drakvil, did you really man to write “There are periods of time that the north or south pole of Uranus is actually pointed at us.”
Misfit, just as there are several theories about the origin of Luna, there are several models on planetary formation. Pluto’s orbital tilt would make a tough fit for some of those theories — meaning that Pluto did not form like the other planets and probably not at the same time. Ergo, not a planet. The issue may never be settled. Future astronomers might witness the formation of planets somewhere and think they have an answer, then witness a completely different type of planetary formation somewhere else. (e.g. Odd planets orbiting one way, even planets the other, with two planets orbiting perpendicular to the rest.)
Indeed, and it gets even more nuts outside the Oort cloud. I’ve taken quite a few astrophysics courses at CSU… there is still a great deal of speculation that a brown dwarf may exist outside the Oort cloud you might find interesting: http://en.wikipedia.org/wiki/Nemesis_(star) Right up there with GRBs, in my book!
Yo mama’s so fat she’s a planetoid in the Kuiper Belt.
Biatch.
IMO Pluto is a planet. So what if it has a wierd orbit. It’s not an asteroid. It still orbits the sun. It has a moon. It’s a planet I say. Xena and the other large non-asteroid objects could be labeled planets and it would make more sense than dropping pluto off the map.
Right now we have 3 different types of planets in the solar system – inner, rocky planets, outer gas giants and Pluto. It might make sense to say that anything simular to Pluto is just part of a larger, third catagory, but then we have to face the possibility that the number of planets might grow to be much larger than 12 (the current 9 plus Xena, Sedna, Quaoar). Kids might be learning “My Very Efficient Mother Just Served Us Nine Pickles So Xerxes Quit Playing With Us Because He Hates Pickles Except With Sourkraut…”
But Sedna isnt really in our solar system like pluto is. Just have a look at its orbit.
http://en.wikipedia.org/wiki/Image:Trans-Neptunian_object_2003_VB12.Sedna.orbit_comparisons.jpg
Pluto clearly orbits the sun, which puts it in our solar system. The others , at least Sedna, orbit our solar system and about 100 AU of outer space.
Sedna orbit’s our solar system and about 100 AU of outer space.”
Let’s just put it this way, the sun isnt at the center of Sedna’s orbit like the planets.
Mr. Jablome (hehe),
The sun isn’t really at the center of any of the orbits of the astronomical bodies. Any orbit that isn’t circular (meaning all) orbit one of the two foci of their elliptical orbit. It’s better to consider that Sedna is gravitationally bound to the sun, as are all other objects in the solar system.
This whole naming problem comes about because we don’t understand how our solar system formed. So, instead of distinguishing astronomical bodies by the processes that formed them, we name them by how they look in a telescope. As our understanding improves, so will our ability to truly say what is a “planet” and what isn’t. The way I see it, we will probably create a distinction between planets that formed from the Solar nebula at temperatures below freezing, and those that formed above freezing. This distinction, or some other chemical difference, affects the substance of the planets, not just their size. But, that’s just my guess.
Thanks for all the comments, everyone – thought-provoking as always!
DoctorD said: “Just a point of clarification. I believe that ALL “planets” with “moons” orbit around their common center of mass. The difference comes about when the mass of the “planet” is so much greater than its “moons”, that center of mass lies within the planet.”
That’s absolutely right. I wasn’t clear about it. Thanks for pointing that out!
Misfit7707 said: “Ahem, it seems to me that objects with moons have at least that going for them in terms of planetary recognition, even if their interorbital patterns are unusual.”
Misfit7707 said: “Also, what do these “Quaoar,” “Sedna” and “Xena” look like, anyway? What properties do they exhibit?”
Some asteroids have moons. (Neat, eh?) So does “Xena” (it’s nicknamed “Gabrielle”, surely thanks to fans of the Warrior Princess). And one of the as-yet-unnamed large objects in the Kuiper Belt, 2003 EL61, has two!
It’s only an artist’s rendering, but a size-comparison chart of Pluto and some of the largest known Kuiper Belt objects can be found here. The page includes all the known moons and it links back to individual pages for the objects.
The definition of a planet will probably be at the end of a long series of questions that steadily outline the characteristics of an object, and those questions will probably be based on the characteristics of planets that are not in question. Is the object spherical? Is it’s gravitational field spherical? Does it rotate on a fixed axis? Is it’s orbit stable? Etc. Since no one can agree on a definition of a planet, the answer will probably come from deciding what isn’t a planet and accepting what’s left. (…and, yes, I know those questions aren’t very specific, so don’t nitpick the definition of “fixed axis” or point out the non-spherical shape of Earth, etc. because I’m just trying to summarize my point.)
Obviously, astronomers and similar scientists need to band together to compose a specific definition of a planet. Such an organization could be called…Planned Planethood…
junebee said: “Obviously, astronomers and similar scientists need to band together to compose a specific definition of a planet. Such an organization could be called…Planned Planethood…”
That suggestion is just awesome!
Brahmb said: “Drakvil, did you really man to write “There are periods of time that the north or south pole of Uranus is actually pointed at us.””
Yes, I did mean to write that. Among many other places, you can verify it at: http://www.edu.pe.ca/southernkings/Uranus.htm, or just about any serious astronomy text.
Haywood Jablome said: “But Sedna isnt really in our solar system like pluto is. Just have a look at its orbit.
…
Pluto clearly orbits the sun, which puts it in our solar system. The others , at least Sedna, orbit our solar system and about 100 AU of outer space.”
It’s not possible to orbit the solar system and NOT orbit the Sun… the Sun is at the center of the solar system and makes up 99%+ of the mass of the entire solar system. It isn’t possible to orbit “outer space” because you need a center of mass to orbit around – orbiting empty space is a nonsensical statement unless you are making a huge generalization about an elliptical or circular motion that is actually constrained and caused by other forces.
The decision may come in September, when astronomers, historians, scientists, and teachers are hoping to formalize a definition for ‘planet’ once and for all.
Who, What, Where????
Does anybody know who will be involved in this process or any other information about this???
Also here is another article about Pluto
http://cfa-www.harvard.edu/icq/ICQPluto.html
Why don’t people just look at the definite aspects of the bodies of our solar system that are for sure planets? I.E. what do Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune have in common?
I’ll let people other than myself ponder over those factors.
About the issue of moons, this is something that I’d like to bring up… can moons have their own moons? (wow something about reading that sentence feels weird)
Also, I’ve GOT to open that tilted orbit thing one last time… Marissa mentioned that planets that develop properly are put on a set orbit… I’m not so sure about that, wouldn’t planets be moving in all sorts of directions until they come close to another planet in motion, and then the gravitational pull between the two of those should make their movements similar over time? I’ll bet Pluto just hasn’t existed long enough to get its orbit fixed by the gravity of the other planets…. *hmmmmmm how long has Pluto existed, anyway?*
I think the issue of direction is needed here as well. I may be mistaken if this isn’t a big factor, but all of the planets seem to be orbiting the sun in the same direction: counter-clockwise. Is this just a ‘given’ for everything out there in our solar system? Or could this one day be yet another factor in judging a planet’s…. er.. rites of passage?
AZford said: “The decision may come in September, when astronomers, historians, scientists, and teachers are hoping to formalize a definition for ‘planet’ once and for all.
Who, What, Where????
Does anybody know who will be involved in this process or any other information about this???
Check the link about it at the bottom of the page – it elaborates.
Misfit7707 said: “Also, I’ve GOT to open that tilted orbit thing one last time… Marissa mentioned that planets that develop properly are put on a set orbit… I’m not so sure about that, wouldn’t planets be moving in all sorts of directions until they come close to another planet in motion, and then the gravitational pull between the two of those should make their movements similar over time? I’ll bet Pluto just hasn’t existed long enough to get its orbit fixed by the gravity of the other planets…. *hmmmmmm how long has Pluto existed, anyway?*”
Not quite what I said. The other eight current planets have orbits that lie on a plane. I was just pointing out that this is one of the ways in which Pluto is the single exception among the traditional nine planets.
As for the rest: well, let’s wait until New Horizons gets there and we’ll see whether we can figure it out!
junebee said: “Obviously, astronomers and similar scientists need to band together to compose a specific definition of a planet. Such an organization could be called…Planned Planethood…”
haha u just made the highlight of my day!
Misfit7707 said: “Also, I’ve GOT to open that tilted orbit thing one last time… Marissa mentioned that planets that develop properly are put on a set orbit… I’m not so sure about that, wouldn’t planets be moving in all sorts of directions until they come close to another planet in motion, and then the gravitational pull between the two of those should make their movements similar over time? I’ll bet Pluto just hasn’t existed long enough to get its orbit fixed by the gravity of the other planets…. *hmmmmmm how long has Pluto existed, anyway?*
I think the issue of direction is needed here as well. I may be mistaken if this isn’t a big factor, but all of the planets seem to be orbiting the sun in the same direction: counter-clockwise. Is this just a ‘given’ for everything out there in our solar system? Or could this one day be yet another factor in judging a planet’s…. er.. rites of passage?”
There’s a good reason that all the planets revolve around the Sun in the same direction- all the matter that coalesced to make the Sun, and eventually the planets, began rotating as they condensed due to non-uniformity in density, so it looks like the illustrations/animations you see of an accretion disk surrounding the event horizon of a black hole (or water circling the drain in the tub). When the pressure in what would be the Sun reached the point where nuclear fusion sparked off, the resulting solar wind (charged particles flung outward from the sun) started clearing out the neighborhood around the new star… clumps in that debris formed into the planets and other assorted suff that make up the solar system, but since all that debris was already moving in a uniform circular direction around the Sun, they just continued to do so. The amount of time each object takes to revolve around the Sun is a function of it’s distance. There is a mathematical formula that states that for an equal amount of time, the area of the arc covered between the sun and the planets rotating around it is equal… you get a short, fat slice of pie for the inner planets and an incredibly long, skinny slice of pie for the outer planets – but they all end up with the same amount of pie!
I wonder why we put so much focus on what to call pluto. Regardless of what pluto is, it’s there and our classification won’t change it. It will also definitely not bake a good pie! Oh well, I like pluto and this was a neat article! Thanks Marisa.
There is a mathematical formula that states that for an equal amount of time, the area of the arc covered between the sun and the planets rotating around it is equal… you get a short, fat slice of pie for the inner planets and an incredibly long, skinny slice of pie for the outer planets – but they all end up with the same amount of pie!”
Kepler’s Second Law
The line joining the planet to the Sun sweeps out equal areas in equal times as the planet travels around the ellipse
Here is a nice animation
http://zebu.uoregon.edu/textbook/images1/ellipse.mpg
Marius said: “If a body is larger then our moon, and not in orbit around a larger non-solar body(ie the moons of Jupiter or Saturn) then it is a planet. If not, then it is an asteroid, or planetessimal, or whatever. I did not know, however, about Nix and Hydra. It is sounding more and more like Pluto was once a much larger body that got smashed to bits.”
I agree with using something like the moon as a comparison tool. I doubt very much that they’ll ever be able to make a definitive description of what constitutes planets, moons and asteroids. Should a planet have an atmosphere and a moon not?? Then that rules out Mercury. Should only planets have other bodies orbiting around them? But there are several asteroids that have been found to have smaller asteroids orbiting them. Someone up above said that the Kuiper Belt and Oort cloud objects orbit the solar system, not the sun. But the sun constitutes 98% of the mass of the solar system, hence they are orbiting the sun.
I dunno, what ever they want to call it, Pluto will always be the ninth planet to me. You can’t say it’s not only because it is unusual. Venus is unusual – it’s the only planet to spin retrograde (sun and stars rise in west and set in east), Uranus, as mentioned above, has it’s axis offset by 87 degrees (or 93degrees – that’s another matter of debate) yet we have no trouble saying their planets! Even the earth-moon system is bizarre. To be technical the moon orbits the sun AND the earth. If you plot out the path of the moon with reference to the sun for a year then you’ll see that the moons path is never arced away from the sun but always toward it!
Haywood Jablome said: “But Sedna isnt really in our solar system like pluto is. Just have a look at its orbit.
http://en.wikipedia.org/wiki/Image:Trans-Neptunian_object_2003_VB12.Sedna.orbit_comparisons.jpg
Pluto clearly orbits the sun, which puts it in our solar system. The others , at least Sedna, orbit our solar system and about 100 AU of outer space.”
excuse me but i feel really miniscule after seeing those pictures and thinking that that oort cloud is also miniscule compared to our galaxy, which is also miniscule compared to the entirety of our universe…
i am thinking of hanging myself so if you dont see a post from me in the next 3 months…be worried
now i feel unlucky…
the rope broke :-(
There is something spooky about this ‘Pluto’ issue.
Many believe that the Americans at that time felt like discovering “A Planet” to keep up with international astronomy-related achievements. So they persistently created this propaganda about a “Moon” behind Neptune and called it “Planet” Pluto.
That explains the outrage behind every attempt to degrade the achievement. There was too much defense around the issue that it made spooky.
That in-turn built on the “Fake Moon Landing” propaganda they masterfully created!!!
What do you think…huh?????
someoneisinterested: I say it’s way past your bed time…it’s time for daddy to tuck you in. ;-)
Anthony Kendall said: “This whole naming problem comes about because we don’t understand how our solar system formed. So, instead of distinguishing astronomical bodies by the processes that formed them, we name them by how they look in a telescope…”
…with all due respect to Scott Adams…I nominate three names, that would appear to be most fitting in this situation for such a technologically difficult process and once and for all put the problem associated with naming plants that follow Pluto as follows: 1) Dilbert, 2) Dogbert and 3) Egbert.
All in favor say…AYE! Any opposed? get a life.
Not good enough you say, okay then…how about these…
Robert (Goddard), Carl (Sagan) and Gene (Roddenberry), or
Edison, Fermi and Einstein, or
Wilbur, Orville and Mr. Hanney, or
Kirk, Spock and McCoy, or
Elenore, Esmerelda and Elvira…I can continue…
Drakvil said: “
It’s not possible to orbit the solar system and NOT orbit the Sun… the Sun is at the center of the solar system and makes up 99%+ of the mass of the entire solar system. It isn’t possible to orbit “outer space” because you need a center of mass to orbit around – orbiting empty space is a nonsensical statement unless you are making a huge generalization about an elliptical or circular motion that is actually constrained and caused by other forces.”
Ok your right, Sedna does get some gravitational pull off of the sun. But its orbit is so extreme that it probly only swings remotely close to our solar system every 100 years or so. (i’m no expert thats just a guess) And what I meant was that our star isnt at the center of sedna’s orbit. While it does get gravitational pull from the sun, the sun isn’t in the middle of its orbit according to the image on wikipedia. But I still stand by my original statement, Pluto is a planet IMO and rather than dropping pluto they should add planetoids such as Xena and Sedna. They would just add to Pluto’s planet group. You know we have rocky inner planets, gas giants, and then they can add a new class such as the small, outer rim planets. Ok maybe a better name for the last group. You get the picture.
Haywood Jablome said: “…what I meant was that our star isnt at the center of sedna’s orbit. While it does get gravitational pull from the sun, the sun isn’t in the middle of its orbit according to the image on wikipedia. “
Of course not — for elliptical orbits, the central body (here, the Sun) is at one of the foci of the orbit. See here:
http://csep10.phys.utk.edu/astr161/lect/history/kepler.html
Lorne
Ok ok ok, so i need to brush up on my astronamy. Still, Sedna obviously is on the edge of the sun’s gravitational pull. I will post the link again because Sedna’s orbit blows my mind.
http://en.wikipedia.org/wiki/Image:Trans-Neptunian_object_2003_VB12.Sedna.orbit_comparisons.jpg
Can anyone calculate or estimate the time it takes for Sedna to make 1 full orbit??
Thank You.
Wow i should really research a little more next time before i post. Sedna’s orbit takes 12050 years……………
That’s just crazy..
Misfit7707 said: “I’ll bet Pluto just hasn’t existed long enough to get its orbit fixed by the gravity of the other planets…. *hmmmmmm how long has Pluto existed, anyway?*”
Actually, Pluto orbit has been fixed by the outer planets. It is in an orbit which causes it to go around the sun 2 times for every 3 times that Neptune goes around – this pattern keeps it stable and keeps it from ever hitting Neptune, even though it crosses Neptune’s orbit.
Since Neptune is mostly hydrogen, helium, and methane, wouldn’t the entire planet be engulfed by flames if anything sparked? I guess what i am asking is that if neptune was hit by pluto or a large asteroid that created a bang, would the atmosphere go up in flames?
“Since Neptune is mostly hydrogen, helium, and methane, wouldn’t the entire planet be engulfed by flames if anything sparked? I guess what i am asking is that if neptune was hit by pluto or a large asteroid that created a bang, would the atmosphere go up in flames?”
No way dude!
No oxygen=no fire or explosion
We only know what the uppermost layers of atmosphere are made of so the rest as usual are only guesses. “Science itself is an inexact science”
Cooler stuff at R3concepts.com
New Topic!
How is pluto related to goofy?
Think about it!
gizmus said: “”Since Neptune is mostly hydrogen, helium, and methane, wouldn’t the entire planet be engulfed by flames if anything sparked? I guess what i am asking is that if neptune was hit by pluto or a large asteroid that created a bang, would the atmosphere go up in flames?”
No way dude!
No oxygen=no fire or explosion
We only know what the uppermost layers of atmosphere are made of so the rest as usual are only guesses. “Science itself is an inexact science” “
…Gizmus, I would have thought the same as you, but then…how would you explain the nearest star in our galaxy…the Sun? Wouldn’t all of the O2 have been used up eons ago? …yet it still glows, burns, shines, however you want to define the light/heat that it gives off.
As a little bit of trivia, the name Pluto for our 9th planet was chosen not just because of the Mythological origin of the name, but also as a tip o’ the hat to Percival Lowell for his contributions to astronomy. While he did make many contributions and there still is a Lowell observatory in Arizona, he is best known these days for his profound belief in life on Mars… he read accounts of the “canali” on Mars and mistranslated it from Italian to think it meant there were canals there, so they had to be built by Martians. The real translation is “channels”, which are formed naturally. So the PL in PLuto is a nod to that guy.
As for Sedna’s orbit… one foci of the ellipse does lie in the Sun, and it’s orbit is still inside of the Oort cloud, which is also considered part of the solar system. I remember asking the question in college astronomy where the other foci of Earth’s orbit is, if the first one is in the sun. The answer I got was that it was a great distance away, but within the Sun as well. The Sun is just that big.
There are periodic comets as well that take a great many years to reappear, so they must have a second foci that is really way out there. I don’t remember if it was comet Hale-Bopp or Hyakutake, but the supposed period for that cometary orbit is on the order of 10,000 years.
another viewpoint said: “…Gizmus, I would have thought the same as you, but then…how would you explain the nearest star in our galaxy…the Sun? Wouldn’t all of the O2 have been used up eons ago? …yet it still glows, burns, shines, however you want to define the light/heat that it gives off.”
The Sun has enough gravity to support nuclear fusion, and the energy that results is radiated out from the Sun in the form of radiation, light, and the solar wind. Any collection of gasses much smaller than the Sun does not have the necessary gravity to support a fusion reaction, and won’t amount to anything more than a brown dwarf.
I just realized with my post describing Kepler’s second law that I was perpetuating the curse of Pies in the discussions here…
While it’s true that object’s in elliptical orbit do so around one of the two foci, the orbit’s of the planets are very, very nearly circular and thus orbit almost at the center of a slightly elongated circle. There is an astronomical property called eccentricity which measures the range (0 to 1) of deviation from circular orbit. If the eccentricity is 0, the orbit is circular. Venus has the smallest eccentricity at .007, while earth has an eccentricity of .017. Mercury and Pluto have the most eccentric orbits with eccentricities of .206 and .25 respectively. However, as can be seen here: Eccentricity, an ellipse with .25 eccentricity is still roughly a circle.
that’s true Misthael, and here’s the coolest thing about Mecrurys’ orbit. Because its orbit is so eccentric it’s orbital speed varies dramatically. So much in fact that when Mecury reaches its perihelion (closest approach to sun in its orbit) its orbital speed exceeds its rotational speed. Hence, if you were standing on the surface of Mercury on the side facing the sun as Mercury got to perihelion you would see the sun at first moving normally from east to west, then slow and stop, then start to move back to the east for a while, then slow and stop and then move back in its normal movement to the west. It also has an interesting orbital synchronicity. It rotates fully on its axis three times every two years. Which means that the point closest to the sun (ie., under the sun at midday) for one perihelion will be at midnight for the next perihelion.
Cool hey!!
Drakvil said: “I just realized with my post describing Kepler’s second law that I was perpetuating the curse of Pies in the discussions here…”
Doesn’t it feel good? I’ll quote a great pie for y’all. It said “*steamy sizzle.*” Nice perpetuation.
I think we should invade pluto and make it our 51’st state:)
Misfit7707 said: “I think the issue of direction is needed here as well. I may be mistaken if this isn’t a big factor, but all of the planets seem to be orbiting the sun in the same direction: counter-clockwise. Is this just a ‘given’ for everything out there in our solar system? Or could this one day be yet another factor in judging a planet’s…. er.. rites of passage?”
Do you mean all rotating in the same direction or all rotating counter-clockwise?
Well, whether it’s going clockwise or counter-clockwise depends on the arbitrary decision of which side of the solar system you define as the “top”. If you treat the other side of the solar system as the “top” then it’s rotating clockwise.
Since there is no objective way to determine what side of another solar system is the “top” and they appear in all sorts of orientations, they will only all rotate counter-clockwise if you define the “top” of a solar system as the side where everything rotates counter-clockwise.
As far as I’m aware though, of the few stars known to have multiple planets all of them have planets that all orbit the star in the same direction. That being said, there is a newly forming solar system that has been found to have the materials in it rotating around the center in opposite directions. See here:
Newly Forming Solar System Has Planets Running Backwards (2/13/’06)
http://www.nasa.gov/centers/goddard/news/topstory/2006/opposite_orbit.html
(Note: Ignore the title of the article, no planets have actually formed yet.)
So, while all of the solar systems we know of currently have all of their planets orbiting in the same direction, we may still someday find a star that has planets orbiting in opposite directions that have been doing so since that solar system was formed.
superdude4agze said: “why exactly should we use our moon as the measuring stick for planet size? Does not seem logical that we should measure everything in relation to what we have…”
What else are we going to use? The process of learning involves building on and exrapolating what we allready know. To use something alien to compare and measure with would be completely illogical.
And me being an 18-year old, I may not be at the proper age for remembering this, but I seem to recall something about a “Planet X”??
You probably know this by now, but just for the sake of it; to my knowledge wasn’t the whole Planet X thing dispelled? Uranus was found by following up anomalies in Neptune’s orbit. But there were still anomalies in both planet’s orbits, leading up to a theorized Planet X. Percival Lowell projected co-ordinates for the new planet, and thus Pluto was found. Theories popped up about Pluto actually being much bigger than what was merely visible, but it’s moon Charon put those to rest. In the end Neptune ended up being larger than originally thought when Voyager 2 made it’s trip there, thus there weren’t any problems in the first place.
But it makes sense to think that this isn’t the coincident it’s made out to be. Moreso just inevitability. You have this stack of Kuiper Belt objects floating around that nobody pays attention to. If you point anywhere, nomatter how you got the co-ordinates, you’re bound to find something. Pluto just happened to be where they pinned the donkey’s tail.
Marisa Brook said: “And such a reclassification has actually been done before. Ceres, the largest asteroid and the first to be discovered, was considered a planet from its accidental discovery in 1801 until about 1850.”
Now this (to me at least), is by far the most fascinating part of the article. Because with further investigation, and found this.
Wikipedia: “There is some historical precedent for “demoting” a “planet” in the light of subsequent discoveries. The first four asteroids (1 Ceres, 2 Pallas, 3 Juno and 4 Vesta) were considered to be planets for several decades (in part because their sizes were not accurately known at the time). However, in 1845, the first new asteroid in thirty-eight years was discovered (5 Astraea), just one year before Neptune, and soon every year brought more asteroid discoveries.”
This means that between 1801 and 1845 before Neptune, there was thought to be 11 planets in our solar system.
smokefoot said: “Kids might be learning “My Very Efficient Mother Just Served Us Nine Pickles So Xerxes Quit Playing With Us Because He Hates Pickles Except With Sourkraut…””
Try, “My Very Efficient Mother Just Served Us Cold Pork Jelly Valiantly.”
Number 9… Number 9… Number 9… why redefine what a planet is? Let it be a quaint accident of history that there are nine planets. Sort of like the Masons… don’t let anyone else join, and don’t throw anyone out.
Try, “My Very Efficient Mother Just Served Us Cold Pork Jelly Valiantly.””
Actually, with the asteroids being between Mars and Jupiter, it would have been more like My Very Efficient Mother Chilled Pork Jelly, Voluntarily Just Serving Us.
Haywood Jablome said: “Wow i should really research a little more next time before i post. Sedna’s orbit takes 12050 years……………
That’s just crazy..”
Interesting idea this brings up… I think that rather than a planet, Sedna may more likely be a comet. The comets mostly originate in the Oort cloud and have highly eccentric orbits that can range from 76 years (Halley’s comet) out at least as far as 60,000 years (either Hyakutake or Hale-Bopp if my flawed memory serves right). I guess the way to find out without actually visiting Sedna would be if Sedna’s orbit brings it inside the orbit of Jupiter – that is roughly the demarcation point where the solar wind heats up a comet enough so that it starts to outgas (ice sublimating into a gas) and the debris and gas is blown away from the Sun. It’s strange to note that comets approach the Sun with their tails behind them, but when they leave the comet follows it’s tail out – the tail is always pointing away from the Sun.
I was just now watching a show on this on the National Geographic Channel last night, maybe it was the science channel. But they said things like if we consider Pluto a planet, then we should consider our moon a planet, since our moon is actually bigger than Pluto.
Marisa…..wonderful article!!! I very much enjoyed it. I’ve taught my daughter the 9 planets (she’s 4) and also Sedna as the tenth…so she looks smart to others who haven’t heard of it….hehehe. I haven’t seen much written anywhere about Sedna and can’t remember where I heard of it in the first place. You’re article, however, confirms that it’s real….and many other possible planets too. Thanks for the good read.
And the latest news is that the astronomers just decided that Pluto’s not a planet after all, but instead one of a large number of “dwarf planets.”
Yep, and a different planet way way farther out (which is bigger than Pluto) is either under serious consideration as a planet or has been declared as a new planet-it escapes me which one it is right now.
Of course you wouldn’t use something “alien”, but something “universal” would be an option. Here on earth we have a long tradition of selecting units corresponding to phenomena here on earth. Even though “ells” are mostly gone and “feet” are hopefully on their way out as well, even metric units are (mostly) derived from measurements taken here on earth.
You could base a unit of time on the decay rate of some element, and it would be universally applicable everywhere.
You could base a unit of distance on the wavelength of light, and it would be universally applicable everywhere.
The unit for mass [kg] can be said to be universally applicable as it is the mass of one litre of water.
It’s interesting reading this article now that Pluto is called a “dwarf planet”. A dwarf planet orbits the sun just like other planets, but it is smaller. A dwarf planet is so small it cannot clear other objects out of its path.