I've had it with Pluto not being a planet. Let's cut the crap and admit we don't have a good definition of "planet". Therefore, let's admit to subjectivity and decide what's a planet on the basis of how awesome it is. Pluto clearly qualifies. Case closed.
There, that was easy.
http://www.bbc.co.uk/news/science-environment-33657447
Atmosphere - check
ReplyDeleteNatural satellites - check
Orbits the sun - check
Sounds like a planet.
Spherical - check
ReplyDeleteHistorically part of the search for planets (really the sames 'Sounds like a planet') - check
Visible with amateur equipment - check
Orbits within the Ecliptic - FAIL
ReplyDeleteClears it's neighborhood of debris - FAIL
Roughly circular orbit that does not cross into the orbit of another planet - FAIL
Larger than earth's Moon - FAIL
Why does it have to be a planet to be awesome? Maybe you just have a sentimental attachment to the concept of planet because you live on one, but really they are just big dumb balls of rock.
As it stands, Pluto is the largest KBO, and the only binary dwarf system in the solar system. That's a lot cooler than the smallest planet.
Anyways, Pluto's orbit isn't anything like the other planets. Ceres is more deserving of planet-hood.
Also Oliver Hamilton if atmosphere and natural satellites make something a planet, then Mercury isn't.
Planet = synonymous with "world" in my book.
ReplyDeleteDon't really see what orbits have got to do with anything. If the Earth got tidally ejected from its orbit, it would still be a planet (if it survived). Plus Jupiter hasn't cleared its orbit.
Hence I go for pure subjectivity. To heck with this rigorous objective definition melarky.
If earth got ejected from it's orbit, it would be a rogue planet.
ReplyDeleteAnd the important part is, the planets all formed in the protoplanetary accretion disk. This is why they all seem to line up into the Ecliptic. Pluto did not, so it does not. It's not a planet because it was never part of the protoplanetary disk. It's a very large comet, if it got pushed closer to the sun, you would see it's tail.
As for world. There are plenty of worlds that aren't planets. Stop being so earth-centric.
Rhys Taylor Orbits have plenty to do with it. If Earth were captured by Jupiter, it would be classified as a moon, not a planet. If it were in the Asteroid Belt, it would be classified as a large Asteroid. Because of its orbit, Ceres is a large Asteroid. Somewhere else, it might be classified as a moon, or a planet. Titan is bigger than Pluto, has a thick atmosphere, and we might consider it a "world" -- but it's not a planet, because of its orbit around Saturn. Because of its orbit, Pluto is a large Kuiper Belt object. An incredibly awesome KBO. We don't have to call it a planet for it to be awesome, and we shouldn't change its classification and undermine the meaning of planethood because people somehow think Pluto's feelings are hurt.
ReplyDeleteI think it makes sense to classify objects according to their physical characteristics, just like biology does with life.
ReplyDeleteSo much of Pluto is ices, if it were in Earth's orbit it would have a comet's tail.
Why are we talking about a pluto . 3 billon miles away?Why?
ReplyDeleteChristopher O'Rourke because there is a probe there now.
ReplyDeleteYeah that sends pictures back from 3 billon miles away . yeah right .ha
ReplyDeletePeople believe anything . ha.
ReplyDeleteYou can lead a person to knowledge but you can't make him think.
ReplyDeleteI think you are taking about yourself .that's for sure . ha
ReplyDeleteI'm calling it a planet regardless.
ReplyDeleteThis comment was not for you . David nutcase.
ReplyDeleteGalaxies are awesome and they're not planets, most of the moons in our Solar system are awesome and they're not planets. So, as you can see, going off of being awesome won't work.
ReplyDeleteThere is a good definition of what makes a planet:
1) Must orbit the sun
2) Must have a mass large enough to make it spherical in shape instead of being a rigid body
3) Has cleared it's orbit of debris
Pluto loses out because it has not cleared it's orbit of debris since it is within the Kuiper belt, same reason Eris (almost the same size as Pluto, but no one is losing their minds over it not being a planet) is a dwarf planet, and so is Ceres in the asteroid belt.
Let's forget about the word "planet", and arbitrary definitions for a moment. It's an archaic term, coined in a time during which we knew no better.
ReplyDeleteThey were "wandering stars" among the fixed firmament. We know so much more now about the Universe, and our Solar system specifically, the the word loses its meaning.
If we were to approach the classification of Solar system bodies in the same way we do with exoplanetary systems, or phylogeny of living things, or any other group of object that share common properties, but differ in others, it seems clear to me that Pluto has no more in common with the terrestrial planets, than Earth does with Jupiter. It makes no sense to me to have a scientific definition of "planet" that puts Saturn and Mars the same status.
I propose we dump the term "planet" from the scientific lexicon, keeping it only for common usage among laypersons, and develop a classification based on size, composition, orbital characteristics and such that better describe the relationships between the objects, their formation and evolution.
By all means, call Pluto a planet, if it makes you feel all warm and fuzzy, but that isn't what makes good science.
Kevin Franklin Neil deGrasse Tyson suggested something similar recently. The terrestrial planets (Mercury, Venus, Earth, Mars) are very different from the gas giants, and should not all be lumped into the same vague "planet" category. This makes good sense.
ReplyDeleteMichael Rector Great point about Ceres and Eris. I don't understand why people get so worked up over whether Pluto is called a planet or not, but don't care at all about Ceres or Eris.
ReplyDeleteHelen Read Ceres and Eris do not have cartoon dogs named after them. Just goddesses.
ReplyDeleteGo figure.
Nat Sheppard Ceres has cereal named after it, though! Cereal is one of the world's best foods!
ReplyDeleteNot as important as cartoon dogs.
ReplyDeleteNat Sheppard Meh, I don't know. I never liked most cartoons even as a kid. I've always loved cereal.
ReplyDeleteI realise you're all being a bit tongue-in-cheek, but really, are we going to classify objects on the basis of far they have penetrated popular culture?
ReplyDeleteIt's the reason, not an excuse.
ReplyDeletePeople want pluto to be a planet because it has a dog named after it. That does not make it right though.
Is not ought.
"I propose we dump the term "planet" from the scientific lexicon, keeping it only for common usage among laypersons, and develop a classification based on size, composition, orbital characteristics and such that better describe the relationships between the objects, their formation and evolution."
ReplyDeleteI would have adopted a different approach. Keep "planet" as an overarching term for all bodies large enough to be spherical that aren't undergoing fusion or orbiting another planet. Then instead of defining "planet" and "dwarf planet", which is grammatically confusing, define instead "giant planets" and "dwarf planets" and/or "gas planets" and/or "terrestrial planets".As you say, Jupiter and Earth are completely different yet both are planets. Use "planet" for basically everything, but have lots of sub-categories. Schoolchildren will thus learn about the eight "major planets" but also be aware that these are not the only planets.
Moons would be any planets orbiting other planets. Double/multi-planet systems would be where the centre of gravity lies outside both/all objects.
I still don't get what clearing the orbit has to do with anything though.
To me a planet is a big ball of stuff orbiting a star. Moons are just big balls of stuff orbiting planets and so what. To me Pluto will always be a planet. The name does not diminish it to me in any way.
ReplyDeleteI still want to go visit it, look around, take a p1ss, put my flag out there and continue on.
Kevin Franklin the only defination of planet should be - "one, which harbours life".
ReplyDeleteHelen Read your description actually explains why these descriptions would never work programmatically. You wouldn't change the class of a thing because of what it is linked to. Maybe we just need to call everything StellarObject, give it properties and relationship links to other StellarObjects and call it good. Technically, in this particular case, we are talking about SOs that orbit within the heliosphere. It's relationship to other SOs, crossing their orbit, etc - really is very 2d thinking. It's orbiting the Sun within the heliosphere - what else matters?
ReplyDeleteIf you want to be really scientific about what defines a planet then you should look not at it's surrounds (ie did it clear it's neighbourhood) but what it actually IS. mass, composition, chemistry, is it a giant nuclear fusion reactor (star) etc. To be fair this is still to some degree an open question. I was just being childish earlier (I enjoyed it greatly). If the earth were suddenly beset with similar amounts of debris sharing our orbit (ignoring our impending doom) we wouldn't deny it's planet hood all of a sudden.
ReplyDeletePSR B1620-26 contains a planet 2.5 times bigger than Jupiter that orbits a binary system... It's sun is no longer on the same 2d plane as it was when it was a single star system... The planet orbits the new center of mass, not sun 1 or sun 2.
ReplyDeleteRhys Taylor Sure, call them anything you want. But be consistent with it. Insisting that Pluto be called a planet, and ignoring all the other spherical objects orbiting the Sun seems like sentimentality.
ReplyDeleteKevin Franklin I'm not ignoring all the other spherical objects. At no point did I suggest that Ceres isn't a planet. And yes, I am being overtly sentimental. :) Which is at least as good an approach to defining "planet" as the current IAU version, in my book.
ReplyDeleteA dwarf star is just a subcategory of stars. Following the same logic, a dwarf planet is still a planet
ReplyDeleteIdiotic post.
ReplyDeleteIt's not a planet.
It's a world, yes. But not a planet.
Planets don't orbit their own moons!
It's one of a great many comparable planetoids.
It's just a matter of fucking nomenclature!
Idiotic Not supposed to be taken entirely seriously post.
ReplyDeleteRhys Taylor
ReplyDeleteFairy nuff.
Yaa
ReplyDeleteI say go with:
ReplyDeleteGas giants- Jupiter, Saturn, Neptune, Uranus
Terrestrials- Mercury, Venus, Earth, Mars
Dwarfs- Pluto, Ceres, Charon, Eris, Sedna, Makemake, Orcus, Ixion, Varuna, Quaoar.
And we skip all the alpha-numeric signified ones.
Children would only have to learn 18. That's just twice as much as before.