Pluto Should Be Reclassified as a Planet, Experts Say

Pez

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I'm sorry. Pluto never stopped being a planet to me. Unless it gets woke or blows up, it'll always be a planet.
 

Jagger100

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if its round its a planet? so all moons are now planets?
Nope. It has to be able to MAKE itself round likely while in its current state. Also orbiting the sun is likely a common criteria between the competing definitions and therefore not mentioned.
 

PantherBlitz

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The silly thing is that anyone would try to define what a planet is. That is like trying to make a definition on what can be a country. If people recognize Pluto as a planet, its a planet.
 

scojer

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It's a "Dwarf Planet"
It's still a planet
Just like a dwarf is still a person.

The real question is: When did political correctness start applying to celestial bodies?
 

Monkey34

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I have always thought it was a dumb decision to de-classify Pluto as a planet.

If it's spherical, has atmosphere, moon(s), and a complex geology......hello? Planet here. Common sense.

Hopefully, at the very least, the controversy has generated some interest in space and astronomy in people.
 

Nobu

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to further explain what the person above stated. Most planets orbit the sun and their moons orbit them. Pluto and its moon both spin around a point between them and that point is what orbits the sun.
To further further explain what he said, the same can be said about the earth and its moon, except that point resides within the mass of the earth, whereas it resides outside pluto and its moon.
 
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to further explain what the person above stated. Most planets orbit the sun and their moons orbit them. Pluto and its moon both spin around a point between them and that point is what orbits the sun.

Thank you for the knowledge drop, I did not know this
 

Nobu

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Fun Fact, Jupiter is so massive its barycenter (The pivot point where it and the sun orbit with respect to each other) is actually 7% out of the sun's surface.
So technically, Jupiter and the sun are binary stars?
 

Armenius

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So technically, Jupiter and the sun are binary stars?
Jupiter could be a brown dwarf after losing a bet with Sol and decided to chill out with a border fence between the two of them.
 
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DeathFromBelow

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I have always thought it was a dumb decision to de-classify Pluto as a planet.

If it's spherical, has atmosphere, moon(s), and a complex geology......hello? Planet here. Common sense.

The asteroid/dwarf planet Ceres has volcanoes, too.

Pluto has always been an oddball. It has far less mass than our Moon. It crosses Neptune's orbit (it's locked in a resonance so they can't collide), and there are a hundreds of other known objects (Plutoid's) in the same region massive enough to become rounded. Pluto's moon Charon is so massive compared to Pluto that they orbit a common barycenter. None of the major planets have a moon that massive relative to themselves.

Back when the asteroids were first being discovered they were given names and fancy planetary symbols. Ceres was discovered in 1801, then Pallas, Juno, and Vesta... When they got to Fides (#37) in 1855 astronomers finally said **** it and officially created a new category for small objects between Mars and Jupiter: asteroids. The same thing happened to Pluto. People need to get over it.

So technically, Jupiter and the sun are binary stars?

No, because Jupiter has nowhere near enough mass to be a star. I would assume pretty much all stars have enough stuff orbiting around them to induce some wobble, and lots of stars have big gas giant planets like Jupiter. I think his point is that the fact that Pluto/Charon orbit a common barycenter outside of Pluto's surface isn't enough by itself to demote Pluto.
 

Nobu

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No, because Jupiter has nowhere near enough mass to be a star. I would assume pretty much all stars have enough stuff orbiting around them to induce some wobble, and lots of stars have big gas giant planets like Jupiter. I think his point is that the fact that Pluto/Charon orbit a common barycenter outside of Pluto's surface isn't enough by itself to demote Pluto.
I'm aware. It was more a toung-in-cheek question. For one thing, Jupiter isn't on fire. Still, it's an interesting thought–if it was a bit more massive, we could have been in a binary star system...but then conditions on earth would probably have been way different.
 

DeathFromBelow

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I'm aware. It was more a toung-in-cheek question. For one thing, Jupiter isn't on fire. Still, it's an interesting thought–if it was a bit more massive, we could have been in a binary star system...but then conditions on earth would probably have been way different.

That is an interesting thought... the Sun is 150 million miles away. Jupiter is ~365 million miles away from Earth at it's closest possible approach. A small red or orange dwarf in the same orbit as Jupiter might not have much effect on Earth other than being bright enough to read by at night, all other things being equal.
 
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Filter

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I thought i read an article somewhere. If you stuck earth in plutos orbit it wouldnt clear its neighborhood either. So would earth not be a planet if it was in plutos orbit.

Still looking for article
 

lcpiper

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Memes aside, this guy is suggesting that there should be hundreds of planets in our planetary system, which is ridiculous.

No he isn't, he just failed to mention the other criteria required to classify a body as a planet.
 

DeathFromBelow

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I thought i read an article somewhere. If you stuck earth in plutos orbit it wouldnt clear its neighborhood either. So would earth not be a planet if it was in plutos orbit.

Still looking for article

From Wikipedia:
The phrase refers to an orbiting body (a planet or protoplanet) "sweeping out" its orbital region over time, by gravitationally interacting with smaller bodies nearby. Over many orbital cycles, a large body will tend to cause small bodies either to accrete with it, or to be disturbed to another orbit, or to be captured either as a satellite or into a resonant orbit. As a consequence it does not then share its orbital region with other bodies of significant size, except for its own satellites, or other bodies governed by its own gravitational influence. This latter restriction excludes objects whose orbits may cross but that will never collide with each other due to orbital resonance, such as Jupiter and its trojans, Earth and 3753 Cruithne, or Neptune and the plutinos.[3] As to the extent of orbit clearing required, Jean-Luc Margot emphasises "a planet can never completely clear its orbital zone, because gravitational and radiative forces continually perturb the orbits of asteroids and comets into planet-crossing orbits" and states that the IAU did not intend the impossible standard of impeccable orbit clearing.

If you replaced Pluto with an Earth-sized object it would qualify as a major planet under the established definition. There are no Earth-sized objects in the same orbit and the 2:3 orbital resonance with Neptune prevents a collision between the two despite the fact that their orbits cross. As it is Pluto is just one of many 'Plutoids' in the same region.
 

sfsuphysics

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Ah, so Mercury is no planet then?
But Mercury does have an atmosphere, I mean technically there are gases around the planet.

if its round its a planet? so all moons are now planets?
No, moons do not follow the first major criteria for a major planet, which is they primarily orbit the Sun, while yes they do as a whole go around the Sun they actually orbit around the planet (whether major or dwarf)

Re-classifying Pluto was like putting the color peach and making all the Presidents smile on the various US bills.... somebody wanted to be 'involved' in the process and make changes just so they can say they accomplished something... despite it being utterly unnecessary. I've always been in favor of the 'slap the taste outa yer face' law when someone makes a stupid suggestion... because we all know there ARE stupid questions, stupid answers, and even MORE stupid people.
Actually the whole idea of defining what a planet was came about when, whoops we found another planet, then oops, another planet, and yup another one still. Wait are all these things planets? Should we call them planets? And if so do we call the closest one to us a planet now even though ti's been called an asteroid all this years but it is round like a planet? So yeah, this has very little to do with "someone wanting to be involved" and was simply a way to stem the coming tide of our 9 planet system becoming a system of 14 planets, and possibly in the future being a system of 543 plants (no I'm not making that number up either). So some simply classification of objects in the Solar System of major planet, minor (dwarf) planet, small solar system body was made of all objects that primarily orbit the Sun. Don't refer to Pluto as a planet, it has a name, call it Pluto instead of that little dark fellow over there! :D



If it on the same ecliptic level around the sun and is not part of a cluster (like those in the belts) and has smaller objects orbiting it -> planet
It's 17 degrees off the ecliptic though.

The silly thing is that anyone would try to define what a planet is. That is like trying to make a definition on what can be a country. If people recognize Pluto as a planet, its a planet.
See above, it's simply a classification system, can you be a country? why is it silly to say that you can't?


If you replaced Pluto with an Earth-sized object it would qualify as a major planet under the established definition. There are no Earth-sized objects in the same orbit and the 2:3 orbital resonance with Neptune prevents a collision between the two despite the fact that their orbits cross. As it is Pluto is just one of many 'Plutoids' in the same region.
The paths of Neptune and Pluto don't actually cross, sure Pluto gets closer to the Sun at certain times of it's orbit but it never actually crosses paths (see above re: 17° tilt)

I have always thought it was a dumb decision to de-classify Pluto as a planet.

If it's spherical, has atmosphere, moon(s), and a complex geology......hello? Planet here. Common sense.

Hopefully, at the very least, the controversy has generated some interest in space and astronomy in people.
Well we know all this stuff about Pluto NOW, when the classification system was put into place the best photo we had of Pluto was like 8 pixels wide or something tiny like that, every single image you saw before that was "computer enhanced" (i.e. photoshopped), can you really make the determination of spherical from 8 pixels across? Moons we knew of sure, but not atmosphere, and complex geology... that may be a stretch even today, depending upon what your definition of "complex" is.
 

PantherBlitz

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it's simply a classification system, can you be a country? why is it silly to say that you can't?

Look at the countries of the world and try to come up with a common definition. Physical size? Population? Continuous border? Size of the GDP? The only definition that makes sense is that people agree to call it a country.
 

jedijeb13

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What is interesting about the change in definition is that the IAU is normally considered the body that regulates study of stellar astronomy and made the decision without consulting with the groups representing planetary scientists. Many actual planetary scientists still argue for Pluto to be a planet. Sorta like the Federal government telling California that Los Angeles must be the capitol since it is the largest city regardless of what California has in its constitution or what its citizens want.

The debate will continue for many years to come I am sure.
 

DeathFromBelow

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The paths of Neptune and Pluto don't actually cross, sure Pluto gets closer to the Sun at certain times of it's orbit but it never actually crosses paths (see above re: 17° tilt)

Their orbits cross. The reason gravitational interactions don't eventually lead to a collision or ejection of Pluto is because Pluto is in a 2:3 orbital resonance with Neptune, not because of the tilt of it's orbit. Every time Pluto is at perihelion Neptune is 1/4 an orbit away.

Neptune_pluto_orbits.gif


If Pluto was in a non-resonant position it would eventually (after thousands-millions of orbits) have a close encounter with Neptune at one of the crossing points. Neptune's big moon Triton was probably a Plutoid that it captured.

Pluto Orbit.jpg
 

sfsuphysics

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Their orbits cross. The reason gravitational interactions don't eventually lead to a collision or ejection of Pluto is because Pluto is in a 2:3 orbital resonance with Neptune, not because of the tilt of it's orbit. Every time Pluto is at perihelion Neptune is 1/4 an orbit away.

View attachment 103169

If Pluto was in a non-resonant position it would eventually (after thousands-millions of orbits) have a close encounter with Neptune at one of the crossing points. Neptune's big moon Triton was probably a Plutoid that it captured.

View attachment 103172
They don't cross in the sense that the orbits physically intersect is what I meant, if you were to put a piece of rope around both orbits (big ass piece of rope) at no time will either rope touch each other..
 
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