Can We Agree That Pluto and Charon Are A Binary Planet System?

Question

Charon is not a moon of Pluto.Charon and Pluto orbit a common point in space as they orbit the Sun.This makes Pluto and Charon the only known binary planets in the solar system.And I don't care what the IAU says,both Pluto and Charon are planets.

Answer 1

All objects orbit a common point based on the ratios of their mutual gravity and are therefore technically binary.  learn some physics before you declare the IAU wrong, I don't think they care what you thing either.

Answer 2

They aren't planets unless they are called planets by the people who name planets as planets.

Sorry, just because they are sorta planet-sized doesn't make them planets, they don't really follow planet-like orbits, they go out further than neptune and come in closer than neptune - which retains a fairly constant orbit distance like the other 7 official planets.

Answer 3

Not planets.  They're just two KBOs (Kuiper Belt Objects) with gravitational attraction to each other.  

Answer 4

Actually, that's incorrect - Earth/moon is also considered a "binary planetary system" - as our moon is fully 1/4 the size of it's primary.  And, regardless of your feelings, the IAU will determine what is and is not a planet.

Personally.... I don't care what their classification is. They're just labels.

Answer 5

Well coming up for an exact definition of *what* a double planet system is will be the hard part. We can't really say because we can only study our solar system in detail... we can't study other ones. The closest extra-stellar solar system is over 4 light years away.

The IAU hasn't set a specific figure for the proportional amount of mass between the satellite and the planet for anything to be considered a binary planet system, also known as a "double planet".

Although in our hearts Pluto will always be a planet, it is time to let go for now. Pluto and Charon would be a binary dwarf planet system, or a double dwarf planet. More specifically it would be a double plutoid system or a binary plutoid system.

And another question is, should the object of smaller mass be considered a planet? If Pluto was a planet and was considered a double planet with Charon, what should Charon be considered? It can't be considered a planet because it isn't orbiting the sun and is less massive than Pluto, but it can't be considered a moon really because you are calling the system a "double planet". That's up for debate. The AU would probably come up with another name for object B of a binary planet system.

An interesting fact I just discovered is that some might go as far to say that Earth is a binary planet with its moon because proportional to the Earth, the moon is actually pretty large. Although it is not even half of the Earth's size, some think it may be massive enough compared to Earth to be considered a double-planet or a binary planet system. Personally, I do not agree with this. I think that the moon is not massive enough compared to Earth, but then again, I'm not on the IAU's board.

Answer 6

In order to be considered a binary system (whether it's binary planet, or binary plutoid, or binary space rock is beside the point) the objects in question must mutually orbit a center of mass not located within the interior of either object.

The earth/moon system is not, by definition, a binary system becuase the center of mass between the earth and the moon is located somewhere inside the earth.

I'm not sure where the center of mass is located for Pluto/Charron. If in fact the COM is inside one or the other, then it's a true binary system. Otherwise, it is a planet/plutoid/space rock with an orbiting moon.

Answer 7

Charon isn't a planet. It's Pluto's moon.

Answer 8

everything orbits a common point. the earth doesnt orbit the sun. the sun and the earth both orbit their common barycenter.

let me ask you a question. when you see a motorcycle, do you ever say "thats a car and i dont care what anyone else says!"

no, i would assume you dont. why? because the definition of a motorcycle isnt the same is a the definition of a car. pluto and charon do not fit the definition of a planet. your argument is ridiculous, stupid, and to be frank, retarded. your arguing the definition of a word.

charon is certainly not a planet no matter which way you look at it. Nix and Hydra orbit the same barycenter, does that mean they are planets too?

if you want pluto and charon (and charon is never going to be a planet get over it) then you have to accept eris, ceres, makemake and any of the 250 stellar bodies on the waiting list to becoming dwarf planets. so no, your wrong. you dont care what the IAU says, well no one gives a flaming **** what you say.

Answer 9

Depends how small you want your class 'planet' to be.

We've already observed other small binary groups but we call em 'asteroids'.

Answer 10

You need to come up with a definition of a binary planetary system.

I think Pluto and Charon make up a plutoid binary system.

However, once you consider Hydra and Nix - I think this definition becomes troublesome.

But Pluto is more different from the things that are currently defined as planets than the IAU definition of planets suggests.

For details go to:http://stardust.astro.missouri.edu/FTP/

and download:: Pluto_talk.ppt

Answer 11

We can agree that Pluto and Charon are a double planet, with two additional moons, Nix and Hydra.  But the International Astronomical Union currently does not consider Pluto as a planet.  I suppose they consider Charon is a moon, however, and certainly Nix and Hydra.