Will the New Horizons mission bring Pluto back to planet status?

[Jer95]

Pluto was a dwarf planet 3 years ago and New Horizons is on its way to Pluto. Will the mission bring Pluto back to planet status in 2015?

 

[Brad]

Not a chance.... Unless there is some significate changes in what is classified as a planet, Pluto will just be a planetoid.

 

[Ghostrider]

Well, with the next mission we'll send up some more mass and solve the problem.

 

[Linguofreak]

Pluto was a dwarf planet 3 years ago and New Horizons is on its way to Pluto. Will the mission bring Pluto back to planet status in 2015?

Pluto being defined as a planet or non-planet doesn't really have much to do with the New Horizons mission. If the IAU decides it was a mistake to define it as a dwarf planet, they'll change their definition eventually. If not, they won't.

 

[simonpro]

No. Why should it?

 

[garyw]

No. Why should it?

What he said. IAU knows the size of Pluto and I doubt New Horizons will find that pluto is bigger than the size we already have down for it.

In fact, Once New Horizons leaves Pluto and explores the edge of the solar system I'll think it'll become more obvious that Pluto is a KBO.

 

[Ghostrider]

If the IAU decides it was a mistake to define it as a dwarf planet, they'll change their definition eventually. If not, they won't.

Well, we could show them it was a mistake. 5 minutes in a locked room with Jack Bauer would do.

 

[garyw]

Well, we could show them it was a mistake. 5 minutes in a locked room with Jack Bauer would do.

Why so concerned about Pluto's status? it doesn't care!

 

[agentgonzo]

Why so concerned about Pluto's status? it doesn't care!

Some people still live in the dark ages (or Illinois).

 

[Hmuda]

I thought size wasn't the only matter, the fact that it didn't clear out it's path of asteroids and other debris was another factor. That's why Ceres and Eris aren't planets either.

Unless they change this criteria, no matter the size, Pluto will not be conidered a planet again.

 

[RisingFury]

The definition of a planet says nothing about it's size.

These are the three properties an object has to meet in order to be classified as a planet:
- It has to be the primary body in orbit around the Sun (in other words, not a moon).
- It has to be round(ish), due to it's own gravity.
- It needs to clear it's orbit of orbital debris.


Pluto is round due to it's gravity and is the primary body, but it's failed to clear it's orbit of orbital debris. It's in a field densely populated by other objects.



Did you know that in 1803, there were 13 planets?
They didn't know about Pluto back then, but astronomers started finding more objects in orbit around the Sun. One of them was called Planet Cares. Turns out that the vast majority of these bodies were small... really really small... so it was widely decided that these small bodies would be renamed to asteroids. This time it's no different... and trust me... the definition of the word "planet" will change in the future.

 

[bujin]

These are the three properties an object has to meet in order to be classified as a planet:
- It has to be the primary body in orbit around the Sun (in other words, not a moon).

Does this mean that all the Jupiter-mass objects found in orbit around other stars are not technically "planets"? It seems to very specifically state "the Sun"...

 

[insane_alien]

i think that was paraphrasing by RisingFury.

replace "the Sun" by "Stellar body"

 

[agentgonzo]

Did you know that in 1803, there were 13 planets?
They didn't know about Pluto back then, but astronomers started finding more objects in orbit around the Sun. One of them was called Planet Cares. Turns out that the vast majority of these bodies were small... really really small... so it was widely decided that these small bodies would be renamed to asteroids. This time it's no different... and trust me... the definition of the word "planet" will change in the future.

This is the major point. The fact that "there are many similar other bodies" in the local vicinity. This is why Ceres etc were demoted in the 1800s (there were over 25 at some point according to the font of all knowledge. As Fury says, this is exactly the same, except that now, because the whole-world-and-his-dog could listen, they had to come up with a formal definition as "suitably different" is still subjective.

And we'll go through this all again at some point when we start naming planets around other stars and find planets around other stars that turn out to be asteroids, equivalents-of-KBOs, etc.

 

[RisingFury]

For now, exoplanets get the name of the star + b/c/d/...

The reason why we'll need a new definition for the word "planet" is because right now the same word describes a small rocky body and a gas giant with rings.

If I find a new planet, you're gonna ask me: Is is a ball of gas, a rock or a chunk of ice? How big is it? How massive is it? Does it have an atmosphere? Does it have rings? And so on...

We have good definitions for stars, even outside of the formal naming conventions... we have brown dwarfs, white dwarfs, yellow, red or blue stars, we have red giants and even hypergiants. Despite being unscientific, such words do pass on information. The word "planet" does not.

 

[T.Neo]

In my opinion, being large enough to attain a spherical shape, should be the defining factor on whether an object orbiting a star is a planet or not. None of that "hasn't cleared it's orbit of mass" nonsense.

Although I do agree that objects such as Pluto should be given a sub-planetary status, to keep things more organised.

It's much easier to teach a class of unruly children about 8 planets, then it is to teach them about 30.

 

[Ghostrider]

replace "the Sun" by "Stellar body"

Oh, that's easy. Any sane mind would trade a trashy tabloid for Summer Glau.

 

[Zatnikitelman]

I voted yes even though I know it's pointless. I still think of Pluto as a planet even if everyone else doesn't. I learned 9 planets, not 8

 

[cjp]

The reason why we'll need a new definition for the word "planet" is because right now the same word describes a small rocky body and a gas giant with rings.

If I find a new planet, you're gonna ask me: Is is a ball of gas, a rock or a chunk of ice? How big is it? How massive is it? Does it have an atmosphere? Does it have rings? And so on...

We have good definitions for stars, even outside of the formal naming conventions... we have brown dwarfs, white dwarfs, yellow, red or blue stars, we have red giants and even hypergiants. Despite being unscientific, such words do pass on information. The word "planet" does not.

In Google, 'star' gives me a lot more hits than 'brown dwarf'. So I think 'planet' will be around for some time too.

The word 'planet' comes from the Greek, who used it for Mercury, Venus, Mars, Jupiter and Saturn. With all changing definitions of the term, it seems fair to keep these five inside the definition.

The only problem with that approach is that the Greeks also called the moon and the sun planets.

 

[Ghostrider]

The only problem with that approach is that the Greeks also called the moon and the sun planets.

I wouldn't criticize the Greeks' approach.

They may not take it kindly.