Is Pluto a planet?

[Entropian]

8 hours ago, Contellation Aerospace said:

How long have you been in Kgantuya?IAU said that pluto isn't a planet in 2006......

the definition of a  planet:

1.orbits the sun 

2.It was round

3.it can clear its  orbit(Pluto 's orbit is in Kuiper Belt)

So,Pluto isn't a planet

I stated that in the title.  I just wanted to know what people around here thought.

[mikegarrison]

What fools these mortals be.

It is what it is, whether we call it a planet, a star, a dwarf planet, an asteroid, a space rock, a trans-Neptunian object, etc., etc.

[NFUN]

32 minutes ago, mikegarrison said:

What fools these mortals be.

It is what it is, whether we call it a planet, a star, a dwarf planet, an asteroid, a space rock, a trans-Neptunian object, etc., etc.

so let's call every noun "Ted" because terms have no physical effect on reality and thus they do not matter. This Ted of detached Ted doesn't improve Ted, Ted or the Ted of this Ted, and ignores all the Ted that Ted use Ted to understand Ted.

Edited October 24, 2020 by NFUN

[wumpus]

On 10/24/2020 at 7:21 PM, NFUN said:

so let's call every noun "Ted" because terms have no physical effect on reality and thus they do not matter. This Ted of detached Ted doesn't improve Ted, Ted or the Ted of this Ted, and ignores all the Ted that Ted use Ted to understand Ted.

Why not Scott?

Because for this forum at least, naming Pluto a planet gives (33434)Scott Manley an equal shot at being a planet.

- (33434) Scott Manley is more or less a very large asteroid, but big enough to be in the "planet spectrum".

[NFUN]

Scott guess Scott works

[SOXBLOX]

On 10/24/2020 at 5:49 PM, mikegarrison said:

It is what it is, whether we call it a planet, a star, a dwarf planet, an asteroid, a space rock, a trans-Neptunian object, etc.

So, I guess we need to find out what we want to accomplish with our classification scheme.

...

What do we want to accomplish? 

[NFUN]

25 minutes ago, SOXBLOX said:

So, I guess we need to find out what we want to accomplish with our classification scheme.

...

What do we want to accomplish? 

In planetary science (I suppose geologists may have other priorities), to be able to more or less understand the important features of a given body just by its classification (useful when we get more information on exoplanets and people won't have all of the researched ones memorized), particularly in regards to its role in the evolution of its system and its situation today. If it's orbiting a body other than its star, reasonably large, or gravitationally dominant in its location seem to be the most relevant features in those regards off the top of my head, which conveniently more-or-less are the differences between "moon", "dwarf planet" and "planet" under the modern definition. Of course, if needed you may need to get into more detail, but to quickly inform somebody of the general attributes of the body in question, the IAU definition seems at least better than what we had before. 

 

I have no idea why this is crossed out and mobile won't let me fix it

Edited October 26, 2020 by NFUN

[Superfluous J]

2 hours ago, SOXBLOX said:

So, I guess we need to find out what we want to accomplish with our classification scheme.

...

What do we want to accomplish? 

I posit the IAU already figured that out and used it as the basis of their definition.

[kerbiloid]

IAU should extend their definition a little: "Planet is: 1,2,3... orPluto".

Nobody cares if Eris or Sedna are planets...

[sevenperforce]

15 hours ago, wumpus said:

Why not Scott?

Because for this forum at least, naming Pluto a planet gives (33434)Scott Manley an equal shot at being a planet.

- (33434) Scott Manley is more or less a very large asteroid, but big enough to be in the "planet spectrum".

4.6 km is not quite bit enough to be gravitationally rounded.

9 hours ago, SOXBLOX said:

So, I guess we need to find out what we want to accomplish with our classification scheme.

...

What do we want to accomplish? 

I have posited that our classification scheme ought to reflect our need for clear communication and science education.

[kerbiloid]

1 hour ago, sevenperforce said:

17 hours ago, wumpus said:

(33434) Scott Manley is more or less a very large asteroid, but big enough to be in the "planet spectrum".

4.6 km is not quite bit enough to be gravitationally rounded.

Even with silver button?

[wumpus]

11 hours ago, sevenperforce said:

4.6 km is not quite bit enough to be gravitationally rounded.

Bennu is considerably smaller and considering how loosely it appears to be held together, may well be gravitationally rounded.

11 hours ago, sevenperforce said:

I have posited that our classification scheme ought to reflect our need for clear communication and science education.

Those are good goals.  I was greatly irked to find out that animals that could crossbreed and produce grandcritters could still be separate species.  It took me some time to realize that the fact that since such simply didn't happen in nature (typically due to distance), it was silly to allow an experiment to prove they are the same species.

[NFUN]

A little more goes into hydrostatic equilibrium than "looks round to me!"

[wumpus]

On 10/27/2020 at 12:33 AM, NFUN said:

A little more goes into hydrostatic equilibrium than "looks round to me!"

The point is that Bennu doesn't have to be round thanks to hydrostatic equilibrium.  If it is a collection of relatively small rocks held together by gravity, they would have a chance to reform every time it is perturbed.  Granted, not all of those perturbations will lead to roundness (which might get inserted into the planetary definition), but I'd expect them to statistically lean that way and lead to the shape we see now.

[NFUN]

1 hour ago, wumpus said:

The point is that Bennu doesn't have to be round thanks to hydrostatic equilibrium.  If it is a collection of relatively small rocks held together by gravity, they would have a chance to reform every time it is perturbed.  Granted, not all of those perturbations will lead to roundness (which might get inserted into the planetary definition), but I'd expect them to statistically lean that way and lead to the shape we see now.

The point is that the criterion in question isn't "is the planet round?", it's "is the planet in hydrostatic equilibrium?"

[grungar3x7]

On 10/26/2020 at 5:42 AM, kerbiloid said:

IAU should extend their definition a little: "Planet is: 1,2,3... orPluto".

Nobody cares if Eris or Sedna are planets...

Well, I do. I'll admit, however, that I follow the Geophysical Planet Definition put forward by some planetary scientists, the folks who should define the category in the first place. So there. 

[NFUN]

2 hours ago, grungar3x7 said:

Well, I do. I'll admit, however, that I follow the Geophysical Planet Definition put forward by some planetary scientists, the folks who should define the category in the first place. So there. 

why did you link a pdf when their defintion is just "dwarf planets are also planets"? 

 

//this came off more rude than I intended. feel free to take it lightly 

Edited October 31, 2020 by NFUN

[SOXBLOX]

4 hours ago, grungar3x7 said:

I'll admit, however, that I follow the Geophysical Planet Definition put forward by some planetary scientists, the folks who should define the category in the first place. So there.

I like that definition, too. It just needs to distinguish between major planets, sevenperforces' "irregular planets" and moons. Then I'm happy.

[RCgothic]

7 hours ago, grungar3x7 said:

Well, I do. I'll admit, however, that I follow the Geophysical Planet Definition put forward by some planetary scientists, the folks who should define the category in the first place. So there. 

I approve this definition.

[kerbiloid]

While this definition is enough good in whole, let's also don't forget about the very wide-spread case of minor bodies, having equatiorial ridge.

Spoiler

Iapetus

Atlas

Pan

Etc

 

They may belong to their own class: "pelmeni planet" or "ravioli planet"

Spoiler

 

Edited October 31, 2020 by kerbiloid

[grungar3x7]

As a final point, I'll let Dr. Kirby Runyon speak for himself, from the past...

 

Edited November 3, 2020 by grungar3x7
errant capitalization perturbing my sensibilities.