So Pluto is a planet!?

[ZetaX]

I learned more science from german public television broadcasting than from my teachers. We have this great show: "Sendung mit der Maus" (Show with the Mouse).

They had a great broadcast about space travel over 20 years ago. I can't find it on the internet :/

But I found this snippet: It isn't that old, and it gives a nice idea about the format of the show. I recomment watching it, even if you don't understand a word. It is entertaining as hell.

https://www.youtube.com/watch?v=mOORih_yfkU

Now you made me nostalgic...

Someone should make a english translation. I think it is still produced, but I don't know if the quality is the same.

[Mr Shifty]

I am envy about quality of your teaching. My teacher "knew", that we have so cold in Finland, because north latitudes are so much farther (several thousands of kilometers) from the Sun than the equator, and demonstrated it with a slide projector and a globe. Fortunately I had already learned (through the hard way, as real nerd without social skills must do) that it was better to be quiet and not ask "how about the fact that Earth is 5 millions of kilometers closer Sun in January than in July". I was then about 9.

Actually there is a grain of truth in your erstwhile teacher's demonstration: part of the reason high latitudes are colder is because sunlight must travel through a few extra thousand km of atmosphere in order to reach the ground (~3500km at 64°N during equinox.)

[N_las]

Actually there is a grain of truth in your erstwhile teacher's demonstration: part of the reason high latitudes are colder is because sunlight must travel through a few extra thousand km of atmosphere in order to reach the ground (~3500km at 64°N during equinox.)

But the length of atmosphere the sunlight has to traverse is dependent on the angle the surface has to the sun. It has nothing to do with the distance to the sun.

[B787_300]

{MOD}Hey Guys, this thread has gotten derailed from its original purpose which is to discuss Pluto and it's Planethood (is that even a correct term?). This thread should NOT be used to discuss topics such as and not limited too, evolution and climate.

If this thread does not get back on rails and stay on said rails, i will have to close the thread.

{/MOD}

NOW then, personally i think that it was right of the IAU to reclassify Pluto as a Dwarf Planet. and so what that it was classified as a planet... there are new generations that have no idea what a floppy disk is, there will be a generation that was taught pluto as a Dwarf Planet along with Ceres and Vesta. I always thought that it was wonky that pluto with its VERY inclined orbit and eccentricity was classified as a planet, heck it could be a large comet that was pulled into a semistable orbit. Anyways we will know more next year when NEW HORIZONS gets to pluto. http://www.wolframalpha.com/input/?t=crmtb01&f=ob&i=new%20horizons%20spacecraft

[Mr Shifty]

EDIT: Deleted original post here due to non-topical.

I like having a diverse population of solar system bodies and a variety of ways to refer to them. 2015 will be the Year of the Dwarf Planet, as we'll have up close looks at the first two dwarf planets ever to be visited by any spacecraft. Ceres and Pluto should be able to wear the label with pride.

Edited October 3, 2014 by Mr Shifty

[No one]

there will be a generation that has never heard of Pluto, just like they won't have heard of Ceres or Vesta.

FTFY.

I personally had never heard of Ceres until I started playing KSP. Actually I vaguely remember seeing it while randomly reading wikipedia, but to me it was "some sort of icy asteroidish thingy I think I forget". And I'm not sure if I remembered it by name or if I only know that that thing I read about was Ceres because I now know what Ceres is. Most people I know don't play KSP and have never heard of Ceres. When it comes to space, most people have heard of the planets, the sun, the moon, pluto, and then that's it.

[worir4]

Well TBH alot of people at my college can't even name all the planets.

[Superfluous J]

That means we need to believe these things because we learned them in school:

- The tongue taste map

- Diamonds are made from coal

- van Gogh cut off his own ear.

- Einstein couldn't do math.

- Benjamin Franklin discovered electricity by flying a kite which got struck by lighting.

- Newton discovered gravity when an apple dropped on his head.

- Columbus discovered that the Earth was round.

- Napoleon was short.

- Edison invented the light bulb.

Some of the things I could think off.

Maybe it's because I'm older than about 99% of you but I learned a lot of these correctly in my public school. I distinctly remember learning the Ben Franklin, Newton, Columbus, and Edison ones in GRADE school. Maybe 4th grade. And I'm not saying I just learned it correctly. I'm saying I learned "Here's a misconception about Columbus. Here's why it's wrong and here's what actually happened."

I don't remember learning the tongue taste map in school, but I do remember reading about it somewhere and trying it. Seemed real at the time. Most of the diamond/coal references I know stem back to Ferris Bueller, not school And I never heard that Einstein couldn't do math. Do people say that?

[Camacha]

I personally had never heard of Ceres until I started playing KSP. Actually I vaguely remember seeing it while randomly reading wikipedia, but to me it was "some sort of icy asteroidish thingy I think I forget". And I'm not sure if I remembered it by name or if I only know that that thing I read about was Ceres because I now know what Ceres is. Most people I know don't play KSP and have never heard of Ceres. When it comes to space, most people have heard of the planets, the sun, the moon, pluto, and then that's it.

That the whole thing - I feel people should learn about Pluto. And Ceres, and Makemake and all the other bodies that we can say anything about with a certain degree of accuracy. It turns out these smaller planets are a significant part of our solar system and expand our view on the formation and structure of the whole thing. It would be rather silly to only focus on the big 9 (including the sun), just as it would be silly to only talk about Pluto and none of the other small planets.

It might be excessive to expect everyone to learn all those icy bodies out there, but I feel it would be appropriate to teach people about the 15 or 20 largest bodies in the solar system, along with the classes that make up the smaller bodies. As it stands, most even somewhat informed people will say the solar system is just 8 or 9 planets with some comets and asteroids, while a lot more is going on.

Edited October 3, 2014 by Camacha

[-Velocity-]

Similar to what I just said in another thread, I think that the public getting upset about Pluto being a planet or not shows that they are not being taught astronomy correctly. They need to learn about all the objects in the solar system, not just the few we arbitrarily call "planets". ALL the interesting and large worlds need to be covered. More time should be spent learning about Europa or Titan than is spent learning about Mercury or Uranus, for example. And yet, more people know what Mercury and Uranus are than know what Europa and Titan are. Astronomy is not being taught correctly, because of this misguided fixation on "planets".

[Camacha]

Similar to what I just said in another thread, I think that the public getting upset about Pluto being a planet or not shows that they are not being taught astronomy correctly. They need to learn about all the objects in the solar system, not just the few we arbitrarily call "planets". ALL the interesting and large worlds need to be covered. More time should be spent learning about Europa or Titan than is spent learning about Mercury or Uranus, for example. And yet, more people know what Mercury and Uranus are than know what Europa and Titan are. Astronomy is not being taught correctly, because of this misguided fixation on "planets".

I full-hartedly agree. Picturing the solar system as 9 balls with some other floaty debris between them is painfully simplistic.

[m4v]

well, it isn't like you need to know your way around the solar system for live in society.

[SolarLiner]

I full-hartedly agree. Picturing the solar system as 9 balls with some other floaty debris between them is painfully simplistic.

Yes. The asteroid debris. SO MUCH people thinks that the asteroid belt is full of dust and asteroids that it is nearly impossible to pass ... because we get told that there is one asteroid belt there ...

I mean, this is the most boring and unimportant thing about our solar system ! This is time that can better be used to teach about all the satellites our giant planets have!

[Camacha]

well, it isn't like you need to know your way around the solar system for live in society.

I disagree. Giving people a broader sense of and view on things generally makes them nicer people to live and deal with. Maybe that the specific knowledge is of limited use in day to day life, but the same actually goes for a lot of the stuff taught in school.

[metaphor]

Yes. The asteroid debris. SO MUCH people thinks that the asteroid belt is full of dust and asteroids that it is nearly impossible to pass ... because we get told that there is one asteroid belt there ...

I mean, this is the most boring and unimportant thing about our solar system ! This is time that can better be used to teach about all the satellites our giant planets have!

Yeah, the asteroid belt is a tiny portion of the mass of the solar system. The difference in mass between Eris and Pluto (Eris is 27% more massive) is larger than the entire combined mass of the asteroid belt. The Kuiper belt is really more important than the asteroid belt, it's about 100 times more massive, extends across a much larger volume, and contains larger objects. And yet only a tiny portion of the people who learn about the asteroid belt know what the Kuiper belt is (although that might have changed in recent years as textbooks got updated). I'm guessing one of the reasons is that we don't have any good pictures of any representative objects, but that should change next year.

I do think kids should learn about the major satellites of the solar system in school, at least Io, Europa, Ganymede, Callisto, Titan, and Triton.

[Camacha]

I do think kids should learn about the major satellites of the solar system in school, at least Io, Europa, Ganymede, Callisto, Titan, and Triton.

The view that the solar system comprises intricate subsystems and a huge cloud of icy worlds rather than a handful of lone orbs of matter and not much else are quite radically different.

[Mr Shifty]

Yeah, the asteroid belt is a tiny portion of the mass of the solar system.

Well, to look at it another way, the solar system, to a good first approximation, is a star surrounded by empty space. The sun itself comprises 99.9% of the mass of the solar system.

[Camacha]

Well, to look at it another way, the solar system, to a good first approximation, is a star surrounded by empty space. The sun itself comprises 99.9% of the mass of the solar system.

That was exactly what I was thinking earlier in this discussion. Why include the 8 bigger balls? Mass wise they are of very little substance compared to the total mass of the solar system. The same argument people are bringing against the smaller planets actually goes for the bigger ones. Why not just talk about the Sun, or the Sun and Jupiter? Or, alternatively, why not ignore the rocky bodies of the inner solar system, as is justified by their lack of mass? Not to mention that some moons are almost as heavy or big as some planets.

When you look at it in a little more detail it becomes clear Uranus and Neptune are an order of magnitude larger than Earth, Jupiter and Saturn two orders while Mercury and Mars are actually one smaller.

Edited October 4, 2014 by Camacha

[m4v]

I disagree. Giving people a broader sense of and view on things generally makes them nicer people to live and deal with. Maybe that the specific knowledge is of limited use in day to day life, but the same actually goes for a lot of the stuff taught in school.

You're just making assumptions. I know a lot of people that are nice to live with and don't know jack about the solar system, not everyone is interested in what lies beyond the atmosphere.

[Camacha]

Your complaining seems petty to me, they're still planets, dwarf planets, which is very accurate considering their relative size compared to the other 8. And even if we go and call everything a planet, people would still separate them, since there's a clear distinction between the 8 planets and the dwarf ones (being mass, orbit)

This is actually not true. Compare the mass or size of Pluto to that of Mercury, then do the same for either with Earth or even one of the four gas giants. The latter are not remotely in the same league, which - following those guidelines - would mean Mercury should be classified as a dwarf planet. When we look at orbits it is Mercury again that refuses to have a neat near round orbit. Less skewed than Pluto for sure, but where do we put the line?

For the rest I point to my previous post, which is a decent indication that the subdivision would most likely not be along the same lines we make them now. Those eight planets are only viewed as a group the way they are because of the history behind it all.

[Camacha]

You're just making assumptions. I know a lot of people that are nice to live with and don't know jack about the solar system, not everyone is interested in what lies beyond the atmosphere.

It is far from any assumption that developing and teaching people improves society on a broad scale. Some people might not be interested, but then again, some people are also not interested in cars, or in economics, or any other subject. That does not deduct from the value of it.

I am not going to address the fallacy of explaining my statement to mean that no-one could be nice without knowing about the universe, as that one is obvious.

Edited October 4, 2014 by Camacha

[m4v]

This is actually not true. Compare the mass or size of Pluto to that of Mercury, then do the same for either with Earth or even one of the four gas giants. The latter are not remotely in the same league, which - following those guidelines - would mean Mercury should be classified as a dwarf planet. When we look at orbits it is Mercury again that refuses to have a neat near round orbit. Less skewed than Pluto for sure, but where do we put the line?

Okay. Mercury is twice as big and a lot more massive than Pluto, its orbit isn't nowhere near as inclined nor as eccentric: at some points Pluto is closer to the Sun than Neptune, really just look at some 3d map of the solar system (like http://www.solarsystemscope.com/) for see how out of place Pluto is.

In the end, the line is drawn by Soter's planetary discriminant, the magnitude that quantifies how much a potential planet has cleared the neighbourhood around its orbit: Soter's planetary discriminant for Mercury is 91000, while Pluto's is just 0.077, people way more qualified than us already thought this out, it isn't our place to second guess them.

[Camacha]

In the end, the line is drawn by Soter's planetary discriminant, the magnitude that quantifies how much a potential planet has cleared the neighbourhood around its orbit: Soter's planetary discriminant for Mercury is 91000, while Pluto's is just 0.077, people way more qualified than us already thought this out, it isn't our place to second guess them.

You mean the discriminant that tells us there is about as much difference between Mars and Jupiter as there is between Mars and Eris? People keep comparing what are now called dwarf planets to small planets like Mercury, but keep forgetting that the same or bigger differences apply to the big planets and the small planets. Should we eliminate Mercury because its mass is insufficient compared to Jupiter? I mean, when we look at orders of magnitude Jupiter is more off compared to Mercury than Mercury to Pluto. What about removing Mars due to its Soter's discriminant? Or maybe we should talk about removing all the planets, as they represent less than 0,01% of the mass or volume of the solar system?

See some of the trouble there?

really just look at some 3d map of the solar system (like http://www.solarsystemscope.com/) for see how out of place Pluto is.

I can advise anyone to look at both Universe Sandbox² and SpaceEngine, both of those will give you a wonderful sense of how things relate to each other in the solar system US² even has a chart function that allows you to sort and view all the bodies in a nice line-up. SpaceEngine is better at giving you the feeling of actually being there and the scale of things. It is quite a sight to see Charon rising and, almost as amazing, it is free.

Edited October 4, 2014 by Camacha

[m4v]

You mean the discriminant that tells us there is about as much difference between Mars and Jupiter as there is between Mars and Eris? People keep comparing what are now called dwarf planets to small planets like Mercury, but keep forgetting that the same or bigger differences apply to the big planets and the small planets. Should we eliminate Mercury because its mass is insufficient compared to Jupiter? What about removing Mars due to its Soter's discriminant? What about removing all the planets, as they represent less than 0,01% of the mass or volume of the solar system?

You aren't making much sense. Soter's planetary discrimant is just a quotient between the planet's total mass, and the total mass of the objects in the same orbit, a measurement of the planet "dominance" of its orbit. This value very over 10000 for all the planets (including Mars) and way below 1 for the rest of the known dwarf planets, there's really not much room for debate here.

What about removing all the planets, as they represent less than 0,01% of the mass or volume of the solar system?

Then you would be failing at classifying the objects that orbit the Sun, no? I'm failing to see where are you trying to go with this.

[Camacha]

You aren't making much sense. Soter's planetary discrimant is just a quotient between the planet's total mass, and the total mass of the objects in the same orbit, a measurement of the planet "dominance" of its orbit. This value very over 10000 for all the planets (including Mars) and way below 1 for the rest of the known dwarf planets, there's really not much room for debate here.

You are missing the point - the difference between the planets is as big as between them and dwarf planets. The actual value is hardly interesting, it is how they relate to each other.

Then you would be failing at classifying the objects that orbit the Sun, no? I'm failing to see where are you trying to go with this.

I am indicating that all those obvious lines some people see are not as obvious as they are supposed to be. They are arbitrary, which is not necessarily a problem in itself, but the fact that they are vague is a problem. As soon as you add data or apply it to another system your classification system will fall apart. Sure, defining planets by roundness like I advocate also means arbitrarily establishing a threshold value, but is pretty clear-cut beyond that.

I feel star, planets and moons should simply be a hierarchic matter. Star, then planets, then moons. To avoid any piece of junk being a planet the extra qualification of roundness is added. For sure that means subdividing the resulting planets, but we already do that.

Edited October 4, 2014 by Camacha