Author Topic: Applying planetary classes to real planets  (Read 11972 times)

Offline Indefatigable

  • Junior Member
  • Posts: 73
  • Deo Adjuvante
    • View Profile
Applying planetary classes to real planets
« on: March 29, 2010, 08:11:31 PM »
I've been trying to work out whether the Rodenberry system for classifying planets would ever work in real life.  If so, it sounds a much more effective system than talking about 'Hot Jupiters' or 'Super-Earths' for the various exoplanets we keep discovering.  Not sure if this is in the right place, but it certainly comes under Trek science.  This is a bit longwinded, so please bear with me.

Here goes:
Class A (Geothermal): Io kept artificially hot by tidal forces from Jupiter and the other Jovian moons
Class B (Geomorteous): Mercury
Class C (Geoinactive): Luna (not sure if I'm right about this one) Ganymede, Callisto, Ceres, Phobos, Diemnos Loads of other moons and asteroids
Class D (Dwarf): Pluto, Charon, Sedna Other Kuiper Belt Objects
Class E (Geoplastic): Earth Hadean Era
Class F (Geometallic): Earth Archaean Era
Class G (Gecrystelline): Earth Proterozoic Era
Class H (Desert): None known, but potential fate of Earth if something weird happens to the atmosphere
Class I (Ice Giant): Uranus, Neptune
Class J (Gas Giant): Jupiter, Saturn Possibly several exoplanets, but not easy to detect that far from the parent sun
Class K (Adaptable): Mars
Class L (Marginal): Potentially Mars before the loss of atmosphere that may have happened, or Earth in the Paleozoic Era
Class M (Terrestrial): A certain little mostly harmless place
Class N (Reducing) Venus
Class O (Pelagic): None known, but theoretical, often called an 'ocean planet'
Class P (Glaciated): Europa
Class Q (Variable): None known, but a nice theory
Class R (Rogue): Potentially what might happen to Pluto or Mercury according to some theories
Class S (Supergiant): 47 Ursae Majoris b 2.5X as big as Jupiter, and found some way from its parent star (and a 47)
Class T (Close Gas Giant): 51 Pegasi b (Bellerophon) among others currently called a 'Hot Jupiter'
Class U (Ultragiant): 55 Cancri d was the biggest planet I could find, also known as 'Superjovian'
Class V (Close Subgiant): Theoretical 'Hot Neptune'
Class W (Spare class): Gliese 876 d Potential class for a 'Super-Earth', or a very big rock in space (no relation to surface conditions)
Class X (Chthonian): Again, only theoretical, but basically what happens when you strip all the gases from a gas giant, leaving only the metallic core
Class Y (Demon): I call it a 'Super-Venus', somewhere you don't wanna go.
Class Z (Spare class): Not sure what to use for this yet.

Basically, every non-stellar body ever found in the Universe can fit into this system.  My only problem with it is that it is a bit rigid.  If I ever switch from zoology to exogeology, I want to get 'Class M planet' into a mainstream scientific journal.  Perhaps the system might even gain acceptance.  'Gas giant' was coined by James Blish, who wrote the TOS novelizations.

 :-\
Still rambling away...

Offline Edymnion

  • Veteran Member
  • Posts: 1,712
  • Stuck in the 80's
    • View Profile
Re: Applying planetary classes to real planets
« Reply #1 on: March 30, 2010, 08:22:54 AM »

Offline lt ponytail

  • Member
  • Posts: 236
  • Status: Unknown
    • View Profile
Re: Applying planetary classes to real planets
« Reply #2 on: March 30, 2010, 10:16:53 AM »
Class Z could be for planets that have lost their magnetic field and have a nonexistent or thin atmosphere, like Mars
"My work is as good as the aim of a stormtrooper."
--------------------------------------------------------
General art thread

Offline The Unbound

  • Active Member
  • Posts: 303
    • View Profile
Re: Applying planetary classes to real planets
« Reply #3 on: March 30, 2010, 01:58:22 PM »
Well, I think if anything, Mars might qualify as class C or H in that scheme. I doubt if Mars-type planets are unusual enough to be banished to the far end of the alphabet.

About the scheme itself, I don't really see any overriding system to it. Planetary classification might depend on a raft of metrics, not all of which are necessarily relevant to a particular planet; talking about the mineral composition of a gas giant, for instance, is rather pointless. On the other hand, a lot of those classes ignore metrics that might be very relevant. the M-class, for instance, completely ignores size and magnetic field, which would be important in assessing habitability. On the other hand, the D-class speaks only of size, and ignores environment, magnetic field and mineral composition, which might be important as well. And I'm not exactly sure how you'd classify Titan.

This doesn't necessarily invalidate the scheme, it's just not very fine grained. A planet might fit into several classes, a planet with an Earth-like environment goes in class M, but it might also go in class D, if it's very small, or class W if it's very large. It might be more informative if these coinciding characteristics get separate parameters, like one letter for environment and another for physical characteristics (size, mineral composition, possibly magnetic field)

You might be interested in looking at the classification system they use for asteroids at the the moment, not that that's an example of what I just said, or in any way perfect.
Steady on.

Offline Indefatigable

  • Junior Member
  • Posts: 73
  • Deo Adjuvante
    • View Profile
Re: Applying planetary classes to real planets
« Reply #4 on: March 31, 2010, 11:00:29 AM »
Well, I think if anything, Mars might qualify as class C or H in that scheme. I doubt if Mars-type planets are unusual enough to be banished to the far end of the alphabet.

About the scheme itself, I don't really see any overriding system to it. Planetary classification might depend on a raft of metrics, not all of which are necessarily relevant to a particular planet; talking about the mineral composition of a gas giant, for instance, is rather pointless. On the other hand, a lot of those classes ignore metrics that might be very relevant. the M-class, for instance, completely ignores size and magnetic field, which would be important in assessing habitability. On the other hand, the D-class speaks only of size, and ignores environment, magnetic field and mineral composition, which might be important as well. And I'm not exactly sure how you'd classify Titan.

This doesn't necessarily invalidate the scheme, it's just not very fine grained. A planet might fit into several classes, a planet with an Earth-like environment goes in class M, but it might also go in class D, if it's very small, or class W if it's very large. It might be more informative if these coinciding characteristics get separate parameters, like one letter for environment and another for physical characteristics (size, mineral composition, possibly magnetic field)

You might be interested in looking at the classification system they use for asteroids at the the moment[/url], not that that's an example of what I just said, or in any way perfect.

Thanks, and to Edymnion, that's quite interesting.

I may have got C and D the wrong way round.  Mars went in as Class K, because it seemed to be traditional, but the Saturnine moons are actually a bit awkward.  Titan seems to be a kind of deep-frozen Class G, but that's questionable.  Rhea and Phoebe all seem to have quite thick ice coatings, but probably not enough to make them Class P.  Mimas is probably a more standard C or D.

Here's another system I found.  http://en.wikipedia.org/wiki/Sudarsky_extrasolar_planet_classification  Classes I and II seem to match Class J, Class III seems close to S, Class IV to T and Class V to U.  The last is practically a brown dwarf.
Still rambling away...

Offline ZardoZ

  • Active Member
  • Posts: 276
    • View Profile
    • ZardoZ the Technomage
Re: Applying planetary classes to real planets
« Reply #5 on: April 04, 2010, 11:48:20 PM »
Use the letter to give info about ambiental conditions/compositon/magnetic field/atmostfere and use a number to give info about size : -> Earth like planets should be M3 , Jupiter big planets, should be like J33 (Jupiter its like 11 times more bigger that Earth), etc.... Omiting the number, should interpreted that is a planet of these type wich the typical size. (aka M type, should havea typical size of 3, J type, should be around 9-12, etc...)
I think that are more precise and logical that trying using alone a letter.
Yep, i have a blog
http://zardoz-technomage.es
[/center]

Offline The Unbound

  • Active Member
  • Posts: 303
    • View Profile
Re: Applying planetary classes to real planets
« Reply #6 on: April 05, 2010, 08:55:39 AM »
Something like that. Though it might be better to use some sort of logarithmic scale for size. After all, it matters more if a planet is four or five times the size of Earth than if it is 64 or 65 times the size.
Steady on.

Offline ZardoZ

  • Active Member
  • Posts: 276
    • View Profile
    • ZardoZ the Technomage
Re: Applying planetary classes to real planets
« Reply #7 on: April 06, 2010, 09:07:11 AM »
Sounds logical
Yep, i have a blog
http://zardoz-technomage.es
[/center]

Offline Bernd

  • Administrator
  • Distinguished Member
  • Posts: 7,865
  • Lord of the Bored
    • View Profile
Re: Applying planetary classes to real planets
« Reply #8 on: May 12, 2010, 08:09:32 AM »
I always liked the planetary classification of Star Trek very much (although only a few of the classes from A to Z are canon). It is a quite practical system, at least for a spacefaring civilization that can actually visit these places.

I always wondered why there was no planetary classfication in real life (as opposed to stellar spectral classes). A simple answer is that the existing nine (eight) planets in our solar system, even if we include all moons, may be a too small sample of all the planets that possibly exist in deep space. Also, it is clearly more practical to refer to the "interesting" planets (as opposed to asteroids that are usually just pieces of rocks) by their names than by a class.

Now that we know several extrasolar planets (even though they are all much bigger than Earth and clearly no good sample of the entirety of planets), it may make more sense to classify them. But I doubt that the classification would be with letters that unite multiple different criteria (size, density, atmopsphere, temperature etc.). Modern scientific classfications tend to separate different criteria and may wind up as more complex.

Offline Indefatigable

  • Junior Member
  • Posts: 73
  • Deo Adjuvante
    • View Profile
Re: Applying planetary classes to real planets
« Reply #9 on: May 16, 2010, 09:47:24 AM »
I always liked the planetary classification of Star Trek very much (although only a few of the classes from A to Z are canon). It is a quite practical system, at least for a spacefaring civilization that can actually visit these places.

I always wondered why there was no planetary classfication in real life (as opposed to stellar spectral classes). A simple answer is that the existing nine (eight) planets in our solar system, even if we include all moons, may be a too small sample of all the planets that possibly exist in deep space. Also, it is clearly more practical to refer to the "interesting" planets (as opposed to asteroids that are usually just pieces of rocks) by their names than by a class.

Now that we know several extrasolar planets (even though they are all much bigger than Earth and clearly no good sample of the entirety of planets), it may make more sense to classify them. But I doubt that the classification would be with letters that unite multiple different criteria (size, density, atmopsphere, temperature etc.). Modern scientific classfications tend to separate different criteria and may wind up as more complex.

I'm not sure whether the IAU have ever thought about it, probably for the very reason you suggest.  Rodenberry came up with the system so that he would have some convenient way of saying 'just like Earth' while sounding more scientific.  Presumably, people added classes as needed (like pulling out Class Y in "Demon") and a few mistakes confused things a bit.  If I was an astronomer, I would use the system myself, and try to get it into as many journal articles as possible.  There is a chance the IAU may come up with something eventually, but it will probably be more complicated and harder to remember.  After all, we won't have to ask 'Is it safe to beam down?' for a while yet.
Still rambling away...

Offline Bernd

  • Administrator
  • Distinguished Member
  • Posts: 7,865
  • Lord of the Bored
    • View Profile
Re: Applying planetary classes to real planets
« Reply #10 on: May 18, 2010, 05:23:57 AM »
I agree. Astronomers may prefer a complicated system, but for manned spaceflight the short classification will have its advantages.

By the way, I think the Star Trek way to number planets such as in "Sol III" for Earth is not (yet) applicable in real life either.

Offline The Unbound

  • Active Member
  • Posts: 303
    • View Profile
Re: Applying planetary classes to real planets
« Reply #11 on: May 20, 2010, 05:37:24 AM »
It isn't used, certainly. Mostly because it's often completely impossible to say whether the exoplanets we can actually find, by virtue of them being very large and/or very massive, are actually the first, second or nineteenth planet of their star system.
Steady on.

Offline Indefatigable

  • Junior Member
  • Posts: 73
  • Deo Adjuvante
    • View Profile
Re: Applying planetary classes to real planets
« Reply #12 on: May 27, 2010, 03:08:12 PM »
It isn't used, certainly. Mostly because it's often completely impossible to say whether the exoplanets we can actually find, by virtue of them being very large and/or very massive, are actually the first, second or nineteenth planet of their star system.

The planets orbiting 55 Canceri A go e, b, c, f, d.  If we are able to catalogue the entire system one day, they may change that.

Provisionally, 55 Canceri 1 (e) is Class W, 2 (b) and 3 (c) are Class T, 4 (f) is Class J and 5 (d) is Class U
Still rambling away...

Offline Bernd

  • Administrator
  • Distinguished Member
  • Posts: 7,865
  • Lord of the Bored
    • View Profile
Re: Applying planetary classes to real planets
« Reply #13 on: May 28, 2010, 05:57:01 AM »
Since the star (part of a binary or trinary star I suppose) already has a letter appendix, it will be more practical for the planets to go by numbers.

Offline The Unbound

  • Active Member
  • Posts: 303
    • View Profile
Re: Applying planetary classes to real planets
« Reply #14 on: May 28, 2010, 07:24:22 AM »
Not necessarily. A lot of stars have names that end in numbers. Imagine calling a planet HD 209458 II.
Steady on.

Offline Indefatigable

  • Junior Member
  • Posts: 73
  • Deo Adjuvante
    • View Profile
Re: Applying planetary classes to real planets
« Reply #15 on: May 28, 2010, 04:46:40 PM »
It really ought to go number-letter-number-letter, to avoid getting confused, which might mean we can add letters for moons as well (55 Canceri A 5 B).  However, we're bound to run out of letters eventually (Jupiter has 113 known moons, and I'd imagine a typical Class U would have 300-500).  Classification systems always get more and more complicated, I should know, I'm a biologist.

Not necessarily. A lot of stars have names that end in numbers. Imagine calling a planet HD 209458 II.

I imagine that in Trek, HD 209458 would be the T____ian System. ;D
Still rambling away...

Offline Aemielius

  • New Member
  • Posts: 8
    • View Profile
Re: Applying planetary classes to real planets
« Reply #16 on: August 14, 2010, 10:53:16 PM »
A very good question.   Why don't real astronomers use a very simple system like Star Trek's to classify exo-system planets or even the ones within the Sol system?

The answer is quite simple; they are nerds.

Now I don't mean this as a bad thing and look, we're all Trek fans here (how nerdy is that?) but let's face it, there is a good chance those most scientists were the victims of high school bullies and likely had more than enough Nair hair remover sprayed down their pants or into their athletic supporters.
On the other hand, there is nothing more dangerous than a nerd with a mean streak or at least a taste for revenge.
One way my friends and I got even with the bullies was to dazzle them with brilliance and baffle them with bullshit.  In other words, confuse the ever luvin' crap out of them using half logic and possibility rather than probability.

The reason Astronomers use such a complex system for planet classification is for the same reason, to keep the general public (whom they see as bullies) dazzled, baffled and confused because it has become a safe place for them to hide.    If they keep it complex and hard to understand, we will never ask them to explain it.

Now this is all my opinion, and others will take offense, but as a recovering electronics engineer, I can say that this is much of what my once fellow engineers do, and why I left the field.   I couldn't stand not keeping things simple.


James Aemielius
Wolverine Studios

Offline Indefatigable

  • Junior Member
  • Posts: 73
  • Deo Adjuvante
    • View Profile
Re: Applying planetary classes to real planets
« Reply #17 on: August 19, 2010, 08:15:47 PM »
A very good question.   Why don't real astronomers use a very simple system like Star Trek's to classify exo-system planets or even the ones within the Sol system?

The answer is quite simple; they are nerds.

Now I don't mean this as a bad thing and look, we're all Trek fans here (how nerdy is that?) but let's face it, there is a good chance those most scientists were the victims of high school bullies and likely had more than enough Nair hair remover sprayed down their pants or into their athletic supporters.
On the other hand, there is nothing more dangerous than a nerd with a mean streak or at least a taste for revenge.
One way my friends and I got even with the bullies was to dazzle them with brilliance and baffle them with bullshit.  In other words, confuse the ever luvin' crap out of them using half logic and possibility rather than probability.

The reason Astronomers use such a complex system for planet classification is for the same reason, to keep the general public (whom they see as bullies) dazzled, baffled and confused because it has become a safe place for them to hide.    If they keep it complex and hard to understand, we will never ask them to explain it.

Now this is all my opinion, and others will take offense, but as a recovering electronics engineer, I can say that this is much of what my once fellow engineers do, and why I left the field.   I couldn't stand not keeping things simple.

I know exactly what you mean.  I left university last year over something very similar, the idea that I think that scientific papers should be written so that normals would want to read them.  Perhaps not Sun readers, but certainly Times or Independent readers.  I just hate reading scientific papers, because they are dry and hard to read.  Don't water down the facts, but say 'this is what we did' when you did something, write in active language, define any term that would baffle a secondary school student and never use acronyms that could be confused with something else.  If we don't do that, the scientific community is in danger of disappearing up its own backside, completely cut off from the real world.  I had several flaming rows with my course tutor over this, then decided to take a year off.

Back to the topic, I think you're probably right.
Still rambling away...

Offline Stoo

  • an all too ordinary story
  • Global Moderator
  • Eminent Member
  • Posts: 5,303
    • View Profile
    • A Force for Good
Re: Applying planetary classes to real planets
« Reply #18 on: August 22, 2010, 07:21:31 AM »
... the hell?

Yes scientific papers can be kind of dry. They're here to get lots of very technical information across, not take a friendly conversational tone to explain basic concepts for for your bedtime reading. If you want the latter, go grab a book off the popular science shelves.

newsflash: science is hard sometimes. And rigorously describing theories and discoveries sometimes needs lots of nasty math and precise terminology not used in day to day conversation.

I've no idea what sort of classification system scientists have for exoplanets (discovery of them was just taking off when I was at uni) but neither that, nor anything else, is made unnecessarily complicated just to keep the plebs out.

« Last Edit: August 22, 2010, 07:25:59 AM by Stoo »

Offline Indefatigable

  • Junior Member
  • Posts: 73
  • Deo Adjuvante
    • View Profile
Re: Applying planetary classes to real planets
« Reply #19 on: August 22, 2010, 03:06:55 PM »
... the hell?

Yes scientific papers can be kind of dry. They're here to get lots of very technical information across, not take a friendly conversational tone to explain basic concepts for for your bedtime reading. If you want the latter, go grab a book off the popular science shelves.

newsflash: science is hard sometimes. And rigorously describing theories and discoveries sometimes needs lots of nasty math and precise terminology not used in day to day conversation.

I've no idea what sort of classification system scientists have for exoplanets (discovery of them was just taking off when I was at uni) but neither that, nor anything else, is made unnecessarily complicated just to keep the plebs out.

I'm thinking we ought to move this to "general discussion", it might be interesting.

My perspective on it is this.  The paper itself is merely a vehicle for the data, data analysis and conclusions.  Unless you really need to do otherwise, you read the abstract and the conclusions, looking at the data for confirmation.  In theory, it should be possible to publish an abstract, a data table and the conclusions without anything else, and it would be just as informative.  However, you need a detailed description of what led to those conclusions.  However you write that, it does not affect the data itself, so it does not really matter if it is active or passive, dry or enthusing.  The problem is that dry language and technical terms written in the passive voice are difficult to read.  Making it easier to read will not affect the actual data, or the conclusions.

You can either be outward-looking and inclusive, writing papers that people will understand and appreciate, or you can be inward-looking and exclusive, writing papers that nobody would ever want to read.  If you do the former, there is a good chance that you will reach people outside the scientific community and make a difference to society (however small, improving everybody's understanding must be the ultimate aim).  If you do the latter, some people in the scientific community will agree, others will disagree, nobody outside will care.  Scientists are as much to blame as the wider community for the increasing divide between the two, and should lead the way in bridging it.  That's my aim in life.
Still rambling away...

Offline Shik

  • Senior Member
  • Posts: 3,113
  • There's a million things I haven't done
    • View Profile
Re: Applying planetary classes to real planets
« Reply #20 on: August 22, 2010, 03:15:11 PM »
This is like Stephen fry's Making History...

Offline Stoo

  • an all too ordinary story
  • Global Moderator
  • Eminent Member
  • Posts: 5,303
    • View Profile
    • A Force for Good
Re: Applying planetary classes to real planets
« Reply #21 on: August 22, 2010, 05:45:02 PM »
I'm all for helping the wider public to better understand how science works, what it's currently investigating and how it changes our lives. I don't think imposing some new style on journals is the way forward. The current style is the most efficient way for scientists to present reports to their peers.

A better way forward would be to get more science on TV - like this. And more (and better informed) reporting in the news, and a push for good standards in schools (and getting girls involved more).

(shik I never read that, googled it and am still baffled)


Offline Shik

  • Senior Member
  • Posts: 3,113
  • There's a million things I haven't done
    • View Profile
Re: Applying planetary classes to real planets
« Reply #22 on: August 22, 2010, 06:39:01 PM »
(shik I never read that, googled it and am still baffled)

The main character has finished his doctoral thesis in history, specifically on the early life of Adolf Hitler. He has, however, placed throughout it sections of "historical fiction"--what he calls "prose poems"--to lighten the mood of the thesis, as he feels much like Indy up there. When his advisor comically takes him to task about them, he notes that they are based on fact & he felt the "lent colour and drama" to the thesis.

Offline The Unbound

  • Active Member
  • Posts: 303
    • View Profile
Re: Applying planetary classes to real planets
« Reply #23 on: August 24, 2010, 07:17:25 AM »
Articles in scientific publications are written expressly for other scientists, who, in turn, read it with the express purpose of picking it apart to find errors, miscalculations or bad conclusions. For that reason, scientific articles tend to adopt a slightly defensive tone, seeking refuge in using the most precise and correct language the author is capable of, which doesn't tend to make for a very active language. That doesn't mean that scientists are unwilling or incapable of using a more engaging form of language. Look at Scientific American. Or Richard Feynman.
Steady on.