Project Orbiter Galaxy

[donatelo200]

You don't really need a specific system. Just one with a venusian planet but here are the cordinates. location: -1001/945/0
name: 226.6f-0.1j65510.9b Besides the annoying venusian planet it's a pretty nice system.

 

[jedidia]

Hmmm... I guess I just didn't look at them close enough. Thanks for the info, I'll see what's going on.

The atmospheric pressure itself is correct but it's dencity is wildy off making the atmophere a very extended. Densitys of these atmospheres should be extremely high on the order of 250g/ml for this planet but the density is only 94 g/ml.

Just now I'm understanding that you're actually saying that the density is TOO LOW. It's definitaley not all of them, the one in Eta Casiopaiae looks pretty normal, but I'll find out what's going on. It's well possible that it's got to do with the composition...

---------- Post added at 10:18 AM ---------- Previous post was at 09:36 AM ----------

Erm... what are your seed settings? there are NO venusian planets in that system with default seed settings. Planet e is one of the buggy Gas Dwarfs , do you happen to refer to that one? Then it would be no miracle that the atmosphere extends that high... quite some pressure, but very light gases. They are supposed to be handled as gas giants, but there is some bug in their classification I haven't found yet.

Other than that, you either changed the milkyway seed settings, or... something REALLY weird is going on, i.e. your computer designating something other than mine. That would indicate undefined behaviour, an unitialised variable in the classification code maybe...

 

[donatelo200]

Here are my seed setings

//Core Age in Millions of years
13000
//maximum dimensions of the core bar in parsec (x,y,z)
6500x2830x2800
//angle of the bar (counterclockwise, x+ = zero degrees)
45
//maximum age of the thin disc in millions of years
9000
//average age dropoff of the thin disc towards the rim, in millions of years per decaparsec
2
//Thickness of the thin disc in parsec
350
//Thickness of thick disc in parsec
3070
//Reference coordinates for the naming system (CubeX,CubeY,CubeZ,X,Y,Z)
0,-798,2,0,0.25,0
//Seed for the star generator
42
//Seed for the system generator
3664226

 

[jedidia]

In other words, you haven't changed anything. This is red alert! Please, go back to that cube and take a screenshot of the system overview of the system you mentioned above. While you're at it, take a closer look at one of the closer system too, let's say eta casiopaiae (24 eta cas), so I have a bit of something to compare.

If you're getting different systems than I do with the same settings, I have a *very* serious bug in there somewhere. Until I see the screenshot, I'll just assume that you accidentaly posted the wrong system name, to keep peace of mind... oh dear, oh dear! :sos:

---------- Post added at 09:16 AM ---------- Previous post was at 08:24 AM ----------

Belay that! It is I that had the wrong system (just as well. At least the seeding is working correctly :lol. Although copy pasting, I still managed to focus the wrong system afterwards, one that was standing close by. I'll have to introduce some visual marker to improve oversight.

So, I have your venusian planet, I should find the time somewhen today to find out what's wrong with it.

---------- Post added at 09:33 AM ---------- Previous post was at 09:16 AM ----------

You know, there's nothing really wrong per se with that planet... it has one hell of a pressure. 1446 atmospheres? Venus is a vacuum compared to this monster! On the other hand, density is rather low (almost the same as earths), which is probably due to the bloody heat on the surface (over 2000 K at roughly earths distance to a comparable star. NOW talk about "pressure cooker"!). Nothing wrong with the calculation as far as I can tell, but maybe gases under such extreme conditions would require a different formula to calculate the density?

Now, the question is wheather such a planet falls into the realm of the realistic, or if this would make more of a gas dwarf than a venusian planet. I think it should be, but somehow the gas to dust fraction isn't high enough, which is also no miracle considering the core is a whopping super earth 3.5 times its mass. So, what we have here is obviously a categorization issue. The atmospheric conditions are not unlike a gas dwarf, while the gas-to-dust-ratio wouldn't strictly qualify for that classification.

Basically, I have three options: Leave as is, classify planets with atmospheric pressure above a certain limit as gas dwarfs by default or introduce a new "super-venusian" class, so the player sees at a glimpse that this is a bit tougher than your average venus.

I would tend for option 3, but what do my esteemed voters think?

Or, It might really be that the formula I use for the density just doesn't do the trick in such an extreme environment... anyone fit enough with gases to tell?

 

[Pyromaniac605]

Super-Venusian sounds awesome, Gas Giants haven't got a chance! :lol:

Darren

 

[jedidia]

PS: After backtracking through the ideal gas law, it is indeed completely normal (if somewhat counterintuitive) that the density DECREASES when pressure increases, because increasing pressure means increasing temperature, which means expanding gases, which means lower density. So the conditions on that planet are in correct relation with each other, at least according to the ideal gas law. My knowledge is not adavances enough to say wheather that is still aplicable under such extreme conditions, but I wouldn't have found anything claiming the contrary.

It seems what we have here is a perfectly possible planet that doesn't quite fit its classification and of which we have not yet encountered an example. If we ever find one, I will claim title of "first prophet of super-venus"! :lol:

 

[Hielor]

PS: After backtracking through the ideal gas law, it is indeed completely normal (if somewhat counterintuitive) that the density DECREASES when pressure increases, because increasing pressure means increasing temperature, which means expanding gases, which means lower density. So the conditions on that planet are in correct relation with each other, at least according to the ideal gas law. My knowledge is not adavances enough to say wheather that is still aplicable under such extreme conditions, but I wouldn't have found anything claiming the contrary.

I'm not sure about this. If you're increasing the temperature as a result of increasing the pressure, there is no requirement to then also increase the volume that the gas fills (and thus decrease density), since the pressure and temperature increases can already make up for each other. You only need to increase volume/decrease density to make up for an increase in temperature if you want to hold pressure constant.

The ideal gas law also isn't as good for very high pressures, I think...

 

[Notebook]

Super-Venusian sounds awesome, Gas Giants haven't got a chance! :lol:

Darren

Another Super-Venusian....

http://www.dandare.org.uk/DanDareReprint1.htm

(He was only Ultimate Ruler of Northern Venus)

N.

 

[IgnoreThisBarrel]

How about a "formal" classification system? Like spectral types:
Letter is assigned for mass or planet type, roman numerals for subtype (or atmospheric type).

For example, assuming "I" is ~Earth mass, then I2 would be super-Venusian, I3 would be Titanian, I4 would be habitable, I5 about 50 to 20 kilopascals, I6 Martian, I7 trace, and I8 none.

 

[jedidia]

The ideal gas law also isn't as good for very high pressures, I think...

After a bit more digging this seems to be correct. While the calculations are correct according to boyles law, a Gas deviates from its ideal behaviour the higher the pressure gets... up to the point where the pressure forces the gas to become liquid, which at such pressures as described above would turn most of the above described nitrogen atmoshere into one gigantic nitrogen ocean covering the planet. No idea yet what that will do to the temperature, though.

Since there is no hydrosphere type currently (all hydrosphere is assumed to be water), this problem is unsolvable with my current model. It will have to wait for the overhaul of planetary generation routines for version 0.7, so currently everyone will have to live with those planets, I'm afraid, but thanks a lot for bringing the subject to my attention. Now I'll definitaly be forced to introduce a complex hydrosphere model... Which at times will probably have to include even molten metals for planets very close to the sun.

Darn, this will be one hell of a challenge! I'll probably have to discard the whole static gas/liquid/solid concept that came with stargen and put a full periodic table including densities for every state, melting and boiling point as well as critical point into the code. Woe to me!:suicide:

 

[Columbia42]

How about a "formal" classification system? Like spectral types:
Letter is assigned for mass or planet type, roman numerals for subtype (or atmospheric type).

For example, assuming "I" is ~Earth mass, then I2 would be super-Venusian, I3 would be Titanian, I4 would be habitable, I5 about 50 to 20 kilopascals, I6 Martian, I7 trace, and I8 none.

I remember Star Trek used a pretty good planetary classification system although I have no idea where they got it. Here's a link: http://www.sttff.net/planetaryclass.html
Doesn't look very scientifically based but it might be a good start.

 

[jedidia]

I remember Star Trek used a pretty good planetary classification system although I have no idea where they got it. Here's a link: http://www.sttff.net/planetaryclass.html
Doesn't look very scientifically based but it might be a good start.

This seems to be pretty similiar to what I already have, except a bit less "Solarocentric" i.e. the class names are not derived from "specimen" known from the solar system. If there's going to be a change in classification, It'll be in 0.7, and I'll have to think about what makes most sense. A composed classification as suggested by Barrel might yield the most information at a short glance, but only to nerds who learn them by heart, so I'm not sure how practical it is. Suggestions are of course welcome, maybe we can come up with a good compromise.

For now, I'll try exchanging my density calculation based on the ideal gas law with a density calculation based on the Van der Waal equations and see what happens... Presumably, I'll then get gases with densities higher than they would have in liquid state until I implement a new atmosphere/hydrosphere/lithosphere model (I really liked that system in Starflight, although it wasn't very accurate physics-wise), I.E. you still might not be able to land on planets because their gases are so dense that you'll effectively swim on top of the atmosphere.

---------- Post added at 04:11 PM ---------- Previous post was at 02:43 PM ----------

I just noticed that the problem is a bit deeper than I thought. I reworked that density formula twice already, but it seems it doesn't serve me well... Stay tuned.

 

[IgnoreThisBarrel]

Hey! I learned the stellar classification system in just under a week!
Oh Be A Free Gyroscope and Kineticize Motion.

Then the I-VI and it took me another week to realize that the 0-9 number was to signify the star's spectral type more accurately.

 

[donatelo200]

Super venus sound right. I have a super venus in the GI 581 system with 5.6 Earth masses and a atmospheric pressure of 2891 atmosphers and an atmospheric density of 566.993 G/ML. The surface temp is a little over 6900 F 3800 C. Theis is a non-fictional planet so Super-venus planets sound like a good classification.

 

[jedidia]

Oh Be A Free Gyroscope and Kineticize Motion.

wtf? :lol: "oh be a fine girl kiss me" is somewhat easier to memoryze...

Working on that density. It isn't quite so wrong as I thought, I simply read the wrong numbers :blush:

Anyways, the results of my formula are pretty accurate for Venus itself. They get a bit less accurate if temperature drops, like e.g. for Mars, but the higher the temperature, the more accurate it gets, although high pressures counter this effect. Still, on said planet, we're having a temperature of over 2000 Kelvin (the sheer heat by atmospheric compression and greenhouse effect would have molten parts of the surface! That is one hell of an unfriendly planet!), albeit we're also having 1400 atmos of pressure. The result shouldn't be all that far off really, but I'll have to try a test run with Van der Waal equations once I figure them out, but I don't think they will be a lot different. After all, the atmosphere consists majorly of nitrogen, which is a lot less dense than CO2, and still the surface density is a good third above venus density.

I also found out that pressure cannot liquify a gas once it passed critical temperature, which for nitrogen would be somewhere around -150 C, so there won't be any nitrogen oceans either on that planet. It might get pressed into solid form at that heat and pressure, though, but I haven't found any data yet about that process, and it might be rather tricky to simulate...

Anyways, let's see what Van der Waal has to say to my problem. If he confirms the density in a certain error limit, that's just the way it is.

Theis is a non-fictional planet so Super-venus planets sound like a good classification.

Oh? hoorray to stargen, then! even produces planets its creators weren't aware existed...

 

[donatelo200]

Star gen didn't creat it I did it will be in my Gliese 581 system when i finish reworking it. It's actually in the current version just that scientificy inacruate. I'm making the system a little more scientificly accurate and adding two newely discoverd planets in the system. One of witch is [ame="http://en.wikipedia.org/wiki/Gliese_581_g"]Earthlike[/ame]. Unfortunatly the new planets are unconfermed.

O and here is me orbiting the Earthlike planet in the system with the buggy venus planet.

 

[jedidia]

Sorry, I meant that it produces planets with properties the authors had no confirmation existed.

Anyways, calculating with VanDerWaal equations actually leads to LESS density (checked with an online calculator, as integrating it into the code would require several additions to the gas table), but it helped me spot the problem... I'm calculating with monatomic nitrogen, which means the molar mass is only half of what an actual nitrogen molecule actually weights. Calculated with molecular nitrogen, I'm getting a density of 194.53 kg/m^3 with ideal gas law, and 175.08 kg/m^3 with Van der Waal.

Integrating the Van der Waal equations into the code will have to wait until I rewrite the gas table in any case. For now, I could change the atomic weight to molecular weight and see what happens...

---------- Post added at 05:46 PM ---------- Previous post was at 05:26 PM ----------

Ha! Nitrogen seems to be the ONLY gas where the atomic weight instead of the molar weight was listed. So this qualifies for a veritable bug after all, not just a conceptual mistake!

Thanks everyone for helping me find it. I'm currently tinkering Orulex support, so it might be a few days until the next patch is up.

 

[donatelo200]

Orulex support! Sounds awsome!:jiggy: I've ben trying to get orulex support in my systems forever and have never gotten it to where i wanted it to be.:dry:

 

[jedidia]

Well, don't expect too much. It'll be strictly random terrain that doesn't have much to do with the texture (what you know from europa, ganymede etc.). I'm currently trying to come up with some nice functions for the different planet types. Still, for those who don't want the terrain, there will also be the option to let Orulex simply do the microtexturing part, so even flat planets will look a lot nicer when you're landed, which is a bit of a neccessity considering we can maximaly export level 8 (not that my machine could handle anything bigger anyways, I'm waiting for hours for a level 7 to 8 system..)

Oh yeah, the atmosphere on that venusian planet still extends QUITE a bit... but the numbers are pretty accurate now, so that's just the way it is.

 

[donatelo200]

Ahh. Thats how far i got with ourulex compatibility. You should probly do some options on witch planets will have terrain. Like i don't particuarly like Earthlike planets with random terrain as the oceans get terrain and it dosn't feel right on the shore line. Witch reminds me i've noticed that all the Earthlike planets have about 50% ocean and 50% land even if the data sais the have 100% ocean or 1% ocean.