Project Orbiter Galaxy

[gertz]

I think it's cool, but I also think it's in the wrong thread

i know))
i just want to know what are u thinkin` about it

 

[T.Neo]

I had a look at StarGen, it seems pretty impressive.

Is there a way to enter custom parameters into it? Or is it all random?

 

[jedidia]

Is there a way to enter custom parameters into it? Or is it all random?

All parameters are customizable, you can even feed it a complete seed system and it spits out the planets. Allthough, the version I have in my project now is allready quite an extension from the original (adapted for the whole range of solar masses and to create moons of gas giants, allthough it still returns the best results in its original mass range.)

 

[gertz]

All parameters are customizable, you can even feed it a complete seed system and it spits out the planets. Allthough, the version I have in my project now is allready quite an extension from the original (adapted for the whole range of solar masses and to create moons of gas giants, allthough it still returns the best results in its original mass range.)

nice :thumbup:

 

[T.Neo]

All parameters are customizable, you can even feed it a complete seed system and it spits out the planets. Allthough, the version I have in my project now is allready quite an extension from the original (adapted for the whole range of solar masses and to create moons of gas giants, allthough it still returns the best results in its original mass range.)

If you don't mind me asking, what version of StarGen did you base the current version on?

 

[jedidia]

tis one:

http://www.eldacur.com/~brons/NerdCorner/StarGen/StarGen.html

As far as I know, there is no newer version around. The whole thing has been growing since the 70ies(!!), when the first version of acrete was developed, which was later used as a basis for stargen.

 

[jedidia]

Search function finally finished (phew...) Finds Stars in the immediate vicinity and stars from the catalogue. On we go to improve the planet info display.

---------- Post added at 05:21 PM ---------- Previous post was at 11:46 AM ----------

Say, does anyone know the minimum oxygen level of any breathing gas at 1 bar? also, I know that nitrogen and helium make for excellent breathing gas, but are there others? As long as the gas isn't poisonous, does it actually matter what is inhaled along with the oxygen?

 

[Bloodworth]

As long as the gas isn't poisonous, does it actually matter what is inhaled along with the oxygen?

It depends on the quantity of the gas in the mixture. As I understand it, many of the gasses that we take in along with our oxygen range between harmless and essential in the normal quantities we encounter in our air. But if the amount grows, many of those gasses can begin to become deadly. But I believe that some of those have to be under pressure to be dangerous; like oxygen.

 

[jedidia]

It's ok, I found a function doing all the work in the StarGen code. I'll just go with that, since it's very unlikely I'll come up with something better (like, considering atmosphere mix, partial inspired pressure of each gas, aso...)

 

[gertz]

hi, how the things are goin?))

 

[jedidia]

It's going well... I discovered a bug that shows up very rarely, but fataly (read: ctd). It was pure luck that I was able to reproduce it reliably. Now I'm hunting for the cause. On this occasion I discovered another bug where I re-initialized some pointers after having some other pointers pointing to them, and I wonder how the thing worked at all. It seems that these pointers were always re-initialised with the same memory address, but I'm glad I noticed the bugger. Could have caused havoc in a release build.

Still haven't found the bug I was looking for, though. Some nodes are not getting initialised under certain conditions, but no Idea yet what those conditions are. Only happens if I create certain sectors whithout having initialised any other sectors first, and the cause of this eludes me completely. But I'll find it.

On the progress scale, descriptive pictograms to grant an immediate rough overview of planetary conditions have been added, no need to look through the whole data-table anymore just to determine wheather a planet might be suitable for humans or not.

---------- Post added at 05:16 PM ---------- Previous post was at 03:07 PM ----------

Bug's dead. The nasty thing ran from me for quite some time. In the end, I finished it with a lucky shot. I'm still not sure why the old code did what it did, but I'm sure that the new code doesn't do it anymore! ;p

Now it's fixing some minor bugs I never got around to fix, another bit of face-lifting (GUI is finished, but some stuff is a bit hard to read...), code cleaning, directory structure... and we're ready for the demo. Expect it in three or four tuesdays!

 

[Enjo]

On this occasion I discovered another bug where I re-initialized some pointers after having some other pointers pointing to them, and I wonder how the thing worked at all.

"Undefined behavior" from my experience. In this case: things that work despite they shouldn't work, but stop working when you do other normal operations. The best advice is not to rely on the UB

 

[jedidia]

The best advice is not to rely on the UB

I didn't even think of relying on it. changed it right there, and actually expected it to solve the problem I was looking for, but that had another cause. Luckily it's all fixed by now. I hope that was the last of the unexpected ctd's, but We'll see when the demo gets out.

 

[Enjo]

It was a smartass-type joke because its obvious that you never should rely on something fragile.

Awaiting for the demo with a fully defined behavior

 

[gertz]

stargen is perfect tool!!!!
Tnx:thumbup::thumbup::thumbup:

 

[jedidia]

It's been a very productive holyday... unfortunately we had a slight mishap on the way home which led to an even distribution of our car on the road, and I'm having a bit of a pain in my breast currently, but neither me nor my wife have been seriously injured (thanks God!). The laptop also seems to have survived without problems, which is very convinient.

I used the vacation to fix most of the small bugs I never got around to fix. The naming system suggested by T.Neo has been implemented, which in turn led me to discover another hidden bug (some old code I forgott to remove, which overwrote about half of what the new code, that was supposed to replace it, spit out) which made me very happy. Also, the core is now a three-dimensional elipsoid.

I also revisited the stargen code a bit more, Sudarsky classifications for Gas Giants are now implemented. However, this leads to the slight nuicance that I have to find a way between Gas Giants and Ice Giants, and I don't have enough information on the topic yet.

I could just let stargen create a random atmosphere for checking what gases are predominant, but I'm not sure about sizes. It would seem to me that hydrogen should be a lot more abundant than nitrogen and oxygen, so I would expect Ice Giants to be limited in size. The solar system seems to confirm that, but it's only one reference. There don't seem to be any Exo-ice giants discouvered yet, which again might be a pointer that they don't get big enough. I'd apreciate your thoughts: should I set a mass-limit for Ice-giants?

Also, there seems to be no theory yet how they would behave closer to a star (no sudarsky-equivalent for ice-giants, I'm afraid. No data available). In the solar system, they are pretty far out, but most probably they were ejected during the formation by the combined forces of Jupiter and Saturn, and initially formed in the same region. What would happen to them if they migrated inwards seems completely unknown. So I'm thinking about putting in an orbit-limit too. Again, suggestions are highly apreciated.

This is more or less the last hurdle before Demo-release. I would very much love to put in geological attributes and tidal heating for moons (they are turning out pretty boring currently), but that can wait until I have a stable release that works together with Orbiter and lets people fly around in the galaxy.

---------- Post added 06-14-10 at 11:36 AM ---------- Previous post was 06-13-10 at 05:45 PM ----------

Facts I found out about Ice Giants so far:

They are usually under 100 earth masses, and they loose atmosphere more rapidly when heated than Gas Giants. Couldn't find a single bit about their predicted apearance when heated, but I guess I got enough to finish off the Gas Giant code.

 

[Linguofreak]

I also revisited the stargen code a bit more, Sudarsky classifications for Gas Giants are now implemented. However, this leads to the slight nuicance that I have to find a way between Gas Giants and Ice Giants, and I don't have enough information on the topic yet.[/quite]

Partially, I think, because ice giants are not entirely accepted as a separate class.

[quite]
I could just let stargen create a random atmosphere for checking what gases are predominant, but I'm not sure about sizes. It would seem to me that hydrogen should be a lot more abundant than nitrogen and oxygen, so I would expect Ice Giants to be limited in size.

Uranus and Neptune are still mostly H-He (They do have a ~5x greater concentration of methane, but it's still only 1.5% of the atmosphere). The biggest differences I've heard between the "Gas giants" and the "Ice giants" in the sources that even differentiate the two are:

A) The hypothesized core size relative to the atmosphere.

B) The temperature and resulting scheme of what clouds form at what depths, which influences the color.


A) is simply influenced by how easily the core can capture H-He: How big it is and how much was available where it formed.

B) is influenced by how far out the planet formed.

Any atmospheric compositional differences that exist are likely more due to differences in the ease of capture (during formation) and escape (afterwards) of H-He relative to other gases than anything else.

The solar system seems to confirm that, but it's only one reference. There don't seem to be any Exo-ice giants discouvered yet, which again might be a pointer that they don't get big enough. I'd apreciate your thoughts: should I set a mass-limit for Ice-giants?

Well, I'd form a planet first, then assign a classification based on properties, rather than assigning a classification, then determining properties from that.

Depending on what exactly you hold to separate "ice giant" from "gas giant", you might or might not assign a different classification to worlds that are otherwise ice giants, but above a certain mass.

See what's forming in your model and assign names to different types of things that form. Don't try to force the model to conform to the classes you've set up.

As far as "exo-ice-giants", there have been quite a few "hot neptunes" found, and even a few "cold neptunes" (though the latter are hard to find). If you're using mass as the dividing line between "ice" and "gas" giants, then all of these would qualify as "ice giants".

Also, there seems to be no theory yet how they would behave closer to a star (no sudarsky-equivalent for ice-giants, I'm afraid. No data available).

Well, I've generally heard the color differences between J/S and U/N described in terms of the same general factors as the Sudarsky system uses: temperature and the resulting cloud structure. I'm not sure why the Sudarsky system is said to be non-valid for ice giants, it seems it should be fairly well valid for anything with a H-He atmosphere (with trace other gasses) that's too deep to see to the bottom of. It might be the methane content, since that's where the blue comes from, though I think there's also some influence there from what clouds can form and at what depths (I *think* that U/N's clouds are deeper than J/S's, and themselves made of methane, rather than ammonia, so the atmosphere above them has more depth to absorb red light. Don't quote me on that). So basically they're a Sudarsky "0", and look much like a three, though in their case because the clouds are deep and they have more methane.

In the solar system, they are pretty far out, but most probably they were ejected during the formation by the combined forces of Jupiter and Saturn, and initially formed in the same region. What would happen to them if they migrated inwards seems completely unknown. So I'm thinking about putting in an orbit-limit too. Again, suggestions are highly apreciated.

Again, I wouldn't. Let the model make planets, then assign classifications to them based on their properties. Don't limit the properties based on a classification.

 

[T.Neo]

it seems it should be fairly well valid for anything with a H-He atmosphere (with trace other gasses) that's too deep to see to the bottom of.

Or perhaps to a limited extent, terrestrial planets with radically different atmospheres. Both Earth and Mars have ice clouds, for example.

 

[jedidia]

Again, I wouldn't. Let the model make planets, then assign classifications to them based on their properties. Don't limit the properties based on a classification.

That's actually what I'm doing. But I still have to know how to classify the result to assign a type. When I was talking about a mass-limit, The actual question was "should I just classify anything above that mass as a gas-giant".

Anyways, I found some astronomical dictionary, and it pretty blatantly says that an Ice Giant is pretty much everything between 10 and 100 earth masses, so I classified them like that. Thanks for your advice, anyways!

by the way, tomorrow's a tuesday...

---------- Post added 06-15-10 at 12:40 PM ---------- Previous post was 06-14-10 at 05:53 PM ----------

Vaporware no more! :woohoo:

http://www.orbiter-forum.com/showthread.php?p=179885#post179885

 

[Artlav]

Not bad. The only issue i noticed besides graphics is that the solar systems often repeat themselves.

After looking at it, i'm still wondering why did you need the stellar evolution tables.
I haven't noticed time controls.