How a Green Gas Giant happens
Every gas giant has 7 cloud layers, and each one has a temperature. The game colors each layer from a chart of temperature bands. A layer that lands exactly on the line between two bands gets no color. It stays the default green, and that's a GGG.
Last updated 5 Oct 2026.
- Seven cloud layers. Think of them as 7 rungs on a ladder. Each rung has a temperature.
- A colour chart. The game picks each rung's color from a chart split into temperature bands.
- The doorway. The chart only accepts a temperature strictly inside a band. A rung sitting exactly on the line between two bands belongs to neither. It gets no color, so it stays default green.
Play with the ladder
Drag temperature and density, or pick an example. Each dot is a cloud rung. The bright lines are the doorways. When a rung lands exactly on one, the planet turns green.
Band colors are only for illustration. This ladder skips the random nudge, so the temperature starts at 123 K.
Enter the numbers from a scan. It builds the ladder exactly as described above.
How the 7 rungs are placed
- The bottom rung is the surface temperature. That's the temperature in your journal or system map.
- The ladder's reach. The rungs climb from there. How far they reach depends on temperature and density, where density is mass divided by volume. This is the "depth" Dr Ross talked about in Arcanic's video.
reach = 722.2 x (T / 1300)^1.2 x density^0.2 density = MassEM x 5.97219e24 / (4/3 x pi x Radius^3)
T in kelvin, density in kg/m3, Radius in metres. 5.97219e24 kg is one Earth mass.
- A ceiling. The ladder can't reach past a ceiling. For colder classes it's 340 K.
Surface temperature Ceiling below 75 K 100 K 75 to 330 K 340 K 330 to 680 K 700 K 680 to 900 K 1,200 K 900 to 1,400 K 1,500 K above 1,400 K 5,000 K - Seven equal steps. The rungs are evenly spaced. The step is (the top, minus the surface temperature) divided by 7. The top is the reach or the ceiling, whichever comes first.
- Exact numbers. The game keeps each rung to about 7 significant digits. A rung has to land exactly on a crack. Close doesn't count.
Water-based life giants are always dense enough to reach the 340 K ceiling. The rungs then split the gap between the surface temperature and 340 K into 7 equal steps. At these four temperatures, one rung lands exactly on a crack.
| Way | How it works |
|---|---|
| The ceiling "magic" temperatures | A dense planet reaches the ceiling, so density stops mattering. Only the temperature counts. Water-based life at 158 K has steps of (340 − 158) ÷ 7 = 26 K. The rungs go 158, 184, 210, and 210 is a crack. |
| Step limits class III and IV | Class III steps can't be smaller than 30 K. So 640 K gives 640, 670, 700. That's why green class III temperatures come every 30 K, from 520 to 700. |
| Depth density sets the step | The reach stops short of the ceiling, so density changes the step. Temperature and density have to line up together. M17 and Flyiedge KA-V b8-5 3 are this kind. They can be green at almost any temperature. |
It has to be exact. Aemonz UT-R d4-36 10 a at 176.666702 K is green. A planet at 176.666626 K misses 270 by the smallest step a temperature can take, and it looks normal.
Why some GGGs can't be predicted
Some planets get a random nudge before their ladder is built. It moves the bottom rung to a random temperature, and no public data shows where it went. It happens to:
- Cold class II to V giants. That's class II below 280 K, class III below 415 K, class IV below 700 K and class V below 1,500 K.
- Any other giant between 80 and about 122 K.
For these planets the rule can only say "could be green". A visit is the only way to know. About half the catalogue GGGs are this kind, including every class II GGG.
A few of them can escape the nudge. If their own temperature already puts a rung on a crack, they're green unless the nudge moves them. Five catalogue GGGs are like this. They are Floawns FX-L b36-24 1, Dryooe Groa QX-F c16 A 7, Synookio EI-J d9-1 7, Boekh AO-H b27-33 1 and Vegnao PA-S c6-43 3.
Every crack
| Planet type | Cracks (K) |
|---|---|
| Class I, and gas giants with ammonia-based life | 1152502703707009001400 |
| All other gas and water giants | 1142102703707009001400 |
No GGG has been found on the highlighted ones yet. Class I and ammonia-life giants never get hot enough to reach 370 and above.
Every always-green temperature
At these exact surface temperatures a gas giant is green whatever its density, as long as it's denser than the minimum shown. "Rung 1" is the surface itself. Spansh rounds some temperatures down to whole numbers, so check a real scan before you fly.
Water-based life (also water giants, helium and helium-rich)
| Surface temperature | Green rung | Min density | Known GGGs |
|---|---|---|---|
| 158.000000 | 3rd, on 210 K | 315 | 4 |
| 176.666641 to 176.666702 | 5th, on 270 K | 94 | 8 |
| 188.333328 | 2nd, on 210 K | 44 | none yet |
| 210.000000 | 1st, on 210 K | any | none yet |
| 217.499985 to 217.500015 | 4th, on 270 K | 6 | 1 |
| 241.999985 to 242.000015 | 3rd, on 270 K | any | 1 |
Class I and Ammonia-Based life
| Surface temperature | Green rung | Min density | Known GGGs |
|---|---|---|---|
| 129.999985 to 130.000015 | 5th, on 250 K | 2,078 | 2 |
| 115.000000 | 1st, on 115 K | any | none yet, can be nudged |
Class III
| Surface temperature | Green rung | Min density | Known GGGs |
|---|---|---|---|
| 520, 550, 580, 610, 640, 670, 700 | 7th down to 1st, on 700 K | any | 0, 1, 1, 2, 3, 1, 1 |
| 780.000000 | 3rd, on 900 K | any | none yet |
| 370.000000 | 1st, on 370 K | any | 1, can be nudged |
Class IV
| Surface temperature | Green rung | Min density | Known GGGs |
|---|---|---|---|
| 1149.999878 to 1150.000000 | 6th, on 1,400 K | any | 2 |
Class II has none. Every class II GGG comes from a random nudge.
- All 70 catalogue GGGs fit. 37 are never nudged, and every one has a rung exactly on a crack. The other 33 get nudged, and each one could reach a crack. Dryooe Groa QX-F c16 A 7 sits right on the edge. The journal rounds its mass and radius slightly, and most of the true values that rounding allows put it exactly on 250 K.
- 70 million scans in the EDDN archive. Only 44 planets land exactly on a crack, and 42 of them were already in the catalogue.
- Two blind predictions came true. M17 Sector CF-Y c1-23 2 (a depth GGG) and Cyoilz JM-N b26-0 1 (a 242 K water-life GGG) were picked out of old public scans. Neither was in the catalogue. Both were visited on 1 Oct 3312, and both are green. M17's new scan matched its 3304 numbers digit for digit, and the game's Codex logged it as a Green gas giant.
- Two near misses were ruled out. The journal prints gravity to 8 digits, and gravity depends on the same mass and radius. That pins down which rounded values are real. It ruled out Plaa Eurk CA-P d6-6 ABC 1 and Leamiae IQ-O c22-1431 9. Leamiae was visited, and it isn't green.
- Arcanic's own 130 K test. Nyuena AC-B d14-245 7 (density 5,245) is green. Flyae Flyi AC-S d5-2666 6 (597) and Qeajo VC-Y b42-1 1 (1,620) aren't. At 130 K a class I needs about 2,078 kg/m3 to reach the ceiling.
| Question | Answer |
|---|---|
| What is the "mystery property"? | Bulk density. It decides how far the ladder reaches. See the 130 K test above. |
| Why are GGGWBLs always green at 158 and 176.667 K? | They're dense enough to reach the 340 K ceiling every time. After that density stops mattering, and those two temperatures put a rung exactly on a crack. |
| Can a GGGWBL at 217.5 K be green? | Yes. Its 4th rung is exactly 270 K. Shaulai DL-P d5-274 7 is one, at 217.499985 K. |
| Why do class III go green every 30 K? | Their step can't be smaller than 30 K. So 700 minus any multiple of 30 puts a rung on 700. |
| Is it "default green"? | Yes. A rung that finds no band keeps a default of pure green. |
| What about the pink? | This rule doesn't cover it. It seems to come from how the planet is drawn, not from the colour choice. |
Enter the numbers from a scan. It builds the ladder exactly as described above.