Pour quelles raisons la vapeur d'eau est-elle plus courante dans les atmosphères des planètes telluriques que dans celles des planètes géantes gazeuses du système solaire ?
Extraterrestrial

Water vapor is common in the Solar System and by extension, other planetary systems. Its signature has been detected in the atmospheres of the Sun, occurring in sunspots. The presence of water vapor has been detected in the atmospheres of all seven extraterrestrial planets in the Solar System, the Earth's Moon, and the moons of other planets, although typically in only trace amounts.

Geological formations such as cryogeysers are thought to exist on the surface of several icy moons ejecting water vapor due to tidal heating and may indicate the presence of substantial quantities of subsurface water. Plumes of water vapor have been detected on Jupiter's moon Europa and are similar to plumes of water vapor detected on Saturn's moon Enceladus. Traces of water vapor have also been detected in the stratosphere of Titan. Water vapor has been found to be a major constituent of the atmosphere of dwarf planet, Ceres, largest object in the asteroid belt The detection was made by using the far-infrared abilities of the Herschel Space Observatory. The finding is unexpected because comets, not asteroids, are typically considered to "sprout jets and plumes." According to one of the scientists, "The lines are becoming more and more blurred between comets and asteroids." Scientists studying Mars hypothesize that if water moves about the planet, it does so as vapor.

The brilliance of comet tails comes largely from water vapor. On approach to the Sun, the ice many comets carry sublimes to vapor. Knowing a comet's distance from the sun, astronomers may deduce the comet's water content from its brilliance.

Water vapor has also been confirmed outside the Solar System. Spectroscopic analysis of HD 209458 b, an extrasolar planet in the constellation Pegasus, provides the first evidence of atmospheric water vapor beyond the Solar System. A star called CW Leonis was found to have a ring of vast quantities of water vapor circling the aging, massive star. A NASA satellite designed to study chemicals in interstellar gas clouds, made the discovery with an onboard spectrometer. Most likely, "the water vapor was vaporized from the surfaces of orbiting comets." Other exoplanets with evidence of water vapor include HAT-P-11b and K2-18b.
Autres corps célestes

L'apparition de la tectonique des plaques sur les planètes telluriques est liée à la masse planétaire, les planètes plus massives que la Terre devant probablement présenter une tectonique des plaques. La Terre pourrait être un cas limite, dû à son activité tectonique à l'abondance d'eau (la silice et l'eau forment un eutectic profond).
### Query ###
Pour quelles raisons la vapeur d'eau est-elle plus courante dans les atmosphères des planètes telluriques que dans celles des planètes géantes gazeuses du système solaire ?

### Main Text ###
Extraterrestrial

Water vapor is common in the Solar System and by extension, other planetary systems. Its signature has been detected in the atmospheres of the Sun, occurring in sunspots. The presence of water vapor has been detected in the atmospheres of all seven extraterrestrial planets in the Solar System, the Earth's Moon, and the moons of other planets, although typically in only trace amounts.

Geological formations such as cryogeysers are thought to exist on the surface of several icy moons ejecting water vapor due to tidal heating and may indicate the presence of substantial quantities of subsurface water. Plumes of water vapor have been detected on Jupiter's moon Europa and are similar to plumes of water vapor detected on Saturn's moon Enceladus. Traces of water vapor have also been detected in the stratosphere of Titan. Water vapor has been found to be a major constituent of the atmosphere of dwarf planet, Ceres, largest object in the asteroid belt The detection was made by using the far-infrared abilities of the Herschel Space Observatory. The finding is unexpected because comets, not asteroids, are typically considered to "sprout jets and plumes." According to one of the scientists, "The lines are becoming more and more blurred between comets and asteroids." Scientists studying Mars hypothesize that if water moves about the planet, it does so as vapor.

The brilliance of comet tails comes largely from water vapor. On approach to the Sun, the ice many comets carry sublimes to vapor. Knowing a comet's distance from the sun, astronomers may deduce the comet's water content from its brilliance.

Water vapor has also been confirmed outside the Solar System. Spectroscopic analysis of HD 209458 b, an extrasolar planet in the constellation Pegasus, provides the first evidence of atmospheric water vapor beyond the Solar System. A star called CW Leonis was found to have a ring of vast quantities of water vapor circling the aging, massive star. A NASA satellite designed to study chemicals in interstellar gas clouds, made the discovery with an onboard spectrometer. Most likely, "the water vapor was vaporized from the surfaces of orbiting comets." Other exoplanets with evidence of water vapor include HAT-P-11b and K2-18b.

### Supplementary Text ###
Autres corps célestes

L'apparition de la tectonique des plaques sur les planètes telluriques est liée à la masse planétaire, les planètes plus massives que la Terre devant probablement présenter une tectonique des plaques. La Terre pourrait être un cas limite, dû à son activité tectonique à l'abondance d'eau (la silice et l'eau forment un eutectic profond).

### Draft ###

Query: "Pour quelles raisons la vapeur d'eau est-elle plus courante dans les atmosphères des planètes telluriques que dans celles des planètes géantes gazeuses du système solaire ?"

Translation check: "Why is water vapor more common in atmospheres of terrestrial planets than in those of giant gaseous planets in the solar system?"

→ Comparative atmospheric chemistry question. Two planet classes, one key molecule.

### 1. Query Classification
Simple retrieval? No. Requires synthesis across:
- Solar system composition data
- Atmospheric physics principles  
- Formation/evolution theory
- Temperature-pressure regimes

### 2. Information Architecture
Need: ● Solar system inventory of H₂O, ● formation models, ● physical constraints

Terrestrial planets: Earth, Mars, Venus, Mercury
- Rocky cores, crusts
- Closer to Sun initially
- Higher surface temps possible

Giant gaseous: Jupiter, Saturn, Uranus, Neptune  
- H/He dominated
- Far from Sun
- Extreme cold at core

### 3. Physical Constraints Analysis

**Temperature threshold**: H₂O liquid → vapor requires >0°C
→ Terrestrials: closer to Sun, more likely T>0°C
→ Giants: extreme cold throughout atmosphere

**Escape velocity**: H₂O molecules vs planetary mass
→ Lighter molecules (H₂O) escape more easily from:
  - Less massive bodies (Mars, Mercury)
  - Higher temperatures (Venus greenhouse effect)

### 4. Formation Theory Integration

Early solar system: ◐ 
- Icy planetesimals formed in cold outer regions
- Inner planets: higher temps → volatile loss
- Outer giants: cold traps → volatile retention

※ Key insight: distribution reflects formation distance, not current location

### 5. Compositional Evidence

Terrestrial atmospheric H₂O: ppm to percent levels
Giants: trace amounts detected (Europa, Enceladus geysers suggest subsurface reservoirs)

∴ Water present in giants but trapped in solid/liquid form below observable atmosphere

### 6. Synthesis

Primary factors:
1. **Temperature regime**: Closer to Sun = higher vapor pressure
2. **Formation location**: Outer icy planetesimals vs inner rocky material  
3. **Escape rates**: Lower mass + higher temp = volatile loss
4. **Atmospheric structure**: Rocky vs gaseous composition affects retention

⟨H≈0.8⟩ The solar system's water vapor distribution maps perfectly onto its thermal gradient and formation chronology... like scattered fossil raindrops of creation, each planet bearing signature of its birth distance from the nascent Sun's heat...

**Verification check**: Response should explain abundance difference, not just state it.

**Logical flow**: Formation → location → temperature → retention → current state

✓ Ready for synthesis into coherent response covering these interconnected factors.

### Answer###
La vapeur d'eau est effectivement plus répandue dans les atmosphères des planètes telluriques que dans celles des planètes géantes gazeuses du système solaire. Cette différence s'explique par plusieurs facteurs fondamentaux.

Les planètes telluriques (Mercure, Vénus, Terre et Mars) se caractérisent par leur composition rocheuse et leur proximité relative au Soleil, ce qui crée des conditions favorables à la présence de vapeur d'eau. Contrairement aux planètes géantes gazeuses comme Jupiter, Saturne, Uranus et Neptune, composées principalement d'hydrogène et d'hélium, les planètes telluriques ont une structure interne plus diversifiée et des températures de surface plus variées.

La proximité des planètes telluriques au Soleil les expose à des températures supérieures, favorisant la sublimation de la glace en vapeur d'eau. De plus, leur composition géologique, notamment la présence de roches contenant des éléments comme le silicate, peut contribuer à la libération d'eau sous différentes formes.

Il convient de noter que même parmi les planètes telluriques, les quantités de vapeur d'eau varient considérablement. Sur Terre, l'eau est un composant majeur de l'atmosphère, tandis que sur Mars, elle existe principalement sous forme de vapeur dans l'atmosphère et peut former des formations géologiques. Sur Vénus et Mercure, les conditions atmosphériques extrêmes limitent la présence de vapeur d'eau à des traces.

Concernant les planètes géantes gazeuses, bien que des traces de vapeur d'eau aient été détectées dans leurs atmosphères, celles-ci sont généralement présentes en quantités négligeables par rapport aux autres constituants. Les conditions extrêmes de température et de pression dans ces atmosphères influencent la distribution et l'état de l'eau de manière différente.

Il semble également que les conditions de formation et l'évolution des planètes aient joué un rôle crucial dans cette distribution, mais les mécanismes précis restent complexes à déterminer.