Water vapour. Or steam which is the gas state of water.
Evaporation of water from the surfaces of rivers, lakes and mainly the oceans, an important part of the water cycle on Earth.
If by gas you mean an atmosphere, there are no planets with an atmosphere anywhere similar to Earth.
That is called atmosphere.That is called atmosphere.That is called atmosphere.That is called atmosphere.
ATMOSPHERE
Oxygen gas
About 1/5
amount of water vapour in the atmosphere, or in a gas
Atmosphere causes 78% nitrogen to be released as a gas
It is called the humidity of the atmosphere.
Gas
The amount of water vapor in the atmosphere is known as humidity. Humidity can be expressed as specific humidity, relative humidity, or absolute humidity depending on the context.
Humidity is the amount of water vapour in the atmosphere
EARLY ATMOSPHERE have humidity
Neptune is a gas giant with no solid surface, and its atmosphere is composed mainly of hydrogen, helium, and methane. The extreme cold temperatures and lack of water vapor in Neptune's atmosphere make it unlikely to have humidity as we experience on Earth.
Humidity
The sun influences humidity by driving the process of evaporation. When sunlight heats bodies of water, such as oceans and lakes, it causes water to evaporate into the atmosphere, increasing the amount of water vapor present, which raises humidity levels. Additionally, solar energy affects temperature; warmer air can hold more moisture, further contributing to higher humidity in the atmosphere.
For water, higher humidity decreases evaporation because more water is present in the atmosphere. Less water will diffuse into the atmosphere. If it's at 100% humidity, there's no net evaporation.
Jupiter is a gas giant and doesn't have a solid surface, so it doesn't have humidity like Earth. Jupiter's atmosphere is mainly composed of hydrogen and helium with trace amounts of other elements, so humidity as we know it doesn't apply to the planet.