American Meteorological Society Certification (AMS) Practice

The layers of gas surrounding a planet are referred to as the atmosphere. The atmosphere is a complex mixture of gases that envelops a celestial body, held in place by gravity. It plays several critical roles, including providing the air necessary for respiration in living organisms, regulating temperature through greenhouse gases, and protecting the planet's surface from harmful solar radiation and meteoroids.

The terminology related to atmospheric layers can sometimes cause confusion. For instance, the stratosphere and troposphere are subdivisions of Earth's atmosphere, with each layer characterized by different temperature gradients, composition, and functions. The ozone layer is also a specific region within the stratosphere, primarily known for absorbing the majority of the sun's harmful ultraviolet radiation. However, these terms refer to specific parts or components of the overall atmospheric structure rather than defining what encompasses all the gases around a planet. Thus, "atmosphere" is the most encompassing and accurate term for the layers of gases surrounding a planet.