Outgassing

Definition

Outgassing is the process by which gases trapped in solid materials are released into the atmosphere, often occurring when a body undergoes changes in temperature or pressure. This phenomenon is particularly relevant in understanding the formation and evolution of celestial bodies, as it plays a crucial role in shaping the atmospheres and compositions of comets and asteroids.

5 Must Know Facts For Your Next Test

1. Outgassing is essential for understanding the early atmospheres of planetary bodies, as it contributes to the accumulation of gases around them.
2. In comets, outgassing occurs as they approach the Sun, causing their icy nuclei to sublimate and release gas and dust that form the coma and tail.
3. Asteroids can also undergo outgassing, particularly those that are carbon-rich or contain volatile compounds, leading to a change in their surface features.
4. The study of outgassing helps scientists analyze the composition of celestial bodies and can provide insights into their formation history.
5. Outgassing can influence the thermal evolution of comets and asteroids, affecting their orbits and interactions with other celestial objects.

Review Questions

• How does outgassing contribute to the atmospheric development of comets as they approach the Sun?
  • As comets approach the Sun, the increase in temperature causes the volatile materials within their icy nuclei to sublimate. This process leads to outgassing, where gases such as water vapor and carbon dioxide are released. These gases form a surrounding cloud known as a coma, which can expand significantly. The interaction between solar radiation and these gases results in the formation of the comet's tail, making outgassing a key factor in defining a comet's appearance and behavior.
• Evaluate the role of outgassing in shaping the surface features of asteroids over time.
  • Outgassing can significantly alter the surface features of asteroids by releasing trapped gases that may cause erosion or create new geological formations. For carbon-rich asteroids or those containing volatile compounds, this process can lead to observable changes over time, including cracking or cratering on their surfaces. Understanding how outgassing impacts asteroids helps scientists assess their evolution and provides valuable information about their composition and potential for hosting life-related elements.
• Synthesize the implications of outgassing for understanding the origins of water on terrestrial planets.
  • Outgassing plays a pivotal role in theorizing how water might have originated on terrestrial planets like Earth. The process suggests that early volcanic activity could have released significant amounts of water vapor into the atmosphere, contributing to surface water accumulation as temperatures cooled. By studying outgassing in comets and asteroids—both believed to have delivered water during planetary formation—scientists gain insight into how these celestial bodies contributed to establishing Earth's hydrosphere. This synthesis of information highlights a potential link between small body dynamics and planetary habitability.

Related terms

Volatiles:

Substances that can easily vaporize and are often released during outgassing, including water, carbon dioxide, and ammonia.

Cometary Nucleus: The solid core of a comet composed of ice, dust, and other materials that releases gas and dust when heated by solar radiation.

Cryovolcanism: Volcanic activity involving the eruption of substances such as water, ammonia, or methane at low temperatures, often associated with outgassing on icy bodies.