Water ice

Definition

Water ice is the solid form of water that occurs when the temperature drops below 0 degrees Celsius (32 degrees Fahrenheit). In the context of celestial bodies, it plays a crucial role in the composition and behavior of comets and asteroids, contributing to their physical and chemical processes. Water ice not only affects the structure of these bodies but also influences their activity when they approach the Sun, leading to phenomena such as outgassing and cometary tails.

5 Must Know Facts For Your Next Test

1. Water ice is thought to be a significant component of many comets, making up a large part of their nucleus.
2. When comets approach the Sun, water ice sublimates into gas, causing the comet to develop a coma and tail due to the escape of gas and dust.
3. The presence of water ice on asteroids suggests that some may have originated from the early solar system and may have even contributed to Earth's water supply.
4. Spectroscopic studies have detected water ice on various celestial bodies, including Mars and some moons of the outer planets, indicating its widespread distribution in the solar system.
5. Understanding water ice in the context of comets and asteroids helps scientists learn about the conditions present during the formation of the solar system.

Review Questions

• How does water ice influence the activity of comets as they approach the Sun?
  • As comets approach the Sun, the increase in temperature causes water ice within their nucleus to sublimate, turning directly from solid to gas. This process generates gas and dust, which forms a coma around the nucleus and often creates a tail that points away from the Sun. The activity driven by sublimation of water ice is crucial for defining a comet's appearance and behavior during its orbit.
• Discuss the implications of finding water ice on asteroids for our understanding of the solar system's history.
  • The discovery of water ice on asteroids suggests that these bodies are remnants from the early solar system that may contain clues about its formation. The presence of water ice indicates that some asteroids could have played a role in delivering water to Earth, influencing planetary development. By studying these icy asteroids, scientists can gather information about conditions prevalent during the formation of terrestrial planets.
• Evaluate the role of cryovolcanism in shaping our understanding of icy bodies and their potential for hosting life.
  • Cryovolcanism challenges traditional concepts of volcanism by revealing how icy bodies can exhibit geological activity through eruptions of substances like water ice. This phenomenon has been observed on moons like Europa and Enceladus, where subsurface oceans may exist beneath icy crusts. The study of cryovolcanism provides insights into potential habitats for life beyond Earth, as it suggests that conditions suitable for life could exist in these hidden oceanic environments within icy celestial bodies.

Related terms

Comet: A small celestial body made of ice, dust, and rocky material that, when close to the Sun, displays a visible atmosphere or coma and sometimes a tail.

Asteroid: A small rocky body that orbits the Sun, primarily found in the asteroid belt between Mars and Jupiter, which can also contain water ice in its composition.

Cryovolcanism: A type of volcanic activity involving the eruption of substances such as water, ammonia, or methane instead of molten rock, often associated with icy celestial bodies.