Tail

Definition

In astronomy, a tail refers to the elongated, luminous feature that trails behind a comet or asteroid as it approaches the Sun. The tail is formed due to the sublimation of ices and the release of gas and dust when these celestial bodies get closer to solar radiation. The interaction between solar wind and the particles released creates the characteristic appearance of a comet's tail, which can extend millions of kilometers into space.

5 Must Know Facts For Your Next Test

1. Comet tails always point away from the Sun due to the pressure of sunlight and solar wind acting on the released gas and dust.
2. There are two types of tails: ion tails, which are made up of ionized gas and glow blue due to their interaction with solar radiation, and dust tails, which are yellowish and consist of larger particles.
3. As comets travel through the inner solar system, they can develop two distinct tails that can sometimes become separated due to their different compositions and responses to solar wind.
4. The length and brightness of a comet's tail can vary significantly depending on its distance from the Sun and the amount of volatile materials present in its nucleus.
5. Tails can extend for millions of kilometers and can be visible from Earth, leading to significant observations in astronomy throughout history.

Review Questions

• How do comets develop tails when they approach the Sun?
  • Comets develop tails as they approach the Sun due to the process of sublimation. When a comet gets close to solar radiation, its nucleus heats up, causing ices within it to turn directly into gas. This release of gas and dust forms a coma around the nucleus, and as these materials are pushed away by sunlight and solar wind, they create one or two distinct tails that trail behind the comet.
• Compare and contrast ion tails and dust tails in terms of their formation and characteristics.
  • Ion tails are formed from ionized gas that glows blue due to interactions with solar radiation and generally point directly away from the Sun. In contrast, dust tails are composed of larger particles and appear yellowish; they are influenced more by the motion of the comet than by direct solar pressure. While both types of tails are created by materials escaping from the comet as it approaches the Sun, their different properties result in unique appearances.
• Evaluate how understanding comet tails contributes to our knowledge of solar system dynamics.
  • Understanding comet tails enhances our knowledge of solar system dynamics by revealing how celestial bodies interact with solar wind and radiation. The behavior of a comet's tail provides insights into its composition and activity level, allowing scientists to study how comets evolve as they travel through different regions of space. Additionally, observing changes in tail length and brightness can help astronomers track a comet's journey through the solar system, contributing valuable data about gravitational influences and orbital mechanics.

Related terms

Coma: The nebulous envelope around the nucleus of a comet, formed from gases and dust released from the solid core as it heats up near the Sun.

Solar Wind: A stream of charged particles released from the upper atmosphere of the Sun that influences the formation of a comet's tail.

Nucleus: The solid central part of a comet, typically composed of ice, dust, and rocky materials, which becomes active when warmed by solar radiation.