What characteristic best identifies it as a comet? Comets are streaks of light. Comets are larger than asteroids. Comets enter the Earth's atmosphere. Comets develop a fuzzy, cloud-like shell called a coma, as well as a tail.
From Wikipedia:
A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail.
The characteristic that best identifies a celestial object as a comet is the development of a fuzzy, cloud-like shell called a coma, as well as a tail.
To understand this, it's helpful to know how comets are observed and studied. Here's a step-by-step explanation of how scientists identify a comet and determine its characteristics:
1. Observation: Astronomers observe the night sky using telescopes and other instruments. They look for objects that appear as points of light, but with peculiar characteristics.
2. Initial Identification: When a celestial object is initially identified as potentially being a comet, it is usually based on its appearance. Comets are usually faint and exhibit a fuzzy-looking halo or shell known as a coma. This is due to the presence of gas and dust surrounding the comet's nucleus.
3. Tail Formation: As a comet gets closer to the Sun, solar radiation and the solar wind heat and ionize the coma's gases, causing them to stream away from the nucleus, forming a glowing tail. This tail can stretch for millions of kilometers in space and points away from the Sun.
4. Further Study: To confirm the identification of a comet and learn more about it, astronomers conduct further observations and studies. They examine the object's orbit, composition, and behavior as it approaches and departs from the Sun. They also study the gases and dust being emitted by the comet, which can provide insights into its origins and evolution.
5. Comparison with Other Objects: To distinguish comets from other celestial objects like asteroids, astronomers look for specific characteristics, such as the presence of a coma and tail. Unlike asteroids, comets are icy bodies that vaporize and develop a temporary atmosphere (coma) and tail as they come close to the Sun.
Based on these steps, the characteristic that best identifies an object as a comet is the development of a fuzzy, cloud-like shell (coma) and the presence of a tail. This distinguishes comets from other objects in our solar system, like asteroids, which generally do not exhibit these features.