Question 42

A chunk composed primarily of rock, ice, and dust orbiting the Sun in an elliptical path.

Comets are best described as chunks composed primarily of rock, ice, and dust that orbit the Sun in an elliptical path. This definition captures the essential characteristics of comets, distinguishing them from other celestial objects.

A) A small planet orbiting the Sun between Mars and Jupiter.

This option incorrectly describes a comet as a small planet, which is not accurate. While there are small celestial bodies in the asteroid belt between Mars and Jupiter, comets are specifically icy bodies that originate from different regions of the solar system, such as the Kuiper Belt and Oort Cloud.

B) A chunk composed primarily of metal that enters Earth's atmosphere.

This option incorrectly characterizes a comet. While it mentions a chunk that enters Earth’s atmosphere, it suggests a composition primarily of metal, which is not typical of comets. Comets are instead composed of ice, dust, and rocky materials, making this option inaccurate.

C) A chunk composed primarily of rock, ice, and dust orbiting the Sun in an elliptical path.

This option accurately describes a comet. Comets are indeed made up of a mixture of rock, ice, and dust, and they have orbits that are often highly elliptical, bringing them close to the Sun before retreating to the outer parts of the solar system.

D) A dark region that appears periodically on the surface of the Sun.

This option fails to describe a comet accurately, as it refers to a phenomenon related to solar activity rather than a celestial body. Comets do not appear on the surface of the Sun; instead, they are objects that travel through space and exhibit tails when they come close to the Sun due to sublimation of their icy components.

Conclusion

The correct answer, C, accurately defines a comet by emphasizing its composition and orbital characteristics. All other options fail to describe a comet correctly, either by mischaracterizing its physical properties or confusing it with other celestial phenomena. Thus, option C is the only choice that fully encapsulates what a comet is.