MCQ Detailed View

Comets are small celestial bodies that orbit the Sun and are mainly composed of ice and dust. Astronomers often describe them as “dirty snowballs” because they are a mixture of frozen water, frozen gases, rocky particles, and organic compounds. These objects are leftovers from the formation of the solar system over 4.6 billion years ago, making them some of the most ancient bodies still traveling through space.

A comet's structure consists of three main parts:

1. 
   

   Nucleus: The solid core of the comet made up of water ice, frozen gases like carbon dioxide and methane, dust particles, and rocky material.

   
   


2. 
   

   Coma: A glowing cloud of gas and dust that forms when the comet gets close to the Sun and heat causes the ice to vaporize.

   
   


3. 
   

   Tail: Streams of gas and dust pushed away from the comet by solar wind and radiation pressure, always pointing away from the Sun.

   
   

Comets do not produce light of their own. The light we see from comets is reflected sunlight and glowing gases in their coma and tail. Therefore, they are not made of “lights,” which makes options containing “lights” scientifically inaccurate.

Comets usually come from distant regions of the solar system, such as the Kuiper Belt or the Oort Cloud, and travel along long elliptical orbits. As they approach the Sun, the increased temperature causes sublimation of ices, releasing large amounts of gas and dust, creating the visible tail that makes comets so spectacular from Earth.

Studying comets helps scientists understand the early solar system because they contain pristine material that has remained largely unchanged for billions of years. Some scientists even believe that comets may have delivered water and organic compounds to Earth, potentially aiding in the development of life.

The correct answer is Ice and dust, as these are the primary components of comets, with no self-emitted light involved in their composition.