What is difference between asteroids and comets?

1. Asteroids are small rocky plane­toids, while comets are formed of frozen gases held together by rocky and metallic material.
2. Asteroids are found mostly between the orbits of Jupiter and Mars, while comets are found mostly between Venus and mercury.
3. Comets show a perceptible glowing tail, while asteroids do not.

Which of the statements given above is/are correct?

[UPSC Civil Services Exam – 2011 Prelims]

(a) 1 and 2 only

(b) 1 and 3 only

(c) 3 only

(d) 1, 2 and 3

Answer: (b)        

Explanation:

Asteroids:

• Definition: Small, rocky objects that orbit the Sun.
• Size: Much smaller than planets despite orbiting like planets.
• Location: Most found in the main asteroid belt between Mars and Jupiter.
• Total Mass: The combined mass of all asteroids is less than that of Earth’s Moon.
• Appearance: They do not have a glowing tail.

Comets:

• Definition: Frozen leftovers from the formation of the solar system composed of dust, rock, and ices.
• Appearance: When closer to the sun, they heat up and spew dust and gases, creating a giant glowing head/tail larger than most planets.
• Quantity: Likely billions of comets orbiting our Sun.
• Origin: They primarily originate from two regions: the Kuiper Belt and the Oort Cloud.