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UPSC CSE Prelims 2011 · GS Paper I · Space technology

What is the difference between asteroids and comets?

UPSC Civil Services (Preliminary) Examination 2011, General Studies Paper I — Space technology.

Prelims 2011

Space technology Medium

What is the difference between asteroids and comets?

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

Which of the statements given above is/are correct?

Answer & explanation

Answer: (b) 1 and 3 only

Statements 1 and 3 are correct, so the answer is (b). Asteroids are rocky leftovers of the solar system's formation. Comets are icy bodies of frozen gases and dust that grow a glowing tail near the Sun. Statement 2 fails because comets come from the far outer Solar System, not from the zone between Venus and Mercury.

  • ✓ 1. Asteroids are rocky remnants of the solar system's formation. A comet's nucleus is made of icy chunks and frozen gases with embedded dust. This rock-versus-ice contrast is exactly the distinction the statement draws.
  • ✗ 2. The first half is right: most known asteroids orbit in the main belt between Mars and Jupiter. The second half is wrong: comets come from the icy Kuiper Belt beyond Neptune and from the distant Oort Cloud, not from between Venus and Mercury.
  • ✓ 3. Near the Sun, a comet's ices turn to gas and form a coma. Sunlight and the solar wind can blow the coma's dust and gas away from the Sun, forming a long, bright tail. Comets have both a dust tail and an ion tail. Ordinary asteroids do not develop such a tail.

Remember · Asteroids are rocky and orbit mainly between Mars and Jupiter. Comets are icy, come from the Kuiper Belt and Oort Cloud, and grow a coma and tail near the Sun.

Sources

  • NASA Science: Asteroid Facts ↗ “Asteroids, sometimes called minor planets, are rocky remnants left over from the formation of our solar system about 4.6 billion years ago. … The majority of known asteroids orbit within the asteroid belt between Mars and Jupiter, generally with not very elongated orbits.”
  • NASA Science: Comet Facts ↗ “The nucleus contains icy chunks, frozen gases with bits of embedded dust. … The pressure of sunlight and high-speed solar particles (solar wind) can blow the coma dust and gas away from the Sun, sometimes forming a long, bright tail. … a disc-like belt of icy bodies exists beyond Neptune, where a population of dark comets orbits the Sun in the realm of Pluto.”

Question: UPSC Civil Services (Preliminary) 2011, General Studies Paper I. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). ·

Cite this question: UPSC CSE Prelims 2011 — minimalistias.com/pyqs/prelims/2011/q74

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