Prelims 2011 · archive
MediumWhat is the 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?
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. Explanation: Minimalist IAS, checked 25 Oct 2026 (how we verify). ·