1. Consider the following planets:
- Venus
- Jupiter
- Mars
Which of the above have atmospheres composed predominantly of carbon dioxide?
[A] Only 1 & 3
[B] Only 1 & 2
[C] Only 2 & 3
[D] 1, 2 & 3
Show Answer
Correct Answer: A [Only 1 & 3]
Notes:
Venus’s atmosphere is composed mostly of carbon dioxide, and Mars’s thin atmosphere is primarily carbon dioxide. Jupiter’s atmosphere consists mainly of molecular hydrogen and helium, so it does not meet the criterion. Therefore, only Venus and Mars have atmospheres composed predominantly of carbon dioxide.
2. Which of the following people discovered Jupiter’s four largest moons using a telescope in early 1610?
[A] Simon Marius
[B] Tycho Brahe
[C] Galileo Galilei
[D] Johannes Kepler
Show Answer
Correct Answer: C [Galileo Galilei]
Notes:
Galileo Galilei discovered Jupiter’s four largest moons in early 1610, publishing his observations in ‘Siderius Nuncius’. These moons, now known as the Galilean moons, provided strong evidence for the heliocentric Copernican theory. Simon Marius also independently observed them but published his findings later.
3. Which of the following celestial bodies is not a moon of Jupiter?
[A] Callisto
[B] Ganymede
[C] Triton
[D] Europa
Show Answer
Correct Answer: C [Triton]
Notes:
Triton is the largest moon of Neptune, notable for its retrograde orbit, meaning it revolves in the opposite direction to its parent planet’s rotation. Conversely, Callisto, Ganymede, and Europa are three of Jupiter’s four largest moons, collectively known as the Galilean moons, first observed by Galileo Galilei in 1610.
4. Consider the following statements about asteroids:
- They are generally rocky or metallic bodies orbiting the Sun.
- They vary greatly in size; the historically named asteroid Ceres is roughly 940 km across.
- The main asteroid belt lies between Jupiter and Saturn.
Which statements are correct? (UPSC Prelims 1998)
[A] I, II and III
[B] II and III only
[C] I and II only
[D] I and III only
Show Answer
Correct Answer: C [I and II only]
Notes:
I and II are correct. The main belt lies between Mars and Jupiter, making III incorrect. Ceres, historically called the largest asteroid, is now classified as a dwarf planet; its mention preserves the size comparison in the original question.
5. Consider the following planets:
- Mars
- Venus
- Jupiter
- Saturn
Which of the above planets have an intrinsic global magnetic field?
[A] 3 and 4 only
[B] 2 and 4 only
[C] 1 and 3 only
[D] 1, 2, 3 and 4
Show Answer
Correct Answer: A [3 and 4 only]
Notes:
Jupiter and Saturn have intrinsic global magnetic fields generated by the motion of electrically conducting material inside them. Mars has no present-day global intrinsic field, although parts of its crust retain magnetization. Venus also lacks an intrinsic global magnetic field; its weak magnetic environment results from interaction between the solar wind and its atmosphere. Therefore, only planets 3 and 4 meet the condition.
6. Which space agency launched the Jupiter Icy Moons Explorer (JUICE) mission?
[A] National Aeronautics and Space Administration (NASA)
[B] European Space Agency (ESA)
[C] Japan Aerospace Exploration Agency (JAXA)
[D] Indian Space Research Organization (ISRO)
Show Answer
Correct Answer: B [European Space Agency (ESA)]
Notes:
Recently, ESA’s Jupiter Icy Moons Explorer (JUICE) used Earth’s gravity for a major gravity-assist manoeuvre on 28 September 2026. The spacecraft passed about 8,640 km above the Indian Ocean. Earth’s gravity changed JUICE’s direction by about 20° and increased its speed by 3.5 km/s, without a major engine burn. This technique is called a gravity assist or gravity slingshot. JUICE uses the gravity of Earth, Moon and Venus to save fuel and gain the energy needed to reach Jupiter. The Jupiter Icy Moons Explorer (JUICE) is an interplanetary spacecraft mission developed and launched by the European Space Agency (ESA) in April 2023. The mission’s primary objective is to study Jupiter and its three large icy moons: Ganymede, Callisto, and Europa.
7. What is the difference between asteroids and comets?
- Asteroids are small rocky planetoids, while comets are formed of frozen gases held together by rocky and metallic material.
- Asteroids are found mostly between the orbits of Jupiter and Mars, while comets are found mostly between Venus and Mercury.
- Comets show a perceptible glowing tail, while asteroids do not.
Which of the statements given above is/are correct? (UPSC Prelims 2011)
[A] 1 and 2 only
[B] 1 and 3 only
[C] 3 only
[D] 1, 2 and 3
Show Answer
Correct Answer: B [1 and 3 only]
Notes:
Statements 1 and 3 give the conventional distinction: asteroids are mainly rocky or metallic, while comets contain abundant volatile ices and can develop a coma and tail near the Sun. Statement 2 is incorrect: many comets originate in the Kuiper Belt or Oort Cloud, not between Venus and Mercury. Not every comet displays a visible tail at all times.
8. Which country has launched its advanced JUPITER space camera aboard the National Advanced Optical System (NAOS) satellite?
[A] Australia
[B] Israel
[C] Iran
[D] Japan
Show Answer
Correct Answer: B [Israel]
Notes:
Israeli defense technology firm Elbit Systems recently launched its advanced JUPITER space camera aboard the National Advanced Optical System (NAOS) satellite. The satellite was launched from Vandenberg Space Force Base, California, on a SpaceX Falcon 9 rocket. JUPITER supports military operations, environmental monitoring, scientific research, and wide-span observation missions. It features a large aperture, lightweight design, high-resolution panchromatic channel for black-and-white imaging, and a Near Infrared (NIR) channel for vegetation, water, and material analysis. The camera can capture continuous long image strips covering large areas efficiently.
9. With reference to the Lucy Spacecraft Mission, consider the following statements:
- The spacecraft is named after the famous fossil “Lucy,” discovered in Ethiopia, which provides insights into early human evolution.
- The Lucy mission aims to study Trojan asteroids that orbit the Sun in the same path as Jupiter.
- The Lucy spacecraft will complete all its asteroid flybys by the year 2025.
Which of the above statements is / are correct?
[A] 1 and 2 only
[B] 2 and 3 only
[C] 1 and 3 only
[D] 1, 2 and 3
Show Answer
Correct Answer: A [1 and 2 only]
Notes:
The spacecraft is indeed named after the fossil “Lucy,” discovered in Ethiopia, symbolizing the mission’s intent on shedding light on the origins of the planetary system, much like the fossil opens up insights on early human evolution. Its primary mission is to study Trojan asteroids orbiting in the same path as Jupiter. However, the Lucy spacecraft is not projected to complete all its asteroid flybys by 2025 but will continue its mission through 2033.
10. Consider the following statements regarding TOI-2005 b, recently discovered using the TESS telescope:
- It is classified as a “warm Jupiter” due to its size and proximity to its host star.
- Its orbit is nearly circular with very little variation in distance from the star.
- It completes one orbit around its star in less than 20 days.
- The planet receives a relatively constant level of stellar irradiation throughout its orbit.
Which of the above statements is/are correct?
[A] Only 1 and 3
[B] 1, 2 and 4
[C] 2, 3 and 4
[D] Only 1 and 4
Show Answer
Correct Answer: A [Only 1 and 3]
Notes:
TOI-2005 b is known as a ‘warm Jupiter’ owing to its size and proximity to its host star, mirroring characteristics of Jupiter, and completes one orbit around the star in approximately 17.3 days which justifies Option 1. It does not maintain an almost circular orbit, nor does it experience consistent stellar irradiation, discrediting Statements 2 and 4.
