Free Astronomy and Space MCQs with Answers

81. When in the part of its orbit closest to the Sun, Pluto has an atmosphere of nitrogen and methane similar to Triton's, but what happens when it is farther from the Sun ?

• A. These gases are not present
• B. These gases are like plasma
• C. These gases are frozen
• D. These gases are volatile

Explanation: As Pluto moves farther from the Sun, its surface becomes colder and nitrogen and methane condense and freeze onto the surface. This causes much of its temporary atmosphere to collapse.

82. Titan, a moon of __________ , and Triton, a moon of _________ , have atmospheres mainly of _________.

• A. Saturn, Jupiter, Hydrogen
• B. Uranus, Neptune, Nitrogen
• C. Saturn, Neptune, Nitrogen
• D. Mars, Venus, Hydrogen

Explanation: Titan is Saturn's moon and Triton is Neptune's moon; both have nitrogen-dominated atmospheres. Jupiter and Uranus are therefore incorrect planet pairings in the other options.

83. The planet retains an atmosphere when?

• A. Gravity is low and temperature of atmosphere is great
• B. Gravity and temperature both are great
• C. Gravity and temperature both are constant
• D. Gravity is great and temperature of atmosphere is low

Explanation: A planet retains an atmosphere more effectively when its gravity is strong enough to hold gas particles and the atmospheric temperature is low enough to limit their speed. Weak gravity and high temperature allow gases to escape into space.

84. The presence of ice in which region of the moon has been conclusively established?

• A. Southern pole region
• B. Northern pole region
• C. Equator
• D. All of the above

Explanation: Water ice has been conclusively detected in permanently shadowed craters near the Moon’s south pole, where sunlight cannot warm the deposits. These extremely cold regions preserve ice for long periods.

85. The Saturn V rocket that took Apollo 11 to the moon in 1969 stood tall?

• A. 363-feet
• B. 364-feet
• C. 365-feet
• D. 366-feet

Explanation: The Saturn V used for Apollo 11 stood about 363 feet, or roughly 111 metres, tall. It remains one of the largest and most powerful rockets ever flown.

86. The extremely cold temperatures in the polar region of moon mean that it can act as a kind of __________ where things do not undergo much change.

• A. Time capsule
• B. Light capsule
• C. Meta capsule
• D. Natural capsule

Explanation: The permanently shadowed lunar polar regions are described as a natural time capsule because their extreme cold greatly slows chemical and physical change. This allows ancient ice and trapped materials to remain preserved.

87. What is the 2nd closest galaxy to the Milky Way?

• A. Triangulum
• B. Andromeda
• C. Messier 81
• D. Whirlpool

Explanation: Among the major galaxies commonly listed near the Milky Way, the Andromeda Galaxy is the nearest large spiral and the Triangulum Galaxy is often described as the second closest. Smaller dwarf galaxies are closer but are usually excluded by this wording.

88. Which scientist is known as modern father of Astronomy ?

• A. Einstein
• B. Newton
• C. Copernicus
• D. Archimedes

Explanation: Copernicus is commonly called the father of modern astronomy because his heliocentric model placed the Sun, rather than Earth, at the centre of the planetary system. Newton later explained planetary motion through gravity.

89. Pluto is known as dwarf planet because which of the following reason/s:

• A. It has negligible mass
• B. It has not nearly round shaped
• C. It does not have always same neighbouring planet
• D. All of the above

Explanation: A dwarf planet is nearly round but has not cleared the neighbourhood around its orbit of other bodies. Pluto meets this condition, unlike the eight planets, which dominate their orbital zones.

90. Which planet looks reddish in the night sky ?

• A. Jupiter
• B. Saturn
• C. Mars
• D. MercurY

Explanation: Mars appears reddish because iron-bearing minerals in its surface rocks have oxidised, producing iron oxides similar to rust. The other listed planets do not show this characteristic red appearance.