Free Astronomy and Space MCQs with Answers

111. The value of acceleration due to gravity is minimum on which of these planets?

• A. Mars
• B. Jupiter
• C. Mercury
• D. Neptune

Explanation: Mercury has the lowest surface gravity among these planets, about 3.7 m/s², narrowly below Mars. Jupiter and Neptune are much more massive and have stronger gravity.

112. An astronaut sees the colour of the sky as: _________?

• A. Blue
• B. White
• C. Red
• D. Black

Explanation: An astronaut in space sees a black sky because there is no atmosphere to scatter sunlight into different directions. Earth’s sky appears blue because atmospheric molecules scatter blue light more strongly.

113. Recently, scientists observed the merger of giant 'blackholes' billions of light-years away from the Earth. What is the significance of this observation?

• A. 'Higgs boson particles' were detected.
• B. Gravitational waves' were detected.
• C. Possibility of inter-galactic space travel through 'wormhole' was confirmed.
• D. It enabled the scientists to understand 'singularity'.

Explanation: Merging black holes disturb spacetime and produce gravitational waves that can be detected on Earth. This observation did not confirm wormholes or directly detect Higgs bosons.

114. A shooting star is _________?

• A. Sun
• B. A comet
• C. A meteor
• D. An steroid

Explanation: A shooting star is the visible streak produced when a meteoroid burns or glows while passing through Earth’s atmosphere, so it is a meteor. It is not actually a star or a comet.

115. The Shape of earth is _________?

• A. Elliptical
• B. Oblate Spheroid
• C. Oval
• D. Spherical

Explanation: Earth is an oblate spheroid: rotation makes it slightly wider at the equator and flattened at the poles. “Spherical” is a useful rough description but is less scientifically precise.

116. Which is the only planet that rotates clockwise?

• A. Jupiter
• B. Venus
• C. Earth
• D. Mercury

Explanation: Venus rotates retrograde, meaning clockwise when viewed from above its north pole, unlike most planets’ counterclockwise rotation. Its unusual rotation is linked to its slow spin and complex tidal history.

117. Planets having largest amount of Carbon Dioxide is ____________?

• A. Mercury
• B. Jupiter
• C. Mars
• D. Venus

Explanation: Venus has an atmosphere made up of about 96% carbon dioxide, far more than the other listed planets. Mars also has a carbon-dioxide-rich atmosphere, but it is much thinner.

118. Milky Way Galaxy in which type?

• A. spiral
• B. Round
• C. Square
• D. Linear

Explanation: The Milky Way is a barred spiral galaxy, with a central bar and curved arms extending from it. “Round” is too general and does not identify its galaxy type.

119. Who among the following discovered the sunspots?

• A. Johannes Kepler
• B. Einstein
• C. Copernicus
• D. Galileo

Explanation: Galileo was among the first to observe and systematically record sunspots using a telescope in the early seventeenth century. Other astronomers made independent observations, but Galileo is the standard answer among these options.

120. The earth revolves around the sun at a speed of__________?

• A. 18.5 km/sec
• B. 26.6 km/sec
• C. 29 km/sec
• D. 31.9 km/sec

Explanation: Earth travels around the Sun at an average orbital speed of about 29.8 km/s, commonly rounded to 29 km/s. Its speed varies slightly because Earth’s orbit is elliptical.