Free Astronomy and Space MCQs with Answers

131. Which of the following planets rotate from east to west on its exis?

• A. Jupiter, Mars
• B. Mercury, Saturn
• C. Venus, Uranus
• D. Neptune, Earth

Explanation: Venus and Uranus have retrograde rotation, meaning they rotate opposite to the usual eastward direction of most planets. Uranus is often described as rotating backward because its extreme axial tilt makes its spin direction appear retrograde.

132. The brightest colour emitted by the sun is:

• A. Violet
• B. Yellow-Green
• C. Green- Blue
• D. Red

Explanation: The Sun’s visible spectrum has its maximum intensity near the yellow-green region, although sunlight contains all visible colours. This is why yellow-green is used as the best answer rather than red or violet.

133. The subatomic particles arriving from outer space having high energy are called?

• A. Protons
• B. Electrons
• C. Cosmic rays
• D. None of the above

Explanation: Cosmic rays are high-energy particles, mainly protons and atomic nuclei, that arrive from outer space. They are not limited to electrons or protons alone.

134. The time in which Earth completes its revolution around the Sun is________?

• A. 365.25 days
• B. 340 days
• C. 325 days
• D. 360 days

Explanation: Earth takes about 365.25 days to complete one revolution around the Sun, with the extra quarter day accounted for by leap years. This is the basis of the civil year.

135. Which of the following is called as Blue planet?

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

Explanation: Earth is called the Blue Planet because oceans cover most of its surface and make it appear blue from space. Neptune also looks blue, but Earth's standard nickname is being tested here.

136. The movement of earth around sun brings ________?

• A. Tornadoes
• B. Rainfall
• C. Seasons
• D. Earthquakes

Explanation: Earth's revolution around the Sun, combined with the tilt of its rotational axis, produces the seasons. Revolution alone without axial tilt would not create the familiar seasonal pattern.

137. The radiant energy having lowest energy is?

• A. gamma rays
• B. UV rays
• C. visible light
• D. Radio waves

Explanation: Among the listed forms, radio waves have the lowest frequency and therefore the lowest photon energy, since energy is proportional to frequency. Gamma rays have the highest energy, followed by ultraviolet and visible light.

138. Who enunciated the laws of planetary motion?

• A. Nicolaus Copernicus
• B. Johannes Kepler
• C. Isaac Newton
• D. Galile

Explanation: Johannes Kepler formulated the three laws describing planetary orbits, orbital speeds and periods. Copernicus proposed the heliocentric model, while Newton later explained Kepler’s laws through gravity.

139. Galileo was an Italian astronomer who _________?

• A. Developed the telescope
• B. Discovered four satellites of Jupiter
• C. Discovered that the movement of pendulum produces a regular time measurement
• D. All of the above

Explanation: Galileo improved the telescope for astronomy, discovered four large moons of Jupiter, and studied the regular timing of a pendulum's swing. In the usual school-level wording, all three statements are credited to him.

140. Who was the first to measure the earth's circumference?

• A. Eratosthenes
• B. Galileo
• C. Copenicus
• D. Ptolemy

Explanation: Eratosthenes estimated Earth’s circumference by comparing the Sun’s shadow angles at two locations and using the distance between them. Galileo and Copernicus are associated mainly with astronomy and planetary motion, not this measurement.