Free Astronomy and Space MCQs with Answers

141. The _____ is the largest natural source of light?

• A. Sun
• B. Moon
• C. Star
• D. None of these

Explanation: The Sun is a star and is by far the largest and most powerful natural source of light reaching Earth. The Moon mainly reflects sunlight rather than producing its own light.

142. In Astronomy, what are Pallas, Vesta and Davida?

• A. Stars
• B. Comets
• C. Asteroids
• D. None of these

Explanation: Pallas, Vesta and Davida are names of asteroids in the Solar System. Unlike comets, they are mainly rocky or metallic bodies and do not characteristically form bright tails near the Sun.

143. The period of revolution of a geostationary satellite is?

• A. 365 days
• B. 30 days
• C. 24 hours
• D. changing continuously

Explanation: A geostationary satellite must rotate once in the same time that Earth rotates, so it remains above the same point on the equator. This period is approximately 24 hours.

144. The most distant human-made object sent into the space is?

• A. Voyager 1
• B. Pioneer 10
• C. Eris
• D. New Horizon

Explanation: Voyager 1 is the most distant human-made object because it has continued travelling outward since its 1977 launch. Pioneer 10 and New Horizons are also distant probes but remain closer to the Sun.

145. Which of the following celestial bodies contains abundant quantities of helium-3, a potential source of energy?

• A. Earth
• B. Venus
• C. Moon
• D. Saturn

Explanation: The Moon is considered a potential source of helium-3, an isotope discussed for future nuclear fusion fuel. Its possible abundance there makes the Moon the intended choice, not Earth, Venus or Saturn.

146. We always see the same face of the moon, because?

• A. It is smaller than the earth
• B. It revolves on its axis in a direction opposite to that of the earth
• C. It takes equal time for revolution around the earth and rotation on its own axis
• D. It rotates at the same speed as the earth around the sun

Explanation: The Moon rotates once on its axis in about the same time that it revolves once around Earth, about 27.3 days. This synchronous rotation keeps the same lunar hemisphere facing us.

147. Which planet in our solar system has the most gravity?

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

Explanation: Jupiter has the greatest gravitational pull among the planets because its enormous mass outweighs the effect of its large radius. Mercury, Venus, and Neptune all have lower surface gravity.

148. What was the first planet to be discovered using a telescope?

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

Explanation: Uranus was discovered by William Herschel in 1781 using a telescope. The other listed planets were known since ancient times because they are visible to the naked eye.

149. What is total area of the earth?

• A. 510.94 million km²
• B. 492.102 million km²
• C. 392.023 million km²
• D. 692.192 million km²

Explanation: Earth's total surface area is approximately 510 million square kilometres, including both land and oceans. Thus 510.94 million km² is the closest listed value.

150. Which planet is losing its atmosphere at faster than the earth?

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

Explanation: Mars loses atmospheric gas more readily than Earth because its weaker gravity and lack of a strong global magnetic field allow particles to escape into space. Mercury has an extremely thin exosphere, but Mars is the usual comparison in this question.