Free Astronomy and Space MCQs with Answers

231. Year is longest on:___________?

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

Explanation: A planet's year is the time it takes to orbit the Sun. Jupiter takes about 11.86 Earth years, longer than the other planets listed.

232. Which one of the following is applicable to the planet 'Venus'?

• A. Smallest
• B. Brightest
• C. Most dense
• D. Largest

Explanation: Venus is the brightest planet as seen from Earth because its thick cloud cover reflects a large amount of sunlight. It is not the largest or most dense planet.

233. The setting sun often looks oval in the shape because of__________?

• A. The fact that sun really becomes oval in the evening
• B. Refraction of rays of sun passing through the atmosphere
• C. Optical Illusion
• D. Dispersion

Explanation: Atmospheric refraction bends sunlight as it passes through layers of air with different densities, especially near the horizon. This unequal bending makes the setting Sun appear flattened or oval rather than changing its actual shape.

234. Hailey's comet is visible after every_________?

• A. 84 years
• B. 76 years
• C. 1000 years
• D. 365 years

Explanation: Halley's Comet returns approximately every 75 to 76 years because that is its orbital period around the Sun. Its recorded returns are therefore measured in decades, not centuries.

235. Which of the followong spacecrsft enabled man to step on the moon first?

• A. Spuntnik I
• B. Luna II
• C. Vostok I
• D. Apollo XI

Explanation: Apollo 11 carried Neil Armstrong and Buzz Aldrin to the lunar surface in 1969, making them the first humans to walk on the Moon. Sputnik I was a satellite, while Luna II was an unmanned probe and Vostok I carried the first human into space.

236. Among the planets of the Solar system the position of the Earth from the Sun is:_________?

• A. Second
• B. Third
• C. Fourth
• D. Sixth

Explanation: Earth is the third planet from the Sun, after Mercury and Venus. Its orbital position is distinct from its size or distance from other planets.

237. Most important effect of the moon on earth is that it___________?

• A. Causes weather change
• B. Causes earthquakes
• C. Causes solar and lunar eclipse
• D. Effects tides of the ocean

Explanation: The Moon's gravitational pull, together with the Sun's influence, produces the regular rise and fall of ocean tides. Weather and earthquakes are not the Moon's most important established effect on Earth.

238. The Lunar eclipse occurs when:

• A. Moon is b/w the earth and the sun
• B. Earth is b/w the sun and the moon
• C. Sun is b/w the earth and the moon
• D. Earth is at right angles to the direction of the sun and the moon

Explanation: A lunar eclipse occurs when Earth comes between the Sun and the Moon, causing Earth's shadow to fall on the Moon. The opposite arrangement, with the Moon between Earth and the Sun, produces a solar eclipse.

239. Which is the nearest star to our sun?

• A. Proxima Centurai
• B. Alpha Scorpii
• C. Beta Orionis
• D. Vega

Explanation: Proxima Centauri is the nearest known star to the Sun, at about 4.24 light-years away. The other listed stars are much farther from our solar system.

240. Who was the first to measure the earth's radius

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

Explanation: The Greek scholar Eratosthenes estimated Earth's size by comparing noon shadows at two locations and using the angle difference to calculate its circumference and radius. Galileo, Copernicus, and Ptolemy are associated with other major developments in astronomy.