Free Astronomy and Space MCQs with Answers

261. The season changes because of the ____________?

• A. Moon is revolving round the earth
• B. Earth is revolving round its axis
• C. Earth is revolving round the sun
• D. Planet Mars is attracting the sun

Explanation: Seasons result from Earth’s revolution around the Sun combined with the tilt of its axis, which changes the angle and duration of sunlight received. Among the options, Earth’s revolution around the Sun is the relevant cause; rotation on its axis produces day and night.

262. The distance of longitude represents how many minutes difference in time?

• A. 10 minutes
• B. 4 minutes
• C. 15 minutes
• D. 1 minute

Explanation: Earth rotates 360° in about 24 hours, so each degree of longitude corresponds to 4 minutes of time difference. Locations to the east are ahead in time, while locations to the west are behind.

263. What is meant by "Equinox"?

• A. The longest day
• B. The shortest day
• C. The sun-month long day
• D. Equal duration of day and night

Explanation: An equinox occurs when the Sun is over the Equator, making day and night nearly equal in duration across Earth. It occurs around March and September each year.

264. Which one is the brightest star in the night sky?

• A. Betelgeuse
• B. Sirius
• C. Rigel
• D. Polaris

Explanation: Sirius is the brightest star in the night sky as seen from Earth, mainly because it is relatively close and intrinsically luminous. Betelgeuse and Rigel are bright but appear dimmer, while Polaris is much less bright.

265. The large dark patches on the Moon's surface are known as___________?

• A. Dark matter
• B. Maria, or seas, even though there is no water on the Moon
• C. Maria, or seas, because they are filled with water
• D. Moon spots

Explanation: The Moon’s dark plains are called maria, the Latin plural of mare, meaning seas. They were once mistakenly thought to contain water, but they are actually ancient basaltic lava plains.

266. What causes the Moon's phases?

• A. The Sun lights up only one half of the Moon and as the Moon orbits the Earth we can sometimes see the unlit side of the Moon.
• B. The Sun lights up only one half of the Moon and as the Sun orbits the Earth we can sometimes see the unlit side of the Moon.
• C. The Earth's shadow falls on the Moon, blocking the sunlight.
• D. The Moon's shadow falls on the Earth, blocking the sunlight.Physics

Explanation: The Sun always illuminates half of the Moon, but as the Moon orbits Earth, we see different portions of that lit half. Earth’s shadow causes a lunar eclipse, not the regular phases of the Moon.

267. What are the names of the two stars in the Big Dipper used to locate Polaris?

• A. The North Seekers
• B. The Pointer Stars
• C. The Pointer Sisters
• D. None of these

Explanation: The two stars at the outer edge of the Big Dipper’s bowl are called the Pointer Stars because a line through them points toward Polaris. The other names are not standard astronomical terms.

268. The Big Dipper is part of which constellation?

• A. Ursa Major
• B. Ursa Minor
• C. The Great Bear
• D. A. and C. above

Explanation: The Big Dipper is an asterism within Ursa Major, whose name means Great Bear. Therefore both options A and C describe it, making D correct.

269. The sun is made up of 99.9% of ________________ and ______________?

• A. Oxygen and Hydrogen
• B. Hydrogen and Sulfur
• C. Carbon and Silicon
• D. Hydrogen and Helium

Explanation: Hydrogen and helium together account for about 99.9% of the Sun’s mass, with hydrogen making up the larger share. The heavier elements are present only in small amounts.

270. Antares is of the largest known ___________?

• A. Quasars Star
• B. Pulsars Star
• C. White Dwarfs Star
• D. Red Super-giants Star

Explanation: Antares is a red supergiant, a very large, cool star nearing the later stages of stellar evolution. Its reddish appearance comes from its relatively low surface temperature.