Free Astronomy and Space MCQs with Answers

221. Which gas was discovered on the sun about 151 years ago during total solar eclipse?

• A. Hydrogen
• B. Helium
• C. Nitrogen
• D. Flourine

Explanation: Helium was first identified in the Sun’s spectrum during the 1868 total solar eclipse, before it was found on Earth. Its name comes from Helios, the Greek Sun god.

222. Largest moon in our solar system is ________?

• A. Deimos
• B. Ganymede
• C. Phobos
• D. Arche

Explanation: Ganymede, one of Jupiter’s moons, is the largest moon in the Solar System and is even larger in diameter than Mercury. Phobos and Deimos are small moons of Mars.

223. what are stars mainly made of ?

• A. Balls of gass
• B. Rock
• C. Ice
• D. Light

Explanation: Stars are enormous spheres of extremely hot gas, mainly hydrogen and helium. Their light and heat come from nuclear fusion in their interiors, not from being made of light.

224. which Planet is Called Earth's Sister?

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

Explanation: Venus is called Earth’s sister because it is similar to Earth in size, mass and rocky composition. Its thick carbon-dioxide atmosphere and extreme surface temperature, however, make it very different in habitability.

225. How long does the earth take to cover 1° longitude?

• A. 2 Minutes
• B. 3 Minutes
• C. 4 Minutes
• D. 5 Minutes

Explanation: Earth rotates through 360 degrees in about 24 hours, so it turns through 1 degree in 24 minutes divided by 6, or 4 minutes. This is the basis of the time difference between longitudes.

226. Sun is divided into ______ main layers.

• A. 2
• B. 3
• C. 4
• D. 5

Explanation: The Sun is commonly described as having three main internal layers: the core, radiative zone and convection zone. Its atmosphere is separately divided into the photosphere, chromosphere and corona, which is why the wording can cause confusion.

227. The sun is containing _______ % mass of the solar system?

• A. 75.24%
• B. 79.36%
• C. 89.10%
• D. 99.86%

Explanation: The Sun contains about 99.86% of the total mass of the Solar System, with the planets and all other bodies making up the small remainder. Its dominance is due to the large amount of hydrogen and helium gathered during solar-system formation.

228. Sun is moving around the centre of the galaxy at a velocity of _______ km/s?

• A. 205
• B. 210
• C. 215
• D. 220

Explanation: The Sun orbits the centre of the Milky Way at roughly 220 kilometres per second. Its orbital period is about 225 to 250 million years, often called one galactic year.

229. Which Planet has purple rocks according to NASA ?

• A. Jupitar
• B. Neptune
• C. Earth
• D. Mars

Explanation: NASA has reported purple-colored rocks on Mars, especially in observations by Mars rovers. The unusual color comes from mineral coatings and surface weathering, not from purple vegetation.

230. The most brightest planet amongst the eight planets?

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

Explanation: Venus is the brightest planet seen from Earth because its thick cloud cover reflects a large amount of sunlight and it comes relatively close to Earth. Jupiter can also appear very bright, but Venus is brighter.