Free Astronomy and Space MCQs with Answers

251. What is the mass of the Sun?

• A. 1.5×10 Power 30 Kg
• B. 1.98×10 Power 30 Kg
• C. 4.5×10 Power 30 Kg
• D. 8×10 Power 30 Kg

Explanation: The Sun's mass is approximately 1.98 × 10^30 kg, making it about 333,000 times as massive as Earth. Its enormous mass supplies the gravity that holds the solar system together.

252. What is it called when the Earth is closest to the sun _____________?

• A. Aphelion
• B. Perihelion
• C. Apoapsis
• D. Periapsis

Explanation: Perihelion is the point at which an object orbiting the Sun is nearest to it, so Earth reaches perihelion in early January. Aphelion is the farthest point, while periapsis and apoapsis are more general orbital terms.

253. Border line which separates outer space from Earth's atmosphere is known as___________?

• A. Durand line
• B. Space line
• C. Venus line
• D. Karman line

Explanation: The Kármán line, conventionally placed at about 100 km altitude, is widely used as the boundary of outer space. The other named lines are not recognized atmospheric-space boundaries.

254. Study of the Universe is known as___________?

• A. Sociology
• B. Cosmology
• C. Universology
• D. Petology

Explanation: Cosmology studies the origin, structure, evolution and ultimate fate of the universe as a whole. Sociology studies society, so it is not the relevant field here.

255. Big Bang theory explains_____________?

• A. Origin of Universe
• B. Origin of Sun
• C. Laws of physics
• D. None of above

Explanation: The Big Bang theory describes the early origin and expansion of the universe from an extremely hot, dense state. It does not specifically explain the origin of the Sun or establish all laws of physics.

256. Big Bang was an explosion that occurred ?

• A. 10 Billion years ago
• B. 15 Billion years ago
• C. 20 Billion years ago
• D. 25 Billion years ago

Explanation: The Big Bang is estimated to have occurred about 13.8 billion years ago, so 15 billion years is the closest option. Older textbooks commonly round the age of the universe to approximately 15 billion years.

257. Which is correct order of solar system starting from Sun ?

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

Explanation: The planets are arranged outward from the Sun as Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. This order follows increasing distance from the Sun.

258. Diameter of Sun is_____________?

• A. 12 Lakh kms
• B. 13 Lakh kms
• C. 14 Lakh kms
• D. 15 Lakh kms

Explanation: The Sun's diameter is approximately 1.39 million kilometres, which is about 14 lakh kilometres in the South Asian numbering system.

259. Phobos is the natural satellite of which planet__________ ?

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

Explanation: Phobos is one of Mars’s two small natural satellites, the other being Deimos. It orbits very close to Mars and moves around the planet faster than Mars rotates.

260. The final phase of a star's evolution is determined by the star's:

• A. Age
• B. Gravitational pull
• C. Density
• D. Mass

Explanation: A star's mass determines how strongly gravity compresses its core and how rapidly it consumes nuclear fuel. It therefore largely determines whether the final remnant is a white dwarf, neutron star, or black hole.