Measurement of Astronomical Distances
Question
Which one of the following is a reason why astronomical distances are measured in light-years?
Options
Distances among stellar bodies do not change.
Gravity of stellar bodies does not change.
Light always travels in straight line.
Speed of light is always same.
Explanation
Astronomical distances are incredibly vast, making standard units like kilometers impractical; light-years are used because the speed of light in a vacuum is an absolute universal constant (c ≈ 3×10^8 m/s), ensuring an unvarying, reliable baseline for cosmic measurements regardless of time or location. > The speed of light is a universal constant, providing a stable, unvarying baseline for measuring immense cosmic distances. Answer: (d).
Question details
Year
2021
Paper
GS Paper 1
Question
Q76
Subject
Science & Technology
Sub-topic
Space Technology & Astronomy
Type
Factual single
Difficulty
Easy
Nature
Static
Source hint
NCERT Class 11 Physics / General Science
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