space medium mcq

The Baryon Acoustic Oscillations (BAO) serve as a standard ruler for measuring _______.

  1. Stellar ages
  2. Cosmic expansion history
  3. Black hole masses
  4. Galaxy rotation speeds

Answer: Cosmic expansion history

BAO are frozen sound wave imprints in galaxy distribution (~150 Mpc scale), constraining dark energy and expansion rate across cosmic time.

Topic Astronomy - Universe
Exam Relevance SSC CGL, UPSC Prelims

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