space medium MCQ

What is the name of the theoretical boundary of the observable universe?

  1. Event Horizon
  2. Cosmic Microwave Background
  3. Heliopause
  4. Kuiper Belt

Answer: Cosmic Microwave Background

The Cosmic Microwave Background (CMB) radiation is the oldest light in the universe, dating back to about 380,000 years after the Big Bang. It effectively marks the limit of the observable universe in terms of time/light.

Topic Astronomy - Universe
Exam Relevance UPSC Prelims, SSC CGL
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