space hard mcq

The reionization epoch occurred approximately between which redshift ranges?

  1. z=100-50
  2. z=20-6
  3. z=3-1
  4. z=0.5-0

Answer: z=20-6

First stars/galaxies ionized neutral hydrogen between z~20-6 (~180 Myr-1 Gyr post-Big Bang), ending cosmic dark ages; confirmed by CMB polarization and quasar spectra.

Topic Astronomy - Cosmology
Exam Relevance UPSC Prelims, General Science

More Space Questions