Final answer:
We can learn more about quasars by studying nearby active galactic nuclei and radio galaxies because they share similar energy sources, involving accretion disks around massive black holes and emitting radio jets. This comparative study offers insights into the distant and early universe through the light of quasars.
Step-by-step explanation:
The discovery of quasars has greatly expanded our knowledge of the universe. By studying nearby active galactic nuclei (AGN) and radio galaxies, we can gain insights into these distant objects. Both quasars and AGN are powered by material falling into and heating up as it forms a hot accretion disk around a massive black hole. This process releases enormous amounts of energy in a compact space. Additionally, some quasars are observed emitting powerful radio and gamma-ray radio jets from their cores. The study of quasars provides a window into the early universe, as their light has taken billions of years to reach us, offering clues about the cosmos's history and evolution.