The quasar \(3 \mathrm{C} 273\) has a luminosity of \(10^{12} L_{0} .\) Assuming that the total luminosity of a large galaxy, such as the Andromeda Galaxy, is 10 billion times that of the Sun, compare the luminosity of \(3 \mathrm{C} 273\) with that of the entire Andromeda Galaxy.

Astrophysics is the branch of astronomy that deals with understanding the physical principles governing the universe. It studies celestial bodies such as planets, stars, galaxies, and the interstellar medium using the laws of physics and chemistry.
This field covers a wide range of topics, including the life cycle of stars, the nature of black holes, the behavior of galaxies, dark matter, and dark energy.
Astrophysicists use mathematical formulas, computer simulations, and observations to explore these phenomena. For example, they might use telescopes to observe distant galaxies and supernovae, or computer models to simulate the formation of stars.

Galaxy luminosity refers to the total amount of light emitted by a galaxy. It's a crucial metric for understanding the energy output and size of a galaxy.
Typically, astronomers compare a galaxy's luminosity to that of the Sun, denoted as \(L_{0}\).
For example, the Andromeda Galaxy's luminosity is calculated as \(10^{10} L_{0}\), meaning it emits 10 billion times the light of our Sun.
By measuring luminosity, scientists can infer details about the galaxy's star population, age, and even its potential for hosting habitable planets.
Luminosity can vary greatly between different types of galaxies—spiral, elliptical, and irregular—reflecting the diversity in size and star formation activities.

A quasar is an extremely luminous active galactic nucleus, powered by a supermassive black hole at its center. The intense energy output is due to the accretion of matter onto the black hole, which heats up and releases massive amounts of light.
Quasars are some of the most luminous objects in the universe, often outshining entire galaxies. For instance, quasar 3C 273 has a luminosity of \(10^{12} L_{0}\), making it 100 times more luminous than the Andromeda Galaxy.
Observing quasars helps astronomers understand more about the early universe, black hole growth, and the formation of galaxies. Quasars can be observed at great distances, making them valuable for studying the structure and evolution of the universe.