Galaxies form through the gravitational collapse of vast clouds of gas and dust, known as protogalactic clouds.

The Big Bang Theory is the prevailing cosmological model that describes the universe's origin and evolution, including the formation of galaxies.

Galactic mergers occur when two or more galaxies collide and combine, resulting in a larger and more massive galaxy.

Sagittarius A* is the supermassive black hole located at the center of our Milky Way galaxy.

Spiral galaxies, like our Milky Way, have a prominent bulge at the center and a flattened disk with spiral arms extending from it.

Star formation is the process by which gravitational collapse of gas and dust within galaxies leads to the formation of stars.

Elliptical galaxies have a smooth, featureless appearance and lack a prominent bulge or disk.

The cosmic microwave background radiation is the remnant radiation from the Big Bang and provides strong evidence for the theory.

Irregular galaxies have an irregular and chaotic structure, lacking a well-defined shape or pattern.

Galactic evolution refers to the processes that drive the changes in the structure, composition, and properties of galaxies over time.

Barred spiral galaxies have a prominent bar-shaped structure across their center, along with spiral arms extending from the bar.

2MASX J2135-0102 is the largest known galaxy in the observable universe, with an estimated diameter of over 5 million light-years.

Hierarchical galaxy formation proposes that galaxies form through the hierarchical merging of smaller structures over time.

Galactic interactions refer to the gravitational interactions between galaxies, which can lead to various effects such as tidal disruptions, mergers, and accretion.

Elliptical galaxies have a compact and spherical shape, with a high concentration of stars towards the center.