Which factor is essential to the initial formation of galaxies, for either of the theories describing galaxy evolution Small lumps of material merge into larger clumps Gravity acts on existing material, shaping it into a new form The force of orbiting stars generates collisions Massive gas and dust clouds collapse.
Massive gas and dust clouds collapse.
Both of the theories describing galaxy evolution, the hierarchical model and the monolithic collapse model, involve certain essential factors for the initial formation of galaxies. The factor that is essential in both theories is the merging of small lumps of material into larger clumps.
In the hierarchical model, galaxies are formed through a slow process of mergers and acquisitions. Small clumps of material, such as gas clouds or clusters of stars, gradually merge together due to the force of gravity. Over time, these mergers lead to the formation of larger and more massive galaxies.
In the monolithic collapse model, galaxies form from the rapid collapse of massive gas and dust clouds. As these clouds collapse under their own gravitational pull, they begin to spin and flatten into a disk shape. Within this disk, smaller clumps of material merge together to form stars and eventually, galaxies.
So, the essential factor for the initial formation of galaxies in both theories is the merging of small lumps of material into larger clumps, driven by the force of gravity.