Which factor is essential to the initial formation of galaxies, for either of the theories describing galaxy evolution?(1 point)
Small lumps of material merge into larger clumps.
Small lumps of material merge into larger clumps.
Massive gas and dust clouds collapse.
Massive gas and dust clouds collapse.
Gravity acts on existing material, shaping it into a new form.
Gravity acts on existing material, shaping it into a new form.
The force of orbiting stars generates collisions.
Massive gas and dust clouds collapse.
The factor that is essential to the initial formation of galaxies, according to either of the theories describing galaxy evolution, is:
Massive gas and dust clouds collapse.
To determine which factor is essential to the initial formation of galaxies, we can analyze the given choices and consider the theories describing galaxy evolution.
The two theories commonly used to explain galaxy formation are the hierarchical model and the monolithic collapse model. In the hierarchical model:
1. Small lumps of material merge into larger clumps: This process, known as hierarchical merging, is crucial in the formation of galaxies. It involves smaller structures, such as dwarf galaxies or protogalactic fragments, merging and gradually forming larger structures like galaxies.
2. Massive gas and dust clouds collapse: This process, called gravitational collapse, is another essential factor in the formation of galaxies. Massive clouds of gas and dust collapse under the influence of gravity, gradually forming galaxies as they condense and coalesce.
3. Gravity acts on existing material, shaping it into a new form: Gravity plays a significant role in galaxy formation by acting on existing material and causing it to come together, shaping it into new forms, such as spiral galaxies, elliptical galaxies, or irregular galaxies.
4. The force of orbiting stars generates collisions: While this factor can indeed lead to collisions between stars in a galaxy, it is not a primary factor in the initial formation of galaxies.
Based on the given choices and the theories of galaxy evolution, the factors that are essential to the initial formation of galaxies are:
- Small lumps of material merge into larger clumps.
- Massive gas and dust clouds collapse.
- Gravity acts on existing material, shaping it into a new form.
Therefore, the correct choice is a combination of the first three factors.