Monolithic collapse

Definition

Monolithic collapse refers to a model of galaxy formation where a single massive gas cloud collapses under its own gravity to form a galaxy. This process implies that the entire structure forms rapidly and cohesively, leading to a more uniform distribution of stars and materials. This model contrasts with other theories, emphasizing how the environment and initial conditions play crucial roles in determining the resulting galaxy morphology.

5 Must Know Facts For Your Next Test

1. Monolithic collapse suggests that galaxies formed rapidly in their early stages, leading to a more homogenous stellar distribution compared to galaxies formed through hierarchical merging.
2. In this model, large amounts of gas are crucial as they are the primary material that collapses to form stars and eventually galaxies.
3. The initial mass of the collapsing gas cloud significantly influences the final size and characteristics of the galaxy formed.
4. Monolithic collapse can explain certain early-type galaxies which exhibit smooth and featureless morphologies due to their rapid formation.
5. This model has been challenged by observations that show many galaxies do not conform to the expected properties outlined by monolithic collapse, leading to a mix of formation theories.

Review Questions

• How does the concept of monolithic collapse differ from hierarchical formation in galaxy evolution?
  • Monolithic collapse presents a scenario where a single massive gas cloud collapses quickly under its own gravity to form a galaxy, resulting in a cohesive structure. In contrast, hierarchical formation involves smaller structures merging over time to create larger galaxies, which leads to more diverse morphologies. These two models highlight different processes in galaxy evolution, with monolithic collapse suggesting rapid formation while hierarchical models indicate a more gradual and complex development.
• What role does dark matter play in the monolithic collapse theory, and how might it influence galaxy formation?
  • In the monolithic collapse theory, dark matter is essential as it provides additional gravitational pull necessary for the initial gas cloud's collapse. The presence of dark matter can help stabilize these massive clouds during their formation phase, allowing them to overcome internal pressure and efficiently collapse into galaxies. The interaction between visible matter and dark matter can greatly influence how quickly and effectively a galaxy forms in this model.
• Evaluate the strengths and weaknesses of the monolithic collapse theory compared to observational evidence from modern astronomy.
  • The monolithic collapse theory offers a straightforward explanation for the rapid formation of early-type galaxies with smooth morphologies, aligning with some observational data. However, it faces challenges when accounting for the diversity seen in galaxy shapes and sizes in the universe today. Observations reveal that many galaxies do not fit neatly into this model, suggesting that a combination of both monolithic and hierarchical formation processes may be necessary to fully understand galaxy evolution. This evaluation highlights the complexity of galaxy formation and the need for multiple theories to explain varying observations.

Related terms

Hierarchical formation:

A galaxy formation theory where smaller structures merge over time to create larger galaxies, contrasting with monolithic collapse.

Galaxy morphology: The study of the shapes and structures of galaxies, which can be influenced by their formation processes, including monolithic collapse.

Dark matter: An invisible substance that makes up a significant portion of the universe's mass, affecting gravitational interactions during galaxy formation.