One model of galaxy formation occurs when sections of gas clouds collapse into small pieces and then merge into larger pieces due to gravity. The Milky Way is an example of the ______ model or the ______ model.
The Milky Way is an example of the hierarchical model or the bottom-up model of galaxy formation.
The Milky Way is an example of the hierarchal model or the bottom-up model of galaxy formation. In this model, small pieces of gas clouds collapse under their own gravitational forces to form small protogalactic clumps. These clumps then merge over time to form larger structures, such as galaxies.
The Milky Way is an example of the hierarchical model or the cold dark matter model.
To understand why, let's break it down step by step:
1. Gas Cloud Collapse: The process begins with the collapse of sections of gas clouds. These clouds contain various elements, including hydrogen and helium, distributed throughout space.
2. Small Pieces Formation: As sections of the gas clouds collapse under the influence of gravity, they fragment into smaller regions. These regions are known as proto-galactic clumps or mini-halos, which consist primarily of dark matter.
3. Gravity and Merger: The next step involves the force of gravity. The small proto-galactic clumps start to merge and accrete more gas and dark matter from their surroundings. Over time, the accumulation of gas and dark matter leads to the formation of larger structures known as galaxies.
4. Hierarchical Model: The term "hierarchical" refers to the step-by-step merging process, where smaller structures combine to form larger ones. In this model, galaxies like the Milky Way form through a series of mergers between smaller proto-galactic clumps.
5. Cold Dark Matter Model: The concept of cold dark matter is closely related to the hierarchical model. Dark matter is an invisible form of matter that does not interact with light or other electromagnetic radiation. The term "cold" refers to its relatively slow motion, as opposed to "hot" dark matter that moves rapidly. The cold dark matter model postulates that the formation of large-scale structures in the universe, such as galaxies, is primarily driven by the gravitational pull of this cold dark matter.
So, to answer your question, the Milky Way is an example of the hierarchical model or the cold dark matter model of galaxy formation, where gas clouds collapse into small pieces and then merge into larger pieces due to gravity, with the influence of dark matter playing a significant role in the process.