What does the presence of dark matter imply about the universe's structure?

The presence of dark matter implies that the universe has a complex structure that includes hidden mass. Dark matter is a form of matter that does not emit, absorb, or reflect light, making it invisible and undetectable by conventional means. However, its existence is inferred through its gravitational effects on visible matter, radiation, and the large-scale structure of the universe.

Observations, such as the rotation curves of galaxies, reveal that stars in the outer regions of galaxies move faster than expected based on the visible matter alone. This discrepancy indicates that there must be additional, unseen mass contributing to the gravitational pull—this is attributed to dark matter.

Additionally, studies of the cosmic microwave background radiation and the distribution of galaxies throughout the universe further support the idea that dark matter plays a significant role in the universe's overall composition and structure. The concept of dark matter indicates there is more to the universe than what can be observed directly, highlighting its complex nature with components that are not immediately visible.