Final answer:
The Big Bang theory requires dark matter to explain the formation of galaxies and their structural properties. Physicists are using detectors both on Earth and in space to search for signs of dark matter particles, with cold dark matter being the main theoretical proposal for its composition.
Step-by-step explanation:
The Big Bang theory suggests that during the early universe, there were fluctuations in density that served as 'seeds' for the formation of galaxies. To account for the observed rate at which these structures formed, as well as characteristics such as the rotation curves of galaxies, cosmologists propose that a significant amount of dark matter must exist. This invisible matter does not interact with electromagnetic radiation, making it difficult to detect directly. However, its gravitational effects on visible matter, radiation, and the structure of the universe provide evidence for its existence.
Physicists are using a variety of methods to detect dark matter. These include searching for weakly interacting massive particles (WIMPs) with detectors deep underground, which shield the experiments from cosmic rays, and looking for signals in space-based observatories that could indicate the annihilation or decay of dark matter particles.
Cold dark matter, a slow-moving type of dark matter, is currently the leading theoretical candidate, and efforts to refine our understanding of dark matter through cosmological observations and particle physics continue to play a vital role in modern astrophysics.