Dark matter remains one of the

Position 1: Despite decades of research, however, no experiment has yet succeeded in detecting a dark matter particle directly, leaving its fundamental nature unresolved.

Position 2: Although it cannot be observed directly, its gravitational influence on visible galaxies provides compelling indirect evidence of its existence.

Position 3: Consequently, astronomers estimate that dark matter constitutes approximately 27 percent of the total mass-energy content of the universe.

Position 4: Dark matter remains one of the most perplexing unsolved problems in modern astronomy.

Position 5: For instance, stars at the outer edges of spiral galaxies rotate far too quickly to be held in orbit by visible mass alone, suggesting that an unseen mass must be present.