Dark matter remains one of the

Position 1: Despite decades of research, however, no experiment has yet succeeded in detecting a dark matter particle under laboratory conditions.

Position 2: Although it cannot be observed directly, its gravitational effects on visible galaxies provide compelling indirect evidence for 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: These effects include the anomalous rotation curves of spiral galaxies, which spin far too quickly at their outer edges to be explained by ordinary matter alone.