Dark matter remains one of the

Position 1: Despite decades of dedicated experiments, however, no particle candidate for dark matter has yet been conclusively detected.

Position 2: For instance, stars at the outer edges of spiral galaxies rotate far faster than Newtonian mechanics would predict if only visible mass were present.

Position 3: Dark matter remains one of the most perplexing unresolved problems in modern astronomy.

Position 4: This discrepancy led physicists to propose that an invisible form of matter accounts for approximately 27 percent of the universe's total mass-energy content.

Position 5: Although it cannot be directly observed, its gravitational effects on visible galaxies provide compelling indirect evidence for its existence.