The correct answer is dark matter. Dark matter cannot be observed directly, as it does not emit, absorb, or reflect light. Instead, its existence is inferred through its gravitational effects on visible matter, such as galaxies and galaxy clusters. Scientists observe how galaxies rotate and how they interact with each other to deduce the presence and influence of dark matter in the universe.
What can be observed only by observing its effects on gravity?
dark matter
a solar nebula
gas and dust
a planetesimal
1 answer
1 answer