Dark matter is best described as which of the following?

Dark matter is best described as which of the following?

• A. A form of energy that travels through space
• B. Matter that does not give off electromagnetic radiation
• C. Visible matter that emits light
• D. Dark dust in interstellar space

Answer: (B)

Dark matter is best described as matter that does not give off electromagnetic radiation. In other words, it has mass and gravity, but it remains invisible because it does not emit, absorb, or reflect light or other forms of electromagnetic radiation that we can detect. We infer its presence from gravitational effects on visible matter, light, and the universe’s structure: galaxies rotate too fast for the amount of visible matter they contain, gravitational lensing reveals more mass than we can see, and the patterns in the cosmic microwave background point to unseen matter shaping early cosmic structures. It is distinct from energy, from visible matter that glows, or from dust that would interact with light and be detectable in other ways.

Dark matter is best described as matter that does not give off electromagnetic radiation. In other words, it has mass and gravity, but it remains invisible because it does not emit, absorb, or reflect light or other forms of electromagnetic radiation that we can detect. We infer its presence from gravitational effects on visible matter, light, and the universe’s structure: galaxies rotate too fast for the amount of visible matter they contain, gravitational lensing reveals more mass than we can see, and the patterns in the cosmic microwave background point to unseen matter shaping early cosmic structures. It is distinct from energy, from visible matter that glows, or from dust that would interact with light and be detectable in other ways.