What characteristic defines ordinary (baryonic) matter, allowing scientists to detect it across the electromagnetic spectrum?

Answer

Ability to emit, absorb, or reflect electromagnetic radiation

Ordinary matter is defined by its interaction with light; it possesses the property of emitting, absorbing, or reflecting electromagnetic radiation, which allows for its detection via telescopes.

What characteristic defines ordinary (baryonic) matter, allowing scientists to detect it across the electromagnetic spectrum?
universematterdark matterdark energycomponent