What are the two broad categories light reaching an observer in the universe can be divided into?
Answer
Emitted light and reflected light
Light that travels across the cosmos and reaches an observer can be classified into two fundamental categories based on its origin. The first is emitted light, which is light generated intrinsically by a source itself, such as the light produced by stars through nuclear fusion. The second category is reflected light. Objects like planets, moons, and asteroids lack the necessary internal furnace for fusion; therefore, the light observed coming from them is purely sunlight that has struck their surfaces and bounced off, acting like passive mirrors directing a portion of their parent star's energy back into space.
Related Questions
What is the defining mechanism causing a star to generate light and heat energy?What critical temperature must the core reach to force hydrogen nuclei to fuse?What celestial object forms if fusion fails below the mass threshold required for true stars?Which famous equation quantifies the mass converted into energy during stellar fusion?What type of high-energy photon initially results from fusion in the star's core?What are the three primary forms of energy emerging from the star's photosphere?What value represents the measured luminosity output of our Sun?How does the intensity of light received diminish as distance from a star increases?What are the two broad categories light reaching an observer in the universe can be divided into?What is the primary source dominating the energy striking Earth from non-terrestrial sources?What is the intrinsic energy output capability of a star fixed by, according to its observable properties?