Redshift and Blueshift Analysis

The systematic redshift observed for distant celestial objects is commonly attributed to the expansion of cosmic space in mainstream interpretations. This paper adopts the perspective of the Light Origin Theory to analyze the rules governing energy exchange for photons propagating across cosmic space. Within a photon beam emitted by a single source some photons undergo no effective collisions with matter particles along their path and retain their original emission energy forming a natural reference standard. Photons that experience collisions under normal conditions transfer part of their energy to matter particles and lose energy. High energy gamma photons may also gradually lose energy during propagation. Even after multiple energy reduction events their remaining energy can still exceed the expected energy level of hydrogen atomic spectral lines which easily leads to misidentification of spectral signals. While the possibility of photons gaining energy during propagation is not zero its probability is far lower than the probability of energy loss. Photon photon collisions that produce energy gain are extremely rare in ordinary interstellar space and energy gain effects mainly appear in localized extreme high energy regions such as black hole jets. A small number of high frequency signals observed in spectra do not represent blueshift caused by energy gain along the travel path. Such signals may come from inherent high energy radiation or gamma photons that retain a relatively high energy level after partial energy loss and are mistakenly labeled as blueshift. Apparent blueshift seen in observations of nearby sources partly comes from the Doppler effect when an object moves toward the observer and partly arises from confusion in identifying spectral components. This paper also points out a fundamental physical contradiction in the space expansion hypothesis. Photons are discrete energy particles not continuous waves with extended tails so they cannot be stretched by space to change their energy. Even if the expansion hypothesis is assumed to hold it cannot explain the spectral distribution where some photons remain unchanged while others lose energy within the same batch. Hydrogen accounts for the largest fraction of baryonic matter in the universe and radiation emitted by hydrogen atoms forms the main component of observed radiation. Long distance propagation brings cumulative collision effects that produce net energy loss and create the statistical trend that redshift grows stronger with distance. For a long time redshift and blueshift judgments have been confined within fixed preset frameworks and many underlying assumptions lack repeated verification and critical examination. This proposed mechanism does not rely on the assumption of cosmic expansion. It can be tested through future observations numerical simulations and artificial intelligence driven deduction.