The Effect of Fluctuations in the Observer’s Frame of Reference on Blackbody Radiation

This paper describes how the characteristics of blackbody radiation are affected by the observer’s frame of reference (OFR). To date, the specific intensity of a photon emitted by a blackbody has been studied based on the assumption that the OFR remains constant throughout the performance of measurements of the specific intensity; thus, how much the specific intensity of the photon is affected by fluctuations in the OFR remains unknown. In this paper, the specific intensity of a photon emitted by a blackbody is considered as the OFR fluctuates. The average specific intensity of a photon is formulated for two types of variations in the OFR with time: periodic square-wave and periodic sawtooth fluctuations. For these two types of fluctuations, the average specific intensity of a photon that has a frequency much higher than that corresponding to the amplitude of the changes in the OFR is found to be always lower than for a stationary OFR. It is also found that the average specific intensity is inversely proportional to the temperature in the limit that the temperature is much higher than that corresponding to the amplitude of these changes. The average specific intensity of a photon in a fluctuating OFR could be used to explain the characteristics of the cosmic microwave background radiation as observed by an observer located in the cosmic background.