ABSTRACT
A fundamental consequence of Maxwell’s equations is that if a charged particle undergoes acceleration – changes its state of motion – it emits or absorbs electromagnetic (EM) radiation. Objects at non-zero temperature emit radiation due to the random thermal motions of the electric charges within them. The role of an observational astronomer is to measure the spatial, spectral, or polarimetric intensity from a source and then infer information on the physical nature of the source. An example in astrophysics is the radiation from dust grains in interstellar clouds. A charged particle moving in a magnetic field experiences magnetic force, and so undergoes an acceleration, leading to the emission of EM radiation. This is an important emission mechanism in astrophysics. The thermal vibration of the molecule is quantised such that only particular vibrational states are allowed, and transitions between the vibrational energy levels occur with photon emission or absorption.
