Radio waves of 21-cm wavelength originate from which component of the interstellar medium? A) Ionized atomic hydrogen B) Neutral atomic hydrogen C) Carbon monoxide,CO D) Molecular hydrogen,H₂

Question

Quizplus · Accepted Answer

The radio waves of 21-cm wavelength originate from neutral atomic hydrogen, which emits radiation at that specific wavelength during the spin-flip transition of its electron's parallel and anti-parallel spin orientations. This emission is called the 21-cm line and is used by astronomers to map the distribution of neutral hydrogen in the interstellar medium. Ionized atomic hydrogen does not emit at this wavelength, carbon monoxide emits at different wavelengths, and molecular hydrogen does not emit radio waves in the radio frequency range.

Radio Waves of 21-Cm Wavelength Originate from Which Component of the Interstellar