How does the atmosphere affect radio waves at very long wavelengths?

At very long wavelengths, radio waves are significantly distorted by Earth’s ionosphere. This region, which consists of ionized layers of the atmosphere, acts as a barrier that prevents many long-wavelength signals from deep space from reaching ground-based radio telescopes.12

Because of this atmospheric interference, astronomers often utilize Earth-orbiting satellites to conduct observations at these wavelengths, as they are difficult or impossible to perform from the ground. While radio waves above 40 MHz can generally penetrate the atmosphere to reach ground-based instruments, the ionosphere’s tendency to bend, reflect, or distort signals at lower frequencies necessitates space-based platforms for accurate astronomical study.12