The black hole concerned in this instance is at the heart of the Milky Way galaxy, our very own. At http://phys.org/print385979471.html … we are told that at the heart of the Milky Way there is a supermassive black hole – which is quiet. However, it is faint – probably because it is not accreting material, unlike some way out in the universe which have been captured on modern telescopes. It is also faint, we are told, because it is shrouded in dust and clouds of gas.
At https://eos.org/research-spotlights/how-accurate-are-ionospheric-models … which is taken from the Journal of Geophysical Research: Space Physics where it makes the point that understanding the ionosphere is just as important as understanding other parts of the atmosphere and near space. It is a bubble of plasma surrounding the Earth.