7.5 billion light years away and the can confidently state the black hole is 20 million times more massive than our sun...
I fight hard not to be taking in by these morons... Sensationalism drives the reporting class to the extreme...
It’s actually well-established astronomical science to measure the mass of a black hole at great distances.
One can measure the mass of a black hole by tracing the motion of the gas and dust near the black hole that is being pulled-on by the mass of the black hole.
This can be done at many wavelengths, such as by measuring the positions of stars which orbit near a black hole at optical wavelengths.
At radio wavelengths, we can measure the emission from a specific type of emission from the water (H2O) molecule, which occurs at radio wavelengths, to trace the motions of the gas circling the black hole.