The mainstream used Newton’s formula (and its variations from Einstein and Schwarzschild) for gravitational acceleration a = G×M/R², circular velocity v = sqrt(G×M/R), and escape velocity ev = sqrt(2G×M/R), to say that for a massive and dense stellar object of great mass M and small radius R, escape velocity ev exceeds the speed of light c. But since velocities beyond the universal c-speed-limit are unachievable, that means nothing can escape such a dense object’s vicinity. That is how Black Holes appeared on paper, then on images. Problem with such explanation: time in such Black Holes stops, but time stopping requires infinite energy.
What was it like when supermassive black holes arose?
One of the biggest challenges for modern astrophysics is to describe how the Universe went from a uniform place without planets, stars, or galaxies…