debunking BH myths

[notFritzArgelander]

https://phys.org/news/2019-08-black-holes.html

[Gfamily]

Not sure I'd agree with the last one. Hawking Radiation originates outside the EH.

I'd also say the second one is very likely a 'myth' that doesn't exist - at least, I've never heard say "of course, all BHs are the same size"

[notFritzArgelander]

Not sure I'd agree with the last one. Hawking Radiation originates outside the EH.

Your criticism is quite correct for a non rotating Schwarzschild BH. But most BHs rotate and have a double event horizon structure and energy can be extracted from between the two event horizons.

https://en.wikipedia.org/wiki/Ergosphere

The outer event horizon is where the time component of the metric becomes infinite. The inner horizon is where the radial component blows up.

https://en.wikipedia.org/wiki/Kerr_metr ... t_surfaces

I'd also say the second one is very likely a 'myth' that doesn't exist - at least, I've never heard say "of course, all BHs are the same size"

I've had people be astonished that a BH could be as large as the solar system, though. The path to get there is usually through confronting a different myth: "BHs are extremely dense". BHs can have densities as low as you want, the more mass the larger the BH (radius proportional to mass), and the less dense (density proportional to inverse mass squared). People freak out about a BH with the density of water that stretches out to about the orbit of Uranus....