[johnnyanmac]

I mean, when you put it that way black holes as a whole are a mere theory. A theory used to explain gravitational fluctuations and the odd lack of mass in the universe (which still wasn't fully solved and are currently dabbling with dark matter to further fine tune results).

[shiroiushi]

Except we've actually photographed a black hole: https://science.nasa.gov/resource/first-image-of-a-black-hol...