TIL that black holes were first predicted based on Newtonian physics

https://en.wikipedia.org/wiki/Black_hole#History

The idea of a body so massive that even light could not escape was first proposed in the late 18th century by English astronomer and clergyman John Michell and independently by French scientist Pierre-Simon Laplace. Both scholars proposed very large stars in contrast to the modern concept of an extremely dense object.

Michell's idea, in a short part of a letter published in 1784,[6] calculated that a star with the same density but 500 times the radius of the sun would not let any emitted light escape; the surface escape velocity would exceed the speed of light.

what's funny is that he even got the radius (schwarzschild-radius) right. just plug in c for the escape velocity and you get the schwarzschild-radius.

95 points · 4 comments · view on lemmy.world

4 Comments

bright@piefed.social · 8 pts · 61d (1 reply)

But i think back then they didn't know that light had mass

Light doesn't have mass. I have no idea what I'm talking about.

valar@lemmy.ca · 13 pts · 61d

You're right that they didn't know gravity would impact massless objects though.

YaksDC@sh.itjust.works · 6 pts · 61d

In case you wanted to know where this image came from: https://www.nsf.gov/news/media-toolkits/event-horizon-telescope

random_character_a@lemmy.world · 1 pts · 61d

Michell had an idea, but it waan't Newtonian