How did 'escape velocity' contribute to the idea of black holes?

the idea of black holes goes back a long

way actually back into the 1780s and

1790s and they were thinking in terms of

an idea called escape velocity the

escape Velocity is the speed you have to

travel to completely escape the

gravitational pull of something so for

the Earth for example the escape

Velocity from the surface of the Earth

is around 8 m a second if you go bigger

you make a bigger more massive thing

let's go to a star for example like the

sun it's somewhere in the region of 400

m a second the escape velocity increases

because the gravitational pull at the

surface

increases and if you go bigger can you

imagine more and more massive stars

giant Stars such that the gravitational

pull is so large at the surface that the

escape Velocity exceeds the speed of

light and then you wouldn't be able to

see

them