Throwing A Little Darkness On The Subject
Now that we have some ideas about how ordinary stars function how can we learn more about special stars like black holes?
The concept of a black hole is by no means a new one. Mankind has pondered their existence for well over 2 centuries. By the 18th century, educated men in Europe were well familiar with Isaac Newton’s laws of gravity. Surely the rules of gravity would have to apply inside the internal structures of stars just like everywhere else.
In 1783, an Englishman named John Mitchell took this logic to a bold new idea. Mitchell knew that the escape velocity from a star was proportional to the square root of the star’s mass divided by its circumference.
Mitchell reasoned that once a star’s size shrinks to a critical circumference, the “corpuscles” of light, (using 18th century terminology), would not be able to escape the star’s gravity. The star should just “wink out.”
At about the same time a French scientist named Pierre Simon Laplace, working independently of Mitchell, came up with the same conclusion in his work Le Systeme du Monde.
What were these things they called “Dark Stars” and how did they behave? Did they “shine dark”? Were they giant cannonballs of super dense matter? Were they real or just silly extrapolations of Newtonian theory?
At the time men’s ability to do research on these questions was limited by the lack of understanding of what light really was. Laplace seemed to realize this when Christian Huygens renovated the “corpuscle” theory of light.
Light, Huygens argued, was not made of particles called “corpuscles,” but of waves. So the escape velocity of light particles seemed to be a moot subject and Laplace abandoned his idea of “Dark Stars.”
It would be another century before scientists would entertain the idea of light’s duality. But a couple of other things had to be settled before men could say a star’s escape velocity exceeded the speed of light. What was the speed of light? Could the speed be altered in any shape or form?
To approach this mystery we can begin a subject touched on in the 1600’s by Galileo – Frame of Reference.