A "black hole" is created when a star collapses to such asmallradius that the gravitational force at its surface becomessostrong that not even light can escape. This radius is calledtheSchwarzchild radius in honor of Karl Schwarzchildwhofirst solved the equations of General Relativity and showedthatblack holes could exist, at least in theory. Although thepropercalculation requires knowledge of General Relativity,interestinglywe can derive the correct Schwarzchild radius by doingacalculation using classical physics*. That is,you'lluse the equation we derived in class and solve for theSchwarzchildradius assuming that the escape velocity equals thespeed oflight.
What is the Schwarzchild radius for a star of mass M =1.10x 1030kg? (this star iscomparable in mass to ourSun).
1 m
Find the density of such a black hole
2 kg/m3
* The reason the classical calculation yields thecorrectanswer is there are are two errors that are made that"cancel" eachother out and fortuitously give the same answer asthe full,propercalculation using general relativity.
A "black hole" is created when a star collapses to such asmallradius that the gravitational force at its surface becomessostrong that not even light can escape. This radius is calledtheSchwarzchild radius in honor of Karl Schwarzchildwhofirst solved the equations of General Relativity and showedthatblack holes could exist, at least in theory. Although thepropercalculation requires knowledge of General Relativity,interestinglywe can derive the correct Schwarzchild radius by doingacalculation using classical physics*. That is,you'lluse the equation we derived in class and solve for theSchwarzchildradius assuming that the escape velocity equals thespeed oflight.
What is the Schwarzchild radius for a star of mass M =1.10x 1030kg? (this star iscomparable in mass to ourSun).
1 m
Find the density of such a black hole
2 kg/m3
* The reason the classical calculation yields thecorrectanswer is there are are two errors that are made that"cancel" eachother out and fortuitously give the same answer asthe full,propercalculation using general relativity.
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