- #1
bunburryist
- 36
- 2
Question about "pressure" in GR
On
http://math.ucr.edu/home/baez/einstein/node3.html
it says
"Given a small ball of freely falling test particles initially at rest with respect to each other, the rate at which it begins to shrink is proportional to its volume times: the energy density at the center of the ball plus three times the pressure at that point.
What is meant by "pressure" here? Why is it three times the pressure?
On
http://math.ucr.edu/home/baez/einstein/node3.html
it says
"Given a small ball of freely falling test particles initially at rest with respect to each other, the rate at which it begins to shrink is proportional to its volume times: the energy density at the center of the ball plus three times the pressure at that point.
What is meant by "pressure" here? Why is it three times the pressure?