How Do You Calculate the Rate of Heat Flow Outward Across a Star's Surface?

[colinlovesmath]

The temperature in a star of conductivity 1 is inversely proportional to the distance from the center: u=7/(sqrt(x^2+y^2+z^2).
If the star is a sphere of radius 3, find the rate of heat flow outward across the surface of the star.

Not sure where to even start.

 

[EnumaElish]

Put the center at (0,0,0). The temp at the center is infinite (can you see why?)

What is the distance of any point on the surface to the center?

 

[colinlovesmath]

I understand that, the distance of any point on the surface to the center is 3 (the radius). But how do I use gauss Law or whatever?