Originally Posted by

**tecne** I have a question regarding the connection between two solid angles. Let assume a solid angle Q and another solid angle F on the surface of two spheres. One sphere has a unit radius and the other sphere has some other radius bigger than one. Therefore the solid angle subtended by a surface area on the sphere of larger radius should be smaller than the solid angle subtended by the surface area on the sphere with radius=1. **I assume that the surface area is common to both spheres**. What is the connection between the two solid angles?

**In other words how can I express the solid angle of Q (bigger radius) in terms of the solid angle of F(unit radius)?**