Here's why:

* Definition: A solid angle is a measure of the amount of three-dimensional space "subtended" by an object at a given point. It's analogous to the concept of an angle in two dimensions, but instead of measuring a portion of a circle, it measures a portion of a sphere.

* Unit: Solid angles are measured in steradians (sr).

* No Direction: Solid angles don't have a direction associated with them. They only represent the "amount" of space an object covers from a particular perspective.

Think of it like this: Imagine a cone with its apex at your eye. The solid angle is the amount of space the cone encloses, regardless of which way the cone is pointing.