1. Given $P A 、 P B 、 P C$ are three non-coplanar rays emanating from point $P$, and the angle between any two rays is $60^{\circ}$. There is a sphere with a radius of 1 that is tangent to all three rays. Find the distance from the center of the sphere $O$ to point $P$.
Consider the three face diagonals originating from a vertex of the cube, thus, the center of the sphere in the problem is the center of the inscribed sphere of the cube. $O P=\sqrt{3}$.