Gravitational Lensing Question
A massive object between a light source and an observer, bends the light. since the observer assumes light flows in straight lines, the position of the source appears to have moved. In the most extreme scenario, the apparent position of a source directly behind the mass, would be peripheral, to the far left, right, top or bottom.
Q: What happens if there is enough mass surrounding the object so that the light curls back on itself before reaching the observer?