Pinpointing the location of where the gravitational waves comes from is also a challenge. But deflected waves through gravitational lensing combined with machine learning could make it easier and more accurate. Just as the light from the SN Refsdal supernova was detected a second time almost a year after it was first discovered, due to gravitational lensing sending some of the light on a different path through the universe, the same approach could be used for gravitational waves. While still at an early stage, a technique similar to the triangulation used by cell phones to determine their location in relation to GPS satellites, will help astronomers tracking down the origin of the waves.