Gravitational lensing is all the rage in astronomy right now. A confirmation of one of Einstein’s theories, the phenomenon has seen recent use in mapping dark matter and detecting exoplanets.
To avoid making myself look like the bluffer and layman enthusiast that I am, I’ll defer to the experts and let Phil “Bad Astronomy” Plait explain how gravitational lenses work, and point out that the Hubble telescope has just found a big new crop of them. [Image: NASA, ESA, C. Faure (Zentrum für Astronomie, University of Heidelberg) and J.P. Kneib (Laboratoire d’Astrophysique de Marseille)]
“Big deal,” you might be thinking. In which case, I’ll direct you to Centauri Dreams, where you’ll find an explanation of how the phenomenon might be used for the rapid propulsion of interstellar probes or (in the comments) communication between star systems.