In 2016, a few months after LIGO had proven the existence of gravitational waves, Kelly Holley-Bockelmann, an astrophysicist at Vanderbilt University, gave a TEDx talk to the general public and shared her deep enthusiasm for gravitational waves, for black holes, and for LIGO. Her dress was designed and imprinted with a graph of the first wave detection, GW150914, and she had the audience stand up, form their arms in the shape of an interferometric L, and perform along with her a “LIGO wave” dance, which included a mimic of the now well-known “chirp.” Her 18-minute talk was spirited and profound; not only did Holley-Bockelmann succeed in teaching the audience how an interferometer works, and how long and complex the process to build the LIGO observatories was, but in about six slides, she was able to communicate the complex fabric of space-time and demonstrate LIGO’s exquisite sensitivity — detecting an event that occurred somewhere in the neighborhood of a billion years ago. LIGO, she said, was game-changing technology, and gravitational waves were the paradigm-shifting discovery of our generation, able to alter forever our fundamental thinking about the universe. (LIGO co-founders Rainer Weiss, Barry Barish, and Kip Thorne would later be awarded the Nobel Prize in physics in 2017.) Holley-Bockelmann’s final comment was this: That all mass, no matter how large or small — from colliding black holes to human beings — creates gravitational waves. And gravitational waves created by human actions, such as holding our children for the first time or dancing with a beloved, are written in space-time, imprinted on the universe, lasting long after we are gone. “Yes,” she said, “it turns out your actions do matter.” If you haven’t developed your own profound regard for LIGO, turn to Valerie Coffey’s article (read article). Then, check out Coherent’s piece on the NPRO (nonplanar ring oscillator) — a critical component of LIGO’s systems —(read article). And linger over GariLynn Billingsley’s exceptional August 2017 work with LIGO’s test masses (or mirrors) — some of the smoothest known (read article). When you’re done pondering the wonders of LIGO, check out Sean Garner’s article on the capabilities of flexible glass (read article), Hank Hogan’s piece on how optical coatings are responding to harsh-environment demands (read article), and Ken Dzurko’s feature on fiber lasers in industrial application (read article). Also, look for a new column in this issue — “Industry Insight” (read article) — which offers a look into high-level problems and solutions impacting the optics and photonics industries. With warm regards,