https://motherboard.vice.com/en_us/article/zmdbjj/aliens-might-notice-us-if-we-shot-a-giant-laser-at-them-study-says

Scientists have detected many exoplanets that could host liquid water—the key ingredient for life as we know it. But let’s say our wildest hopes (or worst nightmares) are true, and there are alien lifeforms inhabiting nearby worlds. How would we contact them across distances of several light years?

One way to get the attention of local ETs is to shoot a giant laser at them, according to a study published Monday in The Astrophysical Journal and authored by James Clark, a graduate student at MIT’s department of aeronautics and astronautics, along with MIT professor Kerri Cahoy.