
The opening chapter of an incredible adventure includes the destruction of Earth by ten thousand relativistic bombs launched by an alien race in a science fiction thriller and follows the desperate struggles of the remnants of humankind to survive in a hostile universe.
Intentionally signaling to aliens is one of the stupidest ideas I can think of. The Killing Star by Charles Pellegrino and George Zebrowski has a good analogy (longer quote here: http://www.projectrho.com/public_html/rocket/aliencontact.ph... ), describing a thought experiment of surviving the night in a crime-ridden Central Park:
"How do you survive the night? The last thing you want to do is shout, "I'm here!" The next to last thing you want to do is reply to someone who shouts, "I'm a friend!"
What you would like to do is find a policeman, or get out of the park. But you don't want to make noise or move towards a light where you might be spotted, and it is difficult to find either a policeman or your way out without making yourself known. Your safest option is to hunker down and wait for daylight, then safely walk out.
There are, of course, a few obvious differences between Central Park and the universe.
There is no policeman.
There is no way out.
And the night never ends."
[0] https://www.hakaimagazine.com/features/fish-feel-pain-now-wh...