We might actually have been watching that at the same time, assuming you posted shortly after watching. Can't say precisely what time I saw that but it was a few hours ago!

I mean, there's a whole universe out there we can't see. That much we already know. Dark matter is basically "stuff with gravity that we otherwise can't see". Find a more concise definition than that!

What kinda fascinates me is the thought that to dark matter aliens, we're the dark matter. They'd look at their galaxies and think "there's something wrong with this picture". They know we're here because they can see our gravitational effect, but they can't see us. They don't even know that we have a whole variety of elements, molecules, planets, stars, life. We're just stuff, a theory, a mathematical mystery.

How do you send Morse code by using gravitational waves? We can say hello that way.