After the transition to digital TV our broadcasted signals mostly look like noise, though. Maybe an outside observer would assume that our civilization ended sometime in 2010.
Analogue TV would not be much better. How would the aliens know they're supposed to shoot an electron raygun left-to-right 486 times across a screen, then ignore the next 39 lines, then repeat this 29.97 times a second? And that's before you get into interlacing, horizontal blanking intervals, line 21, luma and chroma (encoded by reference to human eyesight), or different standards altogether like PAL or SECAM, etc.
Analogue TV has always felt so much more clever than digital TV to me, at least from a purely technical standpoint. I guess that's because we're mostly digital natives now, so video codecs seem ordinary and programmable electron rayguns do not.
You can still see from far away that our planet's atmosphere has a very unusual chemical composition that's far out of equilibrium.
We are already using spectroscopy to gain insights into the chemical composition of exo-planets, and we have barely begun doing this kind of research. In even just a few decades we'll be massively better at this.
Analogue TV has always felt so much more clever than digital TV to me, at least from a purely technical standpoint. I guess that's because we're mostly digital natives now, so video codecs seem ordinary and programmable electron rayguns do not.