The headline was, “What does Earth look like from across the Universe?” Of course, I replied, “I dunno. Like images of broken light, which dance before me like a million eyes?”
But the thing was, it was a good article, and worth reading. Based on the fact that the farther away something is in space, the farther back in time you’re looking when you see it. Because, you know, even though light is known for its celerity, it does observe a speed limit.
Of course, when Steward Brand finally got his picture of Earth from space, the time factor involved was too small to be interesting. But if somebody’s looking at us from as far away as we ourselves have recently gained the ability to look, it gets interesting.
So he calculated what would have been happening on Earth when seen from various cosmic distances. For instance, seen from Sirius, it would be February 2014 and Barack Obama would still be president. Which would be nice. Any time we could go back to before 2016 would be nice in the same way.
But my fave distance was the one that seems most relevant and likely (using “likely” loosely): from “TOI 700, the first stellar system with an Earth-sized exoplanet discovered in its habitable zone.” An excerpt:
On this world, Earth appears as it does just after the end of the year 1920. The very first radio broadcasts from our planet are just arriving in the TOI 700 system, beginning with station 8MK from Detroit, Michigan. The CO2 levels in Earth’s atmosphere have barely crested the 300 parts-per-million level, sitting at 303. The beginning of the transformation of our atmosphere from industrial activity would be detectable from this exoplanet. 85% of Earth’s surface is still wilderness; only 15% has been modified, largely for food production. Earth is definitely inhabited, and the first signatures that a technologically advanced species lives upon it are appearing. A round-trip message would take more than 2 centuries; in a single human lifetime, you’d never live to hear a response to a sent message….
After that, the distances get so great that you’re talking times when Neanderthals walked the Earth, or before any of the Homo species did, or even before there was an Earth to walk on. All of which are a little harder to identify with. I mean, I may be getting old, but I don’t know anybody who was around then.
No, I don’t have any big point to make, beyond the one I made casually in the headline. I just thought it an interesting intellectual exercise, and thought you might, too…