Let’s take a journey back to a simpler time, back when living was easy and the world was perfect. Mind you, this is long before the contemporary wonders of instant communication, the eradication of small pox and the invention of polypropylene. This is also before the centuries of near-constant war, a millennium of cultural upheaval; long before Palestinian, Greek, and Egyptian cults were inventing one puritanical Jesus after the next. This journey back to the golden age will show us that time before the Chinese invented writing — 8,000 years ago — before Neanderthal hybrids were painting elk and bison on cave walls, 50,000 years ago. It will be long before we might stumble across some tyrannosaurus Rex preening her fluffy feathers after luxuriously munching on yet another edmontosaurus. Not a man in sight! Not a single mammal in sight, for that matter.
If you really want the best of simple times, you will want to return to Proterozoic: Two billion years of sweet, sweet nothing. Just the occasional glacial sheets extending to the equator for several million years before retreating again for a several million more.
Then again, a truly original state, the Archean eon, was about as original as you could ever possibly get while still having what passes for a solid and round planet. Oh, those were the days…
All of this talk about pristine times and the good old days make me wonder how this little planet of ours, covered in ice, might have looked to an observer.
Imagine you are a career astronomer living on a nearby planetary system.
Or, not so near, by the standard of distance within a solar system. Not so far, either. In the same galaxy. Maybe your planet is quite far from the center of the galaxy, out on the Perseus transit or, further still, on the furthest reaches of an outer arm of the galaxy.
Most importantly, it is two billion years ago.
You are living your life and doing what everyone else does from day to day. But, not so typically, you spend your nights huddled in some observatory at ridiculously high altitudes, far away from your coastal home. Every 420 days, your planet’s little orbit comes around to a vista in which the night view points mostly toward the center of the galaxy and every night, during this part of the year, you spend working on a special project.
People had discovered, a century before, that neighboring stars had planets, but your fame was for the discovery of a particularly far away planetary system, farther away, in fact, than had ever been seen to date. You had been lucky enough to discover that there were more planets on that system than the four monstrous planets observed a few years before. It would seem that star anchored not just the now well-known four giant gas planets, one of them blue, one with a quite prominent ring. At least two rocky planets, just like your own little world, orbited closer to its sun than the four giant gas planets.
You have often wondered to yourself whether life could exist and whether it would ever be discovered anywhere else in the galaxy, especially in there, so far in toward the center of the galaxy, and whether it was possible that this younger system might show some signs or possibility of life. Many observations done over a span of years showed that the second or third planet was completely locked in ice, stem to stern. It is too impossible. You can’t help but wonder, if that planet were just a little warmer, like yours, out here in the furthest reaches, where it was obviously a more hospitable part of the galaxy with mature and stable stars…
That imaginary astronomer would be long gone by now. As would that astronomer’s descendants, their descendants and a thousand empires which may have risen and fallen. It seems likely to me that their planet would have been struck by an asteroid or they would have destroyed themselves with war or perhaps their mature sun would have long ago swelled and consumed their planet. Who knows.
Back then, they would have had no way to know that that distant ice planet would turn out to be very much like theirs. They saw an ice covered rock with no life and thought they were alone in the universe. Even now, from our vantage point here on the very planet they watched, we can scarcely imagine that some distant and swollen main sequence star may have once carried a whole planet full of expectations, now silenced forever.