What if this whole cycle, of evolving and building a civilization (humans invent calculus and pizza) and destroying a civilization (humans create global warming and the Kardashians) happened before? Repeatedly. And not in outer space, but here on Earth.
It’s not impossible, says a paper published in the International Journal of Astrobiology in April called “The Silurian hypothesis: would it be possible to detect an industrial civilization in the geological record?”
Silurians, as all good “Dr. Who” fans know, are a race of intelligent, walking reptiles who first popped up in a 1970 episode. According to the story, they had evolved on Earth about 400 million years ago.
Could something like that have really happened without us knowing now? Sure, according to the piece, by Adam Frank, a professor of physics and astronomy at the University of Rochester, and Gavin Schmidt, director of the NASA Goddard Institute for Space Studies.
We wouldn’t know, because nothing is forever. Not even cigarette butts and 8-track tapes of Toto’s greatest hits.
The Earth is about 3.5 billion years old. The best guess is that no artifact or obvious aspect of a civilization like ours could be found or recognized 4 million years after we do ourselves in.
That means the Earth has been here almost long enough for all evidence of an intelligent civilization to have disappeared 1,000 times over. At 2,000 years old, the Roman Colosseum is falling down. When that amount of time has passed 2,000 times, it will just be sand.
Have there been other intelligent civilizations on Earth? Well, since the paper says there wouldn’t be any evidence, that’s an open question. Except it doesn’t quite say there wouldn’t be any evidence. The purpose of the paper, once it gets past the sexy Silurian storyline, is exploring how we’d find evidence of a civilization like ours millions of years after we eat our last Twinkie.
There could be minute traces of fallout from nuclear weapons. Microscopic evidence in the geological record of how we altered carbon by burning fossil fuel. Evidence of commercial farming processes changing the nitrogen balance. Plastic molecules.
It’s fascinating, but daydreaming about long-dead civilizations on Earth, just like daydreaming about civilizations a million light years away, is just the first step of the puzzle. Far more compelling is what such civilizations would tell us about the meaning of life.
What would it mean, for instance, if we were able to communicate with a far-off civilization or a long-dead one and the first message we decoded said “Have you heard the good news about Jesus Christ?”
What would it mean if they hadn’t heard of him?
The spans of space and the sands of time do make arguments over marginal tax rates and fury over who Aunt Grace intended to will her 2003 Toyota Camry to seem petty. We will all die. All evidence that we or anyone we loved or hated ever lived will fade to dust. The dust will fade to atoms.
To live properly, we must know life has meaning. But if it all fades to nothing in the end, the meaning has to be in the effect our good and bad thoughts and good and bad actions have in the moment.
The pain we cause when we behave badly, and the good we cause when we act with love, charity, kindness and courage are real, tangible, and the meaning of life. God or no God. Silurians or no Silurians.
Assuming that the first evidence we find of another civilization is not a decoded message that reads “Have you heard the good news about ‘Keeping Up With the Kardashians?’ ” Then all bets are off.
Lane Filler is a member of Newsday’s editorial board.