The Vastness of Time ⏳
The Fermi question is usually about the vastness of space.
We often think about the vastness of space — measuring distances in units that our brains cannot comprehend (light years) and marveling at deep field photos taken by space telescopes that show countless galaxies, each with countless stars and planets. ✨🪐🔭
But I find the vastness of \time\ equally vertigo-inducing.
The question “Are we alone in the universe?” has the quality of being simple, but it hides the fact that we have to search through both space \and\ time.
A more useful question would be something like “Are we the only ones in this accessible region of the universe during our moment in time?”
We have only had the tech to be space-faring (and barely — we haven’t gone very far) for a few decades, which is nothing on a cosmic time scale. The same goes for the powerful telescopes and radio-telescopes that allow us to look beyond our own backyard (aka the Solar System).
If advanced intelligent civilizations are common and don’t all go radio-silent relatively quickly (either because they invent better ways to communicate than blasting radio-waves omnidirectionally, or for more sinister reasons), we might be able to identify the electromagnetic signature of intelligence out there.
But even if we do find something, the vastness of space will probably keep us isolated. Any ship or probe that we send would take so long to travel that by the time it got there, our own civilization may be gone or changed beyond recognition, or theirs may be gone, or both.
In the scenario where intelligent civilizations are rare in the universe, the vastness of time also makes things difficult; in order for civilizations to ever notice each other, they have to line up temporally.
The starry sky we see at night doesn’t show the universe as it \currently\ exists; instead, the farther we peer into space, the older the photons are by the time they reach our retinas or instruments, presenting us with an increasingly outdated view. We look at many stars that have long gone. It’s possible that we could detect signals of intelligence that belong to long-gone lifeforms.
Time is so vast that it’s easy to miss each other by millions of years. Even thousands of years may be enough for a civilization to rise and fall if things go wrong.
When thinking about our place in the cosmos, we have to consider:
Vastness of Space x Vastness of Time.
I know, it’s kind of a sci-fi shower thought, but it happens…
🧭 This first appeared in Edition 461 of Liberty’s Highlights. New here? I made a page for that: Start Here.
