Astronomers Detect a Possible Signature of Life on a Distant Planet

This is unsettling. If we are not the only intelligent beings in the universe, it adds credence to the idea of a "great filter."

https://en.wikipedia.org/wiki/Great_Filter

The Great Filter hypothesis is based on an analogy with the European conquest of the globe in the 19th century. Little by little all the white spots on the map were first explored, then annexed. The (unspoken) parallel is that an advanced civilization would explore and conquer the entire galaxy. But even if a civilization could achieve interstellar travel capabilities, it is entirely possible that they colonize, let's say, only 80% of the galaxy, not 100%. Or maybe only 50% or 10%. If our solar system is in the complement of their zone, how would we know they are out there. How would we know there are aliens around Alpha Centauri, let's say. They could be busy living their lives, broadcasting in all the regions of the radio spectrum with abandon, maybe even nuking each other from time to time. And we would just hear absolute silence. The distances between stars are just so mind-bogglingly huge.

Infinite expansionism is just one of a whole tower of assumptions that underlie the Fermi paradox. It’s a good thought experiment and does rule out certain scenarios with ET life but beyond that it’s a speculation.

The main scenario it rules out is one where intelligent ET life is common and we are late to the party. I feel like both those things can’t be true or we would see evidence.

I do find it fun to think about because it unfolds under scrutiny into such a vast tree of possibilities. But that same huge tree of possibilities makes it hard to say much.

One of my favorite wild speculations is that there is somewhere more interesting to go than space, and more accessible, and eventually whatever that is gets found before starships get built. What could that be? A traversable multiverse maybe?

That belongs to a subset of scenarios I call “positive great filters.” That’s where the great filter is a big success that renders space flight unimportant or uninteresting but does not result in extinction.

What about hyper-miniaturization. Maybe you can have something the size and scope of a galactic civilization without leaving home by folding your minds and everything else up into quantum states or hidden extra dimensions. Think a civilization of “sophons” (three body problem reference) with trillions upon trillions of minds occupying a few square meters of space and consuming a few hundred watts.

Yet another is some kind of remote sensing that lets you explore without physically moving, like a real equivalent to remote viewing. There’s a sci-fi novel called Blind Lake about this. Combine with miniaturized super efficient information processing and you could have superintelligences that explore everywhere and learn everything without going anywhere.

Lots of speculations and possibilities if you allow for the fact that we’ve only been doing science seriously for about 150 years and surely do not know everything.

> The main scenario it rules out is one where intelligent ET life is common and we are late to the party. I feel like both those things can’t be true or we would see evidence.

There are a thousand scenarios where those things are true, e.g. the Zoo/Planetarium Hypothesis, but they tend to result in the conclusion that we're being somehow manipulated and can't trust our observations, so they're strongly disfavored on scientific grounds... Which does not rule them out.