Is anyone out there?
The Webb telescope is showing us ever-more remote places, but there's no sign that anyone is looking back at us.
SMACS 0723: Red arcs in the image trace light from galaxies in the very early Universe
Webb’s First Deep Field image shows us the thousands of galaxies that exist in a tiny, faraway sliver of the universe. Our own Milky Way Galaxy has an estimated 200–400 billion stars, with billions more planets circling them. That tiny, faraway sliver must also hold billions of planets. But there's no sign that anyone is looking back at us.
Where are they?
The Fermi paradox has been asking this since the mid-1950's. The scale of the universe and simple probability seem to indicate that intelligent life should be common. But, as far as we can tell, it's not.
All life seeks to expand. We did this by colonizing new habitats on Earth. Many of us hope that in the future, we'll go on to colonize our own galaxy, and, subsequently, the surrounding star system. Using technology that's is almost within our reach, it would probably take us about five to fifty million years to colonize this galaxy. That seems kind of slow, but it's a short time on the cosmological scale. If we could do it, why isn't there evidence that someone else did it too?
We should also note that we got to the moon and then, inexplicably, stopped and went back home. If other civilizations stalled in similar ways, they might not have travelled far. But at least we've sent probes out, like Voyagers 1 & 2. The least adventurous forms of intelligent life out there would also have left some evidence of their existence.
We might be Evolution's side gig
One problem with our expectations is projection. We expect intelligent life to be like us in size, in chemical composition, communication methods. We expect them to be what we would like to be in the future. Maybe like the super-intelligent beings in Asimov's 'Foundation' series, beings who look like us but are so much cooler, building powerful structures, ruling galaxies and all that. Unfortunately, our current bodies, ambitions and dreams might just be a short pit stop in the long road trip of evolution.
As Carl Sagan said:
"We are the product of 4.5 billion years of fortuitous, slow biological evolution. There is no reason to think that the evolutionary process has stopped. Man is a transitional animal. He is not the climax of creation."
In his short story (and film, below) "They're Made out of Meat", Terry Bisson answers Fermi's Paradox with a short fictional story about aliens who are looking to make First Contact with Earth.
Their constant probing reveals that humans are sentient meat. Since these aliens are machines, they're horrified by this discovery. All-meat beings do not exist anywhere else in their Quadrant. And Sentient Meat is unheard of.
Officially, they're required to welcome all sentient beings & multi-beings to their fold, but they just can't bear to deal with Sentient Meat. Fortunately, they know that meat can't travel far.
"They can travel to other planets in special meat containers, but they can't live on them. And being meat, they only travel through C space. Which limits them to the speed of light and makes the possibility of their ever making contact pretty slim. Infinitesimal, in fact."
They decide to erase all records of contact and forget the whole thing.
Bisson is evasive about what type of machines these are, but since interstellar travel is their thing, they could be probably be on the level of the beings in Asimov's Foundations, creating huge megastructures that can power ships that blast past the speed of light. They'd be Level II or III on the Kardashev scale, a method of measuring a civilization's level of technological advancement based on the amount of energy it is able to use.
According to this scale, a Type III civilization possesses "energy at the scale of its own galaxy." Type II is capable of harnessing the energy radiated by its own star, perhaps with a ginormous, sun-covering mega-structure like a Dyson sphere.
And, last and least, there's the Type I civilization, which is the closest to our level. But we haven't even reached that mark yet. We're about four orders of magnitude below the cut. And it's not clear how much progress we'll make. The type of civilization that will bring its entire economy and social structure to a screeching halt because it's afraid of a virus is not very bold. But, strangely enough, our COVID disaster offers some hope.
From the very large to the very small
While we haven't gotten very far at building large scale projects in space, we have learned a lot about very small scale things like nuclear fission, nanotech and genetics.
There is an alternative to the Kardashev scale -- John Barrow's "Microdimensional mastery" reverse classification, from Type I-minus to Type Omega-minus:
Type II-minus is capable of manipulating genes and altering the development of living things, transplanting or replacing parts of themselves, reading and engineering their genetic code;
Type III-minus is capable of manipulating molecules and molecular bonds, creating new materials;
Type IV-minus is capable of manipulating individual atoms, creating nanotechnologies on the atomic scale, and creating complex forms of artificial life;
Type V-minus is capable of manipulating the atomic nucleus and engineering the nucleons that compose it;
Type VI-minus is capable of manipulating the most elementary particles of matter (quarks and leptons) to create organized complexity among populations of elementary particles; culminating in:
Type Omega-minus is capable of manipulating the basic structure of space and time.
We're is somewhere between Type III-minus and Types IV-minus according to this classification. Hooray us!
Now for something completely different
Since we chose the small-scale route, I'd guess that other civilizations might also have taken it. The imagined machine-beings in Bisson's story might not have been Kardashev powerhouses. They could have been a self-replicating Utility fog, a hypothetical collection of tiny nanobots that can assemble themselves into any large-scale machine or shape. Bisson's aliens might even have evolved from (or been created by) -- meat.
As small scale, self-assembling beings, they would not be restricted to speed of light travel. The fastest way to get from point A to point B in space is through a wormhole or black hole. That's not tenable for anything but data, but fortunately, we are working on putting data in very tiny places. A strand of DNA can archive a huge amount of information in a very small place. Fiber cables can move data at 99.73 percent the speed light. Roses can conduct electricity. Somehow, these new discoveries could be honed and combined to create (or evolve) an organic Utility Fog, a self-assembling being.
We may not be at the point where we can reduce ourselves to data and re-assemble into our regular meaty forms, but we have imagined that possibility. Star-Trek's under-appreciated Transporter did just that. I always wondered why the Enterprise crew didn't take advantage of that all-purpose tech. It could fix any health problem by returning people to their default, stored info. They could use it to re-assemble and bring everyone who died back to life. But I guess that would have wrecked a lot of plot lines.
A super-small, self-assembling form of intelligent life might might be faster and lighter than we can perceive. They might not live on the surface of planets, they might live within planets or ice moons. They could be the stuff we see swirling around Jupiter, they might travel on waves of sound. They could be like viruses, trillions of imperceptibly small proto-beings falling from the sky.
They could be silicon-based, cyborgs or carbon units. Like a Utility Fog, they could quickly assemble from small-scale to large scale. If this form of life mastered faster than speed of light travel through space and time, mimicking us would be a piece of cake.
He/she/they/it could sitting next to you on the bus. Just a slob like one of us, trying to make his way home.