In his new book Little Book of Aliens, astrophysicist Adam Frank says that we now know almost nothing about aliens, but we will soon learn much more:
Fermi saw that if technologically advanced, star-faring civilizations really were common, they should already be everywhere, including Earth. … Relative to the age of the galaxy, any spacefaring species should be able to reach anywhere in the galaxy in the cosmic blink of an eye, yet we have not seen any definitive sign of them here on Earth. If technologically advanced exo-civilizations are common, then we should already have direct evidence of their existence. … For [Hart], Fermi’s paradox meant that we are the only intelligent life in the entire galaxy, end of story …
[But] there is a whole cottage industry of scientific papers that try to explain away Fermi’s paradox. For example, there’s the zoo hypothesis, which says the galaxy might be full of aliens but they’re purposely leaving Earth alone and watching us from afar. … [Or if] settled planets eventually went dark [then] … those holes might not get filled in for a long time. …
[Thus] the Fermi paradox does not tell us that the universe is silent when it comes to alien life. It speaks only to the question of why the aliens aren’t here, on Earth, right now. It doesn’t say anything about our searches for signals from alien civilizations on distant planets. … [Regarding] evidence of alien life on distant planets, the answer is simple. There is no Fermi paradox of that kind. We just haven’t really looked yet. Until now. …
Over the next ten, twenty, or thirty years, we’re going to be spooling in data from the stars that could finally answer our alien question. I can’t tell you what that answer will be, but I can tell you what we’re going to be looking for. I can tell you that because it is exactly what I, my colleagues, and the entire research community that we are just one small part of are working feverishly on. …
Nothing makes an astronomer’s heart beat faster than the discovery of an Earth-like world in the habitable zone. …No matter how far that planet is away from us, biosignatures will be proof that the planet has a biosphere, proof that it is a living alien world. … looking for pollution in the atmospheres of distant worlds may be the fastest way to find a distant civilization. … JWST for just a few weeks was enough to detect CFCs in our simulated inhabited alien planet. … The signature of these artificial lights will be encoded in the light from any alien planet with a civilization that uses them. … solar panels on planetary scales create clearly detectable technosignatures.
Thus: we see no aliens here now, but we have boring ways to explain that, and the main other way to see aliens is to see when they slightly change the light from a star. We’ve hardly done any of that so far, but will soon do lots more, and so will soon know much more about aliens.
This argument, however, assumes little aliens who are much like us: short-lived communities near the surface of some planet. But what if there could be what I’ve called loud aliens, vast alien civilizations that have expanded for millions or billions of years drastically remaking galaxies or huge groups of galaxies to their tastes? On these we have strong data: we do not see any within a very large distance.
We also have the strong data of our current date, which is very early compared to when we should expect if no other loud aliens will ever appear in our universe. Add in strong data of the durations til life first appeared on Earth and from now til simple life dies on Earth, and you get the grabby aliens model, with three parameters each fit to data, describing the stochastic distribution of loud aliens in space and time.
Thus it seems we do know quite a lot about at least one kind of alien. For example, loud aliens appear roughly once per million galaxies and if we become loud we’ll meet the nearest other loud in roughly a billion years. Furthermore, any reasonable constraint on the ratio of quiet to loud aliens suggests that the chances of finding techno-signatures of quiet aliens at near our level will be very low. We won’t be finding those in the next few decades. Bio-signatures of primitive life, on the other hand, could be much more common.
While Frank does at times try to imagine louder aliens, he seems continually drawn to focusing on aliens like us. For example, he can’t see how multi-star civs could integrate, due to human-like lifetimes:
When it takes two hundred years to send a diplomat between two planets and no one lives more than a hundred years, you have a problem. If no one can travel faster than light, maybe it’s every solar system for itself. In that case, you never get galactic empires, just individual planetary cultures. These cultures might send settlement missions out to cross the stars once in a while, but given the distances and travel times, even if those settlements succeed, they’d quickly diverge culturally from the home world. If this is what happens, then aliens visiting Earth are not representatives from some Zorgovian Galactic Federation with vast experience of many worlds and many cultures. Instead, they’d be one-offs, and we might be their first visit anywhere.
Frank tries to imagine aliens replacing biology with stuff more artificial, but has big doubts:
What if most aliens aren’t gooey? That is, what if intelligent life’s biological phase is relatively short? … Even if some species decide not to download, you could argue that evolution would eventually weed them out on galactic or cosmic scales. The downloaded, machine-melded versions of life would be far smarter and stronger than their goo-bound cousins. … [But] There are counter-arguments to the inevitable rise of the robot overlords. … it’s not clear that AI will ever achieve anything like the kind of “general” intelligence … downloading into a computer may also not be possible. … even if a species went the machine route, they might eventually opt to go back to biology again after a few billion years. … biology may just be better at certain kinds of things. …
Imagine, for example, that an alien race creates machines that rapidly outpace their creators. The machines become essentially alive. They are highly intelligent and can solve the problems of re- production and finding energy rapidly and effectively. They spread throughout the universe in powerful spaceships, chewing up one star system after another for their needs. Through it all, however, they are never self-aware. … We could never talk to creatures like these. There simply wouldn’t be anyone in there to talk to.
And while Frank admits aliens should be far older than us, he doesn’t seem to think it possible to draw any implications from that:
When we do find aliens, … they will have been civilization-ing for millions or even billions of years. … Would a ten- million-year-old civilization be a single continuous entity, or would it rise and fall many times during those eons? … Do they give up on expanding, or do they conquer the galaxy in the name of computers? … Perhaps a ten-million-year-old civilization turns itself into a planet wide forest in which every “tree” is a kind of sentient biological supercomputer networked to every other tree. … As a civilization advances and its technological capacities increase, a point might be reached where it disappears into the laws of physics themselves. … it can feel almost impossible to say anything about ancient civilizations that’s not just a story. There are so many unknowns, and almost none of them have the kinds of constraints science can supply to guide our thinking. … Whether we meet free-loving hippie bonobos or terror-happy fascist chimpanzees may hinge on the details of the environments their planets offered. … Should we be hiding, or should we expect that anyone who has made it to the stars will become an agent of peace?
Frank has high confidence in the universal value of innovations like legs, wings, and eyes, but far more doubts about more recent innovations like metal, tools, roads, factories, language, math, law, property, modularity, management layers, and computers. I am far more confident than he that both we and aliens will long use key innovations like these.
FYI, Frank mentions UFOs in his book, and admits it is possible that some UFOs are aliens. But he insists not at Roswell, and he bemoans “unscientific” evidence:
One of my biggest problems with UFO stuff is that there are no standards of evidence. So much of the time, any fuzzy picture or any witness claim is taken to be evidence … What’s needed is hard data from verified instruments collected via a rational search strategy.
Seems he must also disprove of most evidence offered in most legal trials. He also repeats this oft-noted puzzle:
The problem with UFOs as aliens … is that you have to simultaneously explain why the aliens are always trying to hide and also why they suck so badly at it. …
If these aliens really wanted to remain hidden from us, if they really didn’t want us to see them, then how come we keep seeing them . . . almost. Have they sent us their D team, the one that doesn’t know which button engages the cloaking field? Are they just a bunch of Zorgovian teenagers who stole their parents’ saucer and are out for a joyride? It just doesn’t make sense.
Yet Frank doesn’t even try to consider theories to explain this puzzle. (I consider one here.)
FYI, I invited Frank to discuss his book on our Minds Almost Meeting podcast, but he referred me to his PR person, who declined.
These once-physicists think they don't need to learn read more when they publish in philosophy and social science, but when they do, it's very rare that they don't say foolish things. Frank is not one of those rare cases, though he's not worse than Michio Kaku.
The "we are early" argument is based on assumption that planets orbiting red dwarfs can support life. If it is wrong (and most likely it is), then there is no paradox, we live in an era when yellow dwarf stars are most numerous.
Both ''grabby aliens" theory and the Fermi's paradox itself are based on assumption that the level of technological capabilities far above ours is possible. Again, that is most likely wrong.