It’s hard to hide in space. For example, your ambient heat whether we’re talking a planet or a spaceship would be clearly visible to them even after you’re long dead (like imagine them pointing a telescope at us thousands of lightyears away about the same time in thousands of years). So similar signatures aren’t think you can mask nor can nebula and other physical obstacles really hide them that well. If you’re able to affect your atmosphere or send out radio signals you’re gonna be seen. And if you leave any physical artifacts in space you’re not gonna be unmissed. And this fits with our current situation in our galaxy as the rate of supernova progressively reduced which means there’s been enough time for life not to get hit with the big reset button of radiation. That’s why as much as it would be cool to imagine Vorlons or some other impossibly ancient alien civilization dwarfing us being in the galaxy the odds aren’t in favor of that. What sucks is that we’re gonna have to care for each other as a result. No second chances and all that.
Now this seems the likely outcome. There could be some nearby civs that are a few hundred years ahead in their space age for sure. And by nearby I mean somewhere within a thousand lightyears or more. Anything closer would be damn scary if they’re keen on expanding or being violent for whatever reason.
The Rare Earth theory is one big Lottery Fallacy. We know even from life here on earth that life is extremely adaptable to extremes of heat, radiation, salinity, etc. We evolved to suit our environment, so it seems like our environment is perfect for us. If we’d evolved some other way, that other way would seem perfect. Wherever you are, there you are. It’s a tautology. And incidentally, the book by that same title is long-debunked rubbish.
I think the expectation that any civilization that could visit us would be more advanced technically in all matters is likely but not necessarily true. Think of what drives for instance computer technology. Much of it is pushed by requirements or desires that are cultural; an alien civilization may have little desire for something like a smartphone or CGI. They may have less interest in medical technology . There may have been circumstances that radically changed the nature of technical progress. A civilization that arose earlier in the life cycle of the planet they’re on may have access to uranium ore with a much higher U-235 fraction; for them, nuclear reactors may have required only a shovel to make. Perhaps such a civilization could have constructed fission bombs through more trial and error than science, enabling an Orion type spacecraft. If these people did evolve on such a planet, they might have more robust error correcting in their DNA equivalent mechanisms prompting much longer lifespans than we. This would perhaps allow long voyages at the .15 c speed you could achieve with an Orion type spacecraft to be undertaken. We might be “first contacted” by an Alien species that arrive here on a horribly radioactive spacecraft with a computer comprised of fast electro-mechanical relays. or not
All are hypotheticals and possibly true. In an infinite universe there may well be ultra-long lived aliens putting through a galaxy using a clever variation of steam propulsion at .0001 c.
I mostly just want anyone we do encounter to be able to recognize that we are something more than unimportant local fauna. I really don’t want them to see us as a parasitic infestation on an otherwise habitable planet, for example.
one possibility I have pondered on is a planet of a binary star system that regularly gets kicked out to a cold distant orbit, then returns, maybe twenty years later, thaws out and reanimates all life. Built in deep space hibernation! If it’s not obvious, many years ago I wrote a SF story around this theme: The Space Shuttle (ya, that long ago) races to get there ahead of “The Russkies” and when they do the astronauts all get radiation sickness, but they get the few still living aliens back to earth. They then discover they have nothing to learn from them, but they want to ride the “we have alien technology” thing to intimidate rivals. Yes, it did suck (the story, I mean)
there were a few comments referencing evolution, competition for resources, the seeming inevitably of wars, etc.
i think it’s just an important reminder that natural selection has been taught though the lens of the patriarchy in its common understanding, and so too our armchairing of galactic civilizations
natural selection is “just” the survival of those who survive, and cooperation at least as much as competition has been key to human survival. getting into space and becoming a galactic civilization would be a massive cooperative endeavour, one that probably necessities a great deal of not fighting to get there.
Have you read Gould’s “The Spandrels of San Marco and the Panglossian Paradigm”? High falutin title, yes. But a great, albeit dense, paper about natural selection. Natural selection, as Gould explains, occurs on many planes simultaneously, within each individual and among many organisms and societies. He describes these different modes, as well as debunking the common misperceptions about selection. If you haven’t, it’s worth downloading and taking the time to go through it. It’s free out there on the web if you look. It reads like Chomsky, so get ready.
Sigh. No, it did not, not originally, at the beginning of life stage. The planet came fully equipped with an anoxic, reducing atmosphere, which supported the initiation and early development of anaerobic life. It’s true that layer on, in the great oxidation event, early photosynthetic organisms filled the atmosphere with oxyge, but that can hardly be considered an effort to maintain any kind of balance, since it resulted in a huge extinction event. Our current atmospheric composition is very much a product of our current biosphere, but that was not how it started.
ETA: This was supposed to be in reply to @evilkolbot, but the system glitched and I had to reboot my tablet. Sorry for any confusion. I are a bad techie.
Didja ever take a close look at a T4 bacteriophage?
Small enough to be propelled by the solar wind; the buckyball shell provides reasonable protection for the DNA from the deep-space radiation environment.
I have not read much SF since the '80s, early '90s, then mostly Gibson that I have clear memory of…That book you mention is Vinge I think so I probably read it but have no recollection. The stuff I wrote was just for the exercise, if you know what I mean. I had no pretensions to value. When I was young I wrote compulsively, first on a typewriter with a continuous paper roll and later on computers. Every time I upgraded the old hard drive would be wiped with no regrets That “built in hibernation” thing was I think maybe a common trope, in that it seems pretty obvious. Bears do it, right ? I think I will check out Vinge’s book though, It sounds interesting, thanks for the recc.
You’d have to have a pretty good idea of what to look for, where to look, and - probably most important - when to look for it. The window of opportunity to detect anything radiating less energy than say a brown dwarf, no matter in which part of the spectrum, is very small and very short. Infinitely small.
The stuff we can detect is large (either in size or mass or energy or a combination), relatively stationary, and and has been there for a very long time.
This is where how you define “human” comes in. As we are currently constituted we would make pretty poor space travelers. Mars, Venus, the Jovian moons maybe. Even the moons around Saturn would be a stretch. But who knows what comes next? Maybe FTL in not impossible, we just have physics wrong. Maybe post-singularity we will be immortal hybrid beings and sailing the stars sublight speed is just another Sunday jaunt. Currently, we could be multiplanitary, but not multisystem. If we don’t kill ourselves off in the next millennium or so, things will change. That is certainly not a given, but if…
