Why We’ll Have Evidence of Aliens–If They Exist–By 2035
nautil.us
nautil.us
Overall an interesting article by Seth Shostak of the SETI Institute.
I think he's basing the date on the assumption that we'll have searched 1 million star systems by 2037 and there are a few million broadcasting societies.
Personally I think the odds are pretty damn long, even on the optimistic end of Sagan's and Drake's assumptions. Assuming there are 200-400 billion star systems in our galaxy, that gives us a 1 in 200-400k odds of finding one by 2037? I'll take the bet.
Still a great read, I'm much more fascinated by the idea of artifacts. I believe that the longer we go without finding things, the more seriously we should be thinking about leaving things.
(I don't think that there are a few million broadcasting societies in our galaxy. But if there are, we'd expect to find them soon.)
A ship filled with water has a lot more mass than a ship filled with air. That extra mass compared to what we face, combined with starting from a high gravity world, would mean they would need significantly better propulsion systems than we need to get to orbit.
Could this mean that chemical based rockets would not be sufficient for them to do manned spaceflight? If so, they may never establish a manned orbital presence, and a manned orbital presence may be necessary as a stepping stone to interstellar travel.
Like, the range quoted above is from "10,000 to a few million," so a factor of 200ish from high to low range.
If you think that there are 10, per galaxy, why don't you believe instead that there are 0.3 per galaxy (only off by a factor of 30?)? How much confidence can you have in your highly speculative variables that your output can be constrained down to just a single order of magnitude or so?
Why do we need to expand? Our population growth is already levelling off.
Why do we need to send _our bodies_ rather than with AI, or with our consciouses uploaded into computers? (a la Charles Stross' Accelerando or Greg Egan's Diaspora)
If we're sending AI probes around, why do we need to take all resources to the extent that we prevent other species from developing?
Most of the fundamental science that we want to do can be done right here in our own solar system. There's just not a need to expand.
Yes, of course, they will be AIs or uploads or body printers. Even for an advanced civilization, shipping bags of meat to other star systems would be wasteful. That doesn't mean they won't want to use resources, or that there would be no evidence of them if they were already here.
edit: There's certainly scenarios in which the first species to explore a galaxy doesn't literally prevent other species from evolving. But that doesn't mean they wouldn't be obviously detectable. The likely number of starfaring species in the galaxy given our observations is zero.
It doesn't take a need, just a desire. Someone wanting to be able to say, "I went there. I saw it. I got the T-Shirt."
and there could be aliens in other galaxies! we wouldn't detect them by 2035
article was pretty nonsense imho
Articles like this would be more persuasive if they had qualifiers like "Within our observable universe."
That doesn't mean infinity isn't lurking somewhere beyond though.
My impression is that Multiverse Theories are a fad playing on semantics.
if an infinite number of trees fall and and nobody is there to hear it, do they make a sound?
...and if they want to be found.
Aliens 200 light years away will not detect life on earth for 100 years or so yet (depending on if they are listening and how sensitive their radios are). If they immediately send a reply it will be 200 more years before we can get their reply.
Note that 200 light years is insignificant even on the scale of our galaxy, much less the universe.
What this means is even if we detect aliens that doesn't mean they still exist, we could well detect them, learn about them and then watch as die (war, plague, or any other doomsday scenario) before we can get our "we are here" message to them. That is we might find aliens that do not exist anymore! The universe is large enough that this would not surprise me (though it might be my great-great-great grandchild who discover they have been dead for thousands of years).
Or maybe we will not find any, and then in 2036 discover the first radio transmission of some aliens only a few light years away.
Thus I can well believe that aliens have colonized the other habitable planets in their solar system and failed at all attempts to do anything more. They might have got one robot to a different star, but that is it.
Of course this assumes they are there before us by a significant amount. Maybe humans are first to reach our level - it is an arrogant idea but we cannot completely discard it until proven wrong.
That seems like a limited vision of the possibilities of spaceships. Remember that we're now traveling through space ourselves, and barring self-inflicted problems, we're not in great danger of suffering critical failure.
I had to step back for a moment and realize that just 10 years before I was born, such a feat was technically possible, but required massive planning and a high degree of skill involved in all participants.
100 years prior, it was impossible.
The rapid exchange of information afforded by this technological advance is utterly disruptive, and our society is still figuring out what to do with ourselves now that we're no longer separated from each other by huge stretches of travel time and long delays in information exchange. I must wonder, then, if this is the turning point in any global civilization? The part where the intelligent beings on a world can actually work together to solve problems at such a larger scale than any individual can observe.
edit: and by "we" I mean some few genious scientists not including myself except by association
Additionally, I would assume that any "first contact" with an alien entity won't be a face-to-face, lifeform-to-lifeform meet; We're more likely to meet the robotic creations of an advanced alien civilization well before actual living beings.. unless said alien had an extraordinarily long lifespan compared to us.
Even if they're massively more advanced, why invite trouble? We're much more intelligent than fire ants but I for one know I'm not in the habit of sitting on fire ant mounds.
These two can go together. If they contact us and we become belligerent, they may be forced to annihilate us. That would be morally reprehensible to them, so the solution is not to make contact.
Related to the solutions to the Fermi paradox, explanations for why the putatively abundant aliens have not contacted us need to cover all the aliens. And the "Prime Directive" is a very, very, very particular definition of "altruistic". I, for one, don't even agree that it's altruistic. Even Star Trek, where it has basically magical dramatic force severed from real concerns, couldn't really argue consistently that it was altruistic: http://memory-alpha.wikia.com/wiki/Pen_Pals_(episode)
Why wouldn't there be a species that looks at us, concludes we're ultimately irrelevant, and just converts our solar system into computronium anyhow? Why wouldn't that be the cosmic evolutionary winner?
(They could even altruistically upload us into an equivalent simulation; while I don't particularly "believe" it, my favorite pet solution to the Fermi paradox is that Earth was uploaded an arbitrary amount of time ago and we've just been simulated ever since out of ethical concerns, a simulation which for simplicity and perhaps even ethical reasons has no other civilizations in it. For all we know they actually digitized Earth in the dinosaur era and in realtime it may in fact still be "millions of years ago" if our simulation runs faster than real time.)
I can only wonder what game theory would have to say about setting the punishments as in the original. Certainly the whole thing is rigged to begin with. Both serve time if none of them admits to the crime? You'd have to be uncooperative with law enforcement out of principle, never mind nature is probably not generally as sinister and draconicly enforcing morally biased laws. The void of deep space rather doesn't care to set traps like that on purpose. But it could randomly. If weights are set arbitrarilly in the thought experiment, what would probabilty theory say then? Nothing, as there are no priors. But what would attacking and extinguishing an unexpecting existence about our own chances to be terminated at once without aprehension?
... we were still owe are existence to an asteroid (among many other things) that wiped out the dinosaurs.
On top of everything, star time scales in the billions of years, evolution hundreds of millions of years, and semi intelligent life within the tens of thousands of years.
if there is other intelligent life out there near by, it either happened billions of years ago or will happen billions of years in the future.
One would guess that aliens with Independence Day technology could figure out how to terraform or build space colonies in their own star system. Even if they ran out of raw material there, surely the next closest one would do.
More than mining resources from planets, its generally 'We need to finish them off, before they finish us off'.
I feel like N is very large. When you factor out all the stars of the 100 billion in the milky way, I think you get something unlikely, let alone on a planet in the habitable zone.
also, something on the other side of the milky way (100,000 light years), is also far away, so its not like we have the entire milky way to choose from.
If we take an average lifespan of 1,000 years and say those cilizations have formed over the last 5 billion years (where planets mostly cooled down throghout the universe) then there are currently only 4-5 broadcastable civilizations in the milky way. Is that correct?
Intelligence (as far as we know) requires a brain, which requires a lot of calories to work correctly. Increasing calorie intake requirements is not something that survival-selecting evolution would select for.
Evolution selects for survival, not intelligence. Sharks and other animals have survived very well for millions of years without ever developing a higher level of intelligence. If anything, intelligence seems like it might be a happy mistake of evolution, and potentially very rare since evolution doesn't select for it explicitly.
So far, we're the only species on Earth to have enough of the right combination to get this far. So maybe it only happens 1 in 1000 worlds with multicellular life.
How many planets does that leave in the Milky Way? That's the sort of calculation SETI does.
I began thinking about it by finding out alligators/crocodiles lived during that time, and they have larger brains. I then wondered why, until I considered the fact that they came from laid eggs, and their 'thing' was the ability to get big when evolution supported it. brains require lots of oxygen and egg shells have limits to how much they can allow through them.
my theory is that they were dumb by design, so that genes could activate and allow them to get really big if it suited them.
[Edit] Who's to say that we're going to broadcast via radio for thousands or millions of years? What if, in 300 years, we discover a much better system? Then we can reasonably assume that a 400 year radio burst is the sign of a species developing intelligence. We can also reasonably assume that SETI chose a poor indicator in their search.
While it's never possible to say "everything has been discovered/invented" we know a great deal about the types of particles and waves that can exist at realistic energy levels for use in communication systems because those energy scales have been so well studied. The odds that there is "new physics" to be discovered at a scale that will supplant radio waves for broadcast communications on a terrestrial scale are pretty low.
No, they aren't. Both are freakishly difficult to detect, and we have no reason at this point to expect that to ever change. And gravity waves are actually terrible for interstellar distances because it is completely unclear how you would produce a source of gravity waves powerful enough to transmit across interstellar distances, and also transmit in a beam. If you can't transmit in a beam, you're stuck with very unfavorable dropoffs as distance increases.
It is also unclear why, having built the utterly massive complexes for transmission or detection of gravity waves, or the massive complexes required for high-probability neutrino reception (transmission in their case is a bit simpler, though collimating the beam is rough) it would not simply be easier to use electromagnetic waves, which are by comparison so easy that if we had a receiver in another star system we could transmit to them today.
Barring some major revelation in physics, aliens will use electromagnetic waves because everything else is literally (and I mean that in its original correct sense) dozens of orders of magnitude worse. Smart aliens do not demonstrate how much smarter they are than us by using engineering solutions dozens of orders magnitude inferior to what we could build today. However, as my previous text implies and as other commenters have already pointed out, the problem there is that efficiency is obtained at that scale with beams, not broad transmission. The galaxy could be hopping with point-to-point links and they would be much harder for us to notice.
(They wouldn't be impossible, because there would be some scattering on the interstellar medium. But they'd be much more difficult than if we were directly the target.)
They are better for long interstellar distance communications because their weakly interacting nature and difficult to produce nature means there is no dispersion relationship to worry about, no absorbtion/attenuation issues to worry about, and no noise sources to worry about. The galaxy is a surprisingly difficult medium to send radio waves through if you want them to be received at great distances (difficult medium, not impossible medium). That's one of the things that led early SETI thinkers like Barney Oliver to propose using the spectral Water Hole[0] as a search target.
Gravity waves and neutrinos are harder to produce and detect but the galaxy itself is much less likely to interfere with their propagation if you can produce and detect them. Also, communications uses of gravity waves would presumably be at much higher frequencies so the detector sizes would be much smaller (the size of an interferometer or Weber bar detector is a function of the center detection frequency of the device... sensitivity is largely independent of the size, other than the choice of center detection frequency).
https://www.nasa.gov/directorates/heo/scan/engineering/techn...
Of course if there's only a few, then we might not see any evidence for them. But 10,000 would probably be detectable at some point in our search.
I suppose there's an outside chance that such a telescope could detect combustion compounds that are difficult to explain geologically or biologically, and that might be used to hypothesise a civilisation. Something like lead smelting might leave a pretty distinct signature, for example. But that would just lead to a hypothesis, not proof, and I imagine it'd be pretty contentious.
Longer-term, it should be possible to create arbitrarily large space-based optical interferometers[2], to the point where one would be capable of imaging cities and agricultural activity on exoplanets. That'd settle matters (Unless it's under water or impenetrable cloud decks, and then you're just out of luck). But that level of resolution is probably a couple of centuries and/or one singularity away from happening, so don't hold your breath.
1: http://www.planetary.org/blogs/guest-blogs/2017/20170623-sta...
2: https://www.noao.edu/meetings/interferometry/workshop-files/...
I wonder if an alien species has been listening for a while they might be able to go back in their archives and conclude that some emissions actually were our experiments - once they have hindsight that humans really were playing with static electricity in those time frames.
... AND actually willing to communicate with us, which is not IMHO to be assumed as given.
We need to find a rather "narrow" set of aliens with a technology similar enough to ours, and animated by a similar curiosity about the rest of the universe.
All such proclamations, predictions, and earnestness about the Drake Equation is limited, absolutely, by the boundaries of what we currently believe is possible.
To be specific, it has always seemed to me hubris of the first order to presume that we know the principles underlying a more advanced civilization's communications (or, maybe, travel).
We aren't aware of mechanisms more efficient, fast, whatever, than e.g. radiowaves, or, polarized lasers, or [insert latest notion]'.
But what the authors of these things seem to never take seriously is what we don't know, is almost certain to be a lot more significant than what we do.
There is a chart in my office lounge showing the advancement of human symbolic reasoning and technology from pre-history, through 15 years ago.
What is striking to me is that in a few brief thousand years, utterly insignificant evolutionarily speaking, we have gone from first formulating written language and mathematics, to e.g. Cassini, rovers, and LIGO.
Ever if the pace of advancement were plateaued (and it isn't) it is baffling to me that someone would think, oh, we've got the basic constraints now in hand; it's just an exercise of application at this point, to e.g. detect other civilizations.
That doesn't even begin to get into the Liu Cixin style game theory issues...
Anyway. Lack of evidence merely means we're not looking in the right way, IMO.
Also one thing that's curious to me is the math here assumes these millions of civilizations all exist now or have set up systems to broadcast these beams forever whether or not they go extinct. So if we make the following assumptions:
These civilizations only last a couple hundred years after they create these powerful directional radio wave beams (which if we use ourselves as an example seems to be a reasonable assumption)
One civilizations dies and another sequentially starts broadcasting radio waves (most favorable option)
It takes 2 billion years to create life
Galaxy is about 13 billion years old
There's been about 2M advanced civilizations in the Milky Way
That means there's a 3.6% chance there's a civilizations broadcasting right now. This goes up if some last longer than 200 years, and if some create machines that can broadcast either indefinitely or for a long time. Within 1 magnitude of relative certainty is pretty good I guess.
Which I agree with (and I also agree with folks who point out that at some point being found may be a bad thing which would encourage hiding).
Like many people I know, I assume there must be other civilizations out there. However it is fun to ask the question, "What if we are unique in all the galaxy?" (really it would be the light cone associated with what we can perceive) What sort of responsibility would it put on humans to get their act together and keep from dying out if we knew we were unique?
Just under 10 years later, he quotes 2035.
Not saying he's wrong.
From the article:
> We can never prove that aliens are not out there, only that they are.
No, he's just saying if we don't find them by 2035 he owes the Internet coffee. Pretty excited, though I'm hoping I can substitute tea.
But it won't be taken that way.
Now, I'm overstating the attention-grabbing headline to reflect a greater degree of certainty than Shostak genuinely believes. But he's stating it with more certainty than he genuinely believes, at least in the headline. If he really believed the headline, he'd say, "If we don't find them by 2035, I will believe that they don't exist" instead of "I will buy everyone coffee".
Didn't Carl Sagan already find the answer by doing math?