That’s true, assuming there are only those two planets. If the advanced civilization knows, or even suspect, there may be other advanced civilisations around, they may be more careful about getting a reputation for being genocidal. Even someone who is normally peaceful might decide that a genocidal civilization has to be removed for the public safety.
That would be an interesting defence against alien invasion. Fake evidence that we’ve been contacted by someone else to make the invaders nervous about who those others might be and what they might do.
Huh. Those are the only possibilities? Occam’s razor may give the nudge to possibility 10: that the distance between societies of intelligent life is just too big, and too insurmountable. Plenty of other folks might be out there, but it’s too darn hard to get in touch.
The one I like is the theory that an egalitarian society is needed for science to flourish, but kings/priests/oligarchs only have to get into power once in order to destroy such systems. If this is true, there are likely millions of planets with intelligent life that are ruled by some idiot who got the job from his/her/its parents.
I always liked the idea that they could be so physically different from us that they simply exist on a whole different time scale. For example, intelligent crystals that take centuries to form a single thought. Would we even recognize such a civilization as such if we encountered one?
Well, we may think our brains to dust and still, without some solid facts we are going to get exactly nowhere. What we need is more time for study & observation, if we manage not to frag ourselves first.
Or maybe we should just go and look around Tokyo.
In Andy Weir’s latest book Project Hail Mary the human protagonist works with an alien to solve a problem threatening both of their planets. At one point the two ponder the odds of both their civilizations being at roughly the same place in technology and intelligence. But the explanation they come up with is that, were either species any dumber, they wouldn’t have built a spaceship, and if either were any smarter they wouldn’t need to and would just solve the problem from home. So that works as a useful plot device for the book but maybe there’s some truth to the idea that if we ever encounter aliens who physically travel in spacecraft we’ll probably be within a couple orders of magnitude of the same intelligence level.
Space is big. Space is really big. Space is so damn big that traveling at the speed of light it would take twice as long as recorded human history just to get across our little galaxy.
…but wait, it gets worse…
Light speed isn’t possible, because even ruling out the insane engineering concerns, as you approach it, your time frame slows down relative to the external world. (At light speed, it stops.) So, at something more reasonable like 1/10th light speed it would take a million years to get to the next galaxy and time dilation would put you considerably into the future. You would probably missing the rise and fall of that civilization you where hoping to find.
And that’s just one galaxy. If we set that as our threshold, 1 earth planet per galaxy, then there’s probably millions upon millions of inhabited planets. However, the odds of two being near enough to hear each other within a 1 million year period are basically impossible. If 4 billion year old earth is a common example, life evolves and goes extinct at a much much faster rate than the time it would take to travel between galaxies.
(apologies to the pedants who look at these imprecise numbers, but even a few orders of magnitude in one direction or another doesn’t even matter. space is just that big.)
so yeah, it’s lonely out here. good thing we’ve got the best planet around for miles…
That’s one of the themes I love from Stanislaw Lem’s Solaris - the behavior of the planet’s ocean is so strange and so inscrutable that there’s a legitimate question whether it’s “intelligent” at all, or just represents a natural phenomenon that humans had not yet encountered and are not equipped to analyze. That the question is never actually answered is the point of the novel.
I don’t understand why the most probable option isn’t listed:
We’re the only technologically developed civilization (in our light cone)
Now the nice thing about this hypothesis is that it both fits our current observations and allows other civilizations to exist, just not accessible to us: they’ve existed before us and have disappeared, or they’ll exist after us.
After all, the current span of human civilization is tiny on the cosmological scale (which, y’know, is a scale above even geological scale, which we can already barely comprehend).
Of course, the scary corollary is: why would prior civilizations disappear, or why would we disappear before we can meet other civilizations? And that leads to the idea of Great Filter: some kind of event or condition that prevents technological civilizations from growing to an interstellar scale.
As we start to face the consequences of our hydrocarbon-fueled growth spurt, the idea is terrifying. Frankly, in evidence of current bickering, I now have little hope that our little collective of free-agents can coordinate our endeavors to reach the next stage
Agree. People think light is fast. But it’s not. Compared to the size of space, it is slow as molasses. Slower. And galaxies are drifting apart FASTER than light. And we might be the first species in our light cone. C’mon, give an Earthling a chance!
Another possibility, is we are among the first 100 intelligent species in our light cone, and are in a race to expand. We better start doing that soon.
I think that option is implied by the discussion of the idea of a past “great filter”. But in the article’s comments I posted a little criticism of the way the article presented that idea, I’ll repost here:
This article actually misrepresents the idea of the “Great Filter”, if you read Robin Hanson’s original paper that coined the term, it talks about the idea of a series of past evolutionary “hard steps”, not a single super-unlikely evolutionary leap. Hanson also says there’s a mathematical argument that if you have a series of such steps that are each very unlikely, if we take the set of planets that do get through all the steps, we should expect a typical planet in that set to have gotten through them in roughly equal time increments, even if the actual probabilities of the different steps are fairly different (this argument was originally proposed in a paper by Brandon Carter, the astrophysicist who coined the ‘anthropic principle’). He then gives some candidates for past hard steps that seem about equally spaced in time, suggesting he thinks it’s plausible the Great Filter is a series of past hard steps. Paul Davies does a similar analysis in his book The Eerie Silence, in the section on the Great Filter.
Here’s an example of how a bunch of medium-small probabilities can give an astronomically small total probability. Say you have 3 evolutionary hard steps that each have a 1/1000 chance of happening on any planet that’s made it through the previous steps, and 4 that have a 1/100 chance. Then the total probability of making it through all the steps would be 1 in 10^17, and since our galaxy has about 10^11 stars, that would mean only about 1 in a million Milky Way sized galaxies would have a single planet that made it through all the steps.
. Here’s my answer:
