View Full Version : Where Are the Aliens? Fermi Paradox Redux

16th August 2010, 16:29
Seth Shostak

Senior Astronomer, SETI Institute
Posted: August 8, 2010 07:22 PM

Some say the story is apocryphal, but even uncorroborated tales are often instructive.

It seems that Enrico Fermi and some physicist pals were sitting around a lunch table in 1950, when Fermi suddenly blurted out "so where is everybody?"

That small statement hardly sounds remarkable -- it's the kind of thing I've said at fundraisers for fresh-water otters. But Fermi was no schlub -- he had won the Nobel Prize a dozen years earlier, and you can bet dollars to Doritos, he meant something deep.

His meaning seems to have been the following: A simple calculation (surely one that Fermi could manage between two bites of a sandwich) shows that colonizing every star system in our galaxy would only take a few tens of millions of years. Since the Milky Way is more than ten billion years old, what Fermi realized was that, if extraterrestrial life is commonplace, there's been more than enough time for an ambitious society to spread out and build their own United Federation of Planets. But we don't see any evidence for a galactic empire, other than on Star Trek re-runs. Does that mean that Homo sapiens is the smartest species within 100 thousand light-years?

That would be remarkable and, judging by my daily interaction with said species, scary. I have always thought it much more likely that the cosmos is replete with thinking beings. After all, my day job is to look for them.

Reconciling an optimistic view of extraterrestrial intelligence with the failure to see any signs of galaxy-wide colonization has become known as the Fermi Paradox, a conundrum that has tempted the imagination of many people. The suggested explanations can -- and have -- filled books.

Just to give you a mini-sample: Some folks have opined that no aliens have colonized the galaxy simply because they inevitably blow themselves up in massive, hi-tech wars before completing the project. Others say that it's too expensive -- you can better stay home, and improve lifestyles in your natal solar system. A personal favorite of mine is the idea that the galaxy might be urbanized, and we happen to live in a largely empty, rural district.

The onset of the digital age has spawned other suggestions: Maybe truly advanced societies don't build big stuff -- honking interstellar rockets for boldly going to someone else's galactic quadrant. Rather, these sophisticated sentients start miniaturizing their technology, eventually uploading their minds into some sort of microelectronic computer, at which point colonizing star systems will seem as tempting as oxcart travel.

A more draconian explanation for why we don't see the trappings of empire is the suggestion that there really is no galaxy and no us. Everything we experience is just a software simulation run by someone as an experiment (or as an amusement). Our daily lives are no more than computer code. And the rules of this giant matrix-like existence forbid contact -- just because.

Fermi's remark continues to pique our imagination, and explanations for his provocative question keep popping up like whack-a-moles. Last month, two researchers in the Ukraine, Igor Bezsudnov and Andrey Snarskii, reported on a computer simulation in which galactic civilizations randomly arise, spread out to a greater or lesser extent, and then -- eventually -- fail and fall. As a time-lapse movie, this would look something like raindrops hitting a pond. Splashes would occur here and there, generating brief waves of local colonization. But eventually each splash would dissipate and die. Well, there's nothing new in this -- the model is just saying that every culture has a finite lifetime. But the Ukrainian scientists added a twist: if two civilizations chanced to overlap in time and space, the resulting contact would give the merged society a longer lifespan. In other words, the researchers assumed that meeting the neighbors was ultimately good for you.

When the simulation was run, it turned out that in some cases (depending on the birth and death rates of societies, not to mention the degree to which they could be mutually beneficial) a galaxy-wide society would emerge. A galactic federation. The authors of the study claim that their work gives insight into Fermi's Paradox by suggesting that either the Milky Way doesn't produce sophisticated societies very often (in which case, we're largely alone), or that it's still too soon to expect a pangalactic empire.

While interesting, the Ukrainian work certainly hasn't satisfied those who are dismayed by the lack of Klingon colonists as far as the eye can see. In the end, of course, the only way we'll resolve Fermi's notorious, sixty-year-old puzzle is to find the aliens, if they're out there. I suspect Fermi probably felt the same way. He doesn't seem to have continued the conversation over dinner.


16th August 2010, 21:43
thanks for that,seth.
this piece reminds me when our band got together for a practice
in a friends garage (and to drink beer).
our talk got around to god and such, when one of the guys blurted his
theory that everything we know in our universe and beyond could very well
be a single molecule in the leg of a giant chair in another reality, space and time.
why not?
I've never forgotten that and still think there's some validity to that beer laden idea.

17th August 2010, 09:19
I've had that thought many many times, generally triggered by our common belief that atoms, solarsystems, galaxies and the whole universe seems to behave in a similar fashion.

But it gets sorta mindboggling when you think about it, since this "theory" really can't put constraints on how many levels this could apply. So we get an infinite world-within-world scenario that can expand outwards and inwards for all eternity.
Min boggling indeed... :P

22nd August 2010, 21:14
Humans think of aliens in human persona. Even though they still claim if we encounter an alien culture, that its going to be so radically different from us in physical/biological, psychological and social aspect, that we might have a hard time recognizing it. Why do I say this? We still keep adding human experience to the equation, and we do add the outcomes and results of this experience. Who's to say that what might hurt or destroy us entirely as a race, is not something that the ETs could survive just like our seasonal flu? They are alien, aren't they? They are different from us in every single way, aren't they?

The idea is still propagated by the search for Earth-like life. In an extended definition of it - carbon-based life, and the way we have it here on Earth. Aliens can't be so much different than us, and yet still, so much similar to us as well. What they are doing is a scientific joke. They should make up their minds. Are we looking for life similar to us, or are we looking for a totally alien life, in every sense of the word?

For now, only G and K-class stars have been searched, who harbor Earth-like planets, who ... hopefully, harbor Earth-like life. M-dwarfs were recently added as possible candidates for life as they last longer than other types of stars so that gives somewhat better conditions for life to develop. But with only these in game, we exclude a large area of space, who involves types of stars and ecosystems who might actually also harbor life, but in very different nature. Let's leave out O and B-class stars, but we do have A and F-class stars, who are quite good candidates, if there is as much as 1% validity to the present day alleged ET contacts, and according to these ETs, life is quite possible in these types of star systems. Excluding them in absolute confidence in our own convictions doesn't really mean we are right. We need to actually visit star systems like that, do a thorough research, and then rule out on the scientific probabilities concerning types of stars and their habitability.

Just my two cents on this issue.