Posted on 05/13/2014 1:43:32 PM PDT by BenLurkin
As Snyder-Beattie explained in the article, the “Great Filter” is a response to the question of why we can’t see any alien civilizations. The “Great Filter” deals with similar issues as the Drake Equation, which talks about the probability of communicating civilizations outside of Earth, and the Fermi Paradox, which asks where the civilizations are.
Simply speaking, the idea is that if a civilization continues to expand (especially at the technological pace we humans have experienced), it wouldn’t take all that long in the lifespan of the universe for artificial processes to be visible with our own telescopes. Yes, this is even taking into account a presumed speed limit of no more than the speed of light. So something could be preventing these civilizations from showing up. That’s an important part of the Great Filter, but more details about it are below.
Here are a few possibilities for why the filter exists, both from Snyder-Beattie and from the person who first named the Great Filter, Robin Hanson, in 1996.
Read more: http://www.universetoday.com/111660/where-are-the-aliens-how-the-great-filter-could-affect-tech-advances-in-space/#ixzz31d9mu0xO
(Excerpt) Read more at universetoday.com ...
Certainly! And doubtless Sagan was a part of the ballyhooment (if there is such a word!).
Still, the Drake equation is a fairly good attempt at bringing some rigor, some attempt at understanding the underpinnings of the Fermi Paradox 'where is everybody?'
We can argue about the terms Drake included, or left out, we can argue about the weight each term was given, have an endlessly debate the resulting value, we can even argue the validity of A+B=C on purely semantic terms (or we could even be anti-semantic).
BUT even if flawed, even if absolutely incorrect, the Drake equation is an intellectual tool, it provides a way of attempting to organize our perception of the universe and an attempt to understand our place in it, and invites each and every one of us to replace it with something better.
That would be the problem. Even stellar events like novas and pulsars would be hard to identify in other galaxies. So, keeping it just to our own galaxy, it still seems unlikely that a Berserker culture could cover the distances to kill all other advanced cultures. Even a half a dozen killer cultures evenly dispersed in our galaxy couldn’t do it.
If we were to assume that life evolved REMOTELY close to the way we did, and that the big bang theory is true just for argument, then only within the last couple hundredish years have any civs had radio.
Our own TV transmissions are still decades away from the closest star. Much less another galaxy.
That is an excellent explanation, and it ties in nicely with the thrust of the article.
(And I like “ballyhooment”. If it isn’t a word then it certainly should be one!)
bkmk
Of course then it all depends on how advanced the advanced culture is. There are, purely theoretical relying heavily on unobtanium, cheats around the light speed limit. If they’re THAT advanced then they could be wiping out civilizations. Of course they still have to find them, and that would still in many ways be hampered by the speed limit (don’t care how fast your ship goes, our radio waves are still “only” going speed of light), so they have to get in the zone.
Which is why I think distance is the true great filter. Every way we have of announcing our presence, or detecting somebody else’s, take a long time to get anyplace and would carry extremely post dated information. The way I think about it is to “assume” there’s another civilization out there 200 light years away growing their technology at an identical rate to us. Their very first experiments in wireless telegraphy haven’t gotten here yet. We’re using very dim flashlights for a very large room.
The first TV transmission passed Alpha Centauri in 1932.
The Berserker Theory fails on many fronts.
More likely is the "fundamental technology’ that ends civilization" theory. The author wasted speculation on the ridiculous Glowbull Warming idea. How about the discovery of a virulent toxin, chemical or biological, that some crackpot releases and kills all life? Consider the insane things people do like kids attacking their schools, the Jim Jones cult, Muslims and so on so forth.
One intelligent but extremely psychotic nutball gets a hold of a planet-killing technology or substance and executes a plan to employ it. Perhaps neurosis is a fundamental aspect of biological life forms and sooner or later every civilization unwittingly creates the opportunity for one insane individual to wipe the whole thing out.
“SEND MORE CHUCK BERRY”
It took us four billion years to get from algae to us. There were a lot of tripping points along the way like “snowball earth”. I’d think life would be fairly common but our level of semi intelligent ape without destroying themselves ? Then there are the distances to be dealt with. Plus, we’re impatient due to our short life spans.
bkmk
Got me there. How about the next? point being though, out of trillions of stars, we or they have not had the time broadcasting to see each other.
I think you’ve given the Occam’s Razor answer to the question.
Detectable signals probably have only reached a few scores of stars. Odds are we haven't gotten a recognizable transmission to any technological civilization.
Worse, the first signals anyone is apt to receive aren't coherent broadcasts, they aren't 'easily' decoded entertainment radio or TV, they are powerful early warning radar transmissions, and those consist of randomly (or as close to randomly as we could achieve) modulated signals, the better to prevent spoofing.
Even if someone happened to be looking here in the correct radio band, and at the correct time, they'd just get literally meaningless noise!
*Average distance between stars in our neck of the woods is something like 5 light years. In the roughly 100 years we've been broadcasting that bubble has about 400 stars.
All this just for rectal probing. The aliens are a bunch of pervs.
The age of the universe and the successive generations of stars needed to fuse the heavier elements, and finally incorporate those elements into a G2V star capable of sustaining intelligent life, would put time constraints on how soon that could occur. At least for us in this corner of the Milky Way that’s been about 13.5 billion years (nuclear time) that it’s taken us to come this far in say, a few million years of humankind.
These constraints would be common preceding any intelligent race anywhere. Thus it appears to me that we’ve all had about the same time to develop, give or take a million years, maybe. And I suspect that if life capable of abstracting information from its environment is out there, it’s just as frustrated as we are that they can’t detect us either.
If you read my earlier post, we’ve transmitted an about 200 light-year bubble from random radio transmissions. Only about 80-year bubble for actual transmissions. (Though these have been directed, so they’re stronger but MUCH less likely to hit something. Like a grenade vs a rifle.) So detectable signals probably haven’t even actually hit anything. Put to the size scale, there are only ~30 planets on the 50 closest stars (within 16 light-years) per Google “closest stars”. Most of these planets aren’t even close to habitable, either gaseous supergiants, or just barren rock (lava). It would probably take you 100s if not thousands of light-years to find a planet similar to ours that could possibly have similar life.
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