Why Astronomers and Journalists should pay heed to Biologists about ET

The Milky Way is around 100000 light years wide. Humans have had the capability to look for ETs (as we expect them to sound) for what, 40-ish years?<p>Considering the time and space scales involved, it&#x27;s hard for me to believe we have enough data for a conclusion either way, particularly without assuming faster than light travel and also given the &#x27;youth&#x27; of the universe. Even if we did assume faster than light travel, it seems like you&#x27;d have to have insane levels of population growth to make it all that far from home without going very very slowly. And if you do start moving out, would it really be worth trying to signal home if it would take 1000 years or 100 years to reach &#x27;home?&#x27;<p>Another issue I have is what I&#x27;d term anthropological environmental constraints as applied to aliens, namely it&#x27;s quite conceivable that some home worlds would not offer the resources needed to make it into space, or would contain them in an inaccessible way. If a race of Einstein-like aliens is stuck on the a planetary equivalent of a desert island we&#x27;ll never hear from them.<p>As far as the self replicating robots go, I see two issues: first, it should still be pretty slow without light speed travel, and second, if these robots don&#x27;t have a realistic chance of reporting back to their source civilization, why would the civilization even bother? (We can barely understand the ancient Maya. When a robot returns after 30 million years, this problem seems like it&#x27;d only be exacerbated. Likewise, the time horizon is so far out it&#x27;d be unlikely a particular group would see an ROI argument to attempt it other than as a hobby.)<p>So I really feel like it&#x27;s a bit premature to draw conclusions about the &#x27;Fermi Paradox.&#x27;

One paragraph stands out for me:<p>”In his article Dobzhanksy turned Sagan’s argument on its head. Dobzhansky cited the fact that of the more than two million species living on Earth only one had evolved language, extragenetically transmitted culture, and awareness of self and death, as proof that it is “fatuous” to hold “the opinion that if life exists anywhere else it must eventually give rise to rational beings.”“<p>I find this interesting because some scientists are open to the fact that dolphins[1] and elephants[2] may be significantly more intelligent than we previously supposed, and possibly as intelligent as humans. The difficulty lies in defining exactly what intelligence is - and how we measure it in other animals.<p>That in turn leads to more questions. Suppose that there is, in fact, at least 3 human-level sentient species on our own planet. Observe: only one of them have developed tools to the extent that space travel is a problem that we&#x27;re trying to solve. Perhaps the reality is that there <i>are</i> as many intelligent species as astronomers posit - maybe multiple species per planet! - but almost all of them have no interest in exploring and settling on other planets.<p>[1]<a href="http://www.dolphins-world.com/dolphin-intelligence/" rel="nofollow">http:&#x2F;&#x2F;www.dolphins-world.com&#x2F;dolphin-intelligence&#x2F;</a> [2]<a href="http://en.wikipedia.org/wiki/Elephant_cognition" rel="nofollow">http:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Elephant_cognition</a>

* Snarky comment numero uno: If I understand the author and the Less Wrong, Bayesian, weirdish probability thought process, I suspect that the correct conclusion to this article is that humanity doesn&#x27;t actually exist.<p>* Snarky comment numero dos: The Drake equation includes a term:<p>&quot;L = the length of time for which such civilizations release detectable signals into space&quot;<p>(I originally heard that as the length of time before or probability of a civilization destroying itself. Yay, collapse of the Soviet Union! Progress!)<p>Anyway, I believe that humanity is no longer trying to outshine stars with our radio broadcasts, or at least that we are not getting any brighter. So here&#x27;s a question or two for the author&#x27;s model:<p>What is the probability that a civilization will release self-replicating probes? (Granted, that anything that <i>can</i> be done <i>will</i> be done, <i>must</i> be done by someone, sometime.) What is the probability that you will be able to detect such probes if one was standing next to you right now? I&#x27;ll just note that in a comment on another article, the author writes, &quot;But if 1000 years from now we start sending probes out to explore and replicate across millions&#x2F;billions of stars. We’d have detectable radio traffic and other signs that SETI would pick up.&quot;<p>Snarky comment numero tres: So, evolutionary biologists believe that Darwinian evolution, if it leads to intelligent life, further <i>inevitably</i> leads to self-replicating robotic space probes?<p>I suspect the only reasonably hard conclusion that biology lends to the goofy debate is that life, not necessarily intelligent life, is <i>everywhere</i>, given that our one anecdote here indicates that life developed incredibly quickly on the scale of planetary existence.

I think this piece makes a very good point and makes it very well.<p>One thing I wonder about, vis-a-vis SETI-style projects, is the idea the humans could identify extraterrestrial communication even after receiving it. I&#x27;m fine with assuming that extraterrestrial life is attempting to communicate with us and is using technologies we&#x27;d be familiar with (eg., electromagnetic radiation transmitting binary data) — until we ourselves develop some other technology, this is our safest assumption. But we should also assume that a sufficiently-advanced lifeform would transmit data near the information theoretical maximum efficiency, and of course, maximally-efficient data will appear entirely random to an observer who has no means to make sense of it.

When approaching the Fermi paradox astrobiologists usually use the principle of convergent evolution [1], where multiple types of life will evolve similar features because of similar environmental pressures. (the application is the development of intelligence.) I&#x27;m a big fan of this, because it affirms my hope that life exists elsewhere. But unfortunately we don&#x27;t really know what &quot;life&quot; and &quot;intelligence&quot; is -- an intelligent dolphin might never think or desire to leave the ocean, and an intelligent four-legged creature might never think to look up at the sky and wonder, the way that humans have always done.<p><a href="http://en.wikipedia.org/wiki/Convergent_evolution" rel="nofollow">http:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Convergent_evolution</a>

So why is it inevitable that any civilization that can evolve to the point of space travel will necessarily have the desire and capability to continue to expand before extinction? We&#x27;ve only been around a relatively short time and there is no certainty that we will be around long enough to be able to spread across the galaxy. If someone had told me in 1969 that 45 years later we would have lost the capability (or desire) to colonize the moon, I would have thought it highly unlikely. But here we are.

A few people in different threads here talk about self-replicating robots or probes. The way they write, it seems as though we already have the technology to make them - which comes as a surprise to me.<p>So: for those of you who have talked about self-replicating machinery - where exactly are we at with that technology? And why are so many people sure it&#x27;s more attainable than, say, faster-than-light travel?

Taking a cynical view of the paradox, saying that not having already detected ET means that ET couldn&#x27;t exists, opens a new paradox. What if every intelligent civilization looked at the same problem and reached the cynical point of view: why bother looking?<p>And what&#x27;s to say we&#x27;re not aliens ourselves? That Prometheus movie hinted at the possibility, so did Star Trek. Both point to an original creator that uses simple biology and knowledge of evolution to seed planets with life and let it grow. Modern astrobiology, as documented in the recent Cosmos reboot, thinks that life has already been traversing the galaxy on space rocks; crashing into planets in an ice ball and taking hold where it can. While not intelligent by human standards, it still spreads ET life. With the time scales involved, it seems like space rocks with simple life on them might be spreading ET fairly evenly through our galaxy and beyond.<p>As smart as we are, we have only recently been able to hurtle some space junk out of our solar system and into deep space. The distances involved and the limitations of our current understanding of physics make it seem likely that we wouldn&#x27;t be in direct contact already. It&#x27;s taken 2 generations for Voyager 1 to travel that far.<p>Using ourselves as the perfect example, our own broadcasts haven&#x27;t reached very far into our own galaxy. If we are typical and our understanding of physics is reasonably accurate, there could be numerous human-like civilizations broadcasting and sending out probes constantly and we just haven&#x27;t waited long enough -- the distances are too vast for us to have heard them. Or worse, we&#x27;re not intelligent enough yet to listen to the broadcasts that are being sent to us already.<p>I say we build these magical self-replicating probes and send them out and hope we don&#x27;t accidentally create the Borg. The only way to beat the paradox is to play along. And if we don&#x27;t find anything, then we&#x27;d better get to colonizing!

Nathan Taylor introduces the (in my eyes) most comfortable explanation for the Fermi paradox. While I think it&#x27;s a perfectly reasonable explanation, I also wanted to add my own from a while back: <a href="http://jcfrei.com/my-take-on-the-fermi-paradox" rel="nofollow">http:&#x2F;&#x2F;jcfrei.com&#x2F;my-take-on-the-fermi-paradox</a>

I take a Kurzwielian view. There is probably a significant transition in the physical bodies of an intelligent lifeform past a certain point of evolution. and a dramatic increase in cognitive ability.<p>Fermi&#x27;s Paradox makes more sense when you theorize that ET transforms its biology into a computational substrate prior to gaining the ability to travel between stars, as will likely happen with us. When it does this it turns into something we won&#x27;t even recognize, something likely a million times smaller than us due to miniaturization, and a trillion times smarter. Even if they are around they probably don&#x27;t have the patience to interact with us, dumb as we are and with minds that travel 10^5 or so slower.

I&#x27;ve read two books on this and my current favored solution to the Paradox is Supernovae and&#x2F;or Gamma Ray Bursts. Particularly GRB as they have to ability to sterilize whole galaxies. There is a possibility even Earth has already faced one 440m years ago.<p><a href="http://www.youtube.com/watch?v=7HIokbQMHB8" rel="nofollow">http:&#x2F;&#x2F;www.youtube.com&#x2F;watch?v=7HIokbQMHB8</a>

In summary: The universe is very young and we might be one of the first type &gt;= 0 civilizations.

A friend of mine is professor in genetics in Columbia university. He spent many years experimenting around the RNA world hypothesis and his opinion is that the origin of Earth life was a very unlikely event. Once in a Universe unlikely.

The Fermi Paradox is nothing of the sort. It is simply an expression of how thoroughly ignorant we are about the nature of advanced technological and interstellar life, no more. It might mean that we are ignorant of the short lifespan or extreme rarity of technological civilizations, but we have insufficient data to support conclusions along those lines. It is more likely that our surmises about the nature of colonizing interstellar civilizations are just fundamentally in error in some way we cannot even really understand today in the same way that someone in the year 1500 BC would not truly understand the internet or antibiotics or electricity produced by way of nuclear fission and so wouldn&#x27;t understand their impact on our way of life.