Explain xkcd: It's 'cause you're dumb.
The Fermi Paradox is the contradiction that arises between high estimates of the likelihood of extraterrestial life and the fact that no evidence for it has thus far been found.
Cueball and Megan are having a conversation regarding this — since new planets are found all the time around distant stars, Cueball comments that this makes it an even greater paradox. Megan suggests that perhaps our search for extraterrestrial life is like looking at a patch of ocean floor looking for a fish. The diver knows that there must be a fish somewhere, but is unable to actually find it. She then goes on to ask why the fish would be hidden — i.e. camouflaged, and what it means about the remaining fish. The suggestion is that the fish would be hidden to avoid being eaten by predators, and perhaps the reason no extraterrestrial life is sending any sign of existence back is that they fear they might be destroyed soon after they revealed their location. Maybe they have even actively tried to hide the presence of their entire planet if they obtain the technological means. This potentially refers to the Deadly Probes scenario where a space faring species has developed deadly probes that self replicate and spread through the void between the stars - homing in on radio signals and destroying young civilizations in the cradle...
The camouflaged fish could be identified by using more sophisticated technologies like infrared cameras. Looking at the Earth from space beyond Low Earth orbit only with the naked eye wouldn't show any hint to our ecosystem. This is like the actual possibility in astronomy when observing exoplanets — the nature of those more than 1,500 known planets is unknown due to the lack of better technologies to the scientists. And there are a couple of hundred Billion planets at our galaxy still camouflaged to human scientists.
The final panels take the metaphor further, suggesting that there is literally a planet sized shark swimming through space eating planets, and since the view is panning away from earth and over to the shark, the shark seems to be heading our way. It looks like Earth is the next fish, presumably because we did not reach a high enough technology level in time to recognize the danger and hide.
This also explains the title text that has the theme from the movie Jaws playing while astronomers look into their telescopes. This may also be a reference to the film Alien, which was pitched with the three word proposal "Jaws in Space."
Stephen Hawking famously warns, “If aliens visit us, the outcome would be much as when Columbus landed in America, which didn’t turn out well for the Native Americans.” Even Carl Sagan called the practice of Broadcasting and Signaling presence of Life on Earth “deeply unwise and immature,” and recommended that “the newest children in a strange and uncertain cosmos should listen quietly for a long time, patiently learning about the universe and comparing notes, before shouting into an unknown jungle that we do not understand.”
- [Cueball and Megan are walking down a hill.]
- Cueball: The Fermi paradox keeps getting worse. If planets are common, where is everybody?
- Megan: Imagine you're a scuba diver looking at the ocean floor. You know there's a fish there, but you can't see it. Why?
- Cueball: Maybe the fish looks like sand.
- Megan: Yeah...
- [Zoom out to the Earth from space.]
- Megan: ...and what would that tell you about the ecosystem?
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- [The Earth is moving out of the panel and then a shark is shown swimming through space towards Earth.]
I took it to mean that we are the camouflaged fish and the extraterrestrials are the shark. We have been naturally selected to be hard to find through some means, probably by distance from a predator life form or just being tiny, and have thus not encountered any of them. -- Irino (talk) 06:57, 4 June 2014 (UTC)
So, Fermi's paradox is a good defense for why you caught no fish, even though "there's plenty of fish in the sea." 126.96.36.199 09:06, 4 June 2014 (UTC)
- Not the Fermi paradox itself, that just questions why we could not find an evidence of extraterrestrial life out there, but this possible explanation of it. There are also other possible explanations, see Wikipedia for them. STEN (talk) 15:50, 4 June 2014 (UTC)
- No, but it could explain why I can't find a girlfriend...
188.8.131.52 22:41, 4 June 2014 (UTC)
- Maybe you just are actually sexually oriented towards guys and don't consciously know it. Wait, is that a possible new explanation for the paradox itself? 184.108.40.206 04:11, 5 June 2014 (UTC)
The most probable predator to civilizations is another civilization. There may be civilization out there which is so scary everyone is quiet so they don't find him. Wait ... WE may be that civilization. Half of civilization in our galaxy fears the battleships from our sci-fi shows because they thinks they are real and the other half fears that civilization with that kind of shows is going to build real battleships soon.
Ok, seriously, I already commented elsewhere ... we don't have anything so valuable it would be worth the resources needed for sending attack fleet here. We would need to REALLY piss someone off to be attacked. At least ... physically. Hey, those telescopes searching for signals from other civilization ... how good antivirus protection they have? -- Hkmaly (talk) 10:22, 4 June 2014 (UTC)
- We don't have anything valuable so long as another civilization doesn't need and earth sized supply of calcium, potassium, sodium, nickle, and iron.--Bmmarti3 (talk) 12:34, 4 June 2014 (UTC)
- We do have pet ferrets. They are cute, It is unlikely that there is another source of pet ferrets in the galaxy. 220.127.116.11 13:32, 4 June 2014 (UTC)
- They can get all of this closer. In fact, even if they actually arrive in our solar system, mining the asteroid belt would require less resources that bothering with Earth. -- Hkmaly (talk) 10:21, 6 June 2014 (UTC)
- I've always found this to be terrible logic. In addition to sci-fi, we also broadcast news and documentaries. In addition to fictional triumphs, we also have real-life failures. We've broadcast that funding to NASA has been cut, and how he haven't been farther than the moon in what, 50 years? We have Mythbusters which is constantly debunking stupid stuff that humans believe, and also showing off the limits of our technology in a practical manner. We broadcast war, so they would be able to see just how deadly we actually are. Worst of all, we broadcast Fox News. I don't see aliens fearing us (if they're technologically advanced enough to spy on us without us seeing them), I see them wondering just what the Hell is going on here. 18.104.22.168 18:57, 4 June 2014 (UTC)
- This all assumes that they didn't go through their own cultural phases similar to our own. 22.214.171.124 18:59, 4 June 2014 (UTC)
- Maybe they do know about us, but they want us (as a species) to first grow out of our weird adolescent years and crazy ideas before they interact with us. You don't go around inviting random rebellious teenagers to your house for no reason, do you? 126.96.36.199 06:29, 7 June 2014 (UTC)
- They won't have complete annotated list. They will have pieces. They will have hard time understanding our language - or the method we encoded the images with. They don't need to have more advanced technology than we have to spy on us (well ... maybe little). The task of UNDERSTANDING what they received would be the hard one. With the percentage of broadcast occupied with real and fictional wars, it IS possible that only things they decode will make them conclude contacting us might be dangerous. -- Hkmaly (talk) 10:21, 6 June 2014 (UTC)
- I think that while they would know we are weak, they could fear us because we might someday develop enough technology to become a threat to them. That a civilization might be so paranoid as to attempt to destroy all other instances of intelligent life in the Universe when it finds tham does not seem so far-fetched to me. Of course, such a civilization only needs to fail once to be wiped out, so it's not the greatest survival strategy. -- Quadibloc (talk) 17:35, 6 June 2014 (UTC)
I think the problem is that traditional SETI methods are of dubious effectiveness at actually detecting radio transmissions from other civilizations due to the low initial power of said transmissions which then only get weaker as they propagate. Switch to our new optical methods of planet detection which have detected scores of planets in just a few years and the "paradox" might need to be reevaluated. Optical detection also makes it doubtful that any civilization would be able to effectively hide. Sturmovik (talk) 12:45, 4 June 2014 (UTC)
- If we would use our methods of planet detection on our solar system, we would notice Jupiter, Saturn ... and unknown source of radio emission stronger that Sun itself. -- Hkmaly (talk) 10:21, 6 June 2014 (UTC)
By the way, the Chinese sci-fi writer Liu Cixin has published a trilogy called "Three Body", focusing on this idea (he called it "dark forest"): what if all the visible civilizations have been destroyed? What if revealing your neighbor's location to the universe is similar to the MAD (Mutual assured destruction) situation? The English version should hit the market this year. --Ent (talk) 15:51, 4 June 2014 (UTC)
This is very similar to a *lot* of SF out there. Pellegrino's "The Killing Star" is one good example (with R-bombing and the problems associated with it), but it's certainly not the only one. Listing some of these might be good. Listing the "Central Park at night" example from "The Killing Star" might be a reasonable addition. Brdavis (talk) 16:23, 4 June 2014 (UTC)
The real reason seems clear to me: existence of other life forms in the universe is probabilistically certain, but universe is so huge (in space and time) that we have no hope of reaching it. Regarding "huge in time", for example Mars might have been like nowadays's earth one billion years ago with elaborate civilisations and yet we now struggle to find a trace of life
. Regarding "huge in space", no hope of reaching it or even have definite proof of discovery. Or, err. Well, I have not said "never", right ? But the point remains: universe is so huge that a lot of life can be "statistically everywhere" and we just can't see it because its density is too small. Which is another way to say: life most certainly exists on many planets (and other types of systems) yet the fact that we don't detect it easily means that the kind of life we are looking for never had a chance to propagate quickly enough gain enough statistical density to be easily noticed. Compare life with Cantor Dust
) 10:11, 6 June 2014 (UTC)