Talk:Fermi paradox
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Redirects: Fermi Paradox, Fermi principle, Fermi Principle
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Kudos
I think this article is a prime example of best features of Wiki type encyclopedic entries. It is by far larger than any entry I've found on the subject in a standard bound book style encyclopedia. It also presents a number of different points of view on the subject which covers the requirement of NPOV by providing as many (currently) reasonable POV(s) as possible.
The editing is superb and the contributions beautifully executed. Thanks to Uryian who started this article on January 27, 2002. --Wjbean 01:51, 13 Jan 2005 (UTC)
It doesn't strike me as quite as organized as I'd like, but I can't clearly say why. But the information content is quite good. I do think, however, it mixes the universe and our galaxy a bit. Fermi and Drake generally deal with the possibility of civilizations within our galaxy, with the assumption that intergalactic distances are too far for civilizations to spread. Yet the article asks questions about life in the universe, and doesn't clarify that Fermi is only galactic. --Belltower
Hi. Just came around to say that this article is outstanding, certainly one of the best I've seen in Wikipedia. Zaha 22:12, 13 Jan 2005 (UTC)
Brilliant work, everyone! All the related articles are really interesting too. A subject like this is nice since it has no political implications, celebrity figures, and really makes one think. Thanks!
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I agree this is a fine article but does no one think that most of this material should be moved to the extraterrestrial life article (which is rather sparse considering the popularity of the subject)? If I'm searching Wiki on this general topic I'm trying "extraterrestrials" or "aliens" not Fermi's paradox.
Changes
I removed the following from the article (under sub-heading "Current Data" just after mention of SETI):
- The rationale behind such a search is the observation that seen from several light years away, the solar system would appear to be extremely peculiar in that terrestial broadcast causes the solar system to radiating in the radio spectrum at serveral orders of magnitudes more energy than can be taken into account through natural means.
First, the "several orders of magnitude" comment needs substantiation (I am not aware that we had passed that threshold yet). Second, the sentence needs a bit of copyediting. Third, this statement would be more appropriate in the SETI article because it is stating the rationale behind SETI and not the topic (Current Data). Fourth, it is redundant; a similar sentence is already the topic sentence of "ET Phone Home". maveric149
This was also removed (From the end of "ET Phone Home"):
- A counter-argument to this points out how rapidly terrestrial civilization is moving from broadcast to cable transmissions; 100 years is a tiny fraction of the history of a planet, and we might not be in the right place and time to pick up the radio leakage of any star close enough for it to be distinguishable from noise. Still others contend that it would not be feasible for a civilization to depend upon cable-based communication for very long -- given the vast distances between moving bodies in even a solar system (let alone the distance between solar systems).
The first part of this statement is misleading: Just because cable television appears to be making broadcast television obsolete, doesn't mean that the radio signature of the Earth is going to diminish whatsoever. Satalites are receiving and beaming increasingly strong signals to and from the Earth -- causing very significant and growing "leakage". The second part of the removed section states additional fallacies.
This was also removed:
- Yet another explanation which has been advanced by some science fiction writers is that civilizations are deliberately hiding themselves in order to avoid destruction from some danger that we are not aware of.
I incorporated this statement into an early one a few sentences before. maveric149
Added similar sentence back in. Fear of conquest seems to me to be a strong reason to hide. In the first Star Trek movie, Voyager I managed to cause us a lot of trouble. :-) pstudier 03:40, 2003 Dec 19 (UTC)
2002
- Proposed by physicist Enrico Fermi, the Fermi Paradox attempts to answer one of the most profound questions of all time: 'Are we the only technologically advanced civilization in the Universe?'.
How does the Paradox attempt to answer the question? The paradox shows only that our estimates contradict our observations, for whatever reasons.
- Fermi's response was that if there were very many advanced extraterrestrial civilizations in our galaxy, then, "Where are they? Why haven't we seen any traces of intelligent extraterrestrial life?". Those that adhere to the premise behind the Fermi Paradox often refer to that premise as the Fermi Principle.
What premise are we talking about here? That there are lots of civilizations out there? Did Fermi subscribe to that principle? If not, it shouldn't be called "Fermi Principle". AxelBoldt 01:55 Dec 18, 2002 (UTC)
A widely-accepted view is that terrestrial life originated on the Earth itself. Lately, there has been increasingly more support for an idea first mentioned by Lord Kelvin— that life first came about on Mars and was transported to Earth by a meteorite. This latter position is defended on the basis that conditions which might support Earth-compatible life existed within a relatively short distance hundreds of millions of years before the Earth cooled. The more improbable that one deems life beginning spontaneously, the more likely it becomes that life arose first on Mars.
The last bit of this doesn't make any sense, and I suspect the first is a considerably exaggeration.
ca. 2004
I have a problem with the following para:
"The commonly held belief that the universe has many technologically advanced civilizations combined with our observations that suggest otherwise, appears to be paradoxical, suggesting that either our understanding or our observations are flawed or incomplete."
Firstly, our observations do not "suggest otherwise". If it is true that we have not observed many (or even any) technologically advanced extra- terrestrial civilizations, then it cannot be automatically deduced that such civilizations do not exist. For all our searching, we have still looked at only one drop of water in an entire ocean of universe.
Secondly, such observations as we have made are not "flawed". We have observed what we have observed (whatever that is), no more and no less. Our descriptions or interpretations of those observations may be flawed, but the observations themselves cannot be flawed. But of course they are incomplete, because we are considering not just some finite part of the sky but the entire extra-terrestrial universe. Our observations cannot be other than incomplete, just as a person who sets out to count to infinity can never reach his goal. The fact that our observations are incomplete is therefore not even slightly paradoxical, and the failure to detect any signs at all of what many people consider to be an intellectual certainty is because we have not been looking long enough, or maybe we are not being Proustian enough (you know, the saying about "The real voyage of discovery consists not in seeking new landscapes but in having new eyes". Everything I've read about UFOs, extra-terrestrial life etc convinces me that we have been sharing this planet with sentient beings for a vast period of time, but we don't recognise them as such when we encounter them, and we misattribute the evidence to something from outside the Earth.) How long did it take for Andrew Wiles to prove Fermat's Last Theorem? Centuries. And was this considered unprovable during this period? You betcha. Similar examples abound. It is going against the whole history of mankind's perpetual searching for new truths, to dump this whole subject into the "too hard basket", and suggest that because we who know everything cannot find extra-terrestrial life, it therefore could not possibly exist. What colossal arrogance!! Still, colossal arrogance is also a human trait. JackofOz 02:27, 12 Mar 2004 (UTC)
[1] (http://www.sciam.com/2000/0700issue/0700crawford.html) gives me a page not found. Can anybody find a fresher URL?
Edward 12:44, 2 Apr 2004 (UTC)
- I looked for one close to a year ago - it appears that at least that SciAm article is no longer on the Internet. --mav
Occam's razor
- A common concept used in the scientific method to test the validity of certain ideas is Occam's Razor.
Occam's Razor says nothing whatsoever about the validity of an idea, let alone test it. It only encourages a preference for fewer assumptions and more parsimonious explanations. The rest of the Conclusion paragraph is quite accurate (however much I wish it weren't), but this first line must go. I just having a hard time thinking of a suitable replacement. Any ideas? -- Jeff Q 07:15, 30 May 2004 (UTC)
I'll try "assess the likelihood" for "test the validity" Thincat 10:51, 13 Jan 2005 (UTC)
They haven't heard about us yet
Removed from article:
- If you assume that nothing travels faster then the speed of light, and life only began 4000 million years ago with self replicating RNA, intellegent lifeforms with perfect detection equipment (able to detect RNA from 4000 million light years away) would have to be within 4000 million light years away to notice. Now if you assume that humans are the only meaningfully intellegent life forms on the planet, they only appeared 10 thousand years ago. Any signal of this would take 10 thousand light years to reach other intellegent life forms. That is a pretty small area compared to the size of the universe.
- In additon, we may not have heard about them hearing about us yet. It would take at least equal time after discovering us to get back to us if not longer. Plus they may be to far away to feel it is worth it to contact an "intellegent species" such as ourselves.
The general intent of this section is the same as the 'They exist but have not communicated with us' section. I see no need to have a separate section. Furthermore the RNA bit does not make any sense to me; being able to detect RNA from 4 billion light years away??? Humans also appeared long before 10,000 years ago. The ' may not have heard about them' para is already taken care of in this article. --mav 08:04, 9 Jun 2004 (UTC)
Headings
Do the headings of this aarticle looking a bit odd on purpose, or do they accidentially go from 1-4 at === === level (3=s) and then from 1-7 at 2=s (== ==) level? -- ALoan (Talk) 21:17, 17 Aug 2004 (UTC)
They do not exist YET?
Surely I cannot be the only person in history who's thought of this concept, so there must be theorists with better credentials than I that can be quoted on the idea:
If there are, say, 5,000 intelligent and technologically advanced and xenophilic species in the galaxy at some given point in time (not necessarily now), the chances that they ALL spontaneously popped into existence and advanced at the same rate seems absurdly slim.
Therefore, except for that tiny chance, of those 5,000, one of the species had to evolve and gain technology FIRST.
This has similar arguments to the standard anthropic principle to support it -- the idea in this case being that if a given race IS first, it may not ASSUME it is first -- yet SOMEONE has to be.
Therefore, from this point of view, it's not inconceivable that other intelligent life forms do not, in fact, exist, but that at some point in the future they WILL exist.
I see no mention of this idea, yet it seems sound to me. Maybe I'm missing something, or maybe one of the arguments has just been missed.
The problem is that the galaxy has probably been capable of supporting intelligent life for a good few billion years. Of course, we could still be the first - humans have, after all, taken nearly a third the age of the universe to evolve from the primordial soup.
It seems to me that the Fermi paradox is strong evidence that the galaxy probably hasn't been capable of supporting life very much before the arrival of intelligent life on this planet. I agree with the person who started this section, that this seems to be the point which is missed in the whole debate. Indeed, according to current belief life started on earth 4-5 billion years ago, while the whole universe is just about 15-20 billion years old. This is not a big difference in orders of magnitude and the most plausibe resolution of the Fermi paradox is simply that now is an early stage in the history of the Galaxy, some time before the colonalisation by intelligent beings. And who knows, it could be us, we are still in the race.
Thorsten 21:18, 16 May 2005 (UTC)
One factor in the Drake equation is L, the expected lifetime of an intelligent civilization. So it contains the notion that they'll get here and say, "rats, we just missed them". Blair P. Houghton 21:37, 13 Jan 2005 (UTC)
Weasel words
"Some believe that our current knowledge of both chemistry and of biology strongly indicates that life is an exceptionally improbable thing to arise spontaneously." Who believes this again? - Ta bu shi da yu 01:54, 13 Jan 2005 (UTC)
"Another crucial item is the Moon. Many scientists believe it was formed by a rare collision between the young Earth and a Mars-sized body 4,450 million years ago." - can we have some names of actual scientists who believe this? - Ta bu shi da yu 01:56, 13 Jan 2005 (UTC)
"Those people who believe in the more optimistic assumptions used in the Drake equation proposed by Dr. Frank Drake and the even more optimistic assumptions given by Dr. Carl Sagan, add that intelligent life is also common in the Universe. Some state that by making what they feel are reasonable assumptions and arguments we can ascertain that if life is possible at all, then the universe is so vast that it should not only be possible, but almost certain that there are large numbers of extraterrestrial civilisations in the Universe. However those people who adhere to the premise of the Fermi paradox believe that, due to a lack of evidence to the contrary, in all probability, humans (as a technologically advanced species) are effectively alone in at least our part of the Milky Way. They further say that since we cannot yet determine the variables of the Drake Equation with any real confidence, we cannot determine the numbers of extraterrestrial civilizations based solely on this equation. We must therefore, they argue, rely on data, which is only now beginning to be collected in a significant manner. Only then can we even begin to presume what the values of each of the variables in the Drake equation are, they say."
This whole paragraph is a bunch of weasel words all strung together in sentence form!
- "Those people who believe in the more optimistic assumptions" - who?
- "Some state that by making what they feel are reasonable assumptions and arguments we can ascertain that if life is possible at all, then the universe is so vast that it should not only be possible, but almost certain that there are large numbers of extraterrestrial civilisations in the Universe." - who states this? How am I meant to verify this?
- "However those people who adhere to the premise of the Fermi paradox believe that, due to a lack of evidence to the contrary, in all probability, humans (as a technologically advanced species) are effectively alone in at least our part of the Milky Way." Again, how am I meant to verify this without knowing who believes this? and then how can I verify that: "They further say that since we cannot yet determine the variables of the Drake Equation with any real confidence, we cannot determine the numbers of extraterrestrial civilizations based solely on this equation. We must therefore, they argue, rely on data, which is only now beginning to be collected in a significant manner. Only then can we even begin to presume what the values of each of the variables in the Drake equation are, they say." ?!? - Ta bu shi da yu 01:59, 13 Jan 2005 (UTC)
Fermi's method of estimation
The Drake equation is an example of Fermi's method of estimation, which is like the dimensional analysis taught in freshman physics. Fermi would ask how many piano tuners are there in the city of Chicago?, and then invite computation. His point was that when there are a large number of factors in an estimate, then a miscalculation of one factor is likely to be compensated for by a miscalculation of another factor, resulting in a fairly good estimate. Ancheta Wis 10:19, 13 Jan 2005 (UTC)
Sphere axis of rotation is unstable?
I'm skeptical about the statement that "the axis of rotation of a sphere is unstable"; can we find a reference for it? Does it apply to oblate spheroids? --P3d0 15:14, Jan 13, 2005 (UTC)
It's unstable only in the sense that any external force that isn't perfectly aligned will tilt the axis, and the axis won't return to the former direction without another external force. In the absence of external force and internal asymmetry, it's not going anywhere; but that's not what stable actually means. Stable means that the value will return to its original value after the external force is removed (and then you can look up BIBO stability as well). The statement you're questioning is true under some assumptions, but needs to be qualified with the assumptions to be true always. Blair P. Houghton 21:48, 13 Jan 2005 (UTC)
Stephen Hawking Paradox?
Great article folks. Stephen Hawking similarly 'proved' the impossibility of time travel by questioning the lack of tourists from the future. Seabhcán 18:57, 13 Jan 2005 (UTC)
They haven't heard about us yet
If you assume that nothing travels faster then the speed of light, and life only began here on earth 4000 million years ago with self replicating RNA, intellegent lifeforms with perfect detection equipment (able to detect RNA from 4000 million light years away) would have to be within 4000 million light years away to notice. Now if you assume that humans are the only meaningfully intellegent life forms on the planet, they only appeared 10 thousand years ago. Any signal of this would take 10 thousand light years to reach other intellegent life forms. That is a pretty small area compared to the size of the universe.
In additon, we may not have heard about them hearing about us yet. It would take at least equal time after discovering us to get back to us if not longer. Plus they may be to far away to feel it is worth it to contact an "intellegent species" such as ourselves.
Conclusion
The conclusion paragraph as written is woefully brief and too full of uncritical assertions, imho. The statement of Occam's razor does not illustrate the example assumptions to show that the preferred conclusion has in fact the minimum set of assumptions, as well as ignoring whether it is the quantity of assumptions that is the issue, or the relative magnitude of the assumptions. As, taking the assumption behind the preferred conclusion, that we are alone, is rather large as everything else about the solar system has been shown to be non-unique.
The phrase "as a technologically advanced species we are alone in our part of the Cosmos" also has an unconscious bias that our technology is a-priori 'advanced', when the above discussion refers to cultures more advanced that might have progressed beyond electromagnetic technology for communication. A less biased phrase would just state that "as a species whose communication technology is based on electromagnetism, we are alone in our local region of the galaxy whose limits are defined approximately by the detection threshold of the Arecibo telescope".
The Designer solution
A wonderful article; it subsumes and extends my own personal page (http://www.faughnan.com/setifail.html) on the topic. I do agree though that the conclusion is relatively weak and seems out of keeping with the quality of the overall article. The DMT sections are a bit funny.
The article omits an important explanation however. It is one that humanists/secularists like myself usually omit. It is the Designer hypothesis; the core of which is that the universe was designed so that humans would be alone.
There are two variations of the Designer Hypothesis:
1. The simulation variation. (See my personal page for links). The purposes of the simulation may require that technological civilizations are rare or singluar.
2. The Genesis variation. A Deity created the universe and specified that technological civilizations are rare and rarely intersect.
The Designer hypothesis of course intersects with some of the "alien zoo" variations, but I think it's novel enough to have its own category. Personally I favor the 'inevitable singularity' explanation (technological civilizations go Singular so quickly none of them have time to travel or make much of a footprint); but honesty obliges me to note that the Fermi Paradox can be used as part of an Argument from Design (http://www.existence-of-god.com/argument-from-design.html).
PS. I must note that as I wrote this Wikipedia went offline. Hmmm. :-)
"Only one sentient species has evolved..."
On the "They never existed" section it says:
"Although it is possible that complex life may evolve through other mechanisms, the Rare Earth Hypothesis posits that the prerequisites of life as we know it seem to be rare. Bolstering this is the fact that in the extremely long history of life on the Earth only one sentient species has evolved that has the capability of space flight and developing technologies such as radio."
At least two sentient species developed: Homo Sapiens [Sapiens] and Neanderthal, but the Neanderthals lost, so to speak. The point is, sentient species would compete, so in the end there may be only one left to create space flight, radio, spam, etc. Therefore, this whole "fact that in the extremely long history of life on Earth only one sentient species [etc]" is a misleading statement at best.