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Space Communications Science

Detection of Earth-like Civilizations in Space Now Possible 345

Mr. McGibby writes "Astronomers have come up with an improved method of looking for extraterrestrial life with an Earth-like civilization. Theorist Avi Loeb proposes to use instruments like the Low Frequency Demonstrator (LFD) of the Mileura Wide-Field Array (MWA), an Australian facility for radio astronomy currently under construction. The array could (theoretically) detect civilizations broadcasting in the same frequencies as our own society. From the article: 'Loeb and Zaldarriaga calculate that by staring at the sky for a month, the MWA-LFD could detect Earth-like radio signals from a distance of up to 30 light-years, which would encompass approximately 1,000 stars. More powerful broadcasts could be detected to even greater distances. Future observatories like the Square Kilometer Array could detect Earth-like broadcasts from 10 times farther away, which would encompass 100 million stars. ' The original paper describes the details."
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Detection of Earth-like Civilizations in Space Now Possible

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  • by metlin ( 258108 ) * on Tuesday January 09, 2007 @12:29PM (#17523526) Journal
    The fact that we haven't found any artificial signals from space yet doesn't mean there's nobody out there.

    And to quote Carl Sagan, "Absence of evidence is not evidence of absence."
  • by TubeSteak ( 669689 ) on Tuesday January 09, 2007 @12:30PM (#17523536) Journal
    How long do "earth like" civilizations put out RF energy that is detectable from space?
    How long will we keep doing it?

    Searching for XYZ years worth of RF in a bubble 60 light years across doesn't strike me as very promising.
  • by Minimum_Wage ( 1003821 ) on Tuesday January 09, 2007 @12:33PM (#17523600)
    The flaw with all these searches is that it assumes that any nearby civilizations are exactly at the same level of development as humanity. Isn't high-power broadcast radio actually declining on Earth right now in favor of cable, fiber, and low power systems like the small satellite DBS dishes? If an alien civilization isn't in the same +/- 50 year technological window as we are, we'll probably never hear them even if they are next door. Still, if you don't look you'll never be sure...
  • Re:Hmm. (Score:5, Insightful)

    by silentounce ( 1004459 ) on Tuesday January 09, 2007 @12:39PM (#17523670) Homepage
    "Given the massive distances between stars, astronomical mass extinction theories, and the time evolution takes, aren't the odds of two technically advanced civilizations being around at the same time...umm astronomical? :)"
    The true probabilities are not known. We don't know how common life is. We don't know how often a mass extinction of life occurs. We don't know how long evolution takes except for on our one world. We don't have enough data to accurately predict whether or not life is rare or common in the universe. Another perspective could be that it is in fact more likely that advanced civilizations would be around at the same time if the universe has a consistant timeline. If the way that life-harboring star systems form, the way that life itself forms, and the way that intelligent life evolves is analogous across the universe then this may be the Golden Age of intelligent life throughout our galaxy.
  • by laggist ( 784355 ) on Tuesday January 09, 2007 @12:45PM (#17523760)
    ..they probably know where we live by now :/
  • by Glacial Wanderer ( 962045 ) on Tuesday January 09, 2007 @12:45PM (#17523768) Homepage
    broadcasting in the same frequencies as our own society

    I think the real issue isn't frequency, but technology. Personally I believe there must be a practical way to transmit data at faster than light speeds. We've been using the EM spectrum for transmitting for just over 100 years. If there are better methods of transmitting data, not only will our search area be limited, but we'll be searching for is possibly a short lived technology.
  • by rhartness ( 993048 ) on Tuesday January 09, 2007 @12:48PM (#17523800)
    I've always considered these types of projects pointless. It's not because I think that we are necessarily alone but because the use of radio waves for communication seems like such a simple and quickly evolvable technology that we would never find them. Here's my reasoning.

    Let's assume that we are a 'typical' univeral life form. I'm haven't brushed up on my radio broadcasting history but I'll assume that we've been broadcasting information in some form since the 1910's. Let's now say that for the next 400 years we use this type of technology to communicate. I think that is a very large estimate, though. By that time the human race will have progressed so far (IMHO) that we will need much quicker and reliable forms of communication because of advancements in space travel and that type of communication will even trickle down into normal, everyday communication on earth. Using all modern forms of communication will not suffice if we have bases of operation even as close as our nearest star. I don't know what it will be, but a solution will provide itself and I doubt it will be anything close to what we have now.

    So, Let's assume then that we as humans use radio waves for 500 years, total. If you want, give or take an extra couple 100 years. It doesn't matter for the point I am trying to make. If we only use radio waves for a span of 500 years, than that amount of time is a drop in the bucket compared to the entire, vast expanse of time that has past in our universe.

    If there is another civilization out there. I'm pretty sure that they are either way behind or way ahead of us in technological advancements. If they progressed at even a fraction of the rate that we have (and will), then the span of time at which that have transmitted any type of communication that we can currently understand and interpret is so short that it's a practical impossiblity that we will 'catch' it. Don't get me wrong, I'm not saying that the entire search for intelligent life in space isn't important. I'm just saying that the current technology that we have is in such an infantile state that it's a waste of time and resources that could be put towards better works of science.
  • by MetaPhyzx ( 212830 ) on Tuesday January 09, 2007 @12:51PM (#17523840)
    Essentially, we're looking for someone "out there" that thinks/acts/interacts with their world the way we did with ours. It's almost identical to looking for carbon based life forms like us, on other worlds (Mars as an example). I understand that it's easier to start looking for what you already know, but with the variance of life and how we interact/communicate just on this planet, maybe we can think a bit more outside the box?
  • by Gulthek ( 12570 ) on Tuesday January 09, 2007 @01:14PM (#17524188) Homepage Journal
    That depends on how you are searching. Searching for your keys in a cluttered room with the lights off is going to be difficult, and you may look for quite some time without being able to conclude that the absence of evidence is evidence of the keys' absence.
  • by cowscows ( 103644 ) on Tuesday January 09, 2007 @01:23PM (#17524360) Journal
    Thank you, those are some very useful comments. I'm sure that all the astronomers out there, having read your post, are preparing their resignations, and will instead focus their time on solving all of the world's troubles. Thank you again, for bringing these issues to our attention.
  • Re:Hmm. (Score:2, Insightful)

    by JCOTTON ( 775912 ) on Tuesday January 09, 2007 @01:38PM (#17524556) Homepage Journal
    "but I could see FM radio being obsolete 100 years from now...

    What the hey? I am still using spark gap and CW Morse Code. No, once a technology is in place, it rarely is completely eliminated. Some people still ride horses, ride bicycles, hike, etc, even though they have cars. I use CW even though I have SSB and digital modes available (and a lot of people do also). By the way, FM is already obsolete. Right now that is.

  • by div_2n ( 525075 ) on Tuesday January 09, 2007 @01:39PM (#17524576)
    Your assertion is just wrong. Human beings are indirect proof of the possibility of intelligent life elsewhere. The fact that we haven't found/been given/detected evidence is immaterial.

    Regardless, you are attempting a negative proof or proof of impossibility. This is a logical fallacy. Interestingly, it works both ways. You can't prove a Yeti doesn't exist or that life (intelligent or otherwise) exists on other planets because you don't have evidence and vice versa. People can't prove either exist for lacking evidence. While the Yeti argument is another kettle of fish since life on earth is indirect evidence of life on other planets, it is a bit of a stretch but can be argued that the different primate groups are indirect evidence of the possibility.

    Interestingly, Yeti and ETs share the distinction that there exists no clear evidence of either. It is possible that we will never have proof of the existence of either. Equally, we will likely never exhaust all possibilities to satisfy ourselves that neither definitely don't exist. Unless we plan on leveling all forests, excavating every square inch of earth (for archaeological evidence) and visiting every solar system and planet in the Universe. Both of which are equally absurd.
  • by rleibman ( 622895 ) on Tuesday January 09, 2007 @01:48PM (#17524742) Homepage
    And to quote Carl Sagan, "Absence of evidence is not evidence of absence."

    I'll take your quote and raise: "Extraordinary claims require extraordinary evidence"
  • by exp(pi*sqrt(163)) ( 613870 ) on Tuesday January 09, 2007 @01:52PM (#17524794) Journal
    You are confused about the meaning of the word 'evidence'. When you obtain evidence of X you shift your estimate of the probability of X upwards. That's what 'evidence' means. You need to get this distinction.

    You say "you are attempting a negative proof or proof of impossibility" which demonstrates you didn't actually read or understand the parent post which stated, quite clearly, "Absence of evidence is prima facie evidence of absence.", not "Absence of evidence is prima facie proof of absence". Until you sort out the difference between proof and evidence the rest of what you say is moot.

  • by exp(pi*sqrt(163)) ( 613870 ) on Tuesday January 09, 2007 @03:56PM (#17527052) Journal
    Dictionaries are hopeless for providing definitions in even a slightly technical domain. Almost every definition of "evidence" in a dictionary is hung up on the notion of proof, probably because of the common legal use of the word. For this reason dictionary definitions tend to define 'evidence' in terms of 'proof'. But read just about any scientific literature - you will find many uses of the word 'evidence' but very few uses of the word 'proof'. In fact, 'proof' is something of a taboo word in scientific circles outside of mathematics. The notion of 'evidence' in scientific discussion is quite separate from the notion of 'proof', and its meaning is close to what I originally said: that which tends to increase the assessment of the likelihood of something. Carl Sagan's quotation is fine for legal discourse, but it's way off the mark for scientific discourse, the domain for which it was intended. Even in informal technical discussion the word 'evidence' ceases to carry the sense of being the thing that clinches the proof.

    In science, proof is a very rare thing. All we have are hypotheses that are more or less likely, and evidence that makes them so.

  • by bob_herrick ( 784633 ) on Tuesday January 09, 2007 @05:16PM (#17528948)
    Turn your point around. Assume that evolution of intelligent life is, if not routine, at least reasonably possible. No other intelligent lifeform has, to the best of our knowledge found us, and we have been detectable for several decades (say 30 to put it into the detection context of the article). Doesn't that suggest that the other explanation is not that intelligent life is not out there, but that detection technology is hard?
  • by buzzzz ( 767841 ) on Tuesday January 09, 2007 @05:33PM (#17529380)
    Actually it IS a big deal. It's been said by someone that if their exist two of something than there probably exist several of it.

    If primitive life forms are discovered on any planet other than Earth, there would be an astronomically higher chance of there being primitive life on several planets across the universe and thus an astronomically higher chance of intelligent life out there.

    It would, I hope, motivate a renewed search for life in the universe.
  • by Mozk ( 844858 ) on Tuesday January 09, 2007 @08:10PM (#17532234)
    Still, never hurts to check...

    It does hurt when the funding, research, and effort could be put to better uses. We ought to work on our needs such as learning about our own planet (there's so much that we don't know), and how our species is going to survive, since at the current rate, survival could become a problem fairly soon. What we shouldn't be worrying about is philosophical questions like if there is life on other planets or the infamous "are we alone?" Sure, finding life on other planets can give immense insight into, among other things, how life is created in general and not just on Earth, but we might want to get to a stable point in society and survival where we're able to take time to study it. It also seems somewhat foolish to be looking at other parts of the universe since we're not able to travel anywhere in a resonable amount of time (reasonable as in under 10000 years) unless we develop ways to travel at large fractions of the speed of light. Even then, outside of our galaxy, the next closest galaxy is millions of light-years away, and the information we've received would be millions of years old. Knowledge is great and everything but the search for extraterrestrial life seems very pointless, especially at our current state.

If you want to put yourself on the map, publish your own map.