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Alien Contact Unlikely For Another 1,500 Years, Says Study (msn.com)

An anonymous reader writes: Astronomers at Cornell University predict based off estimates that alien contact is unlikely for another 1,500 years. MSN reports: "According to the astronomers, signals from Earth would need to reach half of all the solar systems in the Milky Way in order to be picked up by an intelligent life form. Given that signals from TV and radio were first sent into space as a byproduct of broadcasting 80 years ago, it will take around 1,500 more years for aliens to receive, decode and respond to the signals." A co-author of the paper who will present it at the American Astronomical Society's meeting on June 16, Evan Solomonides, said, "We haven't heard from aliens yet, as space is a big place -- but that doesn't mean no one is out there. It's possible to hear any time at all, but it becomes likely we will have heard around 1,500 years from now. Until then, it is possible that we appear to be alone -- even if we are not. But if we stop listening or looking, we may miss the signals. So we should keep looking." Stephen Hawking and Russian entrepreneur Yuri Milner announced a $100 million research program in April to send robotic probes the size of postage stamps to nearby stars within a generation.

87 of 159 comments (clear)

  1. What? by Anonymous Coward · · Score: 2, Insightful

    I've already made contact

    1. Re:What? by Anonymous Coward · · Score: 3, Funny

      anal probes in the woods don't count.

    2. Re:What? by NettiWelho · · Score: 4, Funny

      I've already made contact

      Impossible. Aliens are not implemented in this simulation, they only exist in the parent universe.

    3. Re:What? by edittard · · Score: 1

      It might be Elon Musk. I have trouble telling them apart sometimes.

      --
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  2. keep looking by turkeydance · · Score: 2

    we want to get paid

  3. Twenty five thousand light years by Geoffrey.landis · · Score: 3, Interesting

    The Solar System is 25,000 light years from the center of the galaxy. So, it takes 25,000 years for signals from Earth to reach half of the solar systems in the galaxy... and another 25,000 years for them to respond.

    --
    http://www.geoffreylandis.com
    1. Re:Twenty five thousand light years by Zak3056 · · Score: 5, Informative

      In 25,000 years, you'd reach far less than half. I don't feel like trying to do the math, but suffice to say that a circle centered on Sol with a 25,000 LY radius contains more like 25% of the stars in the milky way (if that).

      --
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    2. Re:Twenty five thousand light years by PolygamousRanchKid+ · · Score: 1

      If they see what is on television here . .. . I doubt if aliens would respond to us . . . CSI: Mars, indeed . . .

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    3. Re:Twenty five thousand light years by Calydor · · Score: 1

      Less than that, even, since we're not even getting into the distribution of solar systems across the galaxy, arms vs. the gaps between them and so on.

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    4. Re:Twenty five thousand light years by Calydor · · Score: 3, Interesting

      No they're not.

      Let's assume the aliens are advanced enough to pick up our TV signals and realize this isn't just background noise. At that point the time it will take them to figure out WHAT these signals are would probably be negligible; let's say ten or twenty years since the signals aren't encrypted in any way. 1500 year round trip minus those twenty years is 1480, which means some 740ish light years distant. That's on the optimistic end of the "1000 light years give or take a few hundred" spectrum.

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    5. Re: Twenty five thousand light years by Shakrai · · Score: 1

      Imagine the crushing disappointment of the alien anthropologists when the signals are successfully decoded. I think there was even a Star Trek: The Next Generation, where an alien scientist learns that the Federation monitored her civilization's entertainment broadcasts prior to first contact, and the response is predictable horror. So it is here; American Idol may be the first impression we make on an alien civilian. $deity help us....

      --
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    6. Re:Twenty five thousand light years by Roger+W+Moore · · Score: 1

      In 25,000 years, you'd reach far less than half.

      Exactly and tracing the article back to the original Cornell press release it is not a mistake in the reporting either. I expect there will be a few red faces in the media relations department at Cornell soon...

    7. Re:Twenty five thousand light years by rtb61 · · Score: 1

      Even at that speeds the galaxy has been around for billions of years and even those closest to us in evolutionary terms, cropping up every at logical minimum hundred thousands year to a logical maximum 10 million years, means they have had a shit bucket ton of time to place satellites around every likely planet so they can watch the next species tear itself apart as it tries to evolve from it's planetary cocoon to become a galactic species.

      So what this statement really says is, "I can not imagine any way it can be done by a species 1 million years more advanced than me, even though 1 thousands years ago, posting this stupid message on an electronic forum was completely unimaginable". What the fuck is it with the bullshit that more advanced species have to be stupider than us. Alien contact is far most likely to occur the very instant they feel like it is appropriate to present it to the entire population because they want to accelerate it to the next stage because https://www.youtube.com/watch?..., yeah, suck it up.

      --
      Chaos - everything, everywhere, everywhen
    8. Re:Twenty five thousand light years by Midas+Beurling · · Score: 1

      They are assuming those aliens would be 790 light-years away.

      If those aliens were to respond as soon as they detected our signals, and if we were to detect their response exactly 1,500 years from now, then their distance from us would be 790 light-years. It works out as follows: our signals have already traveled 80 years outwards. In 710 more years they will reach those aliens -- making the outbound trip 790 years. The return trip would take 790 more years making a total from today of 710 years + 790 years = 1500 years.

    9. Re:Twenty five thousand light years by Midas+Beurling · · Score: 1

      There are considerably fewer than 1 percent of the solar systems of the Milky Way within the distance implied by a response arriving to Earth within 1,500 years.

      If those aliens were to respond as soon as they detected our signals, and if we were to detect their response exactly 1,500 years from now, then those aliens would be 790 light-years away. Our signals have already traveled 80 years outwards. In 710 more years they would reach those aliens. The return trip would take another 790 years making a total from today of 710 years + 790 years = 1500 years.

      The Earth is about 26,000 light-years from the center of our galaxy. If we cut the Milky Way into pie slices, how *wide* would a slice have to be 26,000 light-years from the center to accommodate a sphere of 790 light-years? To simplify, let's consider that sphere to have a diameter of about 1600 light-years.

      A circle around our galaxy 26,000 light-years from the center would have a circumference of about 160,000 light-years, so the Milky Way could be cut into *100 pie slices* wide enough 26,000 light-years from the center to accommodate a sphere having a diameter of 1600 light-years.

      This also neglects all the solar systems in our slice which are less than 25,210 light-years from the center of the galaxy, and more than 26,790 light-years from the center of the galaxy. It also neglects all the solar systems in roughly the same zones in the other slices as well so, again, there are considerably fewer than 1 percent of the solar systems of the Milky Way within the distance implied by a response arriving to Earth within 1,500 years.

    10. Re: Twenty five thousand light years by Calydor · · Score: 1

      American Idol isn't what's going to make the aliens decide to give us a wide berth.

      World War II is.

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    11. Re:Twenty five thousand light years by olof_the_viking · · Score: 1

      Yes.
      If an advanced civilization is or was out there, probes will have been placed in a nice and quiet place like Pluto or Mars, and the time it takes them to know about us is the time for their fastest way of communication back home.
      If they decide to come visit is another question, maybe when we have something interesting to offer them.
      If they are not more advanced than us, what is the point in them finding out we exist? Communication?
      An extraterrestrial pen pal would be cool, but the 1500 year reply time would not.
      If they are not really close (in this context a lot less than 1500 ly) or have FTL technology to offer, there is simply nothing interesting we can do "together"!

    12. Re:Twenty five thousand light years by ai4px · · Score: 1

      A probe on Pluto is ridiculous. A probe on the moon, now that's close enough and plausible. It should have the dimensional ratios of 3:2:1 and appear non-descript.

    13. Re:Twenty five thousand light years by martinfb · · Score: 1

      ...unless they have FTL capability.

      --


      Self-importance and self-indulgence is the root of ALL evil.
    14. Re: Twenty five thousand light years by olof_the_viking · · Score: 1

      If you can open a wormhole, sure, but if you are transmitting regular photons, distance from the sun decreases the power requirements â

    15. Re: Twenty five thousand light years by Coren22 · · Score: 1

      I imagine that the two nuclear blasts, and probably the test blasts were far more powerful in the EM spectrum than most of what we broadcast for TV.

      --
      APK likes to ask for responses to the same things over and over. Maybe he just likes the responses?
    16. Re: Twenty five thousand light years by RockDoctor · · Score: 1

      Unless it gets them salivating.

      --
      Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
  4. Sooner than that by Haxzaw · · Score: 3, Funny

    I'm pretty sure the aliens are coming back next week... on June 24th at a theater near you. "Independence Day: Resurgence"

  5. Nothing to see here by maorb · · Score: 1

    *Study funded by Aliens Anonymous

  6. Keep the Skies quiet by Anonymous Coward · · Score: 1

    If you have listening devices at some grid spacing, then you can, with some wiggle room, fire up some kind of kill vehicle for the star that is emitting them. Spend a couple centuries accelerating as close to light speed as you can, make a nice gamma ray burst. Keep the skies quiet.

    Weak aliens wouldn't detect anyone, or make any sign.
    Powerful friendly aliens would have made a big sign trying to sell you alien Jesus, and tell you how to build something helpful.
    Powerful hostile aliens would either try to tell you how to build something suicidal, or would wait for you to make noise and squish you.
    No aliens would not say anything, because they don't exist.

    So either there's no aliens, weak aliens (essentially the same thing), or powerful hostile aliens.

    Why are we trying to communicate again?

  7. Radio interference by scorp1us · · Score: 3, Interesting

    How long until those signals are indistinguishable from background? It's not just that the signal is there, but that the SNR is low enough to stand out.

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    1. Re:Radio interference by Gavagai80 · · Score: 1

      About a light year, I believe -- so nobody is going to be picking up our TV signals. We could send a detectable signal to nearby stars if we wanted to, but we aren't.

      --
      This space intentionally left blank
    2. Re:Radio interference by Applehu+Akbar · · Score: 1

      For this reason, I think that our first detection of aliens will be imaging of large-scale engineering rather than signal leakage. And NOBODY is going to be intentionally signaling.

    3. Re:Radio interference by ChrisMaple · · Score: 1

      For a 1 MW omnidirectional broadcast TV signal, the receiving antenna would have to be have to be a perfectly aligned directional antenna at least 2e-10 radians across. That's 300 miles at 1 light-year. (Warning, that's very sloppily approximated.)

      Conclusion: Nothing is going to see broadcast video from Earth beyond a small fraction of a light year. For signal intercept to happen at hundreds of light years, both sending and receiving antennas have to be very narrow beam and aimed at each other.

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    4. Re:Radio interference by Anonymous Coward · · Score: 1

      No. Our first detection of aliens will be the detection of an unnatural balance of elements in an exoplanet's atmosphere (evidence of fusion, fission or fossil fuel use). This is how they will first detect us as well. Radio signals, intentional or not, require an intentional listening effort to detect, and flat out can't be seen from very far. Exoplanet atmospheres are interesting in their own right, and we are already starting to analyze them with our current technology so it's relatively easy. In a few decades we'll have a very good idea of every nearby exoplanet's atmospheric composition, well before we can get detailed images of anything as small as a planet in another solar system.

    5. Re:Radio interference by delt0r · · Score: 1

      Because of diffraction effects. You need both antennas to be very large as well.

      --
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    6. Re:Radio interference by pghmike4 · · Score: 1

      Even if you're in geostationary orbit, the SNR ratio for most of our TV shows is pretty close to zero. At least with the right definition of "noise."

  8. Well I'm glad that's settled.. by butchersong · · Score: 1

    So using only early 20th century technology and understanding of physics for.. forever and assuming alien life is also operating under this handicap, it is likely to take 1500 years to contact alien life. Good to know.

    1. Re:Well I'm glad that's settled.. by 110010001000 · · Score: 1

      Oh look. Someone who thinks physics is going to radically change and we are going to be flying through wormholes in the future.

  9. Inverse Square Law by casings · · Score: 1

    There is not much possibility of our signals being heard due to the inverse-square law.

    Most of our signals will be indistinguishable from the CMB, and if we generate a massive focused beam, we are going to have to be so precise, that it is most likely not feasible. 2 completely unrelated points traveling in 3 dimensional space, and we would somehow have to send and receive a beam (because sending one way is useless) when there is no way to guarantee where the other point will be due to all the exotic forces in the universe. Sounds like magic.

    This stuff doesn't work like geostationary satellites, you can just point it in one direction and expect in a million years when you get the reply that they will be in the same spot. Honestly the radio search for ET life is pointless, you would think a bunch of scientists and mathematicians would avoid spending their careers playing the lottery.

    1. Re:Inverse Square Law by Kjella · · Score: 1

      and we would somehow have to send and receive a beam (because sending one way is useless) when there is no way to guarantee where the other point will be due to all the exotic forces in the universe. Sounds like magic.

      While we don't exactly understand why the stars seem to be affected by a gravitational pull from dark matter, doesn't mean we can't measure the relative motion with a very high degree of accuracy. It is highly likely that our ability to predict the source of a transmission and the place we'd need to aim to reply - down to arc-milliseconds - far exceeds our ability to focus a beam so narrowly.

      --
      Live today, because you never know what tomorrow brings
    2. Re:Inverse Square Law by nbritton · · Score: 1
  10. The guess work here by Lucas123 · · Score: 1

    Is astronomical

    1. Re:The guess work here by speederaser · · Score: 1

      The guess work here ... Is astronomical

      You might be going for a joke here but I think you're spot on. Humanity has only been space-faring for a few decades and is already (almost?) able to detect oxygen in the atmosphere of another sun's planet. Nothing screams LIFE like detecting earth-like levels of free oxygen. If we detect oxygen, those systems will go to the top of the list for visiting when (not if) we get interstellar capability.

      With 21% oxygen in the atmosphere, the earth has been screaming LIFE to the universe for hundreds of millions of years. Anybody out there even slightly more advanced than we are knows there is something to see here. And I believe that anybody out there significantly more advanced that we are can get here with little trouble.

      The only question is, what will they think of us when they get here? Will they think us peaceful or barbaric? Listen to the news and ponder that question.

  11. Too optimistic by Ferocitus · · Score: 1

    A research paper I read in the last few years showed it's very unlikely for TV and radio signals to propagate far beyond Alpha Centauri without deteriorating to the point of being completely unintelligible. Fox News, doubly so.

    --
    USB, USB, USB!
  12. Shouldn't it be 3000 years? by mveloso · · Score: 2

    1500 years to get there, 1500 years for the reply?

    1. Re:Shouldn't it be 3000 years? by hambone142 · · Score: 1

      No problem. Their receivers to to eleven.

  13. Why do we have to initiate contact? by ortholattice · · Score: 3, Insightful

    The assumption is that we have to initiate contact for them to respond. Why wouldn't they be trying to initiate contact also? In theory, we could hear from them tomorrow if they are more advanced and initiated contact long ago.

    1. Re:Why do we have to initiate contact? by Creepy · · Score: 1

      The assumption also is that they didn't do this, say 2 1/2 million years ago and gave up 5 years later. A lot of factors led to intelligent life on earth and expecting it all to happen at the exact same time somewhere else is ridiculous. I expect when we do find life on other planets, we'll find a lot more dumb life before we find intelligent life.

  14. Re:One bad assumption after another! by sycodon · · Score: 2

    The worst assumption is that anyone would actually be intersted in speaking with us. One look at the TV signals and they'd immediatly place a quarantine around our solar system.

    --
    When Fascism comes to America, it will call itself Anti-Fascism, and tell you to give up your guns.
  15. Such Nonsense by argStyopa · · Score: 3, Insightful

    "predict from estimates" Really?

    Seriously, does anyone even 'journalist' anymore?

    This is a simple wild-ass guess based on NOTHING. Aside from that simple fact...

    They "guess" that signals would have to reach "half the systems in the Milky Way" to have a reasonable chance of being intercepted...but then say that this will happen in only another 1500 years.

    Quick hint: just looking at it as a 2d issue, the Milky Way is 100,000 ly across, more or less. It doesn't take a mathematician to realize that a 1500-ly radius circle doesn't come CLOSE to hitting 'half the systems in the Milky Way'.

    For those mathematically bent, a 50k ly radius circle has an area of about 8x10^9 sq ly.
    A 1500 ly radius circle is 7x10^6...so about 1/1000 of the galaxy, not half.

    "Experts", eh?

    --
    -Styopa
    1. Re:Such Nonsense by Spasmodeus · · Score: 1

      Every time I see another one of these "Scientists predict x% chance of alien life somewhere, somehow" I get more and more annoyed, because the whole thing is about as scientific as predicting the number of angels currently dancing on pinheads, yet this crap somehow keeps getting published.

      We have abolsutely no idea of the likelihood of life on other planets, or of the probability that that life will evolve into something that will be "intelligent" in a way that can comprehend or respond to our signals.

      Our statistics for the evolution of life are based on a sample size of exactly one. We have found life on exactly one Earth-like planet. We can't even say how likely it was that life came to exist on *this* planet, so extrapolating that to the rest of the galaxy is asinine. It is only slightly less scientific than astrology.

      So please, stuff your Drake Equation straight up your Fermi's Paradox, and go back to your marathon of Minesweeper, or whatever it is you were doing before you decided to crap out another prediction for alien life.

    2. Re:Such Nonsense by argStyopa · · Score: 1

      Curiously, I DID check the original work.
      https://arxiv.org/abs/1604.076... says
      "We predict that under 1 percent of the galaxy has been reached at all thus far, and we do not anticipate to be reached until approximately half of the stars/planets have been reached. We offer a prediction that we should not expect this until at least 1,500 years in the future."

      Per my previous math, using a simplistic 2d area of the Milky Way and a simplistic smooth distribution of stars (I know they're not, but they're actually denser further in, so this is really giving the paper the benefit of napkin-math), they say that the signal has to reach HALF the systems to have a reasonable chance of response.

      Again:
      The area of the galaxy (50k ly radius) 7.85Ã--10^9 ly.
      The area of the galaxy covered by our 80 years of emissions -
      - in their summary, they say 1%
      - in fact, it's 2.5x10^-6 or about 0.00025%

      In 1500 years, the coverage will be:
      - in their summary, about half.
      - in fact, 7x10^6 or or 0.09%

      To cover half the milky way would take about 35000 years of broadcasting.

      Rather than being snarky, could you please point out my error in math or understanding?

      --
      -Styopa
    3. Re:Such Nonsense by Spasmodeus · · Score: 1

      My apologies since I wasn't clear enough. I wasn't being snarky about your comment, I was agreeing about the problem with these kinds of "studies" and adding that regardless of how long it takes radio waves from Earth to reach a given portion of the galaxy, we still can't state any meaningful probability of a response because we have no meaningful data on the probability of life on any of the planets reached.

  16. We might not be here in 1500 years by kheldan · · Score: 1

    At the rate things are going, the human race may not exist in any significant way 1500 years from now. We'll either pull ourselves out of the various tailspin-inducing shenanigans, or it'll get us.

    --
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    1. Re:We might not be here in 1500 years by jittles · · Score: 1

      At the rate things are going, the human race may not exist in any significant way 1500 years from now. We'll either pull ourselves out of the various tailspin-inducing shenanigans, or it'll get us.

      Not to mention the Vogons who are lobbying to build an hyperspace bypass.

  17. Re:Do you really think? by fullmetal55 · · Score: 1

    chances are intelligent life does exist, and that there are civilizations that are the same, astonishingly ahead, or behind. and everything in between. The real trick is to catch the right people at the right stage of developement at the right time, in the right place. the odds are against us making random contact. plus who knows maybe we are being contacted, but it's the equivalent of us sending a radio broadcast to a civilization in the middle ages. Yeah there's intelligent life there, but they have no idea what we're sending or how to receive it. It's entirely possible we just aren't listening right.

  18. Re:One bad assumption after another! by rdelsambuco · · Score: 1

    What a bore.

    --
    I comment occasionally so that I can mod others -1 overrated or -1 offtopic.
  19. They already reached all the Solar Systems by TimSSG · · Score: 1

    "Earth would need to reach half of all the solar systems in the Milky Way" I think all the people is science should know there is ONLY one Solar System in the Milky Way. There is a lot of other star systems in the Milky Way. Tim S.

    1. Re:They already reached all the Solar Systems by tsqr · · Score: 1

      The definition is case sensitive. "Solar System" is our Sun and the stuff in orbit about it; "solar system" is any star and the stuff in orbit about it.

  20. Easy : a few AU less than a few ly by aepervius · · Score: 4, Informative

    More or less since the first signal we blasted out for tv and radio where omni-directional , count about 1/r^2 decay in intensity. A few hundred AU at most a few light year (e.g. we are almost not detectable if we had a SETI outpost placed on our nearest neighbors). Basically what our SETI is trying to detect , is intentional unidirectional powerful "we are here" signal sent by an ET civ, like we did in direction of Gliese or M13. There is a nice table with all signals including TV and maximum range : http://www.faqs.org/faqs/astro... scroll to "Table 1 Detection ranges" for assumption and detection range. Basically the only signals ET could detect beyond 10 LY, is our own intentional signals sent from various folk in the last 4 decades, and those maximum are around a few hours duration top.

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  21. How would we respond? by irrational_design · · Score: 1

    If we received broadcast signals from an alien civiliazation how would we respond? We don't have the technology to go there. At best we could send a broadcast toward them. Why would we assume that they are any different? Or is that what they are assuming? That is, our broadcasts will reach them in 750 years and then they will respond quickly so 750 years later we will receive the response?

  22. 1500 more years to live... by marciot · · Score: 1

    So humanity has 1500 more years to live before the aliens come and destroy us.

    1. Re:1500 more years to live... by telchine · · Score: 2

      So humanity has 1500 more years to live before the aliens come and destroy us.

      Only if the aliens can travel at the speed of light

  23. C'mon you can do it faster! by LynnwoodRooster · · Score: 1

    You just have to reverse the polarity of the deflector array. Duh, anyone knows that!

    --
    Browsing at +1 - no ACs, I ignore their posts. So refreshing!
  24. 1500 years? by jouassou · · Score: 1

    If intelligent aliens are watching us from afar, they might have checked the spectroscopic signature of our atmosphere, and realized millions of years ago that we live on a temperate planet with a lot of water, and that the high oxygen content in the atmosphere is an indication of life.

    1. Re:1500 years? by nbritton · · Score: 1

      The volume of the milky way galaxy is about 5.24 * 10^14 lightyears. The volume of earth is about 1.28 * 10^-27. You could fit 4.09 * 10^41 earths within the space of the milky way galaxy. Intelligent aliens are not watching us from afar, we are a needle in a haystack. We are less than a speck of dust when compared with the size of the universe.

    2. Re:1500 years? by Your.Master · · Score: 1

      What's missing is that indications of life might not be strong indications of intelligent life. Depending on the ratio of worlds with life but no intelligence to worlds with intelligent life, and the mean time for intelligent life to develop on a no-intelligent-life world.

  25. Probe Droids disguised as postage stamps? by infuriatedweasel · · Score: 1

    Lord Hawking should send his probe droids to Hoth. Rumor is that there's a detectable signal from a shield generator.

  26. Looking for intelligent life by Hamsterdan · · Score: 1

    They might not find any so we'll be left alone... Joking aside, they might have something akin to a Prime Directive, and we're not advanced enough in technology to be worth contacting, or not civilized enough (we're still trying to extinct ourselves)

    --
    I've got better things to do tonight than die.
  27. Re:One bad assumption after another! by hambone142 · · Score: 1

    You mean to say they wouldn't like to get to know Honey Boo Boo or the Kardashians?
    They wouldn't like our politicians or reality TV (one of the same)?

    How could they pass us up?

  28. Probably not a bad thing by Beeftopia · · Score: 1

    An extra 1500 years before catching the attention of aliens is probably not a bad thing. That's more time to prepare defenses. It's hard to guess the nature of the extremophiles which live in space, or the space-faring races which navigate it.

    We shockingly might not be perceived as peers or equals by space-faring races, but as an inferior species. And the history of superior species meeting inferior ones is not all rainbows and unicorns.

  29. Strange sensation by Opyros · · Score: 1

    It feels strange to hear a pessimistic assessment of SETI from Cornell astronomers. Carl Sagan, we miss you...

  30. Seriously? by rgbatduke · · Score: 4, Insightful

    The "scientists" at Cornell who are getting headlines with this breaking news haven't the foggiest clue how far away the nearest alien intelligent species is from Earth. Possibilities range from living here already among us or lurking in the solar system to "there are no alien intelligent species in the Cosmos", we could be unique. If you assume -- not unreasonably -- that evolution of advanced life requires an extremely unlikely accident -- like a collision with a proto-planet that is just the right size to strip away some atmosphere components and deposit others and rearrange the distribution of massive elements in the developing crust and then produce a moon that initially is very close and produces huge tides, plus a magnetic core, plus the right distance from the right sun, plus the good fortune not to be hit AGAIN just as intelligence is teed up, plus the enormous good fortune of the developing species making it over the self-extinction hump -- we might be alone in the entire galaxy or in very rare company extragalactically, even with a trillion trillion star systems to choose from. Or, the odds could be a D&D 20 sided dice roll per star. We just don't know. There is no evidence, and our theories of planetary evolution and abiogenesis are just that -- theories with very little substantive evidence to support them.

    Then there are the other silly aspects of their claim. It is rapidly looking like a developing civilization is likely to have only a narrow window where they radiate a substantial amount of organized radio wave energy, so one has an even narrower window for retarded detection. Also that emitted (wasted!) energy at its peak is on the order of maybe a megawatt or two in any given channel on its brightest day, and the 1/r^2 law is pitiless. Just one light year away your 10^6 watts are spread out across 4\pi (10^15)^2 ~ 10^31 square meters. Let's see: 10^6/10^31 = 10^{-25} watts per square meter. If you turned an entire planetary surface into a directed antenna, it would have a cross sectional area on the order of 10^14 square meters, leaving you with 10 whole trillionths of a watt receiver power. Sure, why not, a piece of cake we can amplify that and resolve signal from noise -- using a planet-sized antenna and black magic.

    So a better answer is that we will never be visited by space aliens who "pick up our TV signals" any more than we will pick up their signals. If some NEARBY civilization is crazy enough to point a directional, tight beam radio station right at the solar system and pump it with a terawatt or so, sure, maybe we could receive it here. But resolving the waste signal of a civilization order of tens of light years or more away? The amazing thing is that anybody manages to get this sort of thing funded. Simple arithmetic makes a fairly powerful argument that any SETI effort is a complete waste of time and money. No matter how cool -- and dangerous -- it might be.

    rgb

    --
    Even when the experts all agree, they may well be mistaken. --- Bertrand Russell.
  31. Re: One bad assumption after another! by Anonymous Coward · · Score: 1

    Light years are measurements of distance, not time; I know...it's confusing.

  32. Re:Easy : a few AU less than a few ly by Anonymous Coward · · Score: 1

    If we ever invent FTL I wonder if we could travel way out, build a big dish, and retrieve the lost TV episodes of early Dr. Who? Some lost movies?

  33. Re:Easy : a few AU less than a few ly by delt0r · · Score: 1

    If if its not omni directional you still get 1/r^2 decay in intensity. Even with lasers. The beam is still spreading out even with diffraction limited "optics".

    --
    If information wants to be free, why does my internet connection cost so much?
  34. Meanwhile in the 1940-50's... by Adeptus_Luminati · · Score: 1

    I'm just going to leave this here...
    http://majesticdocuments.com/d...

    --
    No trees were killed in the making of this post; however, many trillions of electrons were horribly inconvenienced.
    1. Re:Meanwhile in the 1940-50's... by Adeptus_Luminati · · Score: 1

      Oh in case you prefer video presentation format....
      https://www.youtube.com/watch?...

      --
      No trees were killed in the making of this post; however, many trillions of electrons were horribly inconvenienced.
    2. Re:Meanwhile in the 1940-50's... by dave420 · · Score: 1

      Aaah yes - misinterpreted papers are definitely going to help further science.

  35. 1,500 years to prepare to defend ourselves or run by doobydoobydoo · · Score: 1

    Does this therefore set a timeframe of the order of 1,500 years for us either to colonise other planets, to defend ourselves against unknown aliens of unknown capabilities and intent, or to build the technology for at least some of us to flee?

  36. Then I have time to clean the house by RogueWarrior65 · · Score: 1

    Plenty of time to clean the bathroom and run a vacuum through the place.

  37. Already happened ... publicly will again in ~2024 by UnknownSoldier · · Score: 1

    1. The authors are completely clueless that some humans have already met at _least_ 4 alien species, let alone the public evidence:

      a) NASA's own footage: (Evidence: The Case For NASA UFOs), and
      b) High ranking Government official's testimony Disclosure Project

    2. They are also completely ignorant that First Contact is tentatively scheduled to happen as early as 2024 and as late as 2040. Some bullshit "theory" will always lose to reality.

    It is no longer a matter of "if", but "when" our mass consciousness is ready to accept the facts that humans are:

      a) considered animals by (some) more evolved and intelligent species,
      b) that we don't own this planet, and
      c) that humans were genetically engineered.

    As someone said on YouTube:

    "It can be difficult for people from underdeveloped worlds to hear that their planet is not the only inhabited planet ...ï"

    The good news is that we get to meet our progenitors!

    --
    "Truth is stranger then Fiction"

  38. Re:One bad assumption after another! by Geoffrey.landis · · Score: 1

    Holy fuck. I think you've made one bad assumption after another.

    To the contrary, I didn't make any assumptions at all. I was pointing out that using the assumptions that they stated in the article quoted, their time scales were seriously wrong.

    To be specific, they (not I) wrote "According to the astronomers, signals from Earth would need to reach half of all the solar systems in the Milky Way in order to be picked up by an intelligent life form".

    If that's their assumption, it will be 50,000 years before we get a reply-- not 1500. Yes, you can criticize that assumption. Go take it up with them, not me.

    --
    http://www.geoffreylandis.com
  39. Re:One bad assumption after another! by ai4px · · Score: 1

    I imagine they would decode our TV signals and their interest piqued. They would build a rocket ship and begin their journey here. About 50 years into their trip, they'd see honey boo-boo and the K sisters and turn around.

  40. Well this.... by ai4px · · Score: 1

    Well this certainly explains the 2nd coming of Jesus Christ! 1500-2000 years , give or take....

  41. wrong -- Milky Way is bigger by pghmike4 · · Score: 1

    The Milkyway's diameter is 100,000 light years, so even if we were in the center, we'd need at least about 35,000 years for our signal to reach 50% of the volume of the galaxy. If the reply took 17,000 years to get back (probably doesn't originate at the most distant part), then you're talking about 52,000 years. Minus the 50 or so during which "I Love Lucy" has already been traveling.

  42. Radio: Like Smoke Signals by Wingsy · · Score: 1

    Every civilization goes through a brief period in their history where radio communication is the thing. And then for the next millions of years (if they live that long) they rely on whatever it is that supersedes radio (gamma rays, neutrinos, gravity waves, etc). Everybody knows this. Listening for radio signals is like us watching the plains of Texas for smoke signals from a new native american tribe. Who is doing this today?

    --
    If I didn't have absolutely NOTHING to do, I wouldn't be here.
  43. stupid assumptions by bobvious · · Score: 1

    The only reason I read something with a headline like this is to see what kind of boneheaded assumptions these "scientists" (are astronomers automatically scientists?) make. The idea beings millenia or epochs ahead of us can't travel faster than light is stultifying. Let alone, that they haven't figured out how to communicate in faster modes.

  44. Someone doesn't know how radio waves work. by StephenWilliamSchnar · · Score: 1

    Except because of how radio waves travel, it's like writing on a balloon and expanding it...the message becomes distorted to the point that it becomes unrecognizeable once it passes a certain, relatively short range. We could have had alien broadcasts hitting us since we started listening , and we wouldn't know it.

  45. Headline for Slashdot tomorrow by rcase5 · · Score: 1

    Scientists report receiving a long series of pings from space, embedded with a picture of Adolf Hitler and blueprints for a trans-dimensional space travel machine.

  46. Assumptions by ebvwfbw · · Score: 1

    This is assuming that we have to contact them first. What if they put us here to begin with? As we want to spread out in case of a catastrophic event, maybe they did the same thing and that's why we're here.

    We could also be some kids science experiment.