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posted by martyb on Saturday October 29 2016, @07:41PM   Printer-friendly
from the Betteridge-says-No dept.

A little over 80 years ago, humanity first began broadcasting radio and television signals with enough power that they should leave Earth's atmosphere and progress deep into interstellar space. If someone living in a distant star system were keeping a vigilant eye out for these signals, they would not only be able to pick them up, but immediately identify them as created by an intelligent species. In 1960, Frank Drake first proposed searching for such signals from other star systems by using large radio dishes, giving rise to SETI: the Search for Extra-Terrestrial Intelligence. Yet over the past half-century, we've developed far more efficient ways to communicate across the globe than with broadcast radio and TV signals. Does searching for aliens in the electromagnetic spectrum even make sense anymore ?

[...] After all, if someone from a culture that was versed only in smoke signals and drum beats found themselves deep inside the heart of a forest, they might conclude that there was no intelligent life around. Yet if you gave them a cellphone, there's a good chance they could get reception from right where they stood! Our conclusions may be as biased as the methods we apply.

[...] But if we weren't looking for electromagnetic signals, what would we look at? Indeed, everything in the known Universe is limited by the speed of light, and any signal created on another world would necessitate that we be able to observe it. These signals — in terms of what could reach us — fall into four categories:

Electromagnetic signals, which include any form of light of any wavelength that would indicate the presence of intelligent life.

Gravitational wave signals, which, if there is one unique to intelligent life, would be detectable with sensitive enough equipment anywhere in the Universe.

Neutrino signals, which — although incredibly low in flux at great distances — would have an unmistakeable signature dependent on the reaction that created them.

And finally, actual, macrobiotic space probes, either robotic, computerized, free-floating or inhabited, which made its way towards Earth.

How remarkable that our science-fiction imaginations focus almost exclusively on the fourth possibility, which is by far the least likely !

http://www.forbes.com/sites/startswithabang/2016/10/21/are-we-looking-for-aliens-in-all-the-wrong-ways/ (requires Javascript) (archive.is).

Also covered by: Three Alternate Ways Scientists Should Hunt For Aliens


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  • (Score: 5, Interesting) by AthanasiusKircher on Saturday October 29 2016, @08:50PM

    by AthanasiusKircher (5291) on Saturday October 29 2016, @08:50PM (#420248) Journal

    Could humans a few centuries ago have imagined our modern methods of communication? Would they imagine aliens might make a giant signal flag or some other method of communication that would have been for long distances back then?

    Science and technology continues a relentless push forward. How can we possibly know what our civilization will be like in a few hundred or a few thousand years, let alone a few million? How can we know how an alien race at such a stage might choose to communicate, if it chooses to at all? We have a lot speculation about how we might travel in outer space or how we could communicate, but those are our current priorities, based on a mere few generations of playing around with tech. I think it's crazy to think that we'd have any clue about how a civilizations that's thousands of generations more advanced in technology might do things.

    I'm not saying SETI is completely fruitless. And I understand the arguments that EM radiation seems an obvious place to look for signals. But my guess (admittedly, again, just a guess) is that if there are other advanced civilizations out there, they've either figured out a way to communicate faster-than-light (in which case, would we even know how to pick up their signals?), or they recognize the futility of trying to send messages across large distances that may take thousands of years to get there, so they just don't bother emitting huge amounts of such signals... unless they're really well-targeted. SETI came about at a time when Earth was emitting huge amounts of EM signals that bled out into space because of new communication methods. A couple generations later, we've found ways to make such communication much more efficient, so we're no longer broadcasting with such strong signals. So, now we're proposing METI instead -- deliberately sending out EM signals because our natural signal is no longer strong enough.

    Even assuming that's how aliens would do it, how may years or decades or centuries would a civilization keep up sending out such a signal before giving up? If FTL travel and FTL communication is basically impossible (as some believe based on current physics), it seems likely that the interest might die out long before any successful communication actually occurs, particularly if life is somewhat uncommon. And if FTL travel and communication are possible for advanced civilizations, would they really need us to stand up and "wave a flag" to recognize something new is going on in our region of the galaxy?

    Maybe this is overly cynical. I just think a lot of these debates about whether there are aliens out there, or why aren't we seeing them, or how many REALLY are there, or what should we really be looking for -- they're all based on a civilization that first sent a person into space about 50 years ago. I don't think we have any clue what a civilization might do -- even if it started out very much like us, which is huge assumption -- if it's thousands or millions of years more advanced than we are.

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  • (Score: 2) by HiThere on Sunday October 30 2016, @12:00AM

    by HiThere (866) on Sunday October 30 2016, @12:00AM (#420367) Journal

    Read your H.G. Wells. (Or was it Stapledon?) He once imagined that the Martians tried to communicate with Earth by building geometric constructions large enough to be seen with a good telescope...by which he meant just slightly better than Mount Palomar.

    --
    Javascript is what you use to allow unknown third parties to run software you have no idea about on your computer.
  • (Score: 2) by mcgrew on Sunday October 30 2016, @06:02PM

    by mcgrew (701) <publish@mcgrewbooks.com> on Sunday October 30 2016, @06:02PM (#420580) Homepage Journal

    Could humans a few centuries ago have imagined our modern methods of communication?

    Of course not. The earliest inkling I've seen in print is Murray Leinster's A Logic Named Joe [baen.com], written the year the first programmable electronic computer was patented. The only mention of anything resembling a radio or TV a hundred fifty years ago or older was fairy tales; I'm thinking "magic mirror".

    Oh, Marconi patented the wireless telegraph in 1896, so that would be the earliest date aliens would have heard our signals. Would they be able to tell (maybe if Sirius had an intelligent species in 1905) that they were made by an intelligence? Would they even care?

    --
    Free Martian whores! [mcgrewbooks.com]