How Will We Spot Alien Signals if E.T. Is on a Tight Budget?

By Andrew Moseman | July 22, 2010 11:42 am

AlienCupcakesWe know that the Search for Extraterrestrial Intelligence (SETI) is often strapped for cash. But what if the aliens out there trying to reach us, rather than being far superior technologically and beaming signals in all directions, are actually starving scientists, too?

In a pair of papers in Astrobiology, three members of the Benford family—Gregory, an astrophysicist and sci-fi author; James, president of Microwave Sciences; and James’ son Dominic, of NASA—ponder  the possibility of E.T. trying to reach us on a budget, and say that we might have to revise the way we hitherto have watched.

Aliens wishing to communicate would probably broadcast at frequencies between 1 and 10 gigahertz, where there is less astronomical background noise than in other wavebands. Most SETI projects tune in to the “cosmic water hole” waveband between 1.42 and 1.72 gigahertz. The reasoning goes that alien astronomers might expect earthly scientists to be looking there anyway as this is the frequency of radiation emitted by interstellar hydrogen and hydroxyl clouds [New Scientist].

But, the Benfords say, it would be more cost-effective from the aliens’ perspective to transmit closer to 10 GHz. Given the energy needed to continuously broadcast in all directions, the authors say that aliens probably wouldn’t do that either. Instead, it’s more likely they send short pulses, and that they do it across the plane of the galaxy toward as many stars as possible.

“This approach is more like Twitter and less like ‘War and Peace,'” said James Benford [].

The problem, then, becomes picking out a tweet from the noise in space. The best candidates, the Benfords say, would be brief flashes that shone for a few seconds and then vanished. Because those kinds of signals have been spotted before, they’re trying to get scientists to comb the records for possibilities. But, there are other possible explanations for this kind of phenomena, like flare stars and pulsars.

We don’t have to just sit and watch, either. The Benfords propose a way for humans to create the kind of signals they say aliens are likely to make, and might therefore expect. However, for astronomers focused on cost-cutting, they’re talking about an awful lot of money.

They calculated that a galactic-scale beacon, with an antenna roughly a half-mile (0.9 km) wide with a range of a little more than 1,000 light-years, could be built for $1.3 billion. It would cost $200 million annually to operate. To work economically, it would use only narrow, high-power microwave beams and 35-second bursts aimed at each target star. “Of course, if you want to send a message, first you have to find a billionaire for this,” Gregory Benford [says] [].

Related Content:
80beats: Vatican to E.T.: Hello, Brother
80beats: Upgrading from Analog TVs Is Making Earth Invisible to ETs
DISCOVER: Who’s Out There?
DISCOVER: 20 Things You Didn’t Know About… Aliens
DISCOVER: Is Anyone Out There?

Image: flickr / Tama Leaver

  • Crow

    It’s a tough problem but it has a cheap solution:

  • Andrew Moseman

    I’ve gone through many a strainer helmet that way.

  • Chris the Canadian

    There’s a lot of assumptions there. A budget? Talk about putting a human face on extraterrestrial life!!! I have this feeling that WHEN we discover life on other worlds and other solar systems, they will be so vastly different from our own presumptions of what life is, that they will completely obliterate the narrow paradigms our current science and knowledge base has us pegged into.

    Ever wonder why the Theory of Relativity hasn’t become the THESIS of relativity? Think about it …

  • Chris the American

    Wow that’s a ridiculous post.
    1) Money is going to be an inherent part of any high-tech civilization. How ever would anyone (human or alien) be able to buy/sell/trade/compensate for anything? (Bartering is too complex to conceivably work nowadays)
    2) Budget = estimate of the cost of the materials/work to complete project.
    3) I don’t think they will be quite as different as you are implying. They will follow all the same laws of physics as we do. The biggest differences will be in morphology and culture.
    4) Relativity. You keep using that word. I do not think it means what you think it means. (Also, Thesis isn’t generally part of the scientific method. That’s more a part of the PhD method.)

  • Mitch

    I think searching for life by listening to radio waves is a long shot, in our evolution we’re talking about something that will have been discovered as well as discarded in less than 100 years overall. If we do discover an intelligent broadcast it would most likely be thousands of years old by the time it gets here. I wonder if we’d even notice if we were to pick up a fax signal being broadcast on a carrier wave….
    We’re more likely to discover communications with entangled particles or other mediums that we have yet to explore, and when we find them we will most likely find that there is a veritable storm of communication happening across the universe. We need to be careful in doing so and think very hard about replying as the probability of it all working out completely in our favor would be a long shot. Think about how we treat other life forms on our own planet…

  • Mitch

    BTW why would we want to communicate with aliens on a budget? We need rich aliens or it will drag down the value of the solar system…. We sure don’t need poor aliens sneaking across the border….

  • nick

    It’s not a thesis of relativity because Einstein didn’t do it for his dissertation, he did it after he left school. There is no thesis of quantum mechanics either, and if you don’t believe in that GTFO 20th century technology (hint: transistors would not be possible without our understanding of quantum mechanics, and thus this internet, etc would not exist – at least not as we know it.)

    Money isn’t the only answer. Think about the internet, and how it’s evolving as the cultural mind-hive of our civilization. If, as some predict, we eventually merge with machine intelligence to take our next step in evolution, what need would there be for money? Do the Borg, as an example have a need of dollars?

    Money is just information, it doesn’t ‘exist’ outside our society. You think money is real? You think there are really 2 trillion dollar bills sitting around in a vault representing Chase Bank’s net worth? No, no there isn’t, and don’t even get me started on fractional reserve lending where every loan that’s spent (say you buy a house with a loan…) is 90% re-loaned out to others…..

    I question the need to search for aliens at all – at best we should keep an eye out for incoming alien armadas, at worst we should spend all those millions of dollars improving the lives of the billion people on earth without enough to eat. You never know where the next Einstein or Beethoven may come from… but if history is any suggestion, they wont be coming out of our top-league first-world schools….

  • rabidmob

    Stop trying to communicate with extra-terrestrial life.

    Please try to find them without giving away our position any more than we have already.

    Just because I’m paranoid doesn’t mean they’re not out to get us.

  • Phil

    Technologically speaking, we do not stand a chance against a civilization able to travel their way to us. And based on our own behavior, to assume they would have altruistic interests is plain foolish. How about sitting pretty for a few more thousands of years? Thanks…

  • blueshifter

    SETI = Stupid Efforts To Investigate? Sapping Energy and Time Idiotically?

    Don’t get me wrong, I loves me some Carl Sagan – but come on. Srsly? Radio waves? lol

  • Dewey

    Considering the random events that had to occur for us to be here at all (i.e. demise of dinosaurs to start with), I believe most of the life to be found in the universe will not be what we think of as intelligent life. I’m confident that we will find bacterial life and the like throughout other worlds when we are able to visit/investigate but intelligent life does not follow a guaranteed static, evolutionary, serial flow; more specifically, it will no doubt be unlike anything we have seen here on our speck of blue dust.

    Also, assuming we did meet up with an intelligent life-form, it would be naive to presume it to be benevolent. Start with how we, as a self-absorbed benevolent species, deal with what we consider lower life-forms (e.g. eating them, using them for medical research, killing them for sport, etc.). If the lower life forms on this planet were able to characterize how they perceive us, no doubt they would likely describe us something like a raging elephant stomping around in a chicken coop trumpeting “Every man for himself!”

    Add to the above our tendency (need?) to believe in an afterlife, along with our inability to conceive of the realities and purpose of a pre-Homo Sapiens universe predating our embarrassingly short existence, by multi-billions of years, and we have a recipe for a first contact disaster.

  • chris c

    On an intergalactic scale the speed of light is very slow. I feel using the electromagnetic spectrum (tied to the speed of light) to communicate is akin to natives in Borneo trying to use a larger drum to communicate with someone in Chicago. I don’t know the method an advanced civilization will use for communication, but if we imagine ourself in 1810 who would have been able to imagine radio communication. We haven’t moved much beyond the invention of the radio have we?? SETI keep beating your big drum

  • m

    Maybe they are not even trasmitting. Maybe they are just listening? So millions of species are all sitting around their respective SETIscopes listening.

    Who is going to be the first to say “Hey! We are here!!” ??

    Personally – i dont have a problem with SETI. Perhaps some new technologies will come of it as we refine our filtering techniques or improve our radioscope designs.


  • Clean Star

    maybe instead of using all the budgets on trying to find and learn how to communicate with aliens we should at first try how to better with each other here on this our own planet.
    I think we are having bigger problems to solve here on earth than trying to find out if there are aliens out there or not.
    Just my 2 cents

  • http://n/a Veg Oil Guy

    Hey you can’t see anybody on yonder mountain cause he’s using a cell phone and he could care less about your smoke signals.

  • Brian Too

    One has to think that any alien civilization would face the same essential resource constraints we do: time, energy & matter. They’d want to communicate efficiently.

    However consider the known arc of life here on Earth and the time needed to advance to a level even capable of broadcasting/receiving EM signals. One has to wonder if the vast majority of ET life consists of single cell (or equivalent) organisms.

    Of course if that life started billions of years before our own then it’s had lots of time to get complex and more interesting.

    The essential problem remains. You have to look before you can come to any conclusions. There are so many possibilities.

  • Osso

    Let’s at least become a level two civilization before we reach out to the neighbors. If not for the poor reception we’d give them now, than at least to have a better defense in case they suck too.

  • Phil

    There has probably been a signal transmitted, from within our own galaxy, perhaps in the last 10,000 years, and it will arrive at earth in perhaps another 5,000-15,000 years. When the signal arrives we will all be back in the stone age after being struck by an asteriod. (or some other gobal disaster)
    There have also likely been signals from numerous civilizations that passed earth in the last 200 million years but have ceased some thousands or millions of years ago because those civilizations have gone mute for numerous possible reasons.
    The chances of catching a signal are about like going to a ball park and holding your hand up at any random moment, trying get the attention of the hot dog vendor, and expecting to catch a baseball.

  • http://www, Bonsai King

    What we should be looking for are interplanetary signals made by advanced civilizations. Like the signals that we receive and send to our Mars probes. Not the ordinary radio signal communications leaking out from the planet. These signals are too feeble.

    Intentional transmissions (eg. Contact – Carl Sagan) to say that “we are here . . .” , “we have once lived . . . ” , “let’s communicate . . “, ” we pass our technology to you . . .” are just rhetorics, just good for sci-fi.

    There are only two outcomes for this. First is, we find a signal and confirm existence of ET. Then we stop because we already know. Second, we get tired, stop the program and find other ways to communicate. Either which way, we stop and develop a better communication system. Research would then go to quantum entangled communications. It is impossible to colonize space if we rely on light-speed communications. Space faring civilizations who have colonized more than one world would definitely have a much better communication system. If they don’t, then that is the signal that we wish to catch. For civilizations these advanced, I don’t think transmitting will be that costly. Interplanetary transmissions for them would be like cell phone transmissions to us and hence not budgeted.


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