The Surprisingly Obvious Way We Could Hunt For Alien Life

The Surprisingly Obvious Way We Could Hunt for Alien Life

A team of astronomers is proposing a new way to hunt for intelligent life that sounds rather obvious when you think about it: We need to be the aliens. Or at least, we need to put ourselves in their shoes and think about where in the sky they can see us. Finding other beings like ourselves would change the world, but it ain't going to be easy. The Search for Extraterrestrial Intelligence (SETI) has been hunting since the 1960s, and it's only managed to scan a small drop of the sky for radio signals. Astrobiologists have proposed many ways that we could narrow the search, from focusing on star-rich globular clusters to directing our instruments toward the Galactic centre, where higher rates of star formation imply more possibilities of finding habitable worlds — or perhaps more importantly, where a really clever intelligent species might plant a beacon.

Another way to think about the problem is to ask where in the cosmos alien life can see us. If there are people out there searching for habitable worlds in the same way we are, where would they have to be to spy a world that's 70 per cent ocean-covered, with a nitrogen-rich atmosphere, orbiting 149.6 million kilometres from a G-type star, about halfway between the galactic centre and the Milky Way's rim?

If our cosmic neighbours can see Earth as it transits the Sun, then, René Heller and Ralph Pudritz argue in the journal Astrobiology, it's possible they have already found us. And if that's the case, they might be sending out a signal. That's why Heller and Pudritz argue we should turn our ears to Earth's "transit zone", a thin slice of space containing approximately 100,000 potential stars.

100,000 still sounds like a lot of targets, but it's way less daunting when you consider the 100 billion stars in the Milky Way galaxy — and it happens to be about the volume of space we can see with today's radio telescopes. Last year, Russian billionaire Yuri Milner kicked off Breakthrough Listen, a $US100 million effort to discover alien intelligence. That means that SETI now has both a solid funding source and a potential roadmap.

As with any "we should be looking here for aliens!" argument, there are a thousand caveats and unknowns. We don't know that aliens are out there at all. If intelligent beings do exist, there's no reason to think they're using telescopes and radio waves to study the stars. In fact, many philosophers and SETI researchers will argue that any alien civilisations we can detect are likely to be very old — and thus, they might vastly exceed our technological capacity in every conceivable way. Perhaps, then, it really isn't so wise to be looking for them. Perhaps they don't want to be seen. And so forth.

But it's in our nature to explore and to ask these questions. And if scouring Earth's transit zone slightly increases the odds of us ending our cosmic loneliness — and even better, finding intelligent life that's roughly comparable to us in technology — I say it's a project well worth our effort.

[Astrobiology via Motherboard]

Top image: Abel 1689 Galaxy Cluster, via Wikimedia


    If they are using technology even just a hundred or so years ahead of us, it's likely they can't hear us and for sure they are technologically too far ahead for us to hear or see anything they are broadcasting. I hate to be the naysayer on this, but I really think we need to develop both in technology and maturity before we'll find anything. Besides that, I really think they are right next door and we are a tourist destination.

    Last edited 02/03/16 12:20 pm

      I'm very confused that you argue that a technologically superior race would find it harder to transmit a detectable signal.

        I'm positing that if they are using a higher tech, it's likely it wouldn't find a lower tech, it sounded better in my head now that I think about it. Of course my assumption that they are already here, or next door is my main avenue of thought. Meh! whatever :)

        Last edited 02/03/16 1:13 pm

        If you were looking, would you be looking for morse code? Thats a poor example, but indicative of the point. As our technology improves, we lose touch with earlier versions of a field, and they largely fall into the same realm as dead languages - historical interest only.

        So if someone is looking this way, would they recognise our transmissions as being transmissions, or would it just be lost in the background as they looked for something closer to their technology?

        And the same goes the other way as well. Would we recognise another culture's transmissions? There's nothing to say a different evolution uses the same methods to communicate, so what if they made breakthroughs with (to use a recent headline) gravitational waves and used that as their method?

        How would we know?

          You're correct that we'd have a hard time recognizing transmissions from aliens which expect that a language or similar arbitrary coding system might be useful. In my opinion we should neither try to contact extremely stupid aliens, not hope to.

          "would they recognize our transmissions as being transmissions"

          Yes, any searcher seeing low-entropy fluctuations in sidebands tightly bound to a carrier, such as television or radio would definitely suspect an intelligent source.

          "Would we recognize another culture's transmissions?"
          Two parts to that:

          1: Could we detect them?
          That's a function of technology and distance, I don't think there's any more to say.

          2: Could we decode them?
          If they wanted us to, of course!
          Babies aren't born knowing Spanish!

    Unfortunately, the plane of the solar system is a long way off that of the galaxy, so we don't present as a good candidate for seeing our system's planets transiting the sun from many stars. And our planets are either small or slow. Hard to spot. Perhaps we need to put an infeasibly large veil in space so we can send signals toward the centre of the galaxy?

      Honestly, I'd much rather not be detected, so inhabiting a sneaky system is just fine :)

    All this assuming that other intelligent beings out there will be carbon-based, oxygen-breathing creatures. That assumption always rubs me the wrong way.

      Being that carbon has such a huge valence, they are likely to be carbon based. However, oxygen breathing.....yeah that's another matter entirely. For the majority of Earth's history, life didn't breath oxygen. E.g. there's no reason to think that alien life would NEED oxygen to survive. This would mean, from their point of view, an oxygen rich atmosphere is poisonous and thus worth ignoring for "advanced life".

        Not necessarily. We breath in nitrogen which is significantly more prevalent than oxygen but not particularly poisonous for us as we exhale it. There's no reason to believe that an alien species couldn't breath in oxygen like we do nitrogen, while feeding off of the nitrogen instead afaik.

        Last edited 02/03/16 3:53 pm

          Oh I am not arguing that they COULDN'T breath oxygen, just that we shouldn't assume that they DO breath oxygen. However, being a carbon based life form is more of a probability than any other atomic base, simply due to the prevalence of carbon valence bonds.

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