Changing Planet

Where are the Aliens? Interview With a SETI Researcher

Some future searches for alien civilizations will focus on potentially habitable planets, like in the Kepler 62 system, seen here in this artist illustration. Credit: NASA Ames/JPL-Caltech.

Yesterday the internet was abuzz with talk about UFOs and the Roswell incident, which took place 66 years ago this week.

Discovering life beyond Earth has always been considered by some to be the holy grail of science. However, no little green men or even measly microbes have been conclusively found. But this hasn’t dampened the enthusiasm among astronomers who are still searching the cosmos for signs of extra-terrestrial life.  The current leading search method uses giant radio dishes to scan the stars, listening for possible faint signals coming from distant civilizations.

National Geographic News caught up with SETI (Search for Extraterrestrial Intelligence)  radio astronomer, Andrew Siemion, who is based at the University of California at Berkeley, to chat about how astronomers listen for aliens.


What kind of alien signals are scientists looking for?

There are intentional signals – much like a lighthouse or a beacon – [that] can produce an emission intentionally designed to produce a signal so that other intelligent life know they exist.

Then there is leakage signal — akin to our aircraft radar, and TV broadcasts.  A signal like this, however, would have to be very powerful for us to be able to detect this right now from Earth.  For example, the farthest we could detect signals like what we are leaking right now with our current technology is probably at best only 1 light year out. [The nearest star to Earth is Proxima Centauri at 4.3 light years.]

However if we allow extraterrestrial (ET) telescopes to get large – say a radio telescope that has the diameter of the Earth – then they could detect very weak signals.

Many in the SETI community believe that the first signals we may detect will not be leakage signals but intentional ones designed to notify others of their presence.

But new telescopes are coming online soon, like the Square Kilometer Array, the largest radio telescope ever built in history. It will have 10 times the collecting area of the Arecibo radio telescope in Puerto Rico, and will be sensitive enough to ET signal leakage from 5 to 10 stars of the nearest stars.


Any region of the sky that current searches find particularly exciting?

In just the last two years NASA’s Kepler planet-hunting mission has taught us is that most stars have planets.  We are also learning that the habitable zones are much broader than what we [previously] thought.  We know there are lots of way to get the heat needed to keep water in its liquid form.  What this means is that we are really starting to expand our ideas about the kind of conditions that would be necessary for life to emerge.   At SETI today, we not only do all-sky surveys, but  more and more targeted searches too – focusing on the nearest stars to the Earth.

Research is showing us that 10 to 15% of stars have a planet in the habitable zone -where liquid water could exist on the surface.

Because our equipment is not that sensitive it’s best for us to look at stars that are closest to Earth.

One of my proposed studies plans on focusing on just that – the 100 nearest stars to the Earth.


What are the biggest advances since the start of SETI that allow us to focus these searches?

Technologically we have gotten larger and larger telescopes and faster and faster computers. And for radio SETI, the sensitivity of our experiments and the amount of radio channels we can explore is directly related to how fast our computers are. Because we don’t know where ET might be broadcasting it’s a good idea to look at as many channels as possible.  The first experiments decades ago could look at only 10 channels, and now we can look at billions.

Looking into the future, in perhaps a decade time, we might be able to explore the entire radio spectrum over the entire sky.

So what this means to me is that, if, after a couple of more decades of searching we haven’t discovered a signal, we may have to fundamentally rethink the way we conduct the search for ET.


 What do you think are the chances of finding an ET signal?

Overall the SETI community is optimistic since we continue to learn more about astrobiology, and that conditions suitable for life may be quite ubiquitous and technology is getter faster and more sensitive.

But the bottom line is that we really don’t know since we are constantly restricted by the fact that we only have a single example of life anywhere in the universe.  That severely limits the amount of statistics we can apply.

If we could find just one more genesis of life- even if it was just a lonely microbe – I could answer this question much more scientifically and quantitatively.


Why do you think we haven’t stumbled across a signal yet?

The famous Fermi Paradox asks just that: if intelligent life is so common then where are they? My personal opinion is that electrical engineers in the cosmos are pretty rare.

I think life is pretty common and even intelligent life might be relatively common but technological civilizations like our own may be relatively rare.

If every star had a planet with intelligent life just like our own, were long lasting and survive their technological development, and was altruistic and decided to signal its presence, we would have already detected something.

So clearly intelligent life is not that common.  But we need to explore much more of the radio spectrum to really say something more profound about how rare civilizations like our own might be.


What is the most likely form of a signal we might find a signal?

It might very well happen while an astronomer is conducting a new kind of experiment, maybe something that looks at dark energy or dark matter, something that is very sensitive and they encounter something in their observational data they did not expect.

Perhaps after exhausting all possibilities they may come to the most amazing conclusion about where that anomalous feature in their data is coming from.


What would be our response to a true detection?

Any potential signal will need to be confirmed if it is extraterrestrial in origin. After conducting internal tests to confirm that it is indeed real, we would ask other observatories to check out the candidate signal to look for confirmation.

The world would find out pretty quickly too if this happens- mostly likely through twitter.

We are committed to openness and nobody wants to keep secrets. It would also be impossible for anyone to block our ability for us to see extraterrestrial signals.

So if the signals are out there – we will find them. There is nothing between the researchers and the sky. Rest assured there is no ‘secret black box’ installed on our telescopes that filters out our data – we see everything.


What are your personal thoughts about Roswell and other UFO reports?

I personally think it’s largely a psychological phenomena influenced by the media and technological development, and by the fact that we are a very young space-aware society.

I  have never seen any evidence that would lead me to believe that Earth has ever been visited by any extraterrestrial intelligence.

Astronomers are constantly looking at the sky at all wavelengths, with giant telescopes that are sensitive to little blips of light from across the universe, as well as powerful radars that scan the skies around the Earth- and there is no evidence of anything happening.

Being in science, in fact I think it would be nearly impossible to keep any secret like this.

At the end of the day we require evidence – and in the absence of that-  we can’t just conjecture some fantastic happening that is unsupported.



Follow Andrew Fazekas, the Night Sky Guy, on Twitter and Facebook.


Andrew Fazekas, aka The Night Sky Guy, is a science writer, broadcaster, and lecturer who loves to share his passion for the wonders of the universe through all media. He is a regular contributor to National Geographic News and is the national cosmic correspondent for Canada’s Weather Network TV channel, space columnist for CBC Radio network, and a consultant for the Canadian Space Agency. As a member of the Royal Astronomical Society of Canada, Andrew has been observing the heavens from Montreal for over a quarter century and has never met a clear night sky he didn’t like.
  • Joel G. Sewell Sr

    Mr A, Fazekas , You know it is refreshing to here someone of your knowlage tell it like it is,,,,, all the ( Bubby”s ) of the world need to read your words…… drunk’s of the world see pink hogs and elephants fly all the time, moonshine will do that to anyone..!!!!!!!!!. having worked with the D.O.D years ago, i saw things that would explain every sighting ever reported to the D.O.D….. no little Green men ever found !!!!!! are space ship’s… keep up the good news….

  • Anthony Borelli

    “What is the most likely form of a signal we might find a signal? – It might very well happen while an astronomer is conducting a new kind of experiment…”

    I agree. My bet, now that we can observe quantum states without changing them, is that someone will discover a form of “tuned entanglement” and we will tap into a galactic broadcast of some kind.

  • S G Rae

    From a Buddhist perspective their are many worlds, and three different “types” of human. Of these three, we are the only womb-born humans.

  • Bob brechin

    The universe is so old it is likely that intelligent societies exist out there centuries ahead of ours in their development. Would they want to make contact with such an immature society as oursconsidering all the conflict that exists on this planet ? If these societies are so advanced maybe they have ways of blocking our attempts to make contact, until we have “grown up”.

  • Paul Hayes

    Fascinating subject! Do we send send signals outbound to broadcast that we are here?
    What was the ‘WoW’ signal attributed to?
    Keep up the good work !!!!!

    • I did ask Siemion about the brief radio burst dubbed the ‘Wow!’ signal detected by the Ohio State University Radio Observatory on Aug.15, 1977. He says that it still remains intriguing in that it matches what is expected from an alien signal however the source has never been identified and despite many attempts at listening at the same spot in the sky – the signal has never been repeated. It still may very well be a human-made signal of some sort, some experts suggest, but it’s origins remain pretty much a big mystery.

  • atoure

    i would like to say as a young(17) student its up to my genaration to get down to the bottom of this and i will help its my goal to join seti to help and uncover every rock space is a very special and profitable thing. i have come to the conculsion that we are the only advance life form in this galaxy. not to say there isnt any other life but if there was it would still be stuck to the side of a hydrothermal vent.

  • George Lewis

    Dear Mr. Fazekas, I would like to comment that I believe that the continuation of the SETI project is a very worthwhile cause and should be continued on infinitum, if funding permits. I know of only the one signal, the so-called “WOW” signal, that is of possible extra-terrestrial origin. However my belief is that there are many other intelligent civilzations out in the cosmos, and that they probably already know of our existence here. I have never seen an actual UFO myself, but I have seen plenty of evidence and heard enough testimonials to know that we have probably been visited many times before, and probably will be in the future. The fact that no other signals have been picked up by SETI might mean one of two things- that the transmissions are of a different origin (such as using light) or the transmissions are not being directed towards our planet, on purpose. It is something to think about. And remember to always keep an open mind. There is lots of information out there on UFO’s and alien cultures as well as plenty of hoaxes and disinformation. Just no concrete proof for all of us to see….not yet!

  • columbus

    What if…….. in this region of our galaxy technological societies develop at about the same rate give or take a few hundred years. If we expect to detect signals “nearby”, maybe out to 100 light years, we may be listening too early for societies less advanced or too late for societies more advanced. We’ve only been searching for about 30-40 years? I think it would be presumptuous for us to expect to directly find ET just because we turned our radio on.

  • Pat C Siemion

    A fascinating discussion of a both complex and mysterious subject by a dedicated, intelligent scientist. Live long and prosper. ———- His Father

  • Travis

    This radio signal communication attempt just show the other intelligent life forms how uneducated we humans really are. If they are here, we wont know it. They probably conduct test and experiments on us all the time… off the radar

  • Curt Renshaw

    Below is a link to a talk I gave at NASA’s Astrobiology Science Conference (ABSCICON) in Atlanta in 2012:

  • Randy Wagner

    What an exciting time we live in! We now have the technology to search for intelligent life outside of the bounds of our home planet earth. The sky is the limit!

  • Carlos Manuel Meza Castillo

    hola saludes,
    tuve el gusto de ver algunas información sobre esta pagina y estoy interezado en colaborar

  • Joe Yuna

    As an electronics/radio engineer, I find the idea that they would broadcast at those frequencies ridiculous.
    And why do we assume that their math solely embraced our wave theory whereas longitudinal waves seem more likely as they are the basis for gravitational waves or shifts in the space gradient?

    I would like to think that either our frequencies of interest need to drop down lower (whales boom across the globe at what frequencies?) and our ideas about antennas change if we hope to intercept E.T.s broadcasts.


    le doute systematique & cartesien étant à la base de l’ésprit scientifique, le doute n’est pas relatif à l’éxistance des ET,mais à la possibilité de les detecter…il peuvent tres bien ètre présents dans le système solaire & échanger des informations par le système des multi-canaux codés:chaque octet est transmis sur une longueur d’onde differente suivant une séquence prévue…c’est le principe des radios militaires…or,on ne peut à la fois avoir sensibilité & seléctivité un radiotéléscope cherchant un signal dans la bande100 à 900 Mhz ne verait pas une telle émission non distincte du bruit de fond cosmique…

  • Afolayan sunday

    I love this study and i will want you to continue with the good news.All we need is just a prove

  • Henry

    Of course no one at SETI believes or will admit UFOs are real – ET must being “out there” and “not here” for their funding. As soon as ET lands on the White House lawn, SETI’s funding evaporates. But there’s a huge problem: there are so many Generals, Pilots, Police, and Government Officials going on record about UFOs that it’s impossible to ignore – radar signatures, audio, video, photos, and observations by dozens, hundreds, and even a thousand eyewitnesses.

    Three Western Governments have already stated in writing that UFOs as “real and not imaginary” with an ET origin “the most likely explanation”: The United States (Gen. N. Twining; pre-USAF propaganda), The UK (Ministry of Defense), and France (COMETA). Our government has flip-flopped – the UK and France haven’t.

    Although it’s not preferable, it’s possible intelligent extraterrestrials could be thousands or even millions of years more advanced than our civilization. It’s not a pleasant thought but it may be a reality we will have to accept.

    To assume that we Earthlings would *always* the most technologically advanced civilization in the universe is arrogant, narrow-minded, and ridiculous.

    Just because we can’t travel across galaxies doesn’t mean they can’t.

    Our own limited understanding of physics wouldn’t limit that of another more advanced civilization.

    Several high profile cases with multiple witnesses – some with hundreds or even thousands – offer a compelling argument for more transparency, research, and investigation of unexplained aerial phenomena – structured craft moving at thousands of miles per hour. Out of thousands of cases around the world 5-10% are consistently unexplainable except with an ET hypothesis.

    Prominent scientists are increasingly stating publicly that unexplained cases about unidentified flying objects are worthy of serious scientific investigation rather than willful ignorance or mockery.

    In a Gallup poll 71% of Americans said that the government is hiding something it knows about UFOs, 45% think that UFOs have actually visited earth, and 12% say that they have actually seen a UFO.

    True science is being open-minded and investigating all the facts and options, not just the ones that are convenient or fit into a pre-defined, narrow, comfortable world-view. For SETI to be taken seriously it will have to broaden its scope and consider the possibility that ET might look and behave differently than previously anticipated.

  • sthembiso mavuso

    Keep it up because we want clear proof

  • Al478

    I find this whole notion of life being very common in the universe a little-no, actually a lot over rated. I have never been satisfied with the explanation that certain chemicals can combine and then produce life, which then SOMEHOW creates DNA that recognizes what the living organism NEEDS. Now DNA ITSELF just smacks of intelligence either at the molecular level or just as easily can be explained by intelligent design. But to say it occurs “naturally” is a stretch- otherwise, why haven’t scientists created life and/or DNA in a laboratory under strict sterile conditions? The best they can assemble are “organic” molecules made from carbon molecules that share similar chemical properties with living organisms- but they have never created “life”- a self reproducing organism- much less DNA. So blindly accepting the theory that life is common in the universe to me is incomprehensible since the theory – so overwhelmingly accepted in the scientific community-has never been remotely proven to be a fact, and I doubt it’s actual validity. I happen to believe we are most likely alone in the universe, until such time that REAL evidence proves me wrong.
    To all those who would call me stupid, uninformed, etc…ask yourself this:
    Would you ever consider the notion that this theory of universal life could be wrong? If not, YOU are the one with the closed mind, not I. I would be willing to change my belief IF there was solid, factual scientific evidence to back it…and so far there is zilch, zero, nada …after how many years? At what point do we say the theory is flawed?

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