Interview with Jill Tarter Astronomer for SETI

On this blog I often talk about the search for ET. Whether it be the Fermi Paradox, the Drake Equation, or any other ideas or theories that get thrown in, I love speculating about ET. Recently I came across an article (link below) with SETI astronomer Jill Tarter where she talks about some very interesting ideas.

I reached out to Jill and asked her if she could do a interview for me. She was kind enough to oblige. I was beyond excited when Jill agreed to an interview because I always have some crazy theories and it was nice to talk to an expert and bring my ever growing imagination back down to Earth. Despite my best efforts to get her to do so, she would not brag on herself and her fantastic career, so I will do it for her. Honestly, I do not know where to start, her accomplishments and accolades are almost too many to list. Currently she holds the Bernard M. Oliver Chair at SETI (which is an endowed chair named for famous astronomer Bernard Oliver.) She was awarded a Lifetime Achievement Award by Women in Aerospace in 1989, Received two public service medals from NASA, as named one of the 100 most influential people in the world by Time Magazine in 2004 (Wikipedia) just to name a few. I mean goodness!!  I will stop jabbering now, take it away Jill…


Can you tell us what SETI is and the work the organization does?

The SETI Institute is a non-profit organization incorporated in 1984 to help get the biggest bang from the NASA funding for its High Resolution Microwave Survey.  When Congress terminated that funding, the SETI Institute took up the challenge of raising private funds to continue the search.  Since its incorporation, the Institute has served as a home for research scientists exploring the origin, evolution, distribution and nature of life on Earth and beyond.  All kinds of life – from microbes to mathematicians.  Today we are a very large, and very interdisciplinary center for astrobiology research, one that extends the envelope of research to cover SETI. The scientists at the SETI Institute also have a passion for sharing their work with students and the public. But I’ll bet you only knew about our searching for ETI.


In this Buisiness Insider article you disagree with Stephen Hawking, as he believes that aliens would want to destroy tarter-jillus. I actually disagree with him as well on this sentiment for a variety of reasons. Mainly, I believe that an extremely violent civilization, one that might want to destroy us, would eventually destroy itself. Also, I do not see the benefit or reward for traveling through interstellar space just to make war. Can you elaborate on these comments? 

If another technological civilization can travel here, they are far more technologically advanced, and therefore older than we are.  I think it is perfectly possible that to grow old as a technology, it is necessary to outgrow the aggressive attributes that probably were important in the initial evolution of that intelligent, technological species. To grow old, it may be necessary to learn how to curb population growth and to globally manage an ecosystem. In his recent book The Better Angels of Our Nature, Steven Pinker, a cognitive scientist, suggests that humans today are kinder and gentler than we have ever been, and further that this is a cultural evolutionary trend that will continue.  If Pinker is right, then there may be potential for a less violent encounter between interstellar species than Stephen Hawking imagines. Of course Pinker and I may be wrong and Stephen may be right – none of us has any real data. If there are any others out there, and if they show up in the near future, our speculations will be irrelevant anyway – their technology will be superior, and we will end up playing by their rules, whatever they are.


In that same article you propose that humans could send out signals, but say that we are not ready. Can you explain what you mean by that?

It is more difficult to transmit than to receive, and more costly. The cost comes from the power needed for the signal transmission, and from a time commitment that is far in excess of anything our species has managed to date.  For signal transmission to be successful, it needs to be a long term project.  A two-year or ten-year plan is not enough.  Transmission must continue over timescales that are cosmic, so that the signal is extant when an emerging technology matures to the point of trying to discover it.  An old technological civilization could, in principle, commit to such long-term projects.  We too can make that sort of commitment once we have grown up to become an old technology, but right now we are too young.


Along those lines, if we were to send out any number of signals how far can these signals reach, and are there any planets in that range that could be promising. What I am getting at is even if we send these signals, is there a potential listener within range?

The limitation on the number of listeners is set by time; we have been ‘leaking’ transmissions for nearly a century (radio and TV broadcasts, radars etc.).  Within that 100 light year horizon there are about 10,000 stars, mostly small M dwarf stars.  If we shrink the horizon to 50 light years so that there would have been sufficient time to have our signal detected and a response sent back, then the number of known stars drops to 2000.  The results from the Kepler spacecraft, searching for exoplanets, strongly supports the conclusion that in the Milky Way Galaxy there are more planets than there are stars.  Within a factor of 2, probably 7% of sun-like stars will have an Earth-size planet in an orbit that might make it habitable. Since at least 90% of the nearby stars will be M dwarfs or stars far more massive than the Sun, we can estimate that there could be perhaps as many as 14 planets with listeners who could have overheard our earliest internal transmissions and be responding to us today.


There are those that say that searching for extraterrestrials is a waste of time, money, and resources. I would argue the exact opposite, in fact I believe that if we were to find definite proof of an intelligent civilization out there that it would not only rewrite human history but could completely change our psychological mindset as a species in the universe. How do you think such a discovery would affect us as a species?

A successful detection requires longevity.  Unless, on average, technological civilizations have a very long lifetime, it will be impossible for one of them to be coincident with us in space AND IN TIME over the 10 billion year history of the Milky Way; these are the minimum requirements for detection.  (To within astronomical accuracy i.e. factors of 10, the Drake Equation can be concatenated to N ≈ L.) For this reason Prof. Phillip Morrison has referred to SETI as ‘the archeology of the future’.  By this he meant that the finite speed of light would guarantee that any information received in a signal would tell us about their PAST, but the fact of detection would tell us that WE could in fact have a LONG FUTURE as a technological civilization.  That single bit of information might be all that is required to motivate us to make it so.


If you had to speculate, which of the following scenarios do you think is the most likely universe we live in-

  • There are no other intelligent civilizations out there.
  • There are intelligent civilizations out there, but the vastness of the universe will inhibit us from ever making contact. (This is what Stephen Hawking suggests in A Brief History of Time.)
  • We, humans, are the most advance civilization in the universe, which is why we have not heard from anyone else.


I do not know the answer to the question, nobody does, yet.  It is my preference to search and explore rather than speculate – that’s why I’m and observer and not a theorist.


Personally, why do you think we have not found any evidence of intelligent life out in the universe?

We haven’t yet looked very hard.  When the SETI enterprise turned 50, I did a crude calculation (Tarter et al. (2010) Proceedings of the SPIE, Volume 7819, pp. 781902-781902-13) that argued that if the volume of the 9-dimensional search space in which electromagnetic signals might be found was set equal to the volume of the Earth’s oceans, then we had thus far systematically explored only one 8-ounce glass of that ocean.  Since then we may have done another order of magnitude, but the story is still the same.  Null results are not yet significant.


In his book Meaning of Human Existence, Edward Wilson talks about the evolution of society. We obviously have only one real example of this. How do you think an extraterrestrial civilization might evolve differently from ours? I would think there would be quite a few similar characteristics, the benefit of working together and the like.  

We use technology as a poor, but only practical, proxy for intelligence.  In that regard, although we may soon be able to use biomimicry and additive construction tools to build large systems, such as transmitters, we first had to go through a period of technology manufacture that involved metalworking with flames.  If this is a norm, it would necessarily involve a solid surface interface with oxygenic atmosphere and rule out organized marine mammal societies on remote worlds.  The cooperative bubble-netting hunt by whales is a fascinating use of technology, but one that isn’t detectable over interstellar distances.  This requires more philosophy than I can manage – in the end, I really don’t care whether they are little green men, big blue ladies, or anything else.  If they can build and operate some sort of transmitter over long periods of time, they fall within my realm of possibilities.


As we push closer and closer to Artificial Intelligence do you think that other intelligent civilizations out there could have invented something similar, and for whatever reason this ET AI is all that is left of them. (I am not saying the robots destroyed the civilization, just that they outlived their creators.) If this were the case do you think an ET AI would want to make contact with us?

I would think that a civilization of machines that had replaced their biological precursors would still be curious about what the laws of chemistry and physics operating elsewhere in the cosmos might have produced.  You can run simulations endlessly to experiment with the possibilities for lifeforms, but at the end of the day, you probably want to know what varieties the universe actuated.


Which do you think will happen first humans discover an intelligent civilization in the universe or humans create an AI that is just as smart or smarter than us? 

I tend to favor the AI path, just because that’s where funds are being invested.


In accordance with the Great Filter Theory, in your mind, what do you see as the main obstacle that an intelligent civilization must overcome? What do you see as the next obstacle for the human species?

Growing up and adopting a cosmic-perspective. From a cosmic distance, we are all the same, we are all Earthlings.  That’s a powerful perspective that trivializes the differences among us that cause blood to spill today.


Currently, can you tell the audience your most promising evidence and or planets that could potentially harbor life that SETI has found?

The exoplanet research community has compiled lists of hundreds of potentially Earth-like planets.  See or a recent paper by the VPL group  But all of this involves a lot of speculation because what we really know about these worlds are their stellar host, their orbits, their size and/or mass, and sometimes their density.


In your career you have been published in many journals, achieved some amazing awards, but what has meant the most to you in your career. What are you most proud of and why?

I’m very proud that we have constructed a new type of radio telescope and very wideband receivers.  The Allen Telescope Array is an LNSD array (large number of small dishes) whose architecture has now been adopted by the international Square Kilometer Array.  We also built the ATA in a way that allows traditional radio astronomy and SETI searches to use the array at the same time.  The receivers on the array can also allow us to observe the entire terrestrial microwave window from 1 to 10 GHz at one time.  If we had sufficient funding, we could increase the number of telescopes in the array from 42 to 350 or more and it would then be the most capable radio telescope on the planet.


If you cannot tell I am a huge science fiction fan. I read where you were heavily involved in the making of the movie Contact based on the book by Carl Sagan. Can you talk a little about that experience and what it was like meeting Carl Sagan? And what was it like seeing much of your work portrayed on the silver screen?

Carl Sagan was a scientific colleague of mine for nearly two decades prior to his death. He was in fact a member of the SETI Institute Board of Trustees.  He was impressive as a scientist, as a communicator, and as a human being, and it was a great pleasure to work with him.  The real treat for me from making the movie Contact was meeting Jodie Foster and getting to see some of the really cool technology that is part of the production.  Jodie is very smart, and also very kind.  I got to take her up inside the Gregorian dome hanging 500 feet above the surface of the Arecibo dish and explain how it works – not your everyday experience.


Is there anything else you would like to add?

I’ve really enjoyed being part of the SETI search for past four decades, and have been gratified to be able to help improve our search capability every year.  The frustrating part of this search has always been the unpredictable funding that we’ve had to deal with.  That makes it hard to attract the best and the brightest of the next generation to continue the work.  It takes a special sort of individual to work on a project whose eventual success is not guaranteed, and if you add to that the uncertainty of providing financial support for their families – it means we are missing out on some really talented folks.  And they are missing out on a chance to change the world.

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