Deciphering Celestial Signals in a New Way

By Dr. Gerry Harp, Senior Astrophysicist, Center for SETI Research, SETI Institute, and Gail Jacobs

Trained as a quantum mechanic, Dr. Gerry Harp was deeply interested in possibilities for using the multiple telescopes of the Allen Telescope Array to generate steerable "beams" on the sky -- beams that could be far smaller than any single antenna could produce. Such beams don't emit anything, but work in reverse by capturing only energy that comes from the sky in a certain direction. Gerry joined the SETI Institute in 2000, practically at the telescope's inception and uses the telescope for SETI research.

Gerry's SETI research often focuses on using the array properties of the telescope to speed up SETI by searching large areas of the sky all at one time (imaging SETI). Gerry is also interested in extending the ways we analyze telescope data to search for signals that can contain large amounts of complex information (e.g., spread spectrum signals). Put simply, because of the long times (years) between when they send the signal and when it arrives, the aliens will help us out with some kind of error correction scheme or another. All such schemes introduce redundancy, and by designing algorithms to sense redundancy we can discover complex ET signals without knowing their content.

Gerry, briefly describe your research project.
I'm working with the Allen Telescope Array (ATA), the SETI Institute's own radio interferometer telescope. Working closely with Dr. Jill Tarter, we look for artificial signals coming from outside our solar system. SETI is kind of a long-range cell phone call. Working as the transmitter, your handheld cell phone converts your voice to radio waves and transmits them to a tower which amplifies and registers your voice with a computer. This recording is transferred to your friend's location where it is reconverted to sound.

Allen Telescope Array (click on image for larger view)

In SETI, the only difference is that the speaker is very far away and has almost no bars on their connection. In order to hear them, we build a huge radio telescope (tower) to catch those waves, and transfer the recorded signals to a computer "friend" that carefully listens for us. Because of the long distance, the alien's message is distorted and buried in static. The static can be overcome by listening for a long time or building a larger telescope. Overcoming the distortion is still pretty-much an unsolved problem that I find quite fascinating.

You must accumulate an immense amount of data.
Yes. The world is becoming a better place for scientists, as we now have access to more data than ever before in human history. Today's scientists need ways to analyze astronomical (ha!) quantities of data. To keep up, the role of computers in all kinds of science is growing. Whether they like it or not, all scientists are becoming computer experts.

We use computer tools to expand what it means to "look" at the data. By doing something we call "projecting the data," we look at the data from a different angle or in a different light, if you will. Have you ever been to a place during the day, and then when you came back at night, you couldn't recognize it? You see all sorts of things you didn't notice during the day. In our language, we'd say that the night view shows a different projection of the same scene than the day view.

It turns out that there are an infinite number of possible projections we can use on the light or radio waves that come from outer space. In practice we're limited only by our imagination and choices of which projections we look at. How should we look at the universe? Let's project the data to highlight how the universe changes with time -- or highlight different colors. What color are radio waves? If we highlight color differences, what will we find? First of all, anything white will disappear! If you highlight the similarities between one part of the sky and another part, what can you learn from the result? In fact, how would you even design a program that highlights such similarities? History teaches us one important lesson -- every time we find a new way of looking at the universe, we discover something new.

How does this apply to SETI science?
We again look for differences and similarities. In one experiment, we looked at one part of a signal taken at a specific time and a another part of the same signal captured at a different time. We then highlighted similarities between these two pieces of the same signal. In nature, there are very few similarities from one time to another. It's always newly randomized. But it's very common for artificial signals to repeat. Using this method we can highlight only the artificial signals. Then it is just a matter of proving that the signal comes from outside of our solar system, and you're done!

Allen Telescope Array (click on image for larger view)

Having just done this research over the last year, we're now at the point where we have our results. We looked at the data with a new technique called auto-correlation, which basically looks for repetition in signals. We discovered many new signals -- very strong signals -- that never showed up in any of our previous measurements. You wonder how something like a strong signal could hide, but our usual methods for looking at data did not highlight repetitions. We have tracked down the strongest signals we've found and so far have discovered that they were made by human beings, but this is very exciting research.

In addition to conducting SETI searches, how do you use the Allen Telescope Array?
The ATA pushes the envelope for conventional radio astronomy, and I do astrophysics with the Allen Telescope in my spare time, like on my lunch break! I'm working on time-domain astronomy (galaxies that change over time) and applying SETI signal recovery methods to ordinary astronomical data to learn more about the interstellar "channel," or the contents of the space in between stars and galaxies.

Interestingly, we also use the ATA to locate satellites as they orbit the earth. We rely on satellites for our GPS, telecommunications (satellite TV), weather monitoring (hurricanes) and many other applications. When satellites bump into each other and crash, that causes major problems. They create debris which can crash into other satellites, and even more satellites can get damaged. So we also use the ATA to advise satellite companies where their satellites are and they use that information to avoid future collisions. In addition to private funding, this service helps us pay the bills.

What is the coolest thing about your project?
It is the element of discovery. We are constantly looking at different parts of the sky at different frequencies and analyzing the data in new ways. At every moment, we're learning something new. There could be a huge astronomical effect or interstellar message right under our noses that no one has yet seen because they haven't looked in exactly the right way. I'm excited every day to see what we may find.

What do you currently consider your biggest challenge?
The biggest challenge is having enough time. I'm lucky enough to have many good ideas in front of me, all of which I want to pursue. Choosing which ideas to pursue is a challenge -- but a good challenge.

Why should the general public care about your research?
One thing that may not be emphasized enough about science is the importance of understanding. Practical applications of Einstein's General Relativity Theory don't readily come to mind, yet humans are fascinated with this topic. Physics explains how the universe works; it can tell us how the stars move and how galaxies form and interact with each other. As humans, we place a great deal of value upon this type of knowledge.

My research tries to examine the sky in new ways, ways that differ from seeing or listening. In a small way, it is like developing new human senses or pushing our senses into new domains. Radio Astronomy images offer a new human sense in which we can see the sky as if we had "radio goggles," much like infra-red goggles used in action movies to see at night. In fact, this is exactly what radio telescopes do -- they act as very slow goggles allowing us to see the unchanging parts of the sky in the radio frequency range. We want to speed this up.

In my previous career I worked on similar problems, not using radio waves but x-rays and even electron waves to "see" objects. In that case, the objects were very small (atoms), but the principles are all the same. It is all about adapting data that we can detect with our instruments so it can go through the interfaces of our mind. With these tools, we will make new discoveries and learn more about the universe and our place in it.

We're in a discovery mode. Nearby space is familiar, but it is keeping many secrets. We don't know what we don't know, and finding out those things is the most exciting of all. What we discover may indeed have practical applications -- or it may just be really wonderful.

Is there one fact about your research that surprises most people?
Scientific research has always been a marriage of science and engineering. These days, the most important aspects of science progress are happening in computer science and software engineering. I find myself going to more software conferences than science conferences because large buildings full of computers are becoming the tools of astronomy. We build large telescopes and accumulate huge amounts of data, but astronomers don't have the time to study that data. I see computer science as playing a continually expanding part in the future of astronomy.

What is your personal opinion on the potential for detecting intelligent life beyond Earth?
I have no doubt we will find other life as we explore the cosmos. It's very clear to me that life is an imperative for the universe, so life is going to grow. I believe that, provided the human race survives, we will eventually find life forms of many varieties. And the longer we last, the more life we will find.

Contrary to popular opinion, the universe is still very young. Perhaps the reason we haven't found much life beyond Earth is that we're among the leading edge of intelligent species in the universe, and over time the amount of living creatures in the universe will increase until it is teeming with life. If humans conquer climate change, manage our natural resources and survive for the long term, we may someday face similar issues with our own galaxy.

What was your dream job as a child?
Picasso once said that every child is an artist. I've heard other people say that every child is a scientist. We are born with a scientific curiosity that is evident when you watch children's behavior. They're constantly doing experiments. In giving it some thought, I think I just never grew up. I was born with a desire to do experiments and understand things around me and I simply haven't stopped.

I was very fortunate to have had such a calling. By the time I understood what it meant to be a scientist, science had settled in my heart as a permanent fixture. I count myself lucky since knowing what you want is half the battle to getting it.

When did you first become interested in physics?
My father grew up as a son of a coal miner. Growing up in the Appalachian region of West Virginia, most children went through the sixth grade and that was all the schooling they got. My dad actually went as far as eighth grade, which was considered "higher education" at that time and place. Unfortunately he was never able to get the kind of education he wanted. Despite this, my father never stopped learning and gave himself a classical education while working two to three jobs for much of his life. When I was a child, I learned about Einstein and Plato on my father's knee. That was a very formative time for me. I admired my father and his heroes became my heroes.

What created the connection for you to take your work in Physics and apply it to astronomy and interstellar communication?
As a boy, my parents bought me a telescope and I spent hours staring at the moon and the sun (with appropriate filters, of course). But my primary interests were for things that were very small. At the beginning of my career, I was particularly interested in trying to see atoms by using electrons to make holograms of the atoms. It turns out once you understand something about waves, this knowledge transfers easily to all domains of physics and astronomy, as well as other disciplines.

How do you spend your free time?
I read books about cosmology and other fields of physics. I also love comic books, especially the comic material from Japan, known as Manga. There is a huge amount of Manga comic material in different genres for adults. You can have dramatic, adventures, or even love or detective stories, and I just love this stuff. It's my only vice. A favorite for all ages is Case Closed.

Tell us about your interest in education.
I was a tenured professor of physics spending several years at Ohio University before I came back to California, and I anticipate holding some kind of college teaching position once again in a few years. In the meantime, I've remained involved in education by working with college interns. The SETI Institute sponsors a Research Experience for Undergraduates (REU) summer program as well as an Undergraduate Research at the SETI Institute in Astrobiology (URSA), a partnership between the SETI Institute and San Jose State University. I enjoy working with young people and find working with interns to be very rewarding. Besides, they do a lot of great work!

The SETI Institute REU Class of 2010 at Mt. Lassen, California
(click on image for larger view)

I'd like to bring more young engineers into science. I've seen a barrier between engineering and science. Scientists are often welcomed in engineering, but not vice versa. I believe scientists can learn a lot from the engineering community. I'm continually blown away not only by engineers but by people of all domains and trades. The world is overflowing with amazing people.

I'm also involved in Puente, a California-wide program to support young, first-in-family students entering college, offered at a local college. As someone who was the first in my family to get a degree, I really enjoy working with Puente to help young people adapt to college life, sometimes explaining the basic rules, like getting straight C's is not acceptable, or opening their eyes to an entirely new way of life that a college degree can offer. I usually take the students on tours of the SETI Institute. Many of these young people have not been exposed to white-collar work settings and let me tell you, very few exit the premises without a desire for a comfortable desk job! I also get to meet with the students and their families at an organized dinner party. Here we also help the parents understand college basics, explaining how a college is a worthwhile pursuit, not the least because education is an investment that pays out dramatically over time. If you don't believe me, check out this simple graph on Employment Projections:

Do you have advice for high-school level students who have an interest in science?
I would tell them to study what they enjoy and pursue your love. Don't worry too much about how you're going to make it. Unless money is what you live for (some people just like it!), just focus on what you want and get really good at what you enjoy -- the opportunities will be there. At some point in your life after you graduate college, you'll have to be flexible and figure out how you can apply what you've learned to something that is productive for society. You can do this. The people who are most successful are without exception the people who love what they're doing.

What is your philosophy of life?
The biggest obstacle that you'll face in life is yourself, so try not to get in your own way.

What historic and/or contemporary personalities do you admire and why?
The feat Einstein did all by himself - his leap of understanding - was enormous. At times, I've thought perhaps Einstein was too smart. He made this enormous leap and the rest of us didn't get the opportunity to visit all the stages in between. As a result, it's very difficult for cosmologists to understand what Einstein understood and very few people can enter the field. But what Einstein did was truly marvelous and he is someone I continue to admire.

Another person I've come back to recently is Richard Feynman -- not because of his contributions to physics but because of his contributions to education. I only recently realized that he basically rewrote the entire undergraduate curriculum in physics, with a couple of important partners, at CalTech. I'm revisiting his lectures now with amazement. It's inspiring that kind of accomplishment is possible. I've been thinking a lot about how we could rewrite it again.

I also really admire a lot of the people I work with, Jill Tarter being an excellent example. She excels in ways that I've never seen in anyone else. She has capacities and abilities to think and synthesize and just has enormous energy -- it's fascinating to watch her. I can only stand in awe of what she accomplishes.

Gerry Harp and Jill Tarter in 2010 at Lassen, near Hat Creek, CA, home to the ATA
(click on image for larger view)

What is your favorite vacation destination?
Perhaps my best vacation was a trip to Ecuador and specifically the Galapagos Islands. That trip was like a complete course in biology and in particular, what can go wrong in evolution. I believe that the animals in the Galapagos have not had sufficient predation; they have not been sufficiently challenged by their environment. It's just too nice a place to live. The birds cannot get off the ground under their own power. They have to leap off a cliff in order to get airborne because they're so fat. There are countless similar examples because the environment lacks predators. When I look at them, I can only see ourselves and wonder if perhaps at the moment and as a species, we're not sufficiently challenged.