View from the Pier

Julia Deneva, age 30, is a Postdoctoral Research Associate at

I drove to meet Julia from the mountain town of Utuado to its south, getting quite lost on rural back roads in the process. My husband Tom and I duly noted with some amusement the irony of losing our way en route to see a massive device designed in part to detect life in other galaxies.

Julia’s journey to Arecibo began in Communist-era Bulgaria, where as an adolescent she experienced the fall of the Iron Curtain. As a child, movies depicting space travel inspired her interest in the stars, and she considers her career as a radio astronomer at Arecibo as evidence that “impossible” dreams can come true. This was one of many refreshing reminders in the course of our conversation about the beautiful benefits of open-mindedness. Other themes that Julia touches on are perspective and humility, befitting someone who often works in increments of light years.

The Brain is wider than the Sky -
For put them side by side -
The one the other will contain
With ease – and You beside.

The Brain is deeper than the Sea -
For hold them – Blue to Blue -
The one the other will absorb
As Sponges – Buckets – do.

The Brain is just the weight of God -
For Heft them – Pound for Pound -
And they will differ – if they do -
As Syllable from Sound.

~Emily Dickinson, 1830 – 1886

Meg: Can you describe what it was like growing up in Bulgaria?

Byala

Julia: I grew up in Byala, a small town in the interior of Bulgaria. It was the kind of place where everyone pretty much knew everyone else and extended family trees would include a sizable fraction of the town’s residents, as well as those of surrounding villages. My parents weren’t from Byala but moved there before I was born, so for holidays we would go to visit relatives in Russe, the district center and one of the bigger cities (at about 150 000 people).

Speaking of holidays, until 1989 they didn’t include Christmas. From 1944 until 1989 Bulgaria was ruled by a Communist Party regime that considered religion contrary to its ideology, so religious observances were discouraged, though not explicitly forbidden. Instead of Santa Claus, we had Grandfather Frost who came to give children presents at midnight on New Year’s Eve. After 1989, there were a few years when both Christmas and New Year were celebrated equally and that was a particularly good time to be a child because you got presents and extra days off school for both. We were “latchkey kids” and fended for ourselves between the time school let out and our parents came home from work.

Russe City Park

There were no stay-at-home parents; everyone worked outside the home not only out of necessity but also because everyone was expected to be part of the workforce and help build the “bright future” (a buzz phrase from Communist propaganda). But a lot of jobs were bureaucratic sinecures without real usefulness for society.

People from my generation experienced the tail end of the Communist regime, when things were more relaxed compared to earlier decades. We weren’t required to wear uniforms to school, study “Marxism and Leninism”, or participate in a “brigada” every year (unpaid summer labor like picking fruit or doing other unskilled work)—my parents’ generation had had to do these things when they were in high school and college. We traveled abroad, though only within Eastern Europe. When I was 8, my parents and I went on a month-long road trip through Romania, Hungary, Czechoslovakia, and Poland. That was the first time I experienced other cultures.

Meg: Are there a couple of particular memories or experiences you could share that illustrate what it was like to be in Bulgaria when the “Iron Curtain” fell?

Julia: The Iron Curtain fell at slightly different times for the various countries in the Socialist Bloc, so it wasn’t one concerted effort or uprising that caused this geopolitical shift but rather news from one country influenced or precipitated events in others. (What is happening now in the Middle East and North Africa, starting with the protests in Egypt, reminds me a bit about that era.) While there was civil unrest in Bulgaria, we were lucky that the change happened without casualties or civil war. Bulgarians seemed to focus any destructive impulses on Communist symbols: statues of Communist leaders got toppled, red five-point stars got smashed, propaganda posters were torn. There were massive but peaceful rallies in Sofia, the capital. At the time, people were acutely aware that tensions could easily boil over. When the Iron Curtain fell in Romania, Romanian dictator Nikolae Chaushescu and his wife were executed, and footage of their dead bodies was shown on Bulgarian TV. In former Yugoslavia, the fall of the Communist regime and subsequent unrest marked the beginning of a long-lasting civil war.

Byala Church

In Bulgaria, the changes caused the economy to collapse, which led to shortages of basic foods, widespread lay-offs, and hyper-inflation. The interim government was compelled to institute a ration system for a short time, until international aid and new trade could make up for supplies that had until then come cheaply from the Soviet Union. We had not had a ration system in effect since the World Wars, so at that point the situation was grim. People’s savings evaporated because our currency became devalued almost overnight. There were international efforts to help struggling Eastern European countries at the time with loans, economic policy, and humanitarian aid.

In retrospect, things normalized rather quickly but it was a “new normal.” Private business was growing, but unemployment was still high. There was widespread organized crime and a growing gap between rich and poor. People were eager to travel and see the West for themselves—some emigrated, others went and came back. Those who had family members living in the West for a long time (either since before 1944 or after defecting during the Communist regime) were reunited with relatives for the first time in decades. There were elections, and the first democratically elected president (male) and vice-president (female) were a philosopher and a poet. (Those were idealistic times.)

Meg: Can you share a few early experiences that fostered your interest in astronomy?

Julia: My mom was a fan of a British sci-fi TV show, “Blake’s 7,” and one of my earliest memories is watching it with her. I must have been 3 or 4, the show was subtitled in Bulgarian and I couldn’t read yet so she would read the subtitles to me. Eventually she got tired of doing that and taught me to read. Since “Blake’s 7” included interplanetary space travel, I learned the names of the planets at the same time as the alphabet. The only problem was that I believed everything in the show was real, I was convinced we had spaceships and colonies on other planets, and the only obstacle to taking part of that exciting endeavor was growing up. It was a big disappointment when I got a few years older and found out that wasn’t the case.

Overlooking Russe from Hill of the TV Tower

If almost every child at some point wants to be an astronaut, I’m one of those who never grew out of it. But being an astronaut is not a job you can just decide to do, there is a very rigorous selection process and people who get selected to be astronauts are already accomplished scientists, engineers, or pilots. In light of that, astronomy seemed like a good field to get into. While I was in high school (already after the fall of Communism in Bulgaria), the movie “Contact” came out and that turned out to affect my life in an odd way. Parts of the movie were filmed at the Arecibo Observatory in Puerto Rico, which has the largest radio telescope on Earth. Because there had been so little exchange of information between East and West for decades, the Arecibo telescope wasn’t mentioned in any of the astronomy books I had read. Since “Contact” is a sci-fi movie, it wasn’t obvious whether the Arecibo telescope was real or fictional. An internet search showed that it is a real, gigantic dish 305m across, and I thought, “Someday, I will work there.” At the time, it seemed like a pipe dream, but in 2002 I went to Arecibo as a summer student, and since 2009 I am on the staff. So I’ve made it a point to always have at least one “impossible” dream. You never know.

Meg: Can you describe how your early interest in astronomy influenced life choices you made?

Julia: I had read a lot about the space race between the US and the Soviet Union. After 1989, the Soviet Union/Russian Federation was in a dire economic situation as well. If I wanted to study science, I would have to go to a country that could afford to fund scientific research and space exploration, and the best choice for that was the US. In Bulgaria, there are high schools that specialize in different subjects. If I wanted to become fluent in English, I would have to go to a language high school. Language high schools are public “magnet schools” in the big cities and you have to take entrance exams in order to be admitted to them. Typically kids from all over a district compete for the spots in these schools, which means that those who get in may have to live away from their family if they are not from the district center city.

Most students from other towns live with roommates or by themselves, and go back home for weekends and holidays. When I’ve talked to American parents about this, they tend to be horrified at the idea of a 14-year-old living alone or with roommates of the same age, but it works out. I did it, I knew many others who were in the same situation, and we all did okay. Incidentally, while the idea of school uniforms was despised by students and parents alike in the 1990s as a relic of Communist-imposed conformity, now uniforms with distinctive colors and styles for each school are actually in style. I blame Harry Potter.

At the time I applied for college, it was not very common for Bulgarians to study in the US, for two reasons. First, the difference in average income between Bulgaria and the US was and still is significant, so college education in the US is prohibitively expensive. Second, it was not easy to get a visa to come to the US because people from developing countries are generally viewed as potential illegal immigrants and the burden of proof is on you to convince the consulate officer who interviews you that you won’t immigrate illegally. If you wanted to go to college in the US, you had to get a scholarship, and the more well-known the college you were accepted to, the better your chance of getting a student visa. I was lucky that I was admitted to Vassar College, which has a very good astronomy program and gave me a full scholarship. I majored in Astronomy and Computer Science. After that, I went to Cornell University for my Master’s and Ph.D in Astronomy.

Meg: Now as a radio astronomer, you focus on pulsars at Arecibo Observatory—can you explain what radio astronomy is?

Julia: Radio waves, like visible light, are a type of electromagnetic radiation. We study visible light sources with optical telescopes, which use mirrors and lenses to focus the light and produce an image. We study radio astronomical sources with radio telescopes that have the same basic elements as satellite TV dishes (satellite TV signals are in the radio wave part of the electromagnetic spectrum). The part of your satellite TV dish that sits on three legs above the center is a detector and it is positioned at the point where the dish focuses the radio waves it receives. The sensitivity of a telescope depends on the size of its primary reflector. In optical telescopes used for research today, the primary reflector is a curved mirror. In radio telescopes, it is a large metal dish. The larger the dish or mirror, the more celestial objects you can study, because you also see weaker ones that wouldn’t be detectable with a smaller reflector.

One difference between optical and radio astronomy is that while from the ground you can only do optical observations on a clear night, you can do radio astronomy observations at any time and in almost any weather. Visible light from the Sun is scattered in random directions by molecules in the atmosphere, so if you are on the ground, during the day the sky is bright in all directions and you can’t see any stars. If you are on a spacecraft above the atmosphere, that effect disappears and the sky is black dotted with stars. Radio waves don’t get scattered in random directions by the atmosphere, they go straight through (including through clouds), so the sky is always “black” dotted with stars in radio waves.

Meg: Can you explain what a pulsar is?

Julia: A pulsar is a compact object left over after a massive star dies. The more massive a star, the faster its exhausts the nuclear fuel in its core and the shorter its life. Stars that are about 10 – 20 times more massive than the Sun shine steadily for a few hundred thousand years (in comparison, the Sun has about 5 billion years more of steady shining left), and then explode as supernovae. The explosion is gigantic and expels most of the star’s matter into space. What is left behind is the massive star’s core. Without nuclear fusion, there is not enough outward pressure to balance the inward pull of gravity, and the core collapses to form a neutron star.

NASA Image

Pulsars are a class of neutron stars that emit very regular radio pulses. A pulsar is about seven miles across but has about 1.4 times the mass of the Sun, so it is extremely dense. The densest type of matter we know of is that in an atomic nucleus. A pulsar is in fact composed of the same type of matter, so in some ways it behaves like a gigantic atomic nucleus. Pulsars are the only instance we know of where this kind of matter exists in a large bulk. Deeper within pulsars matter is most likely in even more exotic states that don’t occur elsewhere and we can’t recreate in a lab because of the extreme pressures necessary. Pushing the limits of what we know about the extreme states matter can exist in is one of the main reasons why people study pulsars.

Pulsars spin very fast, a few times to a few hundred times a second is typical. Because of their fast spin rates, they behave like radio lighthouses. Radio emission is generated in their magnetic pole regions, and since the magnetic and rotational poles aren’t exactly aligned, as a pulsar’s magnetic pole sweeps around, we see a pulse of radio waves, like the flash you see from a lighthouse. These radio blips are extremely regular. In fact, some pulsars are more accurate natural clocks than the best atomic clocks we have. This regularity was why when the first pulsar was found by chance (by Jocelyn Bell Burnell in 1967, in the UK), people briefly thought it may be a beacon built by another civilization. However, the properties of pulsar emission show it to be of natural origin, and so far almost 1900 pulsars have been discovered in widely different directions on the sky and at different distances from Earth. It’s extremely unlikely that there are 1900 civilizations that independently decided to use the same type of beacon.

Meg: Can you give an overview of a “day in the life of a radio astronomer”?

Julia: The daily schedule of a radio astronomer can vary a lot depending on whether you have observations, which can be at any time of day or night, and what time of year it is. Most of my time is spent reading and writing. Many astronomy papers are published electronically every day and it is important to keep up with new developments and discoveries in your field. The first thing I do when I get to work in the morning is to skim titles and abstracts that land in my email inbox overnight. You are sometimes asked to review a paper written by someone else in your field that has been submitted to an astronomical journal, and advise the journal editor on whether it should be published. This is the essence of the peer-review system that provides quality control in science. The writing part of an astronomer’s work usually includes papers that are submitted to journals, proposals for observing time, and software to process astronomical data. Nowadays a lot of astronomers are also skilled computer programmers, and most are self-taught.

In the summer, Arecibo hosts about ten college students via the Research Experience for Undergraduates (REU) program. Each student works with a staff member and at the end of the summer students give presentations and write papers on their project. For the first week or two, an advisor may spend the greater part of a day showing their student the ropes and doing some one-on-one teaching of relevant theory that is beyond the scope of college astronomy classes.

Part of the duties of Arecibo astronomers are to assist observers both on-site and remotely. It used to be the case that if astronomers from another institution got time on the Arecibo telescope, they had to come to Arecibo to do their observations. Nowadays people routinely observe remotely by controlling the telescope from their own computer, wherever in the world they happen to be. I train novice users of Arecibo, and I’m also on call if something goes wrong during a pulsar observation.

Meg: Can you provide an overview of Arecibo’s history and mission?

Julia: Arecibo is in Puerto Rico, at about 18 degrees North latitude, so it’s close to the equator. The latitude of your location on Earth determines what stars are visible to you. If you are sitting on the North pole, the North star is always directly overhead. You don’t see stars rise or set but just go around, always at the same elevation above the horizon. The stars you see are all in the Northern celestial hemisphere, you can’t see any stars from the Southern celestial hemisphere, because for an observer at the North pole, they never rise above the horizon. If you are on the equator, the North star is always on the horizon due North and you see all stars from both the Northern and Southern hemispheres rise and set every day, with stars on the celestial equator passing overhead. (The celestial coordinate system is an extension of the Earth-based latitude/longitude system projected on the sky.) You want your telescope to be able to see as much of both celestial hemispheres as possible, so ideally you want to build it as close to the equator as possible.

If you want to build a sensitive radio telescope, you need a very large metal dish. Large structures bend and deform under their own weight if they are tilted this way and that, so you can only have a large, nicely shaped dish that focuses radio waves properly if you keep it stationary. The Arecibo dish is 305 meters (1,000 ft) across and it sits horizontally in a natural karst sinkhole in Puerto Rico. You point to different objects by moving instruments on a platform suspended above the dish. The suitably-sized sinkhole meant that they didn’t have to excavate much when they built the Arecibo dish, so that saved time and money.

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Arecibo was built in the 1960s with the dual intent to study radio astronomical objects and the Earth’s atmosphere. Today there are three science divisions at Arecibo: atmospheric science, radio astronomy, and radar astronomy. Radar astronomy uses a transmitter to study Solar System objects like planets and asteroids. A radar pulse is emitted towards an asteroid for example, and the reflection of that pulse carries information about the asteroid’s velocity, distance, and shape. One important application of radar astronomy is monitoring the trajectories of near-Earth asteroids and making sure there aren’t any on a collision course with Earth.

I have come across various conspiracy theories about what we do, but none of them are true. We look for intelligent extraterrestrial signals via SETI (Search for Extraterrestrial Intelligence), but none have been found yet and we have never talked to aliens. We don’t (and don’t have the capability to) shoot down satellites from orbit. We don’t try to strip the Earth of its atmosphere. Atmospheric scientists do a kind of experiment that involves heating a small portion of the atmosphere for a short time, which is equivalent to pouring a drop of tea in the ocean and is completely harmless. The observatory is open to the public and anyone can visit.

One of the most important discoveries made at Arecibo (and in radio astronomy in general) was the first observational evidence for gravitational waves, ripples in space-time predicted by Einstein’s theory of relativity. Russel Hulse and Joe Taylor observed a pulsar in a binary system for more than 20 years (1970s to 1990s) and noticed its orbit shrink. The rate of shrinkage matched Einstein’s prediction of what it would be if it were due to energy loss via gravitational wave emission. Rotational energy from the system is transferred to the fabric of space-time, making it ripple—in the same way as two lead balls moving around each other on a flexible rubber sheet would. Hulse and Taylor got the Nobel prize for their discovery. Since then this kind of orbital shrinkage has been observed in other pulsar binaries and they all match Einstein’s prediction.

Artist View of Pulsar Planet System by NASA/JPL (NASA)

The first extrasolar planets were discovered at Arecibo by Alex Wolszczan in 1992—and they are around a pulsar! When we say “planets orbit around a star,” that is not precisely true. All bodies in a star system orbit around the center of mass of the system. In the case of the Solar System, the most massive body by far is the Sun, so the center of mass of the system is very close to the center of the Sun. The gravitational tug exerted by the planets on the Sun causes it to slightly wobble around the center of mass. If you have a pulsar with planets around it, the same thing happens. The wobbling causes the observed pulsar period to change periodically: when the pulsar is moving towards us, the pulses arrive closer together; when it’s moving away from us, they arrive farther apart. This is the Doppler effect—the same effect that causes the change in pitch of the sound of an approaching and receding motorcycle or train whistle. The pitch corresponds to how often the crests of sound waves arrive at our ears.

Meg: Could you explain what the “Einstein@Home” program is, and how everyday folks can play a role in astronomical research?

Julia: Computer and internet access now make it very easy for everyone to get into astronomy or any science they are interested in and take part in making discoveries. “Citizen Science” refers to various projects that rely on volunteers from the public to accomplish their research goals. One such project is Einstein@Home. To participate in Einstein@Home, you download a small program and install it on your computer. That program replaces your screensaver and only runs when the computer is on but you are not using it. When Einstein@Home is active, it automatically downloads a small amount of astronomical data, processes it, and uploads the results to a server. Some of the data that Einstein@Home users around the world get is from the Arecibo telescope and what their computers do is search for pulsars in that data. In 2010 volunteers from the US, Germany, Russia, and the UK made the first two Einstein@Home discoveries, and they were both pulsars in Arecibo data.

There are a total of 250,000 registered Einstein@Home users from 192 countries that make this project possible. For comparison, a university or research institute may buy an expensive supercomputer that is equivalent in processing power to a few hundred or a few thousand consumer computers. That will still be dwarfed by the combined computational power that Einstein@Home volunteers provide by donating the idle time of their computers to the project. As Einstein@Home and other similar efforts become more popular, that will allow us to collectively process scientific data faster, cheaper, and make discoveries more often.

There seems to be this myth of the “mad scientist,” “evil genius,” or “science nerd” perpetuated in pop culture, but the reality is quite different. Like almost everything else, science can be a hobby, a profession, a calling, or anything in-between. An Einstein is as rare as a Mozart or a Leonardo da Vinci. The majority of scientists are ordinary people who have spent time learning the skills necessary for their work. Genius or special talent is not required; curiosity and willingness to learn is. And whatever your chosen level or time commitment, there are ways to get involved.

Another unfortunate misconception prevalent in pop culture is that scientists are stodgy and spend all their time in dusty labs. That is also very far from reality. I work across the hall from an atmospheric scientist who is also a jazz guitarist and makes his own electric guitars. Those of us at Arecibo with more modest musical skills have a rock band called “305 Meters of Pain.” We specialize in rock, metal, and alternative, and the name is a nod to the 305m diameter of the Arecibo dish. Some wake up at the crack of dawn equally willingly to do astronomical observations or go surfing. Others keep horses. When I was in grad school at Cornell, students and staff at the astronomy department staged a production of “Romeo and Juliet” as a parody/comedy, to great success. We are in good company—I recently learned from Dava Sobel’s book “Galileo’s Daughter” that Galileo wrote plays and poems for fun. One surviving poem is about the inconvenience of wearing the then-obligatory long academic gown and shows a rather raunchy sense of humor.

Meg: SETI is an active area of research at Arecibo. Can you describe SETI’s work?

Image by R David Paine III

Julia: SETI (Search for Extraterrestrial Intelligence) is a blanket term for past and ongoing attempts to detect radio signals emitted by civilizations on other planets, in other star systems. Because of the physical properties of radio waves and ionized gas in space, radio signals are the only viable option we know of for transmitting information over interplanetary and interstellar distances. It is a good starting assumption that other civilizations at a similar stage of development would have made similar discoveries about the properties of electromagnetic radiation as we have.

The idea of listening for or sending out radio signals to potential alien listeners dates back to the 19^th century, as early as people began to figure out the properties of radio waves. The US and Soviet Union both had government-sponsored SETI programs in the mid-20^th century using radio telescopes to scan the sky. More recent SETI work in the US has been mostly privately funded. In the case of Arecibo, scientists who do SETI work do not get dedicated telescope time, but data taken for projects targeting natural radio astronomical sources also get searched for SETI-type signals.

The key difference between natural and artificial radio signals is their bandwidth. Artificial radio signals are narrow-band and have properties similar to a radio station—they occur only in a very narrow range of radio frequencies (as with radio stations, turn the knob too far and all you get is static, you’ve moved past the station’s frequency). That is true of pretty much all human-made radio emissions including radio and TV stations, cell phones, wi-fi hotspots, garage door remotes, keyless car entry systems, etc. By contrast, the vast majority of natural radio sources are wide-band emitters, and also their emission has properties similar to static as opposed to the blips of artificial signals. That is why SETI projects look for narrow-band signals in radio astronomical data.

And again, anyone can get involved—via SETI@Home, which works in the same way as Einstein@Home, and looks for radio signals from other civilizations in Arecibo data. A forthcoming smartphone app called SETIQuest will give volunteers a more hands-on experience and let them search data from the Allen Telescope Array for potential SETI signals.

Meg: You described an interest in ancient civilizations and subsequently in paleoastronomy. Can you explain what paleoastronomy is?

Julia: I think one of the big influences in my life has been that I grew up in a household full of books on many different topics. We had literary fiction, poetry, and science fiction, as well as historical and travel literature about various parts of the world. I remember being impressed when reading about the large structures that people were able to build in ancient times: the pyramids in Egypt, Stonehenge, the Maya and Inca cities, the moai on Easter Island. Modern-day archeologists and historians were often surprised at the technological and scientific achievements of ancient peoples that we are used to think of as primitive. It would not be easy to build the Great Pyramid or transport and erect a moai even with our present technological know-how, and they did it with tools made of wood, rope, and at best bronze or iron.

Some of these ancient structures are aligned with where the Sun rises and sets at the solstices or equinoxes, for example. There are also surviving inscriptions, carvings, and star charts from ancient times that show sophisticated astronomical knowledge and systematic observations. Paleoastronomy uses historical artifacts and documents related to astronomical observations to aid modern-day science.

Hubble Image

For example, in 1054 AD, people around the world noticed and recorded a new star in the sky. It was so bright that it was visible in daylight for about two months, and it was still visible at night 2 years later. Eventually it disappeared. Nowadays we know that this is what a distant supernova explosion would look like to the naked eye. We also know that supernova explosions leave behind an expanding shell of glowing gas. Using ancient star charts to pinpoint the location of the supernova observed in 1054 AD and comparing that with the location of known astronomical objects allowed astronomers in the 1930s to relate this historical supernova to the Crab nebula.

According to astrophysical theory, pulsars are formed during supernova explosions, so after the first pulsar was found in the 1960s and astronomers started systematically searching for pulsars, the Crab nebula was one of the first places they looked and sure enough, they found a pulsar. That was the first time a pulsar was shown to be connected with a supernova remnant, and the first observational confirmation that pulsars are indeed formed in supernova explosions. Because of the 1054 AD records, the Crab pulsar is one of very few whose exact age is known. Relating age to the pulsar’s present characteristics lets us learn how its rotational parameters change with time, and to estimate the ages of pulsars that are not associated with a historical supernova.

Meg: You told me about an early effort in radio astronomy, where in ’74 or ’75 a message was transmitted to a star cluster 20,000 light years away. Can you describe that experiment?

Julia: The Arecibo message was a one-time radio transmission aimed at the star cluster M13, 25,000 light years away. It was broadcast in 1974, when a resurfacing of the Arecibo dish was completed. This experiment was a demonstration of new equipment installed at the observatory and also a proof-of-concept of an introduction of the human species into space, for whomever out there may be listening. The message consists of ones and zeros–if you translate those into black and white spots and arrange them into rows like the pixels of a TV image, you get a simple-looking picture that is, however, packed with information about us.

The message contains binary representations of the number from 0 to 10. Using these numbers, the building blocks of our DNA are described in terms of the atomic numbers of the elements that comprise each DNA base unit. Following that, there is a pictorial representation of the double helix shape of the DNA molecule, and a human being with the average human height in binary numbers. There is also a simple schematic of the Solar System and a radio telescope, and it is indicated that we reside on and the message comes from the third planet in our star system.

One concern about emitting a message like that is whether we should be advertising our location. What if someone out there is looking for a habitable planet to colonize, or an already developed civilization to enslave and exploit? While the message would be hard even for humans to decipher with no prior knowledge of its format, it can be easily identified as an artificial signal. However, we have had radio and TV stations for decades, and radio waves go out through the atmosphere and into space and radiate outwards indefinitely at the speed of light. Let’s say TV broadcasts became routine and widespread 60 years ago. That means anyone within 60 light years of Earth who has a sensitive enough radio telescope can already figure out we are here, regardless of the Arecibo message. The message target is 25,000 light years away, which means that the message won’t even get to any potential listeners until 24,964 years from now (36 years have already passed since the broadcast). The earliest time we can receive a reply is another 25,000 years after that. A spacecraft would travel much, much slower than the speed of light, so a potential visit from M13 would be a lot more than 50,000 years in the future.

Meg: We talked about science and religion intersecting, and how that has changed from the era of Galileo to today. Could you comment on this?

Julia: One advantage of spending time at Cornell was that a lot of interesting people visit and give public talks. In 2007 the Dalai Lama gave a “lecture,” and I put that in quotes because it was wonderfully candid and unrehearsed. In the Q&A session afterwards, a member of the audience asked something along the lines of, “If there was convincing scientific evidence that contradicted your religious beliefs, how would you go about reconciling the two?” The Dalai Lama thought for a minute, and then said, “Our beliefs would have to change.”

While the Dalai Lama didn’t elaborate on his answer, I would like to offer the following perspective: science and religion are expressions of the same human drive, the drive for exploration and knowledge. We are a species of explorers, we generally want to know how things work, how we can improve our lives, and what is the best way to go about achieving our dreams. We hate not having answers, and for thousands of years we have got our answers to these and other practical and existential questions through a medley of science and religion. We wanted to know what made thunder, why there are seasons, what the Moon is made of, why the Sun shines, why plants are green and the sky blue, why we get sick, etc.

Various religions answered these questions in various ways, often personifying celestial bodies as gods and goddesses with supernatural powers. Science now provides definitive answers to these questions. There are other questions that science has not yet answered definitively: how did life first form on Earth, how did intelligence first emerge, are there other intelligent beings in the Universe? People look for answers to those via science or religion or both, according to individual inclination. The state of scientific knowledge and the state of religious belief continuously change and influence each other. I think it is a natural process.

Meg: I understand the staff at Arecibo is quite diverse—can you describe?

Julia: About 100 people work at Arecibo and include Puerto Ricans, mainland Americans (Puerto Rico is a US territory, so Puerto Ricans are American citizens, but the island is culturally distinct from the mainland), British, Indians, Brazilians, Colombians, a Korean, a Canadian, and a Bulgarian. Colleagues who have recently retired or moved to other places include Portuguese, Chinese, Vietnamese, and Australian. The astronomy community is very international and people tend to move a lot between countries. I heard that sometime before I started working at Arecibo, the staff got mandatory “diversity training.” The friend who told me about it (and who is half of an international couple) laughed about one question in particular in the final quiz they got—it asked, if your officemate is Indian and brings a smelly lunch, what would you do? He wrote down jokingly that he would confiscate the “offending” lunch and eat it himself. The lesson I see from working at Arecibo is that the best diversity training is having a merit-based, nationality-blind hiring policy, and fostering an international community and work environment.

Meg: Can you describe what the term “light year” means, the role time plays in your work, and how dealing in extensive periods of time influences your everyday perceptions of time?

Julia: One light year is the distance light travels in a year, or about six trillion miles. For comparison, the distance between the Sun and the Earth is eight “light minutes” or 90 million miles. The distance to the nearest star other than the Sun is four light years. Our Galaxy, a pancake-shaped conglomeration of stars in whose outskirts the Solar System resides, is 100 000 light years across and 1000 light years thick. The light year is a useful unit for distance because distances in the Universe are vast, and nothing can move faster than the speed of light. How can we explore the Universe if even the fastest spaceship we can build moves so much slower than light that it would take hundreds of years to get even to the nearest star? That’s where astronomy comes in—we can observe things much farther away than we can physically visit.

If light from the Sun takes eight minutes to reach us, and we can only see the Sun by the light it emits, this means we see the Sun not as it is now, at the moment we open our eyes but as it was eight minutes ago. In the same way, by observing a star that is 10 light years away, we see the star as it was 10 years ago. It’s like the cosmic equivalent of constant-speed “snail mail”. If you live in New York and on the same day receive letters from Boston, London, and Tokyo, each letter has taken a different amount of time to reach you. On the same day in New York, you open all letters and find out how your Boston friend was doing two days ago, how your London friend was doing five days ago, and how your Tokyo friend was doing seven days ago. You can extend this analogy indefinitely, but the key point is that by observing objects farther and farther away, we are also able to see the Universe as it was earlier and earlier in its history.

The human life span is much shorter than the average life span of a star (hundreds of thousands to billions of years). But we can learn about the various stages of stars’ lives by observing different stars that are at different stages. The same applies to planets, galaxies, and any other type of astronomical object. In the same way, when we are children, we learn to distinguish young from old people even though we haven’t yet seen any individual person grow old. Old people have wrinkles and grey hair, young people don’t. Old stars also look different than young stars.

Portion of Hubble Image - NASA

I think one “occupational hazard” of being an astronomer is that you start to think in terms of centuries and millenia rather than years. The phenomena that can affect a whole planet or the entire human civilization tend to develop very slowly and may be unnoticeable on a time scale of years or decades. Events that get resolved within a few months or years may cause significant pain to many people (epidemics, wars, economic crises) but in the grand march of what happens to our civilization as a whole, in a sense they are “blips on the radar.” Cures get discovered, dictatorships are overthrown, economies recover. All of these things take hard work, and people are generally willing to put in that work when they know they or at least their children will get to enjoy the rewards.

A different type of hard work is required when the rewards are not in sight. To illustrate, I suggest the following exercise: imagine you are immortal. You can’t die, but you will personally suffer—badly and indefinitely—if you don’t take steps to prevent calamities that may not come for a very long time and depend on your and others’ behavior over a very long time. So will your children and grandchildren, and everyone else you know. As the Earth’s population grows, resources get used up faster and faster (this is true with our mortal population too because any given year a lot more people are born than die). Wars for natural resources get more frequent, famine gets more widespread, infectious diseases spread faster.

There needs to be a balance between what is good for one or another country in the next few years or decades and what is good for our civilization as a whole in the next few hundreds or thousands of years. A global phenomenon like overpopulation or climate change is incomparably easier to predict and prevent than reverse, so the mere possibility of it should give us pause. If slowly accumulating changes go unnoticed or ignored, we will end up like the proverbial frog sitting in slowly heating water until it gets boiled alive, while it could have easily jumped out early on.

A self-sustaining human population can still only survive on Earth, and that makes our civilization extremely vulnerable. We may be an asteroid impact, nuclear war, epidemic, or climate change away from cultural and physical extinction. There is a precedent in the inhabitants of Easter Island: they had a sophisticated civilization but it went into decline and died out because the population became too large for the island, and they cut down all the trees for fuel and building projects. Deforestation caused erosion of the soil and crops declined. The island is isolated, and the lack of trees meant people couldn’t build boats anymore, so they couldn’t move elsewhere. This gradual decline over centuries eventually forced them back into a primitive stone-age-like existence. The knowledge they had acquired and the rich culture they had developed were lost because people destroyed a natural resource that was vital for their survival. The Earth is our island.

Meg: What are your ultimate aspirations?

Julia: I would like to see the first permanent human outpost on the Moon or Mars become a reality, and interplanetary travel become as routine as intercontinental flights are now. Now we think of that as science fiction, but if our civilization survives and prospers, we will have to do it sooner or later. I am personally split between being somewhat at ease because technological progress can hardly be stopped so it’s only a matter of time, and being bothered by the realization that all these exciting developments likely won’t take place within my lifetime. We already have the technology to make some of these things happen, but other priorities intervene.

NASA Artist Rendering - Mars Base

The amount of money spent around the world on space exploration is dwarfed by the amount spent on maintaining armies and developing weapons, for example. To ensure our civilization’s continued survival even in the event of a global disaster on Earth, these priorities will have to change. It is in our collective and individual interest to bring about the future as fast as we can.

I also wish I would be around to see or maybe even be part of the first discovery of extraterrestrial life. It may be microorganisms in a soil sample taken on a planet or asteroid in the Solar System. It may be a radio signal from a star system many light years away. Even in the current absence of evidence for life anywhere apart from the Earth we can’t confidently claim we are alone or unique. For one, we are only beginning to seriously and systematically search for signs of extraterrestrial life. And such a claim is a geocentric statement–it would give Earth and humans a distinction that so far has been disproved.

The original geocentric claim was that the Earth was at the center of the Universe, and it turned out to be wrong. The claim that Earth was at the center of the Solar System was also wrong. The Earth turned out to not be the only planet to have moons. The Sun turned out to not be the only star to have planets–hundreds of extrasolar planets are now known, and soon we will be able to detect Earth-sized planets in other star systems. Humans turned out to not be the only species on Earth to make and use tools (apes do too). We may not be the only species on Earth that has a language (there are indications that dolphins do as well).

These experiences and the laws of statistics tell us that the safest claim to make in the absence of any evidence for extraterrestrial life is that our planet is most likely one of many harboring life, that our planet and we as a civilization are not exceptional but average. And that is not a downer at all–it means we have so much to discover and most likely many others to meet and learn from.

Meg: How has your work in such a vast, unknown area affected your sense of perspective, and what you believe is important—for you personally, and for humankind?

Julia: I think international cooperation will be key for the future of humankind. There seems to be a trend that groups of people with a centralized government do well and gradually accrete to form larger entities that are also governed in a centralized manner. Those do even better because resources get pooled and allocated more efficiently. In the early days of our species, there were family groups that traveled and foraged together. Then there were tribes that included multiple families and eventually settled into villages, each village its own political entity. Then there were cities and city-states with a constellation of villages around them, and then countries. Now we have economical and political alliances of countries like the European Union.

We are already tackling projects that may be too costly for any one country to complete on its own, like the International Space Station. Some scientific projects are made possible by countries sharing data and facilities. And the business sphere is perhaps the most thoroughly globalized one. I believe that these trends will eventually converge and lead to a sort of worldwide federation governed by a single political body. That may not happen for a few hundred years, but it would be the logical next step if we extrapolate from the progression from family group to an alliance of countries. I believe that will be a golden age for scientific discovery.

All of us who are not Einsteins, Galileos, or Leonardos have a very important job—to paraphrase Newton, we provide the shoulders that future giants will stand on. We are part of a massive effort to understand how things work in nature, in the Universe, from the microscopic to the astronomical. And the next groundbreaking, history-altering discoveries will depend on the knowledge we have helped accumulate. We can hardly predict what these discoveries will be and how they will change people’s lives, just like no one foresaw all the applications of the laser or the emergence of the internet. As a pure speculation, I think if something like an interstellar “warp drive” ever becomes possible, it will be at least in part because of what we have learned about the properties of matter and space-time by studying pulsars—and that’s where I do my part.

Einstein@Home press releases for the 2 pulsar discoveries made by volunteers:

http://www.aei.mpg.de/english/contemporaryIssues/akt_news/archiv/2010/pressinfo/index.html

http://www.aei.mpg.de/english/contemporaryIssues/akt_news/index.html

SETI@Home site: http://setiathome.berkeley.edu/

SETIQuest site: http://setiquest.org/

SETIQuest app beta: http://live.seti.hg94.com/