Hitting the Books: What exactly did Jodi Foster hear in 'Contact'?

A real life astronomer breaks down what the 1997 film got right, and wrong.

Warner Bros. Pictures

Art may imitate life but it rarely does so with realistic fidelity. As Naomi Pequette, Space Science Programs Specialist at the Denver Museum of Nature and Science, argues in her essay "The Sounds of Contact" as part of The Science if Sci-Fi Cinema: Essays on the Art and Principles of Ten Films, being "based on a true story" doesn't exactly mean we're getting the whole story.

The Science of Sci-Fi Cinema cover

From The Science of Sci-Fi Cinema: Essays on the Art and Principles of Ten Films © 2021 Edited by Vincent Piturro by permission of McFarland & Company, Inc., Box 611, Jefferson NC 28640.

How would you react if you found out we aren’t alone in the universe? Imagine the moment you discover a radio signal from another civilization had traveled billions of miles through interstellar space, had been detected by some of the most powerful radio telescopes in the world, and decoded by scientists. Would it matter if it was first detected by scientists from your home country? Would the content of the signal matter? Would you want the chance to be able to meet the alien civilization that sent the signal? These are all questions that the movie Contact explores.

The opening sequence of Contact sets the scientific basis for the rest of the film. As the camera travels away from Earth, the audience hears a cacophony of sounds. These sounds, which are radio and television signals traveling out into space, get older and older as we zoom past planets and asteroids. Eventually there is silence as the audience is taken into deep space and past beautiful sights like the Eagle Nebula. While the premise of the sequence has its basis in science, the scale is completely wrong.

Humanity has been transmitting television and radio signals into deep space for over a hundred years. These signals leave Earth and travel at the speed of light. This means that in one year, a signal will travel one light year into space. This has created what scientists call the “radio bubble,” an ever-expanding sphere with Earth at the center, that spans over 200 light years and announces humanity’s presence to the cosmos. These signals have gone well beyond our solar system and out to the nearest stars. However, our own solar system is small in comparison to this vast bubble since it spans just a few light hours across. That means, when Contact was released in 1997, our solar system would have still been listening to the greatest hits of 1997, like the number one Billboard song “I’ll Be Missing You” by Puff Daddy and Faith Evans, not broadcasts of the Kennedy assassination like we hear at Jupiter during the opening sequence. The closest star, Proxima Centauri, is only four light years away, which means any aliens on the planets orbiting Proxima Centauri would be singing along with Whitney Houston’s “I Will Always Love You.” The television signal featuring Hitler at the 1936 Olympic games would have been traveling through space for 61 years, meaning any planet within 30 light years from Earth could have received the signal and sent it back to Earth. This includes more than 20 planets discovered as of 2019 and the all-important star of the film, Vega.

The story in Contact closely parallels the story of the Search for Extraterrestrial Intelligence Institute (SETI). One of SETI’s first projects, Project Phoenix, used radio telescopes to search for narrow-band radio signals, or signals that are at only one spot on the radio dial. These are considered the “signature” of an “intelligent” radio transmission. Much like Dr. Arroway’s research, Project Phoenix heavily relied on existing radio telescopes, such as Arecibo. Despite this, Project Phoenix was still the world’s most sensitive and comprehensive search for extraterrestrial intelligence. Unfortunately, this dependence on existing equipment meant that there were multiple projects competing for observing time. Still, SETI was able to obtain two three-week observing sessions on Arecibo, the world’s largest radio telescope, each year between 1998 and 2005. Instead of broadly scanning the sky, Project Phoenix targeted Sun-like stars within 200 light years since they were believed to be the most likely stars to have a planet capable of supporting life, and thus possibly intelligent life. Nearly two billion channels were examined for each target star.

SETI faced funding woes much like Dr. Arroway. Less than a year after founding the program, NASA withdrew funds from SETI due to pressures. While there were, and still are, questions about whether we could find evidence of extraterrestrial life, most informed parties agreed that SETI was pursuing worthwhile and valid science. However, fervor to decrease the federal deficit and a lack of support from other scientists and aerospace contractors made it an easy program to cut. Since then, SETI has been dependent on foundations and private donors for funding.

We see this reflected in Contact in Dr. David Drumlin who often questions the value and chance of the success of Dr. Arroway’s search. Dr. Drumlin is the science equivalent of a mustache-twirling villain. He will tell politicians whatever they want to hear, is narrow minded with the power to make or break scientist’s careers with funding, and is the stereotypical patronizing “mansplainer” that makes him reprehensible to the audience, or at least to an audience of scientists. He represents the politicians and other scientists who often mocked SETI. “What’s wrong with science being practical, or even profitable?” he muses. There is no immediate return on a search for extraterrestrials and that is often the factor that determines what projects receive funding. This was especially true for national funding of science in the 1990s. During Dr. Drumlin’s visit we hear other scientists at Arecibo scrambling to justify their own research in hopes that they can keep their funding. Dr. Drumlin ultimately pulls the plug on Dr. Arroway’s funding from the National Science Foundation, forcing her to seek funding from private sources. Her research became dependent on funding from a private donor, S.R. Haden, much like SETI’s research.

SETI served as the inspiration for key scientists as well. Dr. Arroway was based on Dr. Jill Tarter, the former director of SETI and the person responsible for the fact that SETI even exists. Like Dr. Arroway, she was inspired and encouraged by her father to pursue engineering and science before he died when she was twelve. She had to elbow her way through school at a time when women didn’t pursue STEM careers and was often not respected by peers because searching for extraterrestrial intelligence was, and still can be, considered fringe. However, like Dr. Arroway, Dr. Tarter persisted and left behind an incredible legacy. Dr. Kent Clarke was based on Dr. Kent Cullers, a project manager for SETI. Dr. Cullers was the first blind student to earn a Ph.D. in physics in the United States and is believed to be the first astronomer who was blind from birth. He developed and implemented complex computer algorithms to sift through mountains of radio signals and search for one that might be from another civilization.

One key difference between Dr. Arroway and Dr. Clarke’s search in Contact and SETI is the telescopes they used. While both Dr. Arroway and SETI utilized Arecibo, SETI never used the Very Large Array in their search. Not only would this have been a significant drop in sensitivity (Arecibo has four-times the collecting area, so it would be more likely to be able to detect a faint signal), it would have created a logistical problem. Since the Very Large Array is made up of 27 radio dishes, this would have required 27 specially designed receivers (one for each telescope) which would have been impossible with SETI’s limited budget.

And forget trying to listen to all those radio signals. While Dr. Arroway sitting in the desert listening for a signal is one of the most iconic visuals of the film (and one visitors of the Very Large Array love to recreate) astronomers don’t listen to signals at all. During Project Phoenix, using only one radio dish, there were 28 million radio channels being monitored simultaneously. Headphones could only listen to one of these channels at a time so the chances of listening to the right channel when the signal arrives is “astronomically” small. Unfortunately, the life of a radio astronomer is not nearly as romantic. It involves a lot of sitting in a control room (with no Wi-Fi or cell phones since that could produce a signal radio telescopes could pick up) waiting for a computer (using complex programs, like those developed by SETI’s Dr. Cullers) to send an alert that there is an interesting signal. However, astronomers are required to make critical decisions about signals that look intriguing.

Much like radio signals we have broadcasted into space in hopes of contacting an alien civilization, scientists speculate that any signal we receive from an intelligent civilization would be distinct from other naturally occurring radio sources. This could be done with the content of the message, like the “Arecibo Message” sent in the 1970s which contained the numbers one through ten and information about our DNA. Certainly, prime numbers or information on how to build an advanced machine would qualify the signal in Contact and make it distinct. In reality, however, it could take years to decode the deeper signals so there needs to be something else to make scientists look twice at a signal.

The aliens in Contact do this by transmitting the signal at a very special frequency that wouldn’t occur naturally. This frequency, 4.4623 GHz is described as “hydrogen times pi (π).” The hydrogen line, which is a common observation in radio astronomy, is the frequency at which hydrogen atoms, the most abundant substance in space, emit radio waves (1420.40575 MHz). While there aren’t a lot of loose hydrogen atoms in space (about one per cubic centimeter of interstellar space) space is vast. So, the collection of all those individual atoms makes for a powerful signal that can be easily detected by small radio telescopes. By multiplying this frequency, that would be well known by scientists, by a mathematical constant, not only are they creating a signal that could not be naturally occurring (since pi is an irrational number), bit would also give the civilization on the receiving end clues to the scientific knowledge of the aliens that sent it. While this frequency isn’t inside the range of frequencies that was observed by SETI’s Project Phoenix, it is within Very Large Array’s observing range of 1–50 GHz.

Another clue that the signal in Contact was not likely to be one that was not from a typical astronomical source is its strength. The signal measured in at 100 Jansky (Jy). A Jansky is a unit used by radio astronomers to describe the “brightness” or strength of a signal. Celestial radio sources are much fainter than terrestrial and are just a few Jy in strength. So, this is a relatively strong signal. The Sun, the brightest celestial radio source is 106–108 Jy in most frequencies, depending on solar activity. Terrestrial radio broadcasts, such as those we listen to on FM radio can be a million to a trillion times brighter than the Sun. So, while strong by astronomical standards, this is still a very faint signal by terrestrial standards and would require a radio telescope to detect.

So, what would happen if a signal is detected? In Contact, we see mixed reactions—excitement, wonder, fear, a sense of loss of control. The closest we have gotten as a society was on October 30, 1938, when CBS Radio systems broadcasted a story that Martians were attacking Earth, starting with a small town in New Jersey. While reports are mixed on whether there was nationwide panic or people simply enjoyed the broadcast of “The War of the Worlds,” many scientists have used this reaction to frame their recommendations for “first contact” protocols. Today’s society is used to getting constant updates via Twitter and other social media, so the post-detection protocols, which were first written in 1989, were revised in 2010, and are currently undergoing another revision.

As in Contact, the first step would be to verify the signal. Since 1997, scientists have become even more connected globally which fosters collaboration and allows for this sort of testing. In an ideal situation, only after the signal had been verified would the world be alerted to the discovery via a press conference. However, in this increasingly connected world with more “news leaks” this is unlikely to happen. The 2010 International Academy of Astronautics (IAA) post-detection protocol, which is only 2 pages long, now includes informing the public earlier in the process than the original version. If the public were to find out before the signal was fully verified, scientists would manage the public’s expectations by using the Rio Scale, a scale which indicates how likely the signal is to be from an intelligent extraterrestrial civilization.

Could a discovery of this possibly be contained by one government like the United States attempts to do in Contact? If the signal is discovered by SETI, which is not funded or controlled by a U.S. governmental agency, it is unlikely. Step three in the IAA post-detection protocol is “[a]fter concluding that the discovery appears to be credible evidence of extraterrestrial intelligence, and after informing other parties [researchers or organizations involved in the detection] to this declaration, the discoverer should inform observers throughout the world through the Central Bureau for Astronomical Telegrams of the International Astronomical Union, and should inform the Secretary General of the United Nations in accordance with Article XI of the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Bodies.” Yes, astronomers send out “telegrams.” However, today they are digital and are used for all major astronomical discoveries that need further observation. This is widely used for the discovery of new supernovae which are some of the brightest phenomena in the universe but fade very quickly and need quick reactions from observatories around the world to maximize observation time. This step in the IAA protocol also includes notifying eight other international organizations. Step five requires the release of all data necessary to confirm detection to be released to the international scientific community. Unfortunately, there have been no confirmed signals yet and there are Dr. Drumlins in the world who would work closely with politicians so, despite the international community’s best effort, we won’t know until it happens.

So how would we react as a society? Michael Varnum of Arizona State University investigated just this. In his study, published in the Frontiers of Psychology in 2018, he found that we might react better than science fiction might lead us to believe. Varnum and his team ran several relevant new stories through a language-analysis program and asked it to determine whether the language used in those articles reflected positive or negative emotions. These news articles included stories about the 1967 discovery of pulsars whose regular, repeating signal was first labeled “LGM” for little green men, stories about the “Wow!” signal from 1977 which is the most likely candidate for an extraterrestrial signal but has never been verified, the 1996 “discovery” of fossilized microbes in a Martian meteorite, and more recently articles about the discovery of earth-like exoplanets and the strange behavior of Tabby’s star, which was thought by some to be acting like an “alien megastructure.” These articles generally turned out to include language reflecting more positive attitudes. The second phase of his study was to conduct surveys of approximately 500 people on their anticipated reaction if we discovered (and verified the existence of) microbial life along with asking another 500 people to read, and write down their reactions to, articles about the 1996 “discovery” of microbial life (now known to be incorrect) as well as an article about the creation of synthetic life here on Earth. In both cases, participants used more positive than negative language. However, this study has been criticized for its focus on microbial life. After all, as SETI scientist Seth Shostak points out, microbes are one thing and little grey aliens with an advanced technological society are another. The reality will be much more complicated than people reading a single article and writing down their reactions. People will be influenced by not only how the story is presented, but also by reactions on social media and their friends. This study also didn’t investigate the effect religion will have on people’s reactions, a central theme in Contact.

If a signal from an intelligent alien civilization is ever detected, it will be a world-changing, paradigm-shifting event. So what are the chances there is life out there that could send such a signal? “There are 400 billion stars out there, just in our galaxy alone. If just one out of a million of those had planets, and just one in a million of those had life, and just one out of a million of those had intelligent life, there would be literally millions of civilizations out there.” Dr. Arroway’s numbers aren’t quite correct and are pessimistic even by the lowest estimates by astronomers. However, even with those numbers, it’s clear that if there wasn’t intelligent life out in the universe, it would be an awful waste of space.