SETI: Everything you need to know about how we're listening in for aliens

Humans are waiting to hear word from another planet.


In 1960, astronomer Frank Drake pointed the Green Bank Observatory’s giant radio telescope at two Sun-like stars for 150 hours hoping to find a hint of alien life.

Drake’s search was unsuccessful but it prompted humanity’s ongoing quest to observe the cosmos in an effort to answer a massive existential question: are we alone in the universe?

More than 60 years later, Drake’s method is still at play, although slightly more finessed. The astronomer’s initial quest to find alien life led to the foundation of the SETI (Search for ExtraTerrestrial Intelligence), a series of interrelated programs looking for intelligent life beyond our solar system, mostly by trying to eavesdrop on their radio signals.

But a recent injection of cash — and some new unconventional detection methods — have brought new life to SETI and brought us closer than ever to finding out just how lonely the cosmos are, or hopefully aren’t.

As SETI researchers lend their ears to the cosmos, Inverse breaks down the history of the institute, their methods to search for aliens, and their ongoing quest to answer humanity’s burning questions.

History of SETI

At the National Radio Astronomy Observatory in Green Bank, Virginia, astronomer Drake pointed a radio telescope toward two nearby Sun-like stars, Tau Ceti and Epsilon Eridani, which seemed like good candidates for hosting planets like Earth.

Drake’s experiment was dubbed Project Ozma and it marked one of humanity’s first real efforts to find alien life. It drew its name from L. Frank Baum’s Wizard of Oz book series, specifically that Oz was, “very far away, difficult to reach, and populated by strange and exotic beings.” Though it turned up empty, Project Ozma inspired the development of the SETI method and the Drake Equation.

Drake would write in his book co-authored with Dava Sobel, Is Anyone Out There?, “We had failed to detect a genuine alien signal, it was true, but we had succeeded in demonstrating that searching was a feasible and even reasonable thing to do.”

The Drake Equation is a formula used to estimate the number of alien civilizations that exist in the universe. It looks at:

  • the average rate of star formation in our galaxy
  • the fraction of those stars that have planets
  • the average number of planets that can potentially support life per star that has planets
  • the fraction of planets that could support life that actually develop life at some point
  • the fraction of planets with life that actually go on to develop intelligent life (civilizations)
  • the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
  • the length of time for which such civilizations release detectable signals into space
CSIRO’s Parkes Radio Telescope is one of several telescopes aimed at the skies in humanity’s modern hunt for extraterrestrial life.John Sarkissian

Following in Drake’s footsteps, several astronomers took interest in trying to detect powerful radio signals that may be coming from alien civilizations.

In 1972, astronomers Patrick Palmer and Benjamin Zuckerman launched a second experiment called Ozma II using a larger telescope at the same observatory. The pair observed 670 nearby stars for about four years.

Around the same time, NASA also began to show interest in SETI.

Project Cyclops is a 1971 NASA project that looked into how SETI should be conducted, looking into the type of hardware, workforce needs, and funding it would take to conduct a robust, realistic, science-based effort at finding aliens.

The team behind the project came up with a design of large numbers of radio telescopes all running in coordination to search for Earth-like radio signals at a distance of up to 1,000 light-years.

Unfortunately, the project was shelved due to its high cost but it laid the groundwork for the SETI methods in searching for alien life.

Does NASA currently fund SETI?

NASA’s High-Resolution Microwave Survey was meant to scan 10 million frequencies using radio telescopes with a funding cost of less than 0.1% of NASA’s total budget. However, Nevada Senator Richard Bryan ensured that it was shut down in 1993.

Since then, NASA was hesitant about putting money towards finding SETI efforts. But recently, the space agency has changed its tune, awarding small funding opportunities towards the hunt for aliens.

NASA’s Astrobiology Institute recently awarded the Penn State Extraterrestrial Intelligence Center a five-year, $7 million grant to support their search for alien civilizations.

What are the current SETI programs?

The SETI Institute began operations on February 1, 1985 as a non-profit organization searching for narrow-band radio transmissions from other planets. Narrowband transmissions are those that, like Earth radio signals, come in at specific frequencies and thus are more likely than wideband transmissions to have come from an intelligent source.

The SETI Institute relies on ground based telescopes such as the Allen Telescope Array to pick up on signals transmitted by aliens on other planets.Seth Shostak/SETI Institute

Scientists at the institute primarily use the ground-based Allen Telescope Array built after the collapse of the High-Resolution Microwave Survey with funding from Microsoft co-founder Paul G. Allen. They also use ground-based optical telescopes for work on optical SETI programs. Facilities include:

  • the Shane telescope at Lick Observatory
  • the W.M. Keck telescopes and IRTF in Hawaii
  • the Very Large Telescopes in Chile

Meanwhile, the Berkeley SETI Research Center conducts experiments that look for electromagnetic signatures of extraterrestrial civilizations that span across different wavelengths from radio to visible light.

The center uses multiple observatories to look for signs of intelligent life such as:

  • the Lick Observatory in California
  • the Green Bank Telescope in West Virginia
  • the Keck Observatory in Hawaii

Berkeley SETI also founded SETI@home, a now-dormant online, volunteer-based program that invited the public to use software to analyze radio signals to decipher their origins.

The Breakthrough Listen Initiative uses the Green Bank radio telescope in West Virginia, the Parkes Telescope in Australia, and the MeerKat Array in South Africa to search for radio transmissions from advanced alien civilizations.

The initiative is described as the most comprehensive search for alien life yet. With $100 million in funding from Russian billionaire Yuri Milner, the initiative is able to book thousands of hours of observation time.

The Penn State Extraterrestrial Intelligence Center aims to search for technosignatures, or signals emitted by any sort of technology from an alien civilization.

The center was awarded a grant by NASA to find fingerprints of pollutants being emitted from other planets, as well as space-based solar panels possibly being used by an alien civilization.

Do we ever try reaching out to aliens?

The SETI method is mainly passive, observing the cosmos to look for signs of life on another world. But a related program wants to reach out first.

The METI (Messaging ExtraTerrestrial Intelligence) Institute sent out its first radio transmission in 2017, and they are currently in the process of building a laser transmitter to reach further distances by encoding messages into narrowly-focused bandwidths.

Rather than waiting to listen in on alien life, METI wants to take the initiative and send out a signal so that Earth could be detected by aliens. It’s not the first time humans have tried to take the first step — the Arecibo Message sent a short hello from Earth toward M13, a cluster of new stars 25,000 light years away.

But not everyone is on board with this method, arguing that it adds little to our progress in making contact with aliens since Earth already emits all types of signals and electromagnetic radiation, showing clear signs of life.

What happens if we find aliens?

So far, SETI programs have turned up nothing concrete, though the Wow! Signal remains enigmatic to this day.

Our hunt for alien life not only informs us of other worlds, but it helps us understand our own existence on Earth a little better.

So far, Earth is the only planet that we know of where life began and continued to survive. But we’re not exactly sure how life began on Earth, and why.

Does Earth possess special ingredients for life that can’t be found on other planets, or was there a little extra special “spark” that ignited life on Earth? And if there is life on other planets, does it look like us? Or did life develop in a completely different way elsewhere?

Finally, if we do find aliens, then should we assume that they are a threat to us or can we develop a way to communicate with intelligent life on another planet that’s not harmful to either side?

These are philosophical questions, but before we begin to think that far ahead, first we have to answer the bigger question: are we alone?