Posted by The search for extraterrestrial intelligence has a start date, which is unusual for a science. Most fields seep into existence over decades and nobody can name the morning they began. This one can. On 8 April 1960, before sunrise, a 29-year-old astronomer named Frank Drake swung an 85-foot dish at the new radio observatory in Green Bank, West Virginia, toward a star called Tau Ceti and started listening. He had two stars on his list, a receiver he had helped build himself, and no expectation that anyone would answer. Nobody did. Sixty-five years later nobody has, and yet the thing Drake started that morning has turned into a real discipline, with instruments, statistics, published null results, and a long institutional memory of its own false alarms.
That memory is the interesting part.
Two Stars and a Borrowed Dish
Drake called it Project Ozma, after the queen of Oz, a place he described as far away and populated by strange beings. His targets were Tau Ceti and Epsilon Eridani, both around eleven light-years out, both roughly Sun-like, and both chosen mostly because there was almost nothing else nearby to choose from. He tuned to 1420 MHz, the emission line of neutral hydrogen. That choice came from a paper Giuseppe Cocconi and Philip Morrison had published in Nature the previous September, arguing that any civilization doing radio astronomy at all would know about the hydrogen line, which made it a natural meeting place on the dial.
The search ran a few months and something like 150 hours of telescope time. Within days of starting, Ozma picked up a strong pulsed signal while pointed at Epsilon Eridani. There was a brief, glorious moment. Then the signal turned up again with the dish aimed somewhere else entirely, and the team concluded it was terrestrial — aircraft radar, most likely. Excitement, then a mundane earthly explanation. That sequence is the oldest tradition in the field.
The Equation Nobody Was Meant to Solve
A year later Drake had to write an agenda for a small closed meeting at Green Bank — eleven or so people, including a young Carl Sagan and the chemist Melvin Calvin, who learned mid-meeting that he had won a Nobel Prize. Rather than list topics, Drake wrote a chain of multiplied factors: the rate of star formation, the fraction of stars with planets, the number of habitable worlds per system, the fraction where life starts, the fraction where life gets clever, the fraction that becomes detectable, and finally L, the lifetime of a technological civilization.
The Drake equation is routinely misread as a prediction machine. It was never that. In 1961 every term past the first was somewhere between an educated guess and a shrug, and Drake has said plainly that the point was to organize the ignorance, not to dissolve it. What has changed since is worth noticing: the first three factors now have measured values rather than invented ones. The last one is still anybody’s guess, and it may be the term that decides everything.
Seventy-Two Seconds in Sagittarius
On the night of 15 August 1977 the Big Ear radio telescope at Ohio State recorded a narrowband burst near the hydrogen line, about thirty times stronger than the background, lasting the 72 seconds it took the sky to drift through the beam. Nobody was watching. The volunteer astronomer Jerry Ehman went through the printout days later, saw the intensity codes 6EQUJ5 stacked in one column, and wrote “Wow!” in the margin in red pen.
It has never come back. Ehman looked. So did others, with Big Ear, with the Very Large Array, with Arecibo, with equipment vastly better than the original. Nothing. A comet was proposed as the source in 2017 and picked apart quickly by other astronomers. So the honest description of the Wow! signal is that it is unexplained, unrepeated, and therefore scientifically useless as evidence — which is a frustrating thing to say about the most famous 72 seconds in radio astronomy, and also the correct one.
The Year the Money Stopped
NASA had been circling this for a long time. The 1971 Project Cyclops study imagined an array of a thousand dishes and came back with a price tag in the billions; it was never built, but the engineering stuck. Two decades later NASA launched a real program, the High Resolution Microwave Survey, on 12 October 1992 — the five-hundredth anniversary of Columbus making landfall. Two halves: a targeted survey of around 800 nearby stars using Arecibo, and an all-sky sweep from the Goldstone antennas in the Mojave.
Congress killed it after one year. The amendment came from Senator Richard Bryan of Nevada, the sum involved was roughly twelve million dollars, and the rhetoric was about ending the taxpayer-funded hunt for little green men. In an American federal budget that number is a rounding error. The consequence was not.
Since 1993, essentially all US work on the search for extraterrestrial intelligence has run on private money.
Phoenix, and the Quiet Decades
The SETI Institute in Mountain View, founded in 1984, picked up the targeted half of the cancelled program and named it Project Phoenix, which was not subtle. Jill Tarter ran it from 1995 to 2004 on donated funds. Roughly 800 Sun-like stars within about 200 light-years, observed with rented time: the Parkes 64-metre dish in Australia first, then the 140-foot at Green Bank, then Arecibo, paired with Jodrell Bank in England so that a candidate signal had to show up in two telescopes thousands of kilometres apart before anyone got excited. Phoenix found nothing. Its verification method, though, became the default everywhere.
Meanwhile Berkeley turned Arecibo’s data exhaust into a screensaver. SETI@home launched in 1999 and ran until 2020; at its peak several million people donated idle processor cycles to sift narrowband candidates. It detected no aliens whatsoever and remains the most effective piece of public science engagement the field has produced.
The Allen Telescope Array at Hat Creek in California saw first light in 2007 with 42 of a planned 350 dishes, built largely on money from Paul Allen. In 2011 it went into hibernation for lack of operating cash. It came back. Arecibo did not: after cable failures in August and November 2020, the 305-metre dish collapsed into its own sinkhole that December, taking with it the most sensitive single dish the search had ever used.
A Signal from the Nearest Star
In July 2015 the investor Yuri Milner committed $100 million over ten years to Breakthrough Listen, which made it instantly the largest programme of its kind ever attempted. Green Bank’s 100-metre telescope and Parkes for radio, the Automated Planet Finder at Lick for optical laser pulses, a target list of a million nearby stars plus a hundred galaxies, and — this mattered — the raw data released publicly.
Then, in observations taken in April and May 2019, Parkes was staring at Proxima Centauri for a completely different project, monitoring the star’s flares. An undergraduate named Shane Smith later found a narrowband tone at 982.002 MHz sitting in that data. It appeared only when the dish pointed at Proxima, and drifted in frequency roughly as you would expect from a transmitter on a moving planet. The candidate got the label BLC1, the story leaked to the press in December 2020, and for a few weeks it was the best signal anyone had seen since 1977.
Two papers in Nature Astronomy in late 2021 took it apart. BLC1 was interference from human electronics, probably a drifting local oscillator somewhere near the observatory, and the team found dozens of look-alike signals hiding in the same dataset once they knew what to search for. The people who killed the candidate were the people who found it. That is not a failure of the process; that is the process, running slowly and in full public view.
What Sixty-Five Years Actually Bought
The lazy reading is that six decades of listening produced nothing. The better reading is that the search changed shape underneath the silence. Drake picked two stars in 1960 because nobody on Earth knew whether planets existed around other suns at all. That ended in 1995, when Michel Mayor and Didier Queloz found 51 Pegasi b. Kepler and TESS have since pushed the count of confirmed exoplanets into the thousands. Proxima b turned up in 2016 around the nearest star to the Sun; TRAPPIST-1 delivered seven roughly Earth-sized worlds in 2017; astronomers are arguing, hard, over whether JWST really sees dimethyl sulfide at K2-18b. Target lists are no longer guesses.
The receivers changed even more drastically. Ozma listened to one 100-hertz channel at a time. Modern backends chew through billions of channels simultaneously, and the searchable volume has grown by many orders of magnitude. And yet a 2018 analysis by Jason Wright and colleagues put the fraction of the “cosmic haystack” examined so far at something like a hot tub’s worth of water drawn from all of Earth’s oceans. A useful antidote to both hype and despair.
Some things have not moved at all. There is still no confirmed detection. The verification bar is still brutally high, and should be. The funding is still private and still precarious, while the radio sky gets noisier every year as satellite constellations multiply overhead.
If any of this pulls at you — the false alarms, the equation that refuses to close, the tiny sampled fraction of the haystack — SETIworld is where we keep following it, story by story, as new results land. Come read alongside us, argue with the interpretations, and see where the next 65 years of the search for extraterrestrial intelligence go.
