These are my notes and expanded thoughts from this month’s Space News segment on ABC Radio Hobart and ABC Northern Tasmania. Every month I join Lucie Cutting on Sunday mornings to chat about what’s happening above and beyond.
Here’s what we discussed, plus some of my notes, and expanded thoughts from this edition of the programme:
SETI@Home’s Final 100 Signals
This month’s show had a theme — letters from strangers — and we started with the biggest crowdsourced search for alien intelligence ever run.
SETI@Home launched on 17 May 1999 at UC Berkeley. You downloaded software that ran as a screensaver, and while your computer was idle it crunched radio data from the Arecibo Observatory in Puerto Rico. They expected maybe 50,000 to 100,000 users. They got 200,000 within days. A million in three months. By the end, 5.2 million people in 233 countries. The whole thing started with $100,000 from The Planetary Society and Paramount Pictures, and most of the time it was run by just four people.
Arecibo’s 305-metre dish — built into a natural sinkhole, the world’s largest radio telescope at the time — observed a third of the entire sky, each area 12 or more times. Some areas hundreds or thousands of times. The project won a Guinness World Record for the largest computation in history in 2008. Over 2 million years of aggregate computing time.
And the result: 12 billion candidate signals. Tiny blips of energy at particular frequencies from particular points in the sky. Most were radio interference — satellites, radar, even microwave ovens. The team spent a decade filtering those down to about a million plausible candidates, then a thousand that needed manual review, and finally 100 that are genuinely unexplained.
So are they aliens?
Almost certainly not. The team fully expects them to turn out to be interference they haven’t been able to identify yet. But the analysis isn’t complete. China’s FAST telescope — 500 metres across, now the world’s largest dish — has been re-observing each of those 100 spots since July 2025. Fifteen minutes per target. Results haven’t been published yet. Two papers appeared in The Astronomical Journal in 2025, but technically the book isn’t closed.
And you can’t go back and check with Arecibo. It collapsed on 1 December 2020 — two support cables failed and the 900-tonne instrument platform crashed into the dish. If you’ve seen GoldenEye or Contact, that’s Arecibo. Gone.
Even if they find nothing, the project set a benchmark. As co-founder David Anderson put it: if there were a signal above a certain power level, they would have found it. A null result is still scientifically valuable — it tells us what’s not out there. And the software platform they built, BOINC, now powers dozens of other projects, from protein folding to gravitational wave searches.
A couple of fun details: at least two people were fired for running SETI@Home on their work computers. One was a state employee in Ohio. A school IT director resigned after his installation allegedly cost his district $1 million in removal — though he was also accused of stealing 18 computers, so SETI was just the icing. About a third of all processing was done on work or school computers. And Arecibo had no internet connection — data was shipped to Berkeley on physical tapes, 2.5 terabytes each, every two to three days.
Ann Druyan called it “the great cosmic lottery” — “A chance for any one of us to find the answer to the question at the heart of our dawning cosmic awareness.”
The Wow! Signal
We spent a fair bit of time on this one. August 15, 1977, 10:16pm EST. The Big Ear radio telescope at Ohio State picks up a 72-second signal that looks exactly like what a message from aliens is supposed to look like. Jerry Ehman — a volunteer astronomer, reviewing printouts by hand from an IBM 1130 — spots the sequence ‘6EQUJ5’, circles it, writes ‘Wow!’ in red pen. Nearly 50 years later, we may finally have an explanation.
The ‘6EQUJ5’ isn’t a message. It’s the signal’s intensity over time — digits 1–9, then letters for 10 and above. The ‘U’ is 30 times background noise. Intensity rose for 36 seconds as the telescope rotated toward the source, peaked, then fell for 36 seconds as it rotated away. That’s exactly what a genuine cosmic signal would do.
The frequency was 1420 MHz — the hydrogen line. Hydrogen is the most common element in the universe, and this is the frequency scientists had long predicted would be the logical choice for interstellar communication. It’s also legally protected — terrestrial transmissions are forbidden there. The signal was narrowband, concentrated at a single frequency. It came from the direction of Sagittarius, near the globular cluster M55. 30 times louder than anything else in the background sky. It lasted 72 seconds — exactly the time Big Ear’s beam could observe any given point as Earth rotated.
It ticked almost every box.
It never came back
Over 50 follow-up searches. Nearly five decades. Far more powerful telescopes. Nothing. And you can’t go back to Big Ear — it was demolished in 1997 to make way for a golf course. A golf course! The university sold the land. One of the most historically significant radio telescopes in the world, the site of the most famous detection in SETI history, and it’s a housing development in Ohio now. Volunteers did save boxes of the original printouts, and those are still being digitised.
There’s also a great typo story: a purchasing department at Ohio State accidentally ordered the wrong oscillator frequency for the telescope’s receiver. The software was rewritten to compensate. This clerical error became part of the signal’s history.
A possible explanation
A team led by Abel Méndez at the University of Puerto Rico found 8 similar but much weaker signals in archived Arecibo data from early 2020. The theory: a magnetar — a neutron star with a magnetic field up to a trillion times stronger than Earth’s — had a violent outburst, and that energy hit a nearby cold hydrogen cloud. The cloud briefly lit up at the hydrogen frequency, like a cosmic camera flash. You need the magnetar, the cloud, and Earth all perfectly aligned, which is why it’s so rare and why it hasn’t happened again.
Magnetars hadn’t even been hypothesised in 1977. They weren’t proposed until around 1992. Only about 30 are known today, but there could be 30 million in the Milky Way.
It’s the most plausible natural explanation we’ve had, but it’s still under peer review. A 2025 reanalysis suggests the signal was actually even stronger than originally measured — peaking above 250 Janskys. The 50th anniversary is August 2027, and the team wants the full Big Ear archive publicly available by then so other researchers can take their own look.
Ehman once said: “I resisted drawing vast conclusions from half-vast data.”
The Voyager Golden Record
In 1977, NASA sent two spacecraft into the cosmos. Each carried a 12-inch gold-plated copper phonograph record — sounds, images, music, meant to represent all of Earth. The whole thing cost $18,000 to produce. The initial budget from NASA was $1,500.
It was curated by a committee chaired by Carl Sagan at Cornell. Ann Druyan was creative director, Timothy Ferris produced it (he was a Rolling Stone editor), and the sound engineer was Jimmy Iovine — recommended by John Lennon. 115 images, greetings in 55 languages, natural sounds (surf, wind, thunder, birds, whale songs), human sounds (footsteps, heartbeats, laughter, a mother’s kiss), a greeting from Sagan’s 6-year-old son Nick, and 90 minutes of music from cultures all over the world. Bach, Beethoven, Chuck Berry’s ‘Johnny B. Goode’, Navajo chant, a Georgian drinking song, a 2,500-year-old Chinese piece. Played at 16⅔ RPM — half speed — to fit more on. The cover has playback instructions, Earth’s location mapped via 14 pulsars, and a diagram of the hydrogen atom. If aliens can decode it, they can find us.
Timothy Ferris hand-etched “To the makers of music — all worlds, all times” in the run-out groove, inspired by Lennon’s trick of etching messages into records. NASA nearly rejected it — a compliance officer flagged it because the inscription wasn’t in the original blueprints. They prepared blank replacement discs. Sagan had to personally appeal to the NASA Administrator, arguing it would be the only example of human handwriting aboard.
Ann Druyan’s brainwaves
One of my favourite details. Druyan had her brainwaves recorded for an hour via EEG at Bellevue Hospital in New York on June 3, 1977. She had a mental itinerary — Earth’s history, civilisation, violence, poverty, falling in love. But just two days earlier, on June 1, she and Carl Sagan had declared their love for each other by phone. They decided to get married during that call. Before they’d even been on a date. That hour of brainwaves was compressed into one minute of audio on the record. It’s in interstellar space right now.
What they left off
No war, no famine, no disease, no crime — all deliberate. Sagan argued that a hostile civilisation wouldn’t care about our weakness, and a benevolent one would see our failures as tragedy. They wanted to show what we aspired to be.
They wanted the Beatles’ ‘Here Comes the Sun’ but EMI wanted $50,000 per record. The entire project cost $18,000. Druyan later said: “Here’s a chance to give a piece of music immortality, and they’re worried about money.” And when ethnomusicologist Alan Lomax objected to Chuck Berry being on there, calling rock music “adolescent”, Sagan replied: “There are a lot of adolescents on the planet.”
Jimmy Carter’s message: “This is a present from a small distant world, a token of our sounds, our science, our images, our music, our thoughts, and our feelings.”
Where Voyager 1 is now
Voyager 2 launched on 20 August 1977. Voyager 1 on 5 September. Yes, 2 launched first.
Voyager 1 is about 16 billion miles from Earth now. It crossed into interstellar space in August 2012. Data rate: 160 bits per second — slower than a dial-up modem. The only antenna that can send it commands is Deep Space Station 43 in Canberra, which went offline for major upgrades in 2025.
This November — around November 13 to 15 — it reaches one light-day from Earth. Send a message at 8am Monday, you won’t hear back until 8am Wednesday. It’s doing 38,000 mph, which works out to about 1 light-year every 18,000 years. The nuclear battery is running down. Instruments are being shut off one by one. It may keep going past the 2027 anniversary. Then eventually it’ll go dark, and drift for a billion years. In about 40,000 years it’ll pass within 1.7 light-years of a star called Gliese 445 in Camelopardalis.
HUMANS: Deep Space Message
This one ties it all together. The Powerhouse Museum in Sydney and MIT are collecting messages from the public to send into deep space on 5 September 2027 — the 50th anniversary of Voyager 1’s launch. Over 2,000 messages so far. Every single one gets included. No curation, no editing, no gatekeeping.
HUMANS stands for Humanity United with MIT Art and Nanotechnology in Space. Co-founded by Dr Maya Nasr (Lebanese-born, now at Harvard) and Lihui Lydia Zhang (Chinese-born, MIT). They met as international students in an MIT space policy seminar. Both had experienced barriers to accessing the space sector as international students. Their question: “What would you like the universe to remember about our story on Earth?”
It’s already been to space twice
In 2023, a 6-inch silicon nanowafer carrying messages in 64+ languages from 80+ countries flew to the ISS on the Axiom-2 mission. Astronauts played the audio on a livestream. For some contributors, their native language was heard in space for the first time. The wafer came back and is at the MIT Museum now.
In March 2025, a 2-inch wafer landed at the lunar south pole on Intuitive Machines’ Athena lander (IM-2), mounted on a Lunar Outpost rover. The lander tipped on its side, which was dramatic, but the wafer made it. Those messages are sitting on the Moon right now.
In September 2027, new messages get transmitted into deep space via radio. Nanotech carriers are also in development at MIT.
How the tech works
Messages — text and audio waveforms — are nano-etched onto silicon at MIT.nano. Professor Craig Carter designed algorithms converting audio into geometric spiral patterns, deliberately echoing the Golden Record’s grooves. World map at the centre, data-packed spirals around it. It’s literally a modern record made with technology that didn’t exist in 1977.
The Golden Record was a letter from about 6 experts on behalf of humanity. HUMANS is humanity speaking for itself. In 1977, Sagan’s team took six months and the public had zero input. Now anyone with a phone can contribute. That’s a bigger shift than the technology.
You can submit a message at humans.powerhouse.com.au.
Next month I’ll be back on ABC Radio Hobart and ABC Northern Tasmania with Lucie for more space news.
View the archive of Space News.