Breakthrough Listen: ten years listening to the universe

Breakthrough Listen, which its organizers describe as the most comprehensive search ever made for signs of technology beyond Earth, is a privately funded science program. Announced in London in 2015, with ten years of observation planned from 2016, it reaches the end of its planned campaign in 2026. On December 18, 2025, it pointed the Green Bank radio telescope, in the United States, at the interstellar comet 3I/ATLAS and found no artificial emission. Ten years on, the answer remains the same: silence, measured with ever greater precision.

What happened

The program was launched on July 20, 2015, at the Royal Society in London, by entrepreneur Yuri Milner, with Stephen Hawking and Frank Drake present. The announced budget was US$ 100 million over ten years. Observations began in January 2016 at the Green Bank telescope and, months later, at Parkes, in Australia. Other partners followed, such as MeerKAT, in South Africa.

Over the decade, the program listened to thousands of nearby stars and about a hundred neighboring galaxies. In 2025, a new analysis of the Green Bank archive covered 3,077 stars, according to its authors the largest dataset ever combed for technological signals. No artificial signal was confirmed.

The most recent case was 3I/ATLAS, the third known interstellar object, discovered on July 1, 2025. Because there was speculation about its nature, the program organized a coordinated listening campaign. On the eve of its closest approach to Earth, Green Bank swept from 1 to 12 GHz and detected nothing coming from the comet, with enough sensitivity to pick up a transmitter of about 0.1 watt. MeerKAT, listening from 900 to 1,670 MHz, found the signatures of hydroxyl, a natural signal linked to the comet's water ice. The SETI Institute's summary was that the object continues to behave as expected of a natural astrophysical process.

Why it matters

The search for intelligent life beyond Earth is one of humanity's oldest questions. Breakthrough Listen turned it into scientific routine: first-rate telescopes, dedicated observing hours, open data and methods published in peer-reviewed journals.

It also showed how hard it is to listen. The search's greatest enemy is not distance, it is human noise. Cell phones, radars and satellites generate signals that look artificial because they are artificial. That is why every candidate goes through tests to rule out interference from Earth, and why the international protection of the 1,400 to 1,427 MHz band, where all emissions are prohibited, is so valuable.

And the 3I/ATLAS case shows the ethics of the method: faced with an object surrounded by rumors, the response was to measure, publish and accept the result.

In Bairo's view

For Bairo, Breakthrough Listen is the portrait of persistence without guarantees. Ten years, a hundred million dollars, the best ears on the planet, and the result is silence. Even so, no one calls it failure. Every measured silence is an answer.

He recognizes in it the rule he drew from his own life: every no is the ground of a yes. In his reading, an honest search is not measured by what it finds, but by the faithfulness with which it keeps asking.

The 1420, for Bairo, is a symbol of this kind of listening, the kind that waits without talking over anyone. That is why the measure he carries is the 21 cm yardstick, and not a device. No one transmits on 1420 MHz.

And there is trust in the data. For Bairo, a record that must be verified for years has to stay intact for years, and that is the benefit he proposes with qrqbits: post-quantum protection, built to withstand the quantum computers of the future as well.

Where this meets the ecosystem

The BTZ Chain proposes a network of records with proof of veracity, in which what was written can be checked by anyone later. It is the same ethic as the 3I/ATLAS case carried into another field: record, allow checking and do not claim what was not measured.

1420mhz, created by CLAIN, carries the name of the line that has inspired the search since 1959. The relationship with Breakthrough Listen is one of theme and inspiration. None of Bairo's fronts takes part in the program.

Sources

• Breakthrough Initiatives, Breakthrough Listen page, accessed October 2026.
• SETI Institute, Breakthrough Listen observations of 3I/ATLAS, 12/19/2025.
• Breakthrough Listen, 3I/ATLAS with Green Bank from 1 to 12 GHz (arXiv), December 2025.
• BBC Sky at Night Magazine, the search on 3I/ATLAS, 01/06/2026.
• New search of the Green Bank archive, 3,077 stars (arXiv), 2025, published in The Astronomical Journal.

Read also

• Frank Drake and the silence of 1420 MHz
• What is SETI's Water Hole
• Every no is the ground of a yes