Aliens could be talking to us right now. This scientist is listening.

Sofia Sheikh’s network is investigating more than a million stars for signs of extraterrestrial life.

Tim Enthoven illustration
It takes a special set of ears to dig through the chatter of the universe.Tim Enthoven

Sofia Sheikh is a PhD candidate in Astronomy and Astrobiology at Pennsylvania State University. This is her story from the field as told to Charlie Wood.

The search for extraterrestrial intelligence has progressed rapidly in the past few decades. Back in the 1960s, researchers would literally tune the radio dial, hoping to hear artificial patterns in the static that would prove we’re not alone. But they could only listen to one slice of the spectrum at a time. Now, thanks to massive radio telescopes, astronomers can pick up wide swaths of it at once. Breakthrough Listen, a global research group I am part of, is investigating more than a million stars for single-tone signals akin to our AM/FM stations.

In 2017, I led a study of 20 intriguing stars—ones from which Earth’s transit in front of our sun is visible. If a civilization in this zone can see us, perhaps they’re reaching out. It took almost five months for every star to rotate into view and another two years to sort through the hundreds of gigabytes of radio crackling we gathered.

During my analysis, one tone seemed powerful and clear, as you would expect an artificial transmission to be. But when I looked more closely, I noticed that the signal’s frequency barely shifted. This implies its source is stationary relative to the telescope rather than zooming around as a planet, moon, or spacecraft would. My money’s on something like a cell tower. That’s 20 stars down, millions to go.

This story appears in the Fall 2020, Mysteries issue of Popular Science.

Breakthrough Listen is the largest ever scientific research program aimed at finding evidence of civilizations beyond Earth. The scope and power of the search are on an unprecedented scale:

The program includes a survey of the 1,000,000 closest stars to Earth. It scans the center of our galaxy and the entire galactic plane. Beyond the Milky Way, it listens for messages from the 100 closest galaxies to ours.

The instruments used are among the world’s most powerful. They are 50 times more sensitive than existing telescopes dedicated to the search for intelligence.

The radio surveys cover 10 times more of the sky than previous programs. They also cover at least 5 times more of the radio spectrum – and do it 100 times faster. They are sensitive enough to hear a common aircraft radar transmitting to us from any of the 1000 nearest stars.

We are also carrying out the deepest and broadest ever search for optical laser transmissions. These spectroscopic searches are 1000 times more effective at finding laser signals than ordinary visible light surveys. They could detect a 100 watt laser (the energy of a normal household bulb) from 25 trillion miles away.

Listen combines these instruments with innovative software and data analysis techniques.

The initiative will span 10 years and commit a total of $100,000,000.