Scientists Begin Search For Radio Signals From ‘Solar System 2.0’

Scientists have just completed an extensive search for signs of alien technology in the TRAPPIST-1 star system, the so-called "solar system 2.0" just 41 light-years distant in the Milky Way.

They found no evidence from within the star system, which is known to have seven planets orbiting a red dwarf star. That makes TRAPPIST-1 the star system most similar to the solar system.

Hunt For Technosignatures

The researchers used the recently upgraded Allen Telescope Array, an installation of 42 antennae in Lassen National Forest, California. This radio telescope's primary purpose is to search for radio signals that could indicate extraterrestrial life.

It specifically looks at technosignatures — scientific evidence of past or present technology that would indicate the presence of life in another star system. Finding technosignatures is thought to be easier than detecting biosignatures — evidence of microbial life — in the cosmos.

Exploring TRAPPIST-1

The team spent 28 hours scanning TRAPPIST-1, the longest single-target search for radio signals from that star system. It has published its results as a preprint before being published in the Astronomical Journal.

TRAPPIST-1 is a red-dwarf star 41 light-years away in Aquarius that in 2015 was discovered to host three Earth-sized planets, with four more found in 2017. Some of its seven terrestrial planets — the most ever to have been found to orbit a single star — orbit in the star's habitable zone, where it's warm enough for liquid water to exist on their surfaces.

The possibility of this essential ingredient for life as we know it makes TRAPPIST-1 a top target in the search for life beyond Earth.

Honing the Search For Life

Although the search for technosignatures at TRAPPIST-1 was fruitless, the research proved a new way to search for such signals in the future. "This research shows we are getting closer to detecting radio signals similar to the ones we send into space," said Nick Tusay, a graduate student research fellow at Penn State University, which conducted the ground-breaking project with the SETI Institute, in a press release .

The researchers studied planet-planet occultations — when one planet moves in front of another — to search for radio signals leaking from TRAPPIST-1. After filtering, they found 2,264 narrowband signals, but none of the signals were judged to be of non-human origin.

Eyes on the Sky

For now, scientists can only search for the kinds of radio signals humans send into the cosmos. However, bigger and better radio telescope arrays will soon be available. "Most searches assume some intent, like beacons, because our receivers have a sensitivity limit to a minimum transmitter power beyond anything we unintentionally send out," said Tusay. "But, with better equipment, like the upcoming Square Kilometer Array (SKA), we might soon be able to detect signals from an alien civilization communicating with its spacecraft."

The SKA is a $2.2 billion project that comprises two large and complex radio telescope networks — 197 radio dishes in Karoo in South Africa's Northern Cape and 131,072 antennas in Murchison, deep in the outback of Western Australia. Together, they will form a total collecting area of one kilometer spanning two continents, allowing the detection of very faint radio signals.

Wishing you clear skies and eyes.