Nestled at an altitude of nearly 10,000 feet, atop a mountain in Chile’s Atacama Desert called Cerro Armazones, scientists and engineers are constructing the largest visible light and infrared telescope in the world. When completed, the appropriately namedExtremely Large Telescope (ELT) will be capable of collecting 100 million times more light than the human eye, and it might even be capable of figuring out whether or notlife exists on distant alien worlds.

The ELT is expected to go into operation and collect first light in 2028, after roughly 12 years of construction and a price tag of more than a billion dollars. The telescope sits about 12 miles away from the European Southern Observatory’s (ESO)Very Large Telescope (VLT), which sits atop the Cerro Paranal mountaintop.

The site was chosen for its altitude, placing the telescope above as much atmospheric disturbance as possible. The air has a low water vapor content and it’s far from the city lights. The top of Cerro Armazones is high, dry, and dark, perfect conditions for peering at the universe.

The primary mirror array will be 128 feet (39 meters) across, allowing it to gather more light and greater detail than any other telescope on Earth. Instead of a single mirror, the array is made of 798 hexagonal segments, each 5 feet across. A total of 949 segments were constructed to allow for cleaning, repair, and replacement. In addition to providing more detailed images of distant objects, the ELT may even be capable of directly imaging rocky planets around other stars and detecting signatures of life in other star systems.

How the Extremely Large Telescope could detect alien life

OnSYFY's The Ark, 100 years in the future, humanity sends a series of crewed spacecraft to nearby stars, including Proxima centauri, the closest star to our own. Once there, the crew of the Ark One is tasked with establishing a colony and ensuring the future of our species, but only if they can get there alive.

Here in the present, real-world astronomers could use the ELT to find out if life already exists at Proxima centauri and elsewhere. The trick is learning to read the light. When starlight from the parent star passes through the atmosphere of a planet, some of the wavelengths get absorbed while others pass through. It’s why we have sunsets and why the sky is blue.

Spectra for five different elements.

Photo: NASA/JPL

When astronomers look at the light passing through the atmospheres of distant planets, they can look at the absorption lines in the spectra and figure out what the atmosphere is made of. Here on Earth, life pumps our atmosphere full of oxygen, creating a biosignature that intelligent aliens could see from a distance. Human astronomers are hoping to do the same thing with the ELT.

The telescope isn’t finished yet, but researchers recently created a simulation to figure out what it might be capable of once it’s completed. The results wereposted to arXiv and suggest that the ELT may be capable of detecting alien biosignatures on nearby exoplanets in a matter of hours.

Simulating the ELT’s observation pipeline, researchers supplied a variety of scenarios including positive biomarkers, potential biosignatures, and false positives in the atmospheres of sub-Neptune and Earth-sizedexoplanets. They also looked for a number of different kinds of life, including those which would have been found on a primitive Earth. When simulating observations of Proxima centauri, they found that it could make a determination with only 10 hours of observation time.

This is an artist's concept of the exoplanet GJ 9827d, the smallest exoplanet where water vapor has been detected in the atmosphere.

Photo: NASA, ESA, Leah Hustak (STScI), Ralf Crawford (STScI)

“For the most accessible nearby target, Proxima Centauri b, our results suggest that we may be able to rule out a sub-Neptune atmosphere in as little as a single hour of observing, and two biosignature disequilibrium pairs (O2/CH4 and CO2/CH4) may be accessible in ∼10 hours for the most optimistic scenario,” study authors wrote.

There’splenty of reason to think that Prox b is barren and devoid of life (not to mention a risky place for humans to set up shop) but the same techniques could be used elsewhere to study the compositions of exoplanets. And, if we’re lucky, we might find evidence of someone else out there.

The third season of SYFY's The Ark is set to premiere in 2026. The first two seasons are now streaming on Peacock.