SETI: How we’re searching for alien life at previously unexplored frequencies

Is there life past Earth? The query has turned out to be one of many hardest to reply in science. Regardless of the seemingly boundless expanse of the universe, which means there’s potential for considerable life, the huge distances between stars render the search akin to finding a needle in a cosmic haystack.

The Search for Extraterrestrial Intelligence (SETI) constitutes a department of astronomy devoted to discovering extraterrestrial life by trying to find uncommon alerts, dubbed technosignatures. The identification of a technosignature would not simply signify the existence of life, however particularly level to the presence of clever life utilizing superior know-how.

That mentioned, 60 years of searches have to this point come up quick. However now my colleagues and I’ve started investigating a beforehand unexplored vary of frequencies.

SETI makes the belief that extraterrestrial civilizations may depend on know-how in an analogous strategy to folks on Earth, corresponding to utilizing cell telephones, satellites or radar.

Since a good portion of such know-how generates alerts which can be prominently detectable in radio frequencies, specializing in these wavelengths serves as a logical place to begin within the quest for potential extraterrestrial intelligence.

Earlier technosignature surveys have included solely the radio frequency band above 600 MHz, leaving lower frequencies nearly unexplored. That is even though on a regular basis communication companies corresponding to air site visitors management, marine emergency broadcasting and FM radio stations all emit one of these low-frequency radiation on Earth.

The explanation it hasn’t been explored is that telescopes that function at these frequencies are fairly new. And lower-frequency radio waves have much less vitality, which means they are often tougher to detect.

In our concluded survey, we ventured into these frequencies for the primary time ever.

The Low Frequency Array (Lofar) is the world’s most delicate low-frequency telescope, working from 10-250 MHz. It is composed of 52 radio telescopes with extra on the way in which, unfold throughout Europe. These telescopes can attain a excessive decision when utilized in unison.

Our survey, nonetheless, solely made use of two of those stations: one situated in Birr, Eire, and the other in Onsala, Sweden. We surveyed 44 planets orbiting different stars than our sun that had been recognized by NASA’s Transiting Exoplanet Survey Satellite. Over the course of two summers, we scanned these planets at 110 to 190 MHz with our two telescopes.

Initially, this does not appear to be a considerable amount of targets, however low-frequency statement boasts a serious benefit in having massive fields of view in contrast with their higher-frequency siblings. That is as a result of the realm of the sky lined decreases with larger frequencies.

Within the case of Lofar, we lined 5.27 sq. levels of the sky for every pointing of our telescopes. This culminated in 36,000 targets per telecope pointing—or greater than 1,600,000 targets in total, once you verify what different stars are close by and embrace their planets as nicely.

Interfering alerts

Trying to find technosignatures from space introduces a big problem—the identical technosignatures are ubiquitous on Earth. This presents an impediment because the telescopes in these searches boast sensitivity ranges that may detect alerts, corresponding to a phone call, from midway throughout the solar system.

Consequently, the information collected is inundated with hundreds of alerts originating from Earth, posing a substantial problem in isolating and figuring out alerts that may very well be of extraterrestrial origin. The necessity to sift by this in depth and noisy dataset provides a layer of complexity to the search.

We got here up with an revolutionary method to mitigating such radio frequency interference, known as the “coincidence rejection” methodology. This takes under consideration the native radio emissions at every of our telescopes. For instance, if I’m utilizing the phone near the telescope in Eire to name my supervisor, that very same name will not seem within the knowledge in Sweden, and vice versa (primarily as a result of the telescope is not pointing in our path, it is pointing at an exoplanet candidate).

So, we determined to solely embrace signatures within the dataset in the event that they exhibited a simultaneous presence at each stations, suggesting they arrive from outdoors Earth.

On this approach, we whittled down hundreds of candidate alerts to zero. This implies we did not discover any indicators of clever life with our search, however we now have solely simply began—and there are prone to be an unlimited variety of Earth-like planets on the market. Realizing that the coincidence rejection methodology works with a excessive success charge could also be key to serving to us uncover life at one in all these planets sooner or later.

There are a lot of methods ahead for technosignature searches at low frequencies. Presently, there’s a sister survey (Nenufar) being carried out on that operates at 30-85 MHz. Together with this, additional Lofar observations will enhance the quantity of the survey by an element of ten over the course of the approaching 12 months. The collected knowledge can be used for investigating astronomical objects generally known as pulsars, quick radio bursts, radio exoplanets and extra.

Fortunately, we’re solely initially of a protracted journey. I’ve little question that many wondrous issues shall be discovered. And if we’re fortunate, we could reap the largest reward of all: some firm within the cosmos.

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