In the heart of UFO news, Astrobiologists Use Radio Telescopes to Look For Extraterrestrial Life, sifting through the vast cosmic tapestry for nuanced hints of distant dwellers. They don’t just hunt for ordinary markers like abandoned debris or peculiar atmospheric gas ratios. Instead, they’re on a mission for “technosignatures”, such as radio waves, TV signals, or radar navigational beacons that could shed light on advanced civilizations. But the real question that remains: Can science truly pin down criteria that distinctly differentiates the living from the lifeless?
Radio Telescopes
Astronomers are using radio telescopes to search for signals that might indicate extraterrestrial life. The modern search began in 1960 with Frank Drake initiating Project Ozma at Greenbank Observatory in West Virginia. “Frank tuned big radio telescopes he thought might be effective for communication and pointed them at nearby stars to see if anything came through,” according to Jason Wright, an astrophysicist from Penn State University.
Radio telescopes resemble large bowl-shaped parabolic reflectors, with an array of feedhorns funneling incoming radio waves towards its focus cabin where a radio receiver amplifies them by one million. After being recorded digitally and stored onto computer disk, a software algorithm then analyzes its signal for patterns or information.
If a signal is identified, the computer then sends out signals to one of 42 radio antennas at the SETI Institute in California, located around the world and tuned to specific frequencies. They remain tuned at that frequency for hours at a time while Earth rotates, so telescopes can record various angles of an object to build up an accurate image.
Scientists are on a search for signs of life on exoplanets, from simple molecules to more advanced technologies. If they succeed, such signs could prompt either manned missions or probes that collect samples for analysis.
Telescopes in Space
Astrobiologists utilize telescopes in space to study all forms of light ranging from X-rays and gamma-rays produced by superhot stars to infrared wavelengths that penetrate planets. Astrobiologists compile lists of potential biosignatures – from gases produced by living things to pigments found on alien plants or microbes. These data help telescope designers know what and when they should look out for.
Telescopes’ ability to detect life is determined by their ability to pick out even subtle variations in light levels it detects, as this enables scientists to distinguish “biosignatures” from natural lighting on planets. That is why researchers have made efforts to develop telescopes that cover a broad spectrum from ultraviolet through infrared.
Future versions of Chile’s Giant Magellan Telescope will have a resolving power 10 times greater than NASA’s Hubble Space Telescope, thanks to a tool known as G-CLEF spectrograph which will detect chemicals released by living things, like oxygen and methane, into planetary atmospheres. Furthermore, when European Extremely Large Telescope opens in 2024 it will offer even more power; its detection range spans infrared wavelengths through near ultraviolet wavelengths with its mirror covering up to 6.5 meters across.
The Fermi Paradox
Astronomers are constantly on the search for alien life, yet know it may never be discovered. Scientists have long considered the Fermi Paradox – named for Nobel Prize-winning physicist Enrico Fermi – which suggests if aliens do exist they should have made contact with us by now; interstellar travel would likely be feasible and motivation for colonizing other star systems within their galaxy would drive this development.
York highlighted several flaws with this argument, starting with Fermi himself never questioning E.T. He was simply skeptical that an advanced extraterrestrial civilization could make such a long journey given technology limitations in 1950 when rockets were still emerging as viable space transportation tools.
UChicago researchers have proposed an approach to address this paradox by formulating new questions to guide the search for biosignatures on other planets, or signs of life. Their rationale rests on the assumption that any living organism modifies its environment in some way that might be detectable with modern instruments; as well as microorganisms’ ability to survive even under extreme conditions on Earth and that raw materials for life exist everywhere in space.
Technosignatures
Scientists typically favor taking an expansive approach to SETI that searches for any signal that cannot be explained using current scientific knowledge alone; while others take a narrower approach and focus on particular technological artifacts that might indicate extraterrestrial life forms – for instance city lights, atmospheric pollution levels, megastructures like Dyson Spheres or satellite debris in stable orbits may all indicate extraterrestrial presence – making biosignatures much harder to spot.
But that doesn’t mean scientists won’t succeed; in fact, at a recent workshop convened as part of a congressional directive rather than NASA mission on technosignatures search, researchers discussed strategies for recognizing various signs ranging from laser emissions and streetlamp glow to chlorofluorocarbon pollution–pollutants not produced naturally by life itself.
One challenge with searching for technosignatures lies in accounting for natural confounders that may be difficult to model accurately; hence upper limits can only be calculated rigorously when their rate and nature have been fully comprehended.
Technosignatures workshop work remains theoretical, such as calculating how long an extraterrestrial civilization would need to detect waste heat from our planet and send signals back that might help solve the Fermi Paradox; however, other participants have started looking for these technosignatures using cutting-edge technology. Most current searches use some combination of ground- and space-based spectroscopy; however advances in instrumentation provide new opportunities to search for possible technosignatures from lasers to greenhouse gases.
