What are Technosignatures? Searching for Signs of Alien Life

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When scientists look for alien life, it usually starts with looking for biosignatures. Biosignatures are substances, elements or molecules that provide scientific evidence of past or present life. For example, presence of oxygen, nitrogen, sulfur, and hydrogen on another planet or moon may suggest the possibility of alien lifeforms. On Jupiter's moon Europa, scientists believe, because of the presence of certain chemicals that provide life here on Earth, that they may find life there.

Another method scientists have started using to look for alien life is by looking for technosignatures, signs of alien technology. NASA scientists have begun to consider what technological traces of intelligent life – “technosignatures” – might look like.

Examples of technosignatures are: radio or optical signals, laser pulses that might be used for communication, artificial satellites or megastructures such as Dyson spheres built to catch a star's light, and any signs of artificial chemicals in the atmosphere.

The SETI (Search for Extraterrestrial Intelligence) Institute is focused on this research, scanning the skies for these signals. Use of artificial intelligence and sophisticated algorithms could really accelerate the search for technosignatures as it is able to sift through large amounts of data for unique patterns that could indicate an artificially-engineered signal.

Looking for technosignatures is a painstaking process but Jill Tarter, co-founder and former director of the Center for SETI Research at the SETI Institute, believes we can grow technosignature studies by "piggyback[ing]" on studies of exoplanets and other cosmic phenomena, which would drive down costs while giving us greater possibility of finding alien life.