Technological Signs of Alien Civilizations
With the recent successes of the Mars missions and the progress made by SpaceX and other private corporations, a lot of people are thinking about space, and indeed wondering, is anyone else out there? Every few years we hear of nearby exoplanets that could be habitable for humans, or at least sustain living things, which makes the question loom bigger.
There’s a lot of movement in the search for extraterrestrial life, and though the science is always shifting, I’m pretty persuaded by the probability that there’s life out there. For many of us not engaged in the field, all of it might seem based on radio communication. You may have heard of the Drake Equation, or the movie Contact, where the search for alien life relies on radio telescopes.
The Very Large Array (VLA) radio telescope in New Mexico. Photo by Donald Giannatti on Unsplash
Of course there are many reasons why we have yet to receive any signals from space that indicate a far-off civilization. When the Fermi Paradox asked “where are they?”, scientists came up with many explanations—maybe they’re hiding from us, or maybe their tech is too advanced or too backward, maybe we just haven’t found them yet. Radio detection relies on communication, a signal being sent and received and there are many reasons such communication could break down.
Lately, the search for alien life has made advances in direct planet observation—maybe we’ll find them if we look for the right signs of life, instead of trying to catch a radio wave. One sign that scientists can search for is energy use: a civilization needs to use energy to grow and sustain itself, and such use of energy is detectable by infrared heat radiation. A powerful enough infrared telescope would be able to detect and observe such energy use, and could be a strong indicator for an alien civilization.
In June 2020, NASA funded research that involves technosignature detection. It’s the first time in three decades that NASA gave a grant for the search for alien life, which only shows how active this specific field of astronomy is. Technosignatures are markers of advanced alien technologies, and "might include industrial pollution of atmospheres, city lights, photovoltaic cells (solar panels), megastructures or swarms of satellites," according to Avi Loeb, one of the researchers involved in the project.
Different kinds of technosignatures; the full paper on which the project is based can be found here.
Although there are many forms of technology and energy expenditure that can be classified as a technosignature, the project will initially focus on two indicators: solar panels and pollutants. Habitable planets would have a certain light signature if it has the means to collect and convert the energy from their star. Also, atmospheric particles could provide clues as to the existence of life and technology on the planet; if there are artificial gases such as chlorofluorocarbons present, then that’s a good indicator of a civilization.
This is all very exciting but the field is far from fully developed. One day, we may be able to point our telescopes and satellites the right way and observe these technological markers on an exoplanet. For now though, at least the interest and the momentum are there.
I’ve been diving into this field because of my current project, which involves a generation ship. In this yet untitled novel, the last of humanity are traveling to find their new home on a distant exoplanet, and along the way they detect civilizations that exist in other planets. How are they able to observe this, and what might they conclude from what they see? How would they view these other civilizations, and might they be enticed to reach out to them instead of heading to their destination?
Photo by Greg Rakozy on Unsplash
This bit of research also makes me think of what kind of technosignatures we Earthlings are giving off. If another species is observing us from far away, what kind of signs are they seeing? Based on the new NASA project’s categories, they might see how many satellites we have, how much man-made pollution is in our atmosphere, how little of our energy use relies on the sun. When they see these markers, what would they think about us?