“Aliens could colonize the galaxy without using spaceships”
In an article published in the International Journal of Astrobiology, scientist Irina K. Romanovskaya proposes that the search for extraterrestrial intelligence (SETI) may be more likely to be successful by including the search for migratory extraterrestrial civilizations.
For example, extraterrestrial civilizations can abandon their planetary systems when faced with existential threats. One of the ways to do this is to travel on floating planets.
Floating planets can provide space and resources, as well as protection from space radiation, for very large populations embarking on interstellar travel.
It is technically impossible that huge starships – also called world ships – can offer the same.
Extraterrestrial civilizations can also use floating planets to send biological or post-biological species to study interstellar space, stars and planetary systems.
Or establish your colonies in various planetary systems to preserve and expand your civilizations before they even face existential threats on your homeworld.
In his article, Romanovskaya discusses how extraterrestrial civilizations can travel on floating planets that are bypassing their home planetary systems, or can travel on planet-like objects ejected from their planetary systems by dying host stars.
Alternatively, extraterrestrial civilizations can use propulsion systems and gravitational assistance events to convert objects equivalent to our Sedna in the Oort cloud into an interstellar means of transport.
Romanovskaya points out that with little starlight hitting floating planets, aliens could use controlled nuclear fusion as a source of energy and could live in underground habitats and oceans to protect themselves from space radiation.
This would also prepare them for colonization of the oceans in planetary systems.
Following their approach to planetary systems, aliens could transfer themselves from their floating planets to selected objects from the Oort cloud that would take them inland and to the parent planets of the systems to be colonized.
Or planetary systems could capture these floating planets. Then aliens would colonize such planetary systems.
To discover aliens on floating planets, Romanovskaya proposes looking for certain technological signatures – electromagnetic emissions produced by alien technologies on and around floating planets – and, in some cases, finding coincident signs of terraforming that could indicate a process. colonization.
If astronomers detect technological signatures produced on a floating planet without detecting the planet itself, they could misinterpret the origin of the signals.
For example, on August 15, 1977, astronomers detected the famous Wow! in the constellation Sagittarius. Forty-five years later, scientists continue to hypothesize why the signal was detected only once.
According to Romanovskaya, if the aliens sent a Wow! of an undetected floating planet and the planet moved away from the line of observations, the signal would not be detected again along that line.
Therefore, astronomers must look for floating planets along the lines of observations of unusual and potentially artificial signals from space.
Romanovskaya proposes that there may be a very small chance that, in the last billions of years, floating planets with intelligent extraterrestrial species have traveled to our stellar neighborhood, and discusses different ways to survey the solar system and beyond its artifacts. systems.
Today, somewhere in space, hundreds of light-years from Earth or closer, migrating intelligent biological species or artificially intelligent post-biological beings may be traveling on floating planets and looking for a new home.
Romanovskaya recommends that the search for such space travelers, the Search for Migratory Extraterrestrial Intelligence (SMETI), be part of our search for intelligent life in the universe.