In about 5 billion years, the Sun will leave the main sequence and become a red giant. It will expand into a flaming, vicious ball that will engulf and destroy Mercury, Venus, Earth, and possibly Mars.
Can humanity survive the red giant phase of the Sun? Extraterrestrial civilizations (ETC) may have already faced this existential threat.
Could they have survived by migrating to another star system without the use of spaceships?
Universe Today readers are well aware of the difficulties of interstellar travel. Our closest neighboring solar system is the Alpha Centauri system.
If humanity had to flee from an existential threat in our solar system, and if we could locate a planetary home at Alpha Centauri, it would still take us over four years to get there – if only we could travel at the speed of light!
It still takes us five years to get an orbiter to Jupiter at our level of technology. There is a lot of talk about generational spaceships where people could live for generations while they are on their way to a distant habitable planet.
These ships do not need to reach the speed of light; instead, entire generations of humans will live and die on a journey to another star that will take hundreds or thousands of years. It’s interesting to think about, but at the moment it’s pure fantasy.
Is there another way we or other civilizations could escape our doomed homes?
Author of a new research article in the journal International Journal of Astrobiology says extraterrestrial civilizations may not need spaceships to avoid existential threats and travel to another star system.
Instead, they could use free-floating planets, also known as rogue planets. Article “ET Migration and Interstellar Colonization: Implications for SETI and SETA”. Author Irina Romanovskaya. Romanovskaya is a professor of physics and astronomy at Houston Community College.
“I hypothesize that extraterrestrial civilizations could use free-floating planets as interstellar transport to reach, explore, and colonize planetary systems,” Romanovskaya writes. And when it comes to finding other civilizations, those efforts can leave behind technosignatures and artifacts.
“I propose possible technosignatures and artifacts that could be created by extraterrestrial civilizations using free-floating planets for interstellar migration and interstellar colonization, as well as strategies to search for their technosignatures and artifacts,” she said.
It is possible that rogue planets in the Milky Way or in other hundreds of billions of galaxies carry their own life with them in subsurface oceans heated by radiogenic decay.
Then, if they meet a star and become gravitationally bound, that life has effectively used the rogue planet to move, hopefully, to a more hospitable place. So why can’t civilization repeat this?
We think of free-floating planets as dark, cold, and inhospitable. And they exist, unless they have warm underground oceans. But they also offer some…