The oldest continents in our galaxy may have arisen 5 billion years before Earth’s, new research suggests — and that means there may be multiple worlds in the Milky Way harboring alien life even more advanced than our own.
Astrobiologists think a planet needs to have certain features to support life: oxygen in its atmosphere, something to shield organisms from dangerous radiation and liquid water, for a start. Although big land masses aren’t strictly necessary for living things to emerge, Earth’s history shows that they’re important for life to thrive and exist for long periods of time. So, if an exoplanet had continents before Earth, it follows that there might be older, more advanced life on that world.
This line of thought led Jane Greaves, an astronomer at Cardiff University astronomer in the U.K., to answer the question: When did the first continents appear on a planet in our galaxy? Turns out, two exoplanets’ continents — and perhaps life — may have arisen four to five billion years before Earth’s.
If life on another planet had a five-billion-year head start, it “could potentially host life more evolved than us,” Greaves wrote in a study, published in the September issue of the journal Research Notes of the American Astronomical Society.
Eh, there are enough possible reasons for a civilization to not expand infinitely or voluntarily declare certain systems off limits that I don’t think it’s crazy to speculate that they might be, or at least may have been out there.
It could be they’re very conservation-minded and set up reserves around any systems with planets that harbor life (UFOs are the assholes that jump wildlife reservation fences to hunt endangered species).
It could be they killed each other to death.
It could be they didn’t exist at all.
It could be that earth was originally destined to be barren but they seeded the world to ensure it wouldn’t be.
Maybe the meteor that deleted the dinos wasn’t a freak physics accident.
Who knows?