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.
If we define “life” as nucleic acid based, water-containing, semi permeable enveloped organisms, then our search for ET will be futile. We should expand the definition to the broadest sense possible, i.e., “life” should be: any entity that locally collects energy from it surrounding by going against the entropic gradient and can replicate this ability to new generations of entities via an information transfer mechanism.