How life began on Earth is a question that has kept scientists curious for centuries. There are theories that claim life started because the meteors brought life-sustaining materials to Earth. Other theories claim life emerged due to a wave of volcanic eruptions which occurred 4.5 billion years ago.
Amid these hypotheses, a new study has now claimed that the oldest continents in our Milky Way galaxy may have emerged five billion years before Earth's. The study, thereby, has given rise to the speculation that there could be multiple worlds in the Milky Way housing alien life.
The study was published in the journal Research Notes of the American Astronomical Society.
What did the researchers find?
Jane Greaves, the Cardiff University astronomer who carried out the study, found that two exoplanets' continents may have come four to five billion years before the 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 the study.
How was the study conducted?
Continents on Earth were formed due to movement of tectonic plates. This occurs because the rocks of the tectonic plates floats over the molten magma. The molten magma remains in that state because of the heat from radioactive elements such as uranium and thorium.
Cardiff University's Greaves analysed levels of uranium present in nearby stars. She then combined the data with the ages of stars measured from the Gaia satellite.
Also watch | Aliens in Mexico? Sensational claim on aliens
She then configured the timeframe that the analysed stars were in when they became hot enough for the first emergence of tectonic plates there. Greaves discovered that the first continents were formed near Sun-like stars a few billion years before Earth's tectonic plates first emerged.
What does it mean?
The study on potentially habitable planets is important for space missions of the future.
Greaves expects that her work will be a stepping stone for future work that will analyse more such planets.