KOMPAS.com – A new study finds that several exoplanets or planets outside the Solar System in the Milky Way galaxy also have continents like Earth.
However, according to researchers, the continent formed 5 billion years earlier than Earth, making it the oldest continent in the galaxy.
Also read: What is the Andromeda Galaxy, which is called the Milky Way’s neighbor?
This finding also provides insight into the possibility of a planet in the Milky Way that hosts alien life, which may be even more advanced than life on Earth.
The formation of continents on exoplanets
Quoted from Live Science, Saturday (11/11/2023), astrobiologists argue that a planet has certain characteristics to support life.
These characteristics include oxygen in its atmosphere, something to protect organisms from harmful radiation, and liquid water.
Although large areas of land are not strictly necessary for living things to emerge, the history of the earth shows that land is important for life to develop and survive over long periods of time.
So, if an exoplanet had continents before Earth, there could be older, more advanced life on that world.
So, when did the first continent appear on a planet in the Milky Way galaxy?
It turns out, according to Jane Greaves, an astronomer at Cardiff University in England, continents on exoplanets may have appeared four to five billion years before Earth, including possibly life on them.
“If the continents of other planets formed 5 billion years ago then they could potentially harbor life more evolved than ours,” Greaves wrote in a study published in the September issue of Research Notes of the American Astronomical Society.
Also read: Interesting Facts about the Milky Way Galaxy that Not Many Know (Part 1)
Tracking the oldest continents on exoplanets
Reporting from Science Times, continents are formed due to plate tectonics, namely the movement of rock plates floating on the molten interior of a planet.
This heat comes from radioactive elements, such as uranium-238, thorium-232, and potassium-40.
Well, most radioactive elements are created from catastrophic cosmic events, such as supernova explosions and collisions between giant, dead stars.
Traces of these elements can be detected in the wavelengths of light emitted by stars.
To track continents on exoplanets, Greaves then used the levels of uranium-238 and potassium present in nearby stars, plus the ages of the stars measured by the Gaia satellite to estimate plate tectonics formed on a rocky planet.
He discovered that the first continents in the Milky Way galaxy formed around planets named HD 76932 and HD 201891, each located 70 to 110 light years from Earth.
The continent was formed 5 billion earlier than Earth and has the potential to become a habitable planet.
Greaves hopes future research will analyze more stars to determine whether they have planets with plate tectonics or not.
Also read: Interesting Facts about the Milky Way Galaxy, Where the Earth is Located (Part 2)
“This could help reveal older systems where there was life before Earth,” Greaves added.
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2023-11-14 10:00:00
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