Scientists announce the discovery of a continent older than the Earth
Scientists announce the discovery of a continent older than the Earth
The oldest continents in our galaxy may have formed 5 billion years before Earth, a new study suggests - meaning there may be multiple worlds in the Milky Way harboring alien life more advanced than our own.
Astrobiologists believe the planet needs certain features to support life, such as oxygen in its atmosphere, which is an essential part of protecting living organisms from dangerous radiation, and liquid water, for starters.
The study explained that although large land masses are not absolutely necessary for the emergence of living organisms, the history of the Earth shows that they are important for life to flourish and exist for long periods of time.
If there were exoplanet continents before Earth, that means there may have been older, more advanced life on that world.
This line of thinking led Jane Greaves, an astronomer at Cardiff University in the United Kingdom, to answer the question: When did the first continents appear on a planet in our galaxy? It turns out that two continents of exoplanets and possibly life may have originated four to five billion years ago from Earth.
If life on another planet began five billion years ago, it would likely host life more advanced than us, Greaves wrote in a study published in the journal Research Notes of the American Astronomical Society.
The study explained that continents are formed due to plate tectonics, which is the movement of rocky plates that float above the molten interior parts of the planet. The heat emanating from the planet's core prevents these elements from solidifying and stops the movement of the continents.
This heat comes from radioactive elements, such as uranium-238, thorium-232, and potassium-40, found in the planet's core, which release energy as they decay.
The study pointed out that most of these radioactive elements came from catastrophic cosmic events, such as supernova explosions and collisions between the dead crusts of giant stars, known as neutron stars.
Traces of these elements can be detected in the wavelengths of light emitted by stars.
In her new work, Greaves used levels of uranium-238 and potassium found in nearby stars, as well as the ages of stars measured by the Gaia satellite, to estimate when a hypothetical rocky planet around each of these stars became hot enough for plate tectonics.
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