Not only could life exist on other planets, but it ultimately arose about five thousand years earlier than on Earth. The hypothesis takes into account the appearance of the first continents on the planet of our galaxy. And this advantage, according to a new study, would support the idea of the existence of extraterrestrial life more advanced than Earth’s.
The recipe that astrobiologists often give for creating life on a planet always contains three elements: an atmosphere with oxygen, liquid water and protection from dangerous radiation. Continents or large areas are not strictly necessary for this purpose. But our Earth’s history tells us that they are the key to thriving and sustaining life over the long term.
This was the clue that led to the research of Jane Greaves, an astronomer at Cardiff University in the UK: If the planet had continents before Earth, there is a chance that it has – or had – life older and more advanced than ours. And Greaves found that at least two exoplanets in our galaxy meet the conditions in this regard.
Planets from two stars slightly smaller than our Sun may have formed continents 5 billion years before us. These are the stars HD 76932 and HD 201891. located respectively between 70 and 110 light years away, in a region known as the “thick disk” of the Milky Way.
Why can there be life on these planets?
The researcher based her analysis on a sample of just 29 stars and astronomers’ best current estimates of the likelihood of the planet harboring conditions for life. “There may be two systems in this sample with more developed biospheres than here on Earth,” Greaves wrote in a study published in September in the journal. Research Notes of the American Astronomical Society.
Tectonic plates are large pieces of rock that make up the Earth’s surface. They move against each other, which gives rise to volcanoes, mountains and continents. They move because they float in magma, the molten interior of this and other planets. The heat from the planet’s core keeps the magma melting, and this heat, in turn, comes from radioactive elements.
Some of these elements in the core are uranium-238, thorium-232 and potassium-40, which release energy when they decay. Most of them arose as a result of catastrophic cosmic events: supernova explosions or collisions of giant stars. That’s because some of these elements leave traces that can be detected in the wavelengths of light emitted by stars.
Greaves used levels of uranium-238 and potassium present in nearby stars. He also looked at the ages of these stars, as measured by the satellite Gaia. The latter is necessary to estimate when a hypothetical rocky planet around one of these stars became hot enough for plate tectonics to occur.
Larger investigation
The prospects for finding rocky exoplanets with continents look very promising, Greaves says. He insists that continued research, particularly into stellar concentrations of thorium and potassium, could help uncover older systems in which life may have arisen earlier than our planet. “Nearby stars like the Sun have already created several candidate hosts,” explains the scientist.
NASA already has plans to commission its Habitable Worlds Observatory. The US space agency said it hopes to launch a powerful new telescope that will begin work in 2040 with the goal of searching for terrestrial planets. outside our solar system. This will be NASA’s first mission specifically designed to search for extraterrestrial life.
Source: Hiper Textual
