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An ancient super-Earth offers an unexpected clue that life in our galaxy could be older than scientists thought


exoplanet rocky TOI561 system

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A rocky, molten planet orbiting one of the galaxy’s oldest stars could be scientists’ best evidence yet that alien life may have arisen in the distant past.

The planet, called TOI-561 b, is a “super-Earth” 280 light-years away. It’s about 50% larger than our planet and three times its mass, but it’s unlikely to host life. It orbits so close to its star that the researchers who discovered it calculated that its surface temperature is more than 3,000 degrees Fahrenheit, turning the top layer of rock into molten magma.

But this super-Earth is far older than scientists previously expected for rocky planets, suggesting that other stars could have ancient Earth-like worlds with temperatures more suitable for life. Such planets may have existed for twice as long as Earth, giving them plenty of time to support complex life and even intelligent civilizations.

The star that TOI-561 b orbits lies in the galaxy’s “thick disk,” the outer region above and below the flat plane that holds most of the Milky Way’s material. Stars in the thick disk are about 10 billion years old, and researchers think that this planet is just as ancient.

“TOI-561 b is the first planet with a confirmed rocky composition around such an old star, demonstrating that rocky planets have been forming for most of the history of the universe,” Lauren Weiss, a postdoctoral fellow at the University of Hawaii and the lead researcher in this discovery, said at a meeting of the American Astronomical Society. “I just wonder if any of them have anyone we’d like to talk to.”

The finding was published in The Astronomical Journal on Monday.

Earth-like planets almost as ancient as our galaxy

The astronomers could tell how old TOI-561 b is because the planet’s density is about the same as Earth’s, even though its mass is three times more. That means it probably doesn’t contain many heavy elements, like iron or magnesium.

It took billions of years for the galaxy to fill with heavy elements, since they have to be forged deep inside stars. When the stars age, die, and explode, these elements disperse and eventually coalesce into new planets. So 10 billion years ago, heavy elements were sparse and planets weren’t very dense. That seems to be when TOI-561 b formed.

“Gosh, if we’ve only been around for 5 billion years, imagine what could have happened on a rocky world that’s been around for 10 billion years,” Weiss said.

Her team discovered TOI-561 b using the W. M. Keck Observatory on Hawaii’s Maunakea. There are two other planets orbiting the star, but their large size and low mass indicates that they’re gaseous, like Jupiter.

The hunt for aliens could include fossils

This discovery adds to a growing body of research that suggests life on other planets could have evolved, developed technological civilizations, and gone extinct long before life arose on Earth.

This could open an entirely new path in the search for extraterrestrial life. Instead of listening for messages from aliens seeking out other intelligent life, scientists may have more luck …read more

Source:: Business Insider

      

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