An alternate Earth
"Astronomers believe they have discovered 'Earth's bigger cousin' orbiting a star that is 15 light years away. The planet could be the first rocky, terrestrial world to be found circling a normal star outside the solar system.
"The new planet orbits the star Gliese 876, located 15 light years away in the direction of the constellation Aquarius. Astronomers have calculated that the planet is about six times more massive than the Earth, making it small enough to be rocky.
"Like other extrasolar planets [refer to earlier post], it was not observed directly but detected by measuring the way its gravity causes the parent star to 'wobble...'
"A slight 'wobble' of Gliese 876 had already revealed that it is being tugged by the gravity of two gas giants as they orbit around the star with periods of 30 and 61 days, respectively.
"But careful monitoring of the star over three years has now confirmed that there is also a small planet six to nine times as massive as the Earth whipping around the star every 1.94 days.
"Unlike the Earth, the planet orbits at a distance of only two million miles from its star. It is so close that its day-side temperature could reach between 200C and 400C -- far too hot for any kind of Earth-like life."
"'In a two-day orbit , it's about 200 degrees Celsius too hot for liquid water,' said Paul Butler of the Carnegie Institution of Washington. 'That tends to lead us to the conclusion that >the most probable composition of this thing is like the inner planets of this solar system--a nickel-iron rock, a rocky planet, a terrestrial planet.'"
"The new planet orbits the star Gliese 876, located 15 light years away in the direction of the constellation Aquarius. Astronomers have calculated that the planet is about six times more massive than the Earth, making it small enough to be rocky.
"Like other extrasolar planets [refer to earlier post], it was not observed directly but detected by measuring the way its gravity causes the parent star to 'wobble...'
"A slight 'wobble' of Gliese 876 had already revealed that it is being tugged by the gravity of two gas giants as they orbit around the star with periods of 30 and 61 days, respectively.
"But careful monitoring of the star over three years has now confirmed that there is also a small planet six to nine times as massive as the Earth whipping around the star every 1.94 days.
"Unlike the Earth, the planet orbits at a distance of only two million miles from its star. It is so close that its day-side temperature could reach between 200C and 400C -- far too hot for any kind of Earth-like life."
"'In a two-day orbit , it's about 200 degrees Celsius too hot for liquid water,' said Paul Butler of the Carnegie Institution of Washington. 'That tends to lead us to the conclusion that >the most probable composition of this thing is like the inner planets of this solar system--a nickel-iron rock, a rocky planet, a terrestrial planet.'"
An alternate Earth
mr damon, 05:37
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