Post by tygerarmy on Oct 28, 2011 20:52:03 GMT -5
Eris was originally thought to be larger than Pluto, and was the primary cause for Pluto's demotion from full planet status.
Pluto, I'll never demote you!
Though the dwarf planet Eris on the edge of the solar system is much denser than Pluto, the two frigid worlds are nearly exactly the same size, a new study finds.
Astronomers accurately measured Eris' diameter for the first time using observations made late last year, when they caught the dwarf planet as it passed in front of a dim star. The observations, made using several telescopes in Chile, revealed that Eris and Pluto are pretty much identical in size, making them "almost perfect" twins, researchers said.
The discovery, announced Wednesday in the journal Nature, runs counter to scientists' original expectations.
When Eris was first discovered in 2005, it was thought to be significantly larger than Pluto. In fact, Eris' discovery was a big reason astronomers demoted Pluto to dwarf planet status in 2006. That decision remains controversial to this day, making Eris' name fitting: Eris is the Greek goddess of discord and strife, who stirred up jealousy and envy among the goddesses, leading to the Trojan War.
The new observations should help astronomers learn more about Eris' composition and evolutionary history. They show, for example, that the dwarf planet has a surface even more reflective than Earth's snow, suggesting it's covered in a thin layer of ice.
"It is extraordinary how much we can find out about a small and distant object such as Eris by watching it pass in front of a faint star, using relatively small telescopes," study lead author Bruno Sicardy, of the Pierre et Marie Curie University and Observatory of Paris, said in a statement. "Five years after the creation of the new class of dwarf planets, we are finally really getting to know one of its founding members."
...
The observations helped scientists determine that Eris' diameter is 1,445 miles (2,326 kilometers), give or take 7 miles (12 km). That makes Eris' size even more precisely known than Pluto's. (Pluto is thought to be between 1,429 and 1,491 miles — or 2,300 to 2,400 km — across.)
It also means that Pluto and Eris are, for all intents and purposes, the same size, researchers said.
Sicardy and his colleagues publish their results in the Oct. 27 issue of the journal Nature.
Astronomers accurately measured Eris' diameter for the first time using observations made late last year, when they caught the dwarf planet as it passed in front of a dim star. The observations, made using several telescopes in Chile, revealed that Eris and Pluto are pretty much identical in size, making them "almost perfect" twins, researchers said.
The discovery, announced Wednesday in the journal Nature, runs counter to scientists' original expectations.
When Eris was first discovered in 2005, it was thought to be significantly larger than Pluto. In fact, Eris' discovery was a big reason astronomers demoted Pluto to dwarf planet status in 2006. That decision remains controversial to this day, making Eris' name fitting: Eris is the Greek goddess of discord and strife, who stirred up jealousy and envy among the goddesses, leading to the Trojan War.
The new observations should help astronomers learn more about Eris' composition and evolutionary history. They show, for example, that the dwarf planet has a surface even more reflective than Earth's snow, suggesting it's covered in a thin layer of ice.
"It is extraordinary how much we can find out about a small and distant object such as Eris by watching it pass in front of a faint star, using relatively small telescopes," study lead author Bruno Sicardy, of the Pierre et Marie Curie University and Observatory of Paris, said in a statement. "Five years after the creation of the new class of dwarf planets, we are finally really getting to know one of its founding members."
...
The observations helped scientists determine that Eris' diameter is 1,445 miles (2,326 kilometers), give or take 7 miles (12 km). That makes Eris' size even more precisely known than Pluto's. (Pluto is thought to be between 1,429 and 1,491 miles — or 2,300 to 2,400 km — across.)
It also means that Pluto and Eris are, for all intents and purposes, the same size, researchers said.
Sicardy and his colleagues publish their results in the Oct. 27 issue of the journal Nature.
Pluto, I'll never demote you!