Astronomers have detected the Methuselah of planets, a world many times older than any other known, a remarkable survivor formed in a violent, primordial setting where planets were not thought to exist.
About 800 times more massive than Earth, the planet was born around a yellow, sun-like star about 13 billion years ago. That is about 9 billion years earlier than any planet previously detected and a mere billion years after the big bang that spawned all space and time -- a time, most astronomers believe, when the universe had yet to create the raw material needed to make planets, according to researchers who revealed their findings yesterday.
The discovery could change theories about how easily nature makes planets from even the skimpiest of raw materials, and about the abundance of planets -- including some that might harbor life -- thriving unexpectedly in odd corners of the cosmos, astronomers said.
"What we think we've found is an example of the first generation of planets formed in the universe," said Steinn Sigurdsson of Pennsylvania State University, a member of the observing team. "We think this planet formed with its star 12.713 billion years ago, when the [Milky Way] galaxy was . . . just in the process of forming."
For a decade, the identity of this object had been an astronomical mystery. The observing team solved it by combining the sharp vision of the Hubble Space Telescope with other instruments and techniques, plus many years of inventive detective work. The results were announced at a NASA headquarters news conference yesterday and in today's issue of the journal Science.
Confirmation that the object is a planet "is a stunning revelation," said Alan P. Boss of the Carnegie Institution of Washington, an expert on the formation of planetary systems who is not a member of the observing team. "This means that 13 billion years ago, life could have arisen and then died out," he said. "This has immense implications."
Andrew Fruchter of the Space Telescope Science Institute, a specialist in pulsar studies not on the discovery team, said the evidence seems convincing but noted that it is only one example. "These are very early days in the study of extrasolar planets, and it probably is too early to rule them in or out just about anywhere," he said.
Less than a decade ago, astronomers were still struggling to confirm the first planet detected beyond the family of the sun. Now, the population of known extrasolar planets exceeds 100. But the latest addition breaks the mold in several ways, Boss said.
Today, the planet orbits an odd couple made up of a cold, collapsed star called a white dwarf and an even more bizarre companion known as a pulsar, which spins on its axis almost 100 times a second. The newfound planet is the only one known to orbit such a double star system.
This eccentric trio resides at the core of the ancient globular star cluster M4, about 5,600 light-years from Earth in the direction of the summer constellation Scorpius. That cluster is visible in binoculars as a fuzzy white smudge very near the bright star Antares.
The planet's habitat is as noteworthy as its longevity, astronomers said. The cluster was the site of a furious firestorm of star birth in its early history, and the young planet must have survived blistering ultraviolet radiation, the shockwaves of stellar cataclysms known as supernovas and other mayhem.
Also, in what is possibly most significant for theories of planet formation, the setting has almost none of what Boss called "feedstock" for making planets. The globular cluster formed so early in cosmic history that it was deficient in heavy elements, such as carbon, silicon and oxygen -- the building blocks of planets such as those in our solar system. All the heavy elements that fill the modern universe were cooked up over time in the nuclear furnaces of successive generations of stars.
But 13 billion years ago, the cluster was almost all hydrogen and helium gas, with only about 1/30th the heavy elements found in our own sun and planets, Boss said. With this deficit in the stuff of rocks, ice and other presumed essentials, some astronomers had argued that globular clusters could not spawn planets, and recent searches had seemed to confirm that.
The new discovery "offers tantalizing evidence that formation processes are quite robust and efficient at making use of a small amount of heavier elements," said Sigurdsson, lead author of the Science paper.
It also means that "the traditional way of making gas giant planets just isn't going to work in this case," Boss said, and that less widely accepted theories, such as one he has proposed that requires nothing more than gas, may get a boost.
The planet is too dim to be directly observed, but the team ferreted out its existence and inferred its tortured history by sifting through generous clues provided by its weird present-day setting -- especially by the pulsar's peculiar properties.
In the early 1990s, radio astronomers had timed the pulses the spinning pulsar emitted -- like beams from a lighthouse -- with exacting precision. They detected a complex wobble caused by the gravity of two unseen companions tugging at it.
The first companion was determined to be a white dwarf in a tight, 191-day orbit around the pulsar. But the other object, orbiting about 2 billion miles from the central pair, remained a mystery.
It was only when the Sigurdsson team used the Hubble Space Telescope to distinguish the movement of the white dwarf that it was able to determine the mass of the third body at 2.5 times the mass of Jupiter. "Several pieces of the puzzle were missing," Sigurdsson said. "The Hubble data snapped it all into place."
Once it determined this unlikely trio's characteristics, the team inferred its adventuresome recent history, which included a plunge through the heart of the cluster, a hostile encounter there that bounced it back out toward the cluster's outskirts, and the transformation of the planet's parent star into the white dwarf.
http://www.washingtonpost.com/wp-dyn/articles/A40612-2003Jul10.html
[This message was edited by The General on July 16, 2003 at 02:07 PM.]
About 800 times more massive than Earth, the planet was born around a yellow, sun-like star about 13 billion years ago. That is about 9 billion years earlier than any planet previously detected and a mere billion years after the big bang that spawned all space and time -- a time, most astronomers believe, when the universe had yet to create the raw material needed to make planets, according to researchers who revealed their findings yesterday.
The discovery could change theories about how easily nature makes planets from even the skimpiest of raw materials, and about the abundance of planets -- including some that might harbor life -- thriving unexpectedly in odd corners of the cosmos, astronomers said.
"What we think we've found is an example of the first generation of planets formed in the universe," said Steinn Sigurdsson of Pennsylvania State University, a member of the observing team. "We think this planet formed with its star 12.713 billion years ago, when the [Milky Way] galaxy was . . . just in the process of forming."
For a decade, the identity of this object had been an astronomical mystery. The observing team solved it by combining the sharp vision of the Hubble Space Telescope with other instruments and techniques, plus many years of inventive detective work. The results were announced at a NASA headquarters news conference yesterday and in today's issue of the journal Science.
Confirmation that the object is a planet "is a stunning revelation," said Alan P. Boss of the Carnegie Institution of Washington, an expert on the formation of planetary systems who is not a member of the observing team. "This means that 13 billion years ago, life could have arisen and then died out," he said. "This has immense implications."
Andrew Fruchter of the Space Telescope Science Institute, a specialist in pulsar studies not on the discovery team, said the evidence seems convincing but noted that it is only one example. "These are very early days in the study of extrasolar planets, and it probably is too early to rule them in or out just about anywhere," he said.
Less than a decade ago, astronomers were still struggling to confirm the first planet detected beyond the family of the sun. Now, the population of known extrasolar planets exceeds 100. But the latest addition breaks the mold in several ways, Boss said.
Today, the planet orbits an odd couple made up of a cold, collapsed star called a white dwarf and an even more bizarre companion known as a pulsar, which spins on its axis almost 100 times a second. The newfound planet is the only one known to orbit such a double star system.
This eccentric trio resides at the core of the ancient globular star cluster M4, about 5,600 light-years from Earth in the direction of the summer constellation Scorpius. That cluster is visible in binoculars as a fuzzy white smudge very near the bright star Antares.
The planet's habitat is as noteworthy as its longevity, astronomers said. The cluster was the site of a furious firestorm of star birth in its early history, and the young planet must have survived blistering ultraviolet radiation, the shockwaves of stellar cataclysms known as supernovas and other mayhem.
Also, in what is possibly most significant for theories of planet formation, the setting has almost none of what Boss called "feedstock" for making planets. The globular cluster formed so early in cosmic history that it was deficient in heavy elements, such as carbon, silicon and oxygen -- the building blocks of planets such as those in our solar system. All the heavy elements that fill the modern universe were cooked up over time in the nuclear furnaces of successive generations of stars.
But 13 billion years ago, the cluster was almost all hydrogen and helium gas, with only about 1/30th the heavy elements found in our own sun and planets, Boss said. With this deficit in the stuff of rocks, ice and other presumed essentials, some astronomers had argued that globular clusters could not spawn planets, and recent searches had seemed to confirm that.
The new discovery "offers tantalizing evidence that formation processes are quite robust and efficient at making use of a small amount of heavier elements," said Sigurdsson, lead author of the Science paper.
It also means that "the traditional way of making gas giant planets just isn't going to work in this case," Boss said, and that less widely accepted theories, such as one he has proposed that requires nothing more than gas, may get a boost.
The planet is too dim to be directly observed, but the team ferreted out its existence and inferred its tortured history by sifting through generous clues provided by its weird present-day setting -- especially by the pulsar's peculiar properties.
In the early 1990s, radio astronomers had timed the pulses the spinning pulsar emitted -- like beams from a lighthouse -- with exacting precision. They detected a complex wobble caused by the gravity of two unseen companions tugging at it.
The first companion was determined to be a white dwarf in a tight, 191-day orbit around the pulsar. But the other object, orbiting about 2 billion miles from the central pair, remained a mystery.
It was only when the Sigurdsson team used the Hubble Space Telescope to distinguish the movement of the white dwarf that it was able to determine the mass of the third body at 2.5 times the mass of Jupiter. "Several pieces of the puzzle were missing," Sigurdsson said. "The Hubble data snapped it all into place."
Once it determined this unlikely trio's characteristics, the team inferred its adventuresome recent history, which included a plunge through the heart of the cluster, a hostile encounter there that bounced it back out toward the cluster's outskirts, and the transformation of the planet's parent star into the white dwarf.
http://www.washingtonpost.com/wp-dyn/articles/A40612-2003Jul10.html
[This message was edited by The General on July 16, 2003 at 02:07 PM.]
