Dark Matter: New Evidence on How Galaxies Are Born
By Michael D. Lemonick Wednesday, Feb. 23, 2011
If you think it's hard to swallow the concept of dark matter, you're not alone. Decades ago, a few astronomers began to suspect that the universe was swarming with some mysterious, invisible substance that was yanking galaxies around with its own powerful gravity. And for those same decades, most of those astronomers' colleagues dismissed the notion as pretty much nuts.
But the evidence kept mounting, and nowadays dark matter is a firmly established concept in modern astrophysics. It pretty much has to exist, in fact, to explain why individual galaxies spin as fast as they do without flying apart, and why groups of galaxies move the way they do in relation to one another. If there weren't 10 times as much dark matter as there are stars and gas clouds and other visible matter, the universe would make no sense. Nature abhors irrationality, and so we live in a universe in which just about every galaxy, including the Milky Way, is held safely inside a huge blob of dark matter like a butterfly floating inside a glass paperweight. (See "The Hubble Space Telescope's Greatest Hits.")
Astrophysicists are also convinced that the dark matter came first, in blobs of various sizes. Those invisible masses then pulled in ordinary matter to make the galaxies. Not all galaxies are created equal, however. Some are pipsqueaks, some are giants and some are true stellar overachievers — so feverishly prolific in their star creation that they churned out up to 1,000 new suns a year for 100 million years. These so-called starburst galaxies have long been a puzzle to astronomers, but a new paper published in Nature may have finally explained them. The answer — once again — is that the dark matter did it.
The creation of a starburst galaxy, says study co-author Asantha Cooray of the University of California, Irvine, is all a matter of blob size. If your blob is too big, hydrogen gas can't fall together efficiently enough to sustain a starmaking frenzy. Instead the gas breaks apart to make several separate, reasonably sedate galaxies. If the dark-matter blob is too small, by contrast, the hydrogen falls together too efficiently. Stars form so quickly and so furiously that their heat keeps the rest of hydrogen from falling in. The frenzy is short-lived. (Watch TIME's video "Herschel: The Telescope for Invisible Stars.")
Cooray and his colleagues figured all of this out with data from the William Herschel Telescope. The Herschel is sensitive to infrared radiation, a type of light originally discovered by the astronomer William Herschel at the turn of the 19th century — which is why the telescope carries his name. Young, far-off, dusty galaxies are especially bright in infrared, and while the Herschel couldn't generate images of individual galaxies, it could measure brighter and dimmer spots in the overall wash of infrared energy streaming in from across the universe. The brighter spots represent denser clots of galaxies; the dimmer spots are sparse regions.
The scientists then compared what they saw with computer simulations of the early universe, which reveal how dark matter should have been distributed. The comparison showed a good match between medium-size lumps of dark matter and starburst galaxies. In other words: the ancient model is consistent with the current reality. "It's not like a new planet, where everyone goes, 'Wow!' " admits Cooray, "but it's a pretty cool result."
Comments on this article by bloggers:
Contrary to the misconception which you perpetuate here, dark matter is not the only option for explaining our observations of galaxies and space. Plasmas are widely accepted to represent 99% of the universe's visible matter. Thus, quite a lot depends upon the accuracy of those models.
Hannes Alfven received the Nobel Physics prize for creating the plasma models around 1970. During his acceptance speech, he warned that he had made mistakes early in his career. Those magnetohydrodynamic models -- the plasma models -- which theorists and astrophysicists to this day rely upon for their computations were in fact "pseudo-pedegagical", meaning that they appeared to help, but in fact were dangerously misleading. He was widely ignored, and we continue to use the same models to this day.
Astrophysicists and cosmologists today claim that galactic rotation curves demand some huge amount of invisible, theoretical matter placed at just the right spot. But, it's worth noting that we also observe magnetic fields to be associated with intergalactic space and the galaxies themselves. This is an incredibly important clue which this space reporter appears to be completely ignoring.
It's important because in the laboratory, magnetic fields and electric currents go hand-in-hand. It's why there is a term "electromagnetic". Where you see one, it is ASSUMED that there exists the other nearby causing it.
But, in space, astrophysicists and cosmologists would prefer to specifically avoid that inference. And yet, plasma is an electrified gas in the laboratory. So, 99% of the matter we see in space with our telescopes is inherently electric. And we can see the magnetic fields to demonstrate it.
Wednesday, February 23, 2011
Monday, February 7, 2011
IceCube - Window on Energy in the Universe
IceCube opens up a window on energy in the universe
AMUNDSEN-SCOTT BASE, ANTARCTICA - The world's newest astronomical observatory is defined by a field of 86 colored flags rippling across an ice-covered polar landscape. Each banner marks a line of glass-covered orbs that stretches down a mile and a half into the ice, like beads on a frozen string.
Known as IceCube, this massive underground array is designed to do what no other observatory has done before - catch a glimpse of elusive neutrinos, ghostly particles that are formed in the hearts of supernovas, black holes and other deep-space objects and may give scientists new information about the origins of the universe.
"The idea with IceCube is to do astronomy, but instead of using light, we're using neutrinos," said Greg Sullivan, a physicist at the University of Maryland who is one of the collaborators on the $279 million project.
"It opens up a window on energy in the universe," he explained. "We've seen particles in outer space that are 10 million times more energetic than the ones we can accelerate on Earth. Neutrinos are a way to try and find out what's causing those very high energy [particles]. It's been a mystery for 100 years."
Astronomers have flocked to the South Pole in the winter for decades, drawn by the sunless skies and atmospheric conditions that make superb star-gazing. A permanent U.S. station has been at the pole since 1956, and several telescopes have been built here to take advantage of the darkness that lasts from late February to early October.
But IceCube is something different, an observatory built entirely beneath the ice. Along each of the 86 cables are strung 60 three-foot spherical detectors, called digital optical modules or DOMs. These glass-covered orbs are designed to find evidence of neutrinos - particles formed in the hearts of stars that are so small they pass right through the Earth (and our bodies) without hitting molecules or other matter.
Since neutrinos have almost no mass and are too small to be seen with a normal telescope, researchers instead are looking for the extremely small and extremely brief flashes of bluish light that are given off when a neutrino's energy trail strikes an oxygen atom in the ice and creates a third particle, called a muon.
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"We thought that if we could . . . detect that light, we could reconstruct the direction and energy of that muon, which would give us the direction of the neutrinos," Sullivan said during a visit last month to the South Pole sponsored by the National Science Foundation.
In the past, scientists have tried to build neutrino detectors in the deep ocean, abandoned mine shafts and the bottom of deep lakes. All the projects failed for different reasons: salt corroded the detectors, for example, or the muon trails were obscured by the natural light given off by plankton.
Astrophysicists have high hopes for the South Pole location. One advantage of the massive icepack is that it provides a "scaffolding . . . infrastructure for the detectors," holding them steady, Jonathan Feng, a particle physicist and cosmologist at the University of California at Irvine, explained in a phone interview. It also presented extreme challenges: Constructing IceCube involved more than 400 technicians and engineers and took seven summers of tough drilling through polar ice.
IceCube's detectors are pointed northward, toward the center of the Earth, so the planet's mass serves as a filter to block most cosmic rays and other particles. Feng noted that in addition to passing through most matter, neutrinos also are not bent by electric and magnetic fields, which can bend other forms of radiation - potentially bringing information more directly from farther corners of the universe.
The National Science Foundation picked up $242 million of Ice Cube's $279 million price tag. The rest was split among science agencies from Germany, Sweden and Belgium, which also cooperated on construction. The University of Wisconsin at Madison, the project's lead institution, coordinated the design, build and software to run it. The university is also coordinating the data distribution, making information available to scientists around the world.
Now that IceCube is up and running, Feng says he's especially interested in what it might reveal about dark matter, mysterious material that scientists postulate makes up five-sixths of the mass of the universe, but which has never been detected directly.
"The entire periodic table is just small fraction of total matter in the universe," Feng said. "The rest is dark matter but it doesn't reflect light or shine light. We don't see it the way we see stars." When dark matter particles inside the sun and other stars collide with each other, neutrinos are created. If IceCube can detect these neutrinos and glean useful data about where they come from, Feng said, "there will be hundreds of scientists jumping up and down to see if it's a signal of dark matter."
Credit for coming up with the idea behind IceCube is generally given to Francis Halzen, a theoretical physicist at the University of Wisconsin. In the late 1980s, Halzen was intrigued by the problem of building a neutrino detector and had studied the failure of other projects. Interviewed at his office in Madison, Halzen said he's forgotten his "eureka" moment back in 1987. "One of my former graduate students says I told him one morning coming out of the elevator," Halzen said. "But I really don't remember. I didn't realize that I would spend most of the rest of my career doing this."
Halzen got together with colleagues at the University of California at Berkeley and began planning a pilot project, called the Antarctic Muon and Neutrino Detector Array, or AMANDA. It began operation at the South Pole in 1993, but only laid a few strings of detectors into the ice.
IceCube, which was conceived in 1999 as a collaboration between U.S. and European agencies, was on a much grander scale. Engineers on the project ran into formidable obstacles. "You can't just buy a drill in Texas and bring it to Antarctica," Halzen said. "We had to figure all these things out."
During the first year summer of drilling in 2004-05, technicians laid only one string of detectors, and Halzen said they nearly gave up. But a University of Wisconsin team developed a special drill that used hot water to drill nearly two miles deep into the ice. Once cooled, the water was pumped back to the surface, reheated and recycled in a closed-loop system. Then the huge hose that carried the water kept breaking under its own weight. "It was a struggle," Halzen said. Finally, one of the engineers found a firm in Venice with the right equipment, "and we eventually made it work."
There were also logistical challenges. Because of limited space at the South Pole station, the IceCube team could deploy no more than 40 workers at a time. Construction crews had to be rotated in by a three-hour flight from the main U.S. facility at McMurdo Station. "It was like solving a crossword puzzle," Halzen said. "Everything and everyone had to fit just perfectly." By the 2008 drilling season, they had put in 20 strings of detectors. The 86th and final string was laid Dec. 19.
IceCube has already found a strange asymmetry to cosmic rays reaching Earth from the southern hemisphere from the direction of a supernova named Vela. "Nobody knows what it means; that's why its interesting," Halzen said.
For all his work in pushing to get IceCube built, Halzen has never been to the South Pole. During the building phase, he said, he was loath to take up valuable space that could have been used for an engineer or construction worker.
"I have had no use to go there, but maybe now," Halzen said. "Last week it was colder here in Madison that at the South Pole."
health-science@washpost.com
AMUNDSEN-SCOTT BASE, ANTARCTICA - The world's newest astronomical observatory is defined by a field of 86 colored flags rippling across an ice-covered polar landscape. Each banner marks a line of glass-covered orbs that stretches down a mile and a half into the ice, like beads on a frozen string.
Known as IceCube, this massive underground array is designed to do what no other observatory has done before - catch a glimpse of elusive neutrinos, ghostly particles that are formed in the hearts of supernovas, black holes and other deep-space objects and may give scientists new information about the origins of the universe.
"The idea with IceCube is to do astronomy, but instead of using light, we're using neutrinos," said Greg Sullivan, a physicist at the University of Maryland who is one of the collaborators on the $279 million project.
"It opens up a window on energy in the universe," he explained. "We've seen particles in outer space that are 10 million times more energetic than the ones we can accelerate on Earth. Neutrinos are a way to try and find out what's causing those very high energy [particles]. It's been a mystery for 100 years."
Astronomers have flocked to the South Pole in the winter for decades, drawn by the sunless skies and atmospheric conditions that make superb star-gazing. A permanent U.S. station has been at the pole since 1956, and several telescopes have been built here to take advantage of the darkness that lasts from late February to early October.
But IceCube is something different, an observatory built entirely beneath the ice. Along each of the 86 cables are strung 60 three-foot spherical detectors, called digital optical modules or DOMs. These glass-covered orbs are designed to find evidence of neutrinos - particles formed in the hearts of stars that are so small they pass right through the Earth (and our bodies) without hitting molecules or other matter.
Since neutrinos have almost no mass and are too small to be seen with a normal telescope, researchers instead are looking for the extremely small and extremely brief flashes of bluish light that are given off when a neutrino's energy trail strikes an oxygen atom in the ice and creates a third particle, called a muon.
ad_icon
"We thought that if we could . . . detect that light, we could reconstruct the direction and energy of that muon, which would give us the direction of the neutrinos," Sullivan said during a visit last month to the South Pole sponsored by the National Science Foundation.
In the past, scientists have tried to build neutrino detectors in the deep ocean, abandoned mine shafts and the bottom of deep lakes. All the projects failed for different reasons: salt corroded the detectors, for example, or the muon trails were obscured by the natural light given off by plankton.
Astrophysicists have high hopes for the South Pole location. One advantage of the massive icepack is that it provides a "scaffolding . . . infrastructure for the detectors," holding them steady, Jonathan Feng, a particle physicist and cosmologist at the University of California at Irvine, explained in a phone interview. It also presented extreme challenges: Constructing IceCube involved more than 400 technicians and engineers and took seven summers of tough drilling through polar ice.
IceCube's detectors are pointed northward, toward the center of the Earth, so the planet's mass serves as a filter to block most cosmic rays and other particles. Feng noted that in addition to passing through most matter, neutrinos also are not bent by electric and magnetic fields, which can bend other forms of radiation - potentially bringing information more directly from farther corners of the universe.
The National Science Foundation picked up $242 million of Ice Cube's $279 million price tag. The rest was split among science agencies from Germany, Sweden and Belgium, which also cooperated on construction. The University of Wisconsin at Madison, the project's lead institution, coordinated the design, build and software to run it. The university is also coordinating the data distribution, making information available to scientists around the world.
Now that IceCube is up and running, Feng says he's especially interested in what it might reveal about dark matter, mysterious material that scientists postulate makes up five-sixths of the mass of the universe, but which has never been detected directly.
"The entire periodic table is just small fraction of total matter in the universe," Feng said. "The rest is dark matter but it doesn't reflect light or shine light. We don't see it the way we see stars." When dark matter particles inside the sun and other stars collide with each other, neutrinos are created. If IceCube can detect these neutrinos and glean useful data about where they come from, Feng said, "there will be hundreds of scientists jumping up and down to see if it's a signal of dark matter."
Credit for coming up with the idea behind IceCube is generally given to Francis Halzen, a theoretical physicist at the University of Wisconsin. In the late 1980s, Halzen was intrigued by the problem of building a neutrino detector and had studied the failure of other projects. Interviewed at his office in Madison, Halzen said he's forgotten his "eureka" moment back in 1987. "One of my former graduate students says I told him one morning coming out of the elevator," Halzen said. "But I really don't remember. I didn't realize that I would spend most of the rest of my career doing this."
Halzen got together with colleagues at the University of California at Berkeley and began planning a pilot project, called the Antarctic Muon and Neutrino Detector Array, or AMANDA. It began operation at the South Pole in 1993, but only laid a few strings of detectors into the ice.
IceCube, which was conceived in 1999 as a collaboration between U.S. and European agencies, was on a much grander scale. Engineers on the project ran into formidable obstacles. "You can't just buy a drill in Texas and bring it to Antarctica," Halzen said. "We had to figure all these things out."
During the first year summer of drilling in 2004-05, technicians laid only one string of detectors, and Halzen said they nearly gave up. But a University of Wisconsin team developed a special drill that used hot water to drill nearly two miles deep into the ice. Once cooled, the water was pumped back to the surface, reheated and recycled in a closed-loop system. Then the huge hose that carried the water kept breaking under its own weight. "It was a struggle," Halzen said. Finally, one of the engineers found a firm in Venice with the right equipment, "and we eventually made it work."
There were also logistical challenges. Because of limited space at the South Pole station, the IceCube team could deploy no more than 40 workers at a time. Construction crews had to be rotated in by a three-hour flight from the main U.S. facility at McMurdo Station. "It was like solving a crossword puzzle," Halzen said. "Everything and everyone had to fit just perfectly." By the 2008 drilling season, they had put in 20 strings of detectors. The 86th and final string was laid Dec. 19.
IceCube has already found a strange asymmetry to cosmic rays reaching Earth from the southern hemisphere from the direction of a supernova named Vela. "Nobody knows what it means; that's why its interesting," Halzen said.
For all his work in pushing to get IceCube built, Halzen has never been to the South Pole. During the building phase, he said, he was loath to take up valuable space that could have been used for an engineer or construction worker.
"I have had no use to go there, but maybe now," Halzen said. "Last week it was colder here in Madison that at the South Pole."
health-science@washpost.com
Wednesday, February 2, 2011
Kepler Finds 1200 Possibilities in New Planets
Kepler Planet Hunter Finds 1,200 Possibilities
By DENNIS OVERBYE
Published: February 2, 2011
New York Times
In a long-awaited announcement, scientists operating NASA’s Kepler planet-hunting satellite reported Wednesday that they had identified 1,235 possible planets orbiting other stars, potentially tripling the number of known planets in the universe.
Of the new candidates, 68 are one-and-a-quarter times the size of the Earth or smaller — smaller, that is, than any previously discovered planets outside the solar system. Fifty-four of the possible exoplanets are in the so-called habitable zones, where temperatures should be moderate enough for liquid water, of stars dimmer and cooler than the Sun; four of these are less than twice the size of Earth, and one is even smaller.
Astronomers said that it would take years to confirm that all these candidates are really planets — by using ground-based telescopes to try to measure their masses, for example — and not just double stars or other strange systems. Many of them might never be vetted because of the dimness of their stars and the lack of telescope time and astronomers to do it all. But statistical tests of a sample of the list suggest that 80 to 95 percent of the objects on it were real, as opposed to blips in the data.
“It boggles the mind,” said William Borucki of the Ames Research Center, Kepler’s leader.
At first glance, none of them appears to be another Earth, the kind of cosmic Eden fit for life as we know it, but the new results represent only four months worth of data on a three-and-a-half-year project, and have left astronomers enthused about the chances they will ultimately reach their goal of finding Earth-like planets in the universe.
“For the first time in human history we have a pool of potentially rocky habitable zone planets,” said Sara Seager of M.I.T., who works with Kepler. “This is the first big step forward to answering the ancient question, ‘How common are other Earths?’ ”
Mr. Borucki noted that since the Kepler telescope surveys only one four-hundredth of the sky, the numbers extrapolated to some 20,000 habitable-zone planets within 3,000 light-years of Earth. He is the lead author of a paper that has been submitted to The Astrophysical Journal describing the new results.
In a separate announcement, to be published in Nature on Thursday, a group of Kepler astronomers led by Jack Lissauer of Ames said they had found a star with six planets — the most Kepler has yet found around one star — orbiting in close ranks in the same plane, no farther from their star than Mercury is from the Sun.
This dense packing, Dr. Lissauer said, seems to violate all the rules astronomers thought they had begun to discern about how planetary systems form and evolve.
“This is sending me back to the drawing board,” he said.
Summarizing the news from the cosmos, Geoffrey W. Marcy of the University of California, Berkeley, a veteran exoplanet hunter and a mainstay of the Kepler work, said, “There are so many messages here that it’s hard to know where to begin.” He called the Borucki team’s announcement “an extraordinary planet windfall, a moment that will be written in textbooks. It will be thought of as watershed.”
Kepler, launched into orbit around the Sun in March 2009, stares at a patch of the Milky Way near the Northern Cross, measuring the brightness of 156,000 stars every 30 minutes, looking for a pattern of dips that would be caused by planets crossing in front of their suns.
The goal is to assess the frequency of Earth-like planets around Sun-like suns in the galaxy. But in the four months of data analyzed so far, a Kepler looking at our own Sun would be lucky to have seen the Earth pass even once. Three transits are required for a planet to show up in Kepler’s elaborate data-processing pipeline, which means that Kepler’s next scheduled data release, in June 2012, could be a moment of truth for the mission.
Habitable planets, in the meantime, could show up at fainter stars than our Sun, where the habitable, or “Goldilocks,” zone, would be smaller and closer to the star and planets in it would rack up transits more quickly.
Attention has been riveted on Wednesday’s data release since June, when Kepler scientists issued their first list, of some 300 stars suspected of harboring planets, but held back another 400 for further study. In the intervening months, Mr. Borucki said, some of those candidates have been eliminated, but hundreds more have been added that would otherwise have been reported in June this year.
One of the sequestered stars was a Sun-like star in the constellation Cygnus that went by the name of KOI 157, for Kepler Object of Interest. It first came to notice in the spring of 2009 when the astronomers saw that it seemed to have five candidate planets, four with nearly the same orbital periods, and in the same plane, like an old vinyl record, Dr. Lissauer recalled. Two of them came so close that every 50 days one of them would look as large as a full moon as seen from the other, Dr. Lissauer calculated.
“I got very interested in this system,” Dr. Lissauer said. “Five was the most we had around any target.” Moreover, the planets’ proximity to one another meant that they would interact gravitationally. In the fall, a sixth planet — the innermost — was found.
By measuring the slight variations in transit times caused by the gravitational interference of the inner five planets with one another, Dr. Lissauer and his colleagues were able to calculate the masses and densities of those planets. These confirmed they were so-called super-Earths, with masses ranging from two to 13 times that of the Earth. But they were also puffy, containing a mixture of rock and gas, rather than being pure rock and iron like another super-Earth, Kepler 10b, a hunk of lava announced last month at a meeting in Seattle.
Dr. Lissauer said, “It suggests that most super-Earths may be more like Neptune than Earth-like.”
Alan Boss, a planetary theorist at the Carnegie Institution of Washington, said the Kepler 11 system, as it is now known, should keep theorists busy and off the streets for a long time. “This system,” he wrote in an e-mail message, “certainly belongs in the pantheon of exoplanet systems: six planets lined up in a plane pointing toward us, waiting patiently for billions of years for humankind to develop sufficient technical capabilities to detect them.”
Mr. Borucki said the growing ubiquity of small planets as revealed by Kepler was a welcome relief from the early days of exoplanet research, when most of the planets discovered were Jupiter-size giants hugging their stars in close orbits, leading theorists to speculate that smaller planets might be thrown away from those environs by gravitational forces or even dragged right into their stars.
“Those little guys are still there,” he said, “and we’re delighted to see them.”
By DENNIS OVERBYE
Published: February 2, 2011
New York Times
In a long-awaited announcement, scientists operating NASA’s Kepler planet-hunting satellite reported Wednesday that they had identified 1,235 possible planets orbiting other stars, potentially tripling the number of known planets in the universe.
Of the new candidates, 68 are one-and-a-quarter times the size of the Earth or smaller — smaller, that is, than any previously discovered planets outside the solar system. Fifty-four of the possible exoplanets are in the so-called habitable zones, where temperatures should be moderate enough for liquid water, of stars dimmer and cooler than the Sun; four of these are less than twice the size of Earth, and one is even smaller.
Astronomers said that it would take years to confirm that all these candidates are really planets — by using ground-based telescopes to try to measure their masses, for example — and not just double stars or other strange systems. Many of them might never be vetted because of the dimness of their stars and the lack of telescope time and astronomers to do it all. But statistical tests of a sample of the list suggest that 80 to 95 percent of the objects on it were real, as opposed to blips in the data.
“It boggles the mind,” said William Borucki of the Ames Research Center, Kepler’s leader.
At first glance, none of them appears to be another Earth, the kind of cosmic Eden fit for life as we know it, but the new results represent only four months worth of data on a three-and-a-half-year project, and have left astronomers enthused about the chances they will ultimately reach their goal of finding Earth-like planets in the universe.
“For the first time in human history we have a pool of potentially rocky habitable zone planets,” said Sara Seager of M.I.T., who works with Kepler. “This is the first big step forward to answering the ancient question, ‘How common are other Earths?’ ”
Mr. Borucki noted that since the Kepler telescope surveys only one four-hundredth of the sky, the numbers extrapolated to some 20,000 habitable-zone planets within 3,000 light-years of Earth. He is the lead author of a paper that has been submitted to The Astrophysical Journal describing the new results.
In a separate announcement, to be published in Nature on Thursday, a group of Kepler astronomers led by Jack Lissauer of Ames said they had found a star with six planets — the most Kepler has yet found around one star — orbiting in close ranks in the same plane, no farther from their star than Mercury is from the Sun.
This dense packing, Dr. Lissauer said, seems to violate all the rules astronomers thought they had begun to discern about how planetary systems form and evolve.
“This is sending me back to the drawing board,” he said.
Summarizing the news from the cosmos, Geoffrey W. Marcy of the University of California, Berkeley, a veteran exoplanet hunter and a mainstay of the Kepler work, said, “There are so many messages here that it’s hard to know where to begin.” He called the Borucki team’s announcement “an extraordinary planet windfall, a moment that will be written in textbooks. It will be thought of as watershed.”
Kepler, launched into orbit around the Sun in March 2009, stares at a patch of the Milky Way near the Northern Cross, measuring the brightness of 156,000 stars every 30 minutes, looking for a pattern of dips that would be caused by planets crossing in front of their suns.
The goal is to assess the frequency of Earth-like planets around Sun-like suns in the galaxy. But in the four months of data analyzed so far, a Kepler looking at our own Sun would be lucky to have seen the Earth pass even once. Three transits are required for a planet to show up in Kepler’s elaborate data-processing pipeline, which means that Kepler’s next scheduled data release, in June 2012, could be a moment of truth for the mission.
Habitable planets, in the meantime, could show up at fainter stars than our Sun, where the habitable, or “Goldilocks,” zone, would be smaller and closer to the star and planets in it would rack up transits more quickly.
Attention has been riveted on Wednesday’s data release since June, when Kepler scientists issued their first list, of some 300 stars suspected of harboring planets, but held back another 400 for further study. In the intervening months, Mr. Borucki said, some of those candidates have been eliminated, but hundreds more have been added that would otherwise have been reported in June this year.
One of the sequestered stars was a Sun-like star in the constellation Cygnus that went by the name of KOI 157, for Kepler Object of Interest. It first came to notice in the spring of 2009 when the astronomers saw that it seemed to have five candidate planets, four with nearly the same orbital periods, and in the same plane, like an old vinyl record, Dr. Lissauer recalled. Two of them came so close that every 50 days one of them would look as large as a full moon as seen from the other, Dr. Lissauer calculated.
“I got very interested in this system,” Dr. Lissauer said. “Five was the most we had around any target.” Moreover, the planets’ proximity to one another meant that they would interact gravitationally. In the fall, a sixth planet — the innermost — was found.
By measuring the slight variations in transit times caused by the gravitational interference of the inner five planets with one another, Dr. Lissauer and his colleagues were able to calculate the masses and densities of those planets. These confirmed they were so-called super-Earths, with masses ranging from two to 13 times that of the Earth. But they were also puffy, containing a mixture of rock and gas, rather than being pure rock and iron like another super-Earth, Kepler 10b, a hunk of lava announced last month at a meeting in Seattle.
Dr. Lissauer said, “It suggests that most super-Earths may be more like Neptune than Earth-like.”
Alan Boss, a planetary theorist at the Carnegie Institution of Washington, said the Kepler 11 system, as it is now known, should keep theorists busy and off the streets for a long time. “This system,” he wrote in an e-mail message, “certainly belongs in the pantheon of exoplanet systems: six planets lined up in a plane pointing toward us, waiting patiently for billions of years for humankind to develop sufficient technical capabilities to detect them.”
Mr. Borucki said the growing ubiquity of small planets as revealed by Kepler was a welcome relief from the early days of exoplanet research, when most of the planets discovered were Jupiter-size giants hugging their stars in close orbits, leading theorists to speculate that smaller planets might be thrown away from those environs by gravitational forces or even dragged right into their stars.
“Those little guys are still there,” he said, “and we’re delighted to see them.”
Monday, January 31, 2011
Kepler Observatory - Life Out There
Life Out There
Gazing Afar for Other Earths, and Other Beings
By DENNIS OVERBYE
Published: January 30, 2011
MOFFETT FIELD, Calif. — In a building at NASA’s Ames Research Center here, computers are sifting and resifting the light from 156,000 stars, seeking to find in the flickering of distant suns the first hints that humanity is not alone in the universe.
Combing 156,000 Stars
Articles in this series will examine the search for Earth-like planets and for new forms of life in the universe.
William Borucki, lead scientist for the Kepler satellite observatory, launched in 2009.
The stars are being monitored by a $600 million satellite observatory named Kepler, whose job is to conduct a kind of Gallup poll of worlds in the cosmos. On Wednesday, Kepler’s astronomers are scheduled to unveil a closely kept list of 400 stars that are their brightest and best bets so far for harboring planets, some of which could turn out to be the smallest and most Earth-like worlds discovered out there to date. They represent the first glimpse of riches to come in a quest that is as old as the imagination and as new as the iPad.
Over the next two or three years, as Kepler continues to stare and sift, astronomers say, it will be able to detect planets in the “Goldilocks” zones, where it is neither too hot nor too cold for liquid water.
“What we want is to find life,” said Geoffrey Marcy, an astronomer at the University of California, Berkeley, who is part of the Kepler team.
William Borucki, 72, the lead scientist, who has spent the last 20 years getting Kepler off the ground, said recently in an interview in his office: “I’ve argued that Kepler is more important than the Hubble Space Telescope. We provide the data mankind needs to move out into space.”
These are science-fiction times. Kepler is only the first step in a process that experts agree will take decades. Both NASA and the European Space Agency have laid plans for a multidecade quest — employing ever more sophisticated and expensive spacecraft — for planets and life beyond Earth.
A roving robot laboratory named Curiosity will depart for Mars on a $2.5 billion mission this fall. Astronomers argue whether the next such mission should go to Jupiter’s moon Europa, with its subsurface ocean; Saturn’s moon Titan, which is coated with a methane slush; or another of Saturn’s moons, Enceladus, which is spouting geysers of water from its interior.
Right now, humans cannot even summon the money or political will to get back to the Moon, let alone set sail for another star. It would take 300,000 years for Voyager 1, now on the way out of the solar system at 39,000 miles per hour, to travel the 20 light-years, or 120 trillion miles, to Gliese 581, one of the nearest planetary systems; Kepler’s planets are from 500 to 3,000 light-years away. NASA and other organizations, like the Planetary Society, have experimented with devices like solar sails, in which a craft is pushed by sunlight or a powerful laser, and ion drives, in which high-energy particles do the propelling.
This is more than just an intellectual exercise, scientists say. Traditional religious images of ourselves as God’s creatures, or even of God, could be in for a rough time if we ever discover pond scum living by completely alien chemical rules on some moon or planet, let alone the Borg — the alien race ruled by a collective mind on “Star Trek” — inhabiting some distant realm.
Moreover, as astronomers keep reminding us, humanity will eventually lose Earth as its home, whether because of global warming or the ultimate plague or a killer asteroid or the Sun’s inevitable demise. Before then, if we want the universe to remember us or even know we were here, we need to get away.
It was only in 1995 that a team of Swiss astronomers led by Michel Mayor of the Geneva Observatory discovered the first planet of another Sun-like star using what is now known as the “wobble” method. A planet gives its star a little gravitational tug as it goes around, causing the star to go back and forth, or wobble, a little as both star and planet circle the same center of gravity. They detected a wobble in the motion of the star 51 Pegasi as an object about half the mass of Jupiter whipped around it every four days.
Like Olives in a Martini Glass
Over the next decade, Dr. Mayor’s group and another planet-hunting team led by Dr. Marcy and R. Paul Butler of the Carnegie Institution leapfrogged each other in finding exoplanets, as they are called. More and more astronomers have joined the hunt, discovering smaller and smaller planets. Astronomers have recorded direct images of four planets swirling like olives in a martini glass around a star known as HR 8799, 130 light-years from Earth in the constellation Pegasus, and another circling Fomalhaut, only 25 light-years from Earth, in the constellation Piscis Austrinus.
There are now more than 500 planets listed on the Jet Propulsion Laboratory’s PlanetQuest Web site. None are habitable.
Among them is the so-called Styrofoam planet — an early trophy of Kepler’s — a planet that is again half as large as Jupiter, but so puffed up by the heat of its star that it is only one-tenth as dense. Another is a planet composed almost entirely of superheated water and sometimes called the Steam World; it is known as Gliese 1214b, about 40 light-years from here in the constellation Ophiuchus.
Last year, a team of American astronomers announced that they had discovered a Goldilocks planet orbiting a dim red dwarf star at just the right distance to harbor water on its surface, making it a potential site for life. Gliese 581g, as it is known, is part of the Gliese 581 system 20 light-years from here, in Libra. But then the Swiss astronomers who first spotted that system were not able to find the Goldilocks planet in their own data, causing many astronomers, but not its discoverers, to doubt that the friendly 581g was real.
The Kepler project grew out of Mr. Borucki’s lifelong love of space.
Mr. Borucki grew up in a small town in Wisconsin, shooting homemade rockets into the sky and praying that they did not hit a neighbor’s cow. “As a kid, this is what you wanted to do,” he said.
After getting a master’s degree in physics from the University of Wisconsin, he went to work on the Apollo Moon program, becoming an expert in precise measurements of light. In 1984, he suggested that such measurements could be used to look for planets.
The idea is that a planet passing in front of its star would block a little of its light — very little. In the case of the Earth, the dip would amount to 84 parts per million in the Sun’s light — less than a hundredth of a percent.
In 1993, when Mr. Borucki and his collaborators proposed building a satellite to do such measurements, NASA said, “If doable, it’s fabulous,” recalled David Koch of the University of Wisconsin, Mr. Borucki’s longtime collaborator. But NASA did not think detectors could be so precise.
NASA rejected their proposal a year later, then again two years after that. “It’s a wonderful thing to have someone tell you over and over again everything that is wrong with your experiment,” Mr. Borucki said. That was the road to improvement.
Peter DaSilva for The New York Times
In 1998, NASA turned the scientists down again, but gave them half a million dollars to spend on lab work. The Kepler mission finally got the nod from NASA in 2001, but with a twist. The Ames Research Center wound up handing over management of the mission, at least until the launching, to the Jet Propulsion Laboratory in Pasadena, Calif., which developed the Vikings and Voyagers. “Here we had been competing against J.P.L. all these years,” Dr. Koch said. “We got over that.” Control has since reverted to Ames.
Kepler was launched from Cape Canaveral into an orbit around the Sun on March 6, 2009. Its gaze is fixed on a patch of sky about 20 full moons across near the Northern Cross, in the constellations Cygnus and Lyra, containing about 4.5 million stars. That is the neighborhood for Kepler’s cosmic census. The job is simply to measure the brightness of 156,000 of those stars every half-hour, looking for the repeated dips caused by planet crossings, or “transits.”
The more times a planet crosses its star, the more easily it is picked up and tagged by computers analyzing Kepler’s data. And Kepler’s first hits were indeed of planets that orbited their suns in a few days in close orbits that would produce oven-cleaner temperatures. The Earth, of course, takes a year to go around the Sun, so it would take two or three years for its analogue orbiting some star in Cygnus to show up in the Kepler data.
“We will find Earth-size planets in habitable zones,” Dr. Marcy stated flatly last month in Seattle.
Required: Absolute Proof
There is a hitch to confirming those planets, however. Such planets would not exert enough of a gravitational tug on their suns to be detectable by the “wobble” method, the main way their masses can be measured. Instead of confirming such planets, Kepler astronomers talk about “validating” them by using high-powered telescopes to make sure, for example, that there is only one star there and not a pair of eclipsing stars or some other phenomenon that could mimic a planet’s shadow.
“Earths are difficult,” Mr. Borucki said. “We’re concerned not to announce anything until we’ve proven six different ways it can’t not be a planet.”
As a result, more and more of Kepler’s future pronouncements will be statistical in nature. Natalie Batalha of San Jose State University, the deputy science team leader for Kepler, said it could be that they will wind up with, say, 100 planets they are 80 percent sure of, which could translate to 80 planets — useful for a census, not so helpful if you’re looking for a place to live.
“It’s a bitter pill to swallow,” said Sara Seager, an M.I.T. planetary astronomer who works with Kepler. “We will be faced with hundreds of planet candidates that may never be fully vetted as planets. We just have to live with statistics.”
But providing statistics, and not pinpointing individual planets, has always been Kepler’s prime mission. The road map to new worlds, Dr. Batalha explained, goes like this: First, Kepler figures out how abundant Earths are and how far you have to go out into the universe to find one. That information is needed to design the next step — a mission that would search the sky for Earth-like planets that are close enough to study. But at 500 to 3,000 light-years away, Kepler’s planets are too far for intense direct scrutiny.
“Once you know where they are, you study the heck out of them,” looking for spectral indications of an atmosphere and anything else, including biomarkers that are the signature of living things, Dr. Batalha wrote in an e-mail. “Everyone and their dog will be looking for biomarkers on these worlds.”
One idea for such a mission is a “starshade” that would float in front of a telescope in space and cancel out the bright light from a star, allowing its much dimmer planets to stand out.
Shading a New Telescope
Indeed, some astronomers have proposed building such a starshade for the James Webb Space Telescope, Hubble’s successor, which is scheduled to be launched by NASA later this decade. “It could potentially not only image an Earth-like planet, but provide some information about its atmosphere and surface,” said David Spergel, an astrophysicist from Princeton.
Mr. Borucki likes to compare the quest for other worlds to the building of the great cathedrals, a task handed from generation to generation of believers. And what if we finally find what we are looking for?
“The fact that we find lots of Earths just means that we have to spend a lot more money to build the next mission and go and find out if they speak English or French,” Mr. Borucki said.
If we are alone, on the other hand, “maybe we’re going to go conquer the whole galaxy,” he said. “Nobody’s out there to stop us.”
Gazing Afar for Other Earths, and Other Beings
By DENNIS OVERBYE
Published: January 30, 2011
MOFFETT FIELD, Calif. — In a building at NASA’s Ames Research Center here, computers are sifting and resifting the light from 156,000 stars, seeking to find in the flickering of distant suns the first hints that humanity is not alone in the universe.
Combing 156,000 Stars
Articles in this series will examine the search for Earth-like planets and for new forms of life in the universe.
William Borucki, lead scientist for the Kepler satellite observatory, launched in 2009.
The stars are being monitored by a $600 million satellite observatory named Kepler, whose job is to conduct a kind of Gallup poll of worlds in the cosmos. On Wednesday, Kepler’s astronomers are scheduled to unveil a closely kept list of 400 stars that are their brightest and best bets so far for harboring planets, some of which could turn out to be the smallest and most Earth-like worlds discovered out there to date. They represent the first glimpse of riches to come in a quest that is as old as the imagination and as new as the iPad.
Over the next two or three years, as Kepler continues to stare and sift, astronomers say, it will be able to detect planets in the “Goldilocks” zones, where it is neither too hot nor too cold for liquid water.
“What we want is to find life,” said Geoffrey Marcy, an astronomer at the University of California, Berkeley, who is part of the Kepler team.
William Borucki, 72, the lead scientist, who has spent the last 20 years getting Kepler off the ground, said recently in an interview in his office: “I’ve argued that Kepler is more important than the Hubble Space Telescope. We provide the data mankind needs to move out into space.”
These are science-fiction times. Kepler is only the first step in a process that experts agree will take decades. Both NASA and the European Space Agency have laid plans for a multidecade quest — employing ever more sophisticated and expensive spacecraft — for planets and life beyond Earth.
A roving robot laboratory named Curiosity will depart for Mars on a $2.5 billion mission this fall. Astronomers argue whether the next such mission should go to Jupiter’s moon Europa, with its subsurface ocean; Saturn’s moon Titan, which is coated with a methane slush; or another of Saturn’s moons, Enceladus, which is spouting geysers of water from its interior.
Right now, humans cannot even summon the money or political will to get back to the Moon, let alone set sail for another star. It would take 300,000 years for Voyager 1, now on the way out of the solar system at 39,000 miles per hour, to travel the 20 light-years, or 120 trillion miles, to Gliese 581, one of the nearest planetary systems; Kepler’s planets are from 500 to 3,000 light-years away. NASA and other organizations, like the Planetary Society, have experimented with devices like solar sails, in which a craft is pushed by sunlight or a powerful laser, and ion drives, in which high-energy particles do the propelling.
This is more than just an intellectual exercise, scientists say. Traditional religious images of ourselves as God’s creatures, or even of God, could be in for a rough time if we ever discover pond scum living by completely alien chemical rules on some moon or planet, let alone the Borg — the alien race ruled by a collective mind on “Star Trek” — inhabiting some distant realm.
Moreover, as astronomers keep reminding us, humanity will eventually lose Earth as its home, whether because of global warming or the ultimate plague or a killer asteroid or the Sun’s inevitable demise. Before then, if we want the universe to remember us or even know we were here, we need to get away.
It was only in 1995 that a team of Swiss astronomers led by Michel Mayor of the Geneva Observatory discovered the first planet of another Sun-like star using what is now known as the “wobble” method. A planet gives its star a little gravitational tug as it goes around, causing the star to go back and forth, or wobble, a little as both star and planet circle the same center of gravity. They detected a wobble in the motion of the star 51 Pegasi as an object about half the mass of Jupiter whipped around it every four days.
Like Olives in a Martini Glass
Over the next decade, Dr. Mayor’s group and another planet-hunting team led by Dr. Marcy and R. Paul Butler of the Carnegie Institution leapfrogged each other in finding exoplanets, as they are called. More and more astronomers have joined the hunt, discovering smaller and smaller planets. Astronomers have recorded direct images of four planets swirling like olives in a martini glass around a star known as HR 8799, 130 light-years from Earth in the constellation Pegasus, and another circling Fomalhaut, only 25 light-years from Earth, in the constellation Piscis Austrinus.
There are now more than 500 planets listed on the Jet Propulsion Laboratory’s PlanetQuest Web site. None are habitable.
Among them is the so-called Styrofoam planet — an early trophy of Kepler’s — a planet that is again half as large as Jupiter, but so puffed up by the heat of its star that it is only one-tenth as dense. Another is a planet composed almost entirely of superheated water and sometimes called the Steam World; it is known as Gliese 1214b, about 40 light-years from here in the constellation Ophiuchus.
Last year, a team of American astronomers announced that they had discovered a Goldilocks planet orbiting a dim red dwarf star at just the right distance to harbor water on its surface, making it a potential site for life. Gliese 581g, as it is known, is part of the Gliese 581 system 20 light-years from here, in Libra. But then the Swiss astronomers who first spotted that system were not able to find the Goldilocks planet in their own data, causing many astronomers, but not its discoverers, to doubt that the friendly 581g was real.
The Kepler project grew out of Mr. Borucki’s lifelong love of space.
Mr. Borucki grew up in a small town in Wisconsin, shooting homemade rockets into the sky and praying that they did not hit a neighbor’s cow. “As a kid, this is what you wanted to do,” he said.
After getting a master’s degree in physics from the University of Wisconsin, he went to work on the Apollo Moon program, becoming an expert in precise measurements of light. In 1984, he suggested that such measurements could be used to look for planets.
The idea is that a planet passing in front of its star would block a little of its light — very little. In the case of the Earth, the dip would amount to 84 parts per million in the Sun’s light — less than a hundredth of a percent.
In 1993, when Mr. Borucki and his collaborators proposed building a satellite to do such measurements, NASA said, “If doable, it’s fabulous,” recalled David Koch of the University of Wisconsin, Mr. Borucki’s longtime collaborator. But NASA did not think detectors could be so precise.
NASA rejected their proposal a year later, then again two years after that. “It’s a wonderful thing to have someone tell you over and over again everything that is wrong with your experiment,” Mr. Borucki said. That was the road to improvement.
Peter DaSilva for The New York Times
In 1998, NASA turned the scientists down again, but gave them half a million dollars to spend on lab work. The Kepler mission finally got the nod from NASA in 2001, but with a twist. The Ames Research Center wound up handing over management of the mission, at least until the launching, to the Jet Propulsion Laboratory in Pasadena, Calif., which developed the Vikings and Voyagers. “Here we had been competing against J.P.L. all these years,” Dr. Koch said. “We got over that.” Control has since reverted to Ames.
Kepler was launched from Cape Canaveral into an orbit around the Sun on March 6, 2009. Its gaze is fixed on a patch of sky about 20 full moons across near the Northern Cross, in the constellations Cygnus and Lyra, containing about 4.5 million stars. That is the neighborhood for Kepler’s cosmic census. The job is simply to measure the brightness of 156,000 of those stars every half-hour, looking for the repeated dips caused by planet crossings, or “transits.”
The more times a planet crosses its star, the more easily it is picked up and tagged by computers analyzing Kepler’s data. And Kepler’s first hits were indeed of planets that orbited their suns in a few days in close orbits that would produce oven-cleaner temperatures. The Earth, of course, takes a year to go around the Sun, so it would take two or three years for its analogue orbiting some star in Cygnus to show up in the Kepler data.
“We will find Earth-size planets in habitable zones,” Dr. Marcy stated flatly last month in Seattle.
Required: Absolute Proof
There is a hitch to confirming those planets, however. Such planets would not exert enough of a gravitational tug on their suns to be detectable by the “wobble” method, the main way their masses can be measured. Instead of confirming such planets, Kepler astronomers talk about “validating” them by using high-powered telescopes to make sure, for example, that there is only one star there and not a pair of eclipsing stars or some other phenomenon that could mimic a planet’s shadow.
“Earths are difficult,” Mr. Borucki said. “We’re concerned not to announce anything until we’ve proven six different ways it can’t not be a planet.”
As a result, more and more of Kepler’s future pronouncements will be statistical in nature. Natalie Batalha of San Jose State University, the deputy science team leader for Kepler, said it could be that they will wind up with, say, 100 planets they are 80 percent sure of, which could translate to 80 planets — useful for a census, not so helpful if you’re looking for a place to live.
“It’s a bitter pill to swallow,” said Sara Seager, an M.I.T. planetary astronomer who works with Kepler. “We will be faced with hundreds of planet candidates that may never be fully vetted as planets. We just have to live with statistics.”
But providing statistics, and not pinpointing individual planets, has always been Kepler’s prime mission. The road map to new worlds, Dr. Batalha explained, goes like this: First, Kepler figures out how abundant Earths are and how far you have to go out into the universe to find one. That information is needed to design the next step — a mission that would search the sky for Earth-like planets that are close enough to study. But at 500 to 3,000 light-years away, Kepler’s planets are too far for intense direct scrutiny.
“Once you know where they are, you study the heck out of them,” looking for spectral indications of an atmosphere and anything else, including biomarkers that are the signature of living things, Dr. Batalha wrote in an e-mail. “Everyone and their dog will be looking for biomarkers on these worlds.”
One idea for such a mission is a “starshade” that would float in front of a telescope in space and cancel out the bright light from a star, allowing its much dimmer planets to stand out.
Shading a New Telescope
Indeed, some astronomers have proposed building such a starshade for the James Webb Space Telescope, Hubble’s successor, which is scheduled to be launched by NASA later this decade. “It could potentially not only image an Earth-like planet, but provide some information about its atmosphere and surface,” said David Spergel, an astrophysicist from Princeton.
Mr. Borucki likes to compare the quest for other worlds to the building of the great cathedrals, a task handed from generation to generation of believers. And what if we finally find what we are looking for?
“The fact that we find lots of Earths just means that we have to spend a lot more money to build the next mission and go and find out if they speak English or French,” Mr. Borucki said.
If we are alone, on the other hand, “maybe we’re going to go conquer the whole galaxy,” he said. “Nobody’s out there to stop us.”
Saturday, December 18, 2010
Babylonia Ahead of Their Time
* Scribes in Old Babylonian period knew Pythagoras's theorem 1,000 years before he did
* Cuneiform tablets in New York exhibition show sophistication of Babylonian mathematicians
* Interest in this strand of history growing
(CNN) -- Over 1,000 years before Pythagoras was calculating the length of a hypotenuse, sophisticated scribes in Mesopotamia were working with the same theory to calculate the area of their farmland.
Working on clay tablets, students would "write" out their math problems in cuneiform script, a method that involved making wedge-shaped impressions in the clay with a blunt reed.
These tablets bear evidence of practical as well as more advanced theoretical math and show just how sophisticated the ancient Babylonians were with numbers -- more than a millennium before Pythagoras and Euclid were doing the same in ancient Greece.
"They are the most sophisticated mathematics from anywhere in the world at that time," said Alexander Jones, a Professor of the History of the Exact Sciences in Antiquity at New York University.
He is co-curator of "Before Pythagoras: The Culture of Old Babylonian Mathematics," an exhibition at the Institute for the Study of the Ancient World in New York.
They are the most sophisticated mathematics from anywhere in the world at that time
--Curator Alexander Jones
"This is nearly 4,000 years ago and there's no other ancient culture at that time that we know of that is doing anything like that level of work. It seems to be going beyond anything that daily life needs," he said.
Many scribes were trained in the ancient city of Nippur in what is now southern Iraq, where a large number of tablets were discovered between the mid-19th century and the 1920s.
Typical problems they worked on involved calculating the area of a given field, or the width of a trench.
These problems, says Jones, required the kind of math training taught to American Grade 10 students, but not in a format we would now recognize.
"It's not like algebra, it's all written out in words and numerals but no symbols and no times signs or equals or anything like that," he said.
This system, and the lack of recognizable Western mathematical symbols such as x and y, meant that it was several years before historians and archaeologists understood just what was represented on these tablets.
It took a young Austrian mathematician in the 1920s, named Otto Neugebauer, to crack the mathematical system and work out what the ancient Babylonians were calculating. But despite his advances, it is only recently that interest in Babylonian math has started to take hold.
"I think that before Neugebauer and even after Neugebauer, there wasn't a lot of attention placed on mathematical training in Babylon even though we have this rich cuneiform history with the tablets," said Jennifer Chi, Associate Director for Exhibitions and Public Programs at Institute for the Study of the Ancient World.
When we think of ancient mathematics, the first names that come to mind are Pythagoras and Euclid. That shouldn't be the case.
One of the aims of the institute, she says, is to find interconnections between ancient cultures as well as look at what the institute sees as under-represented ancient cultures -- and the culture of ancient Babylonian math, she says, is ripe for popular revision.
"When we think of ancient mathematics, the first names that come to mind are Pythagoras and Euclid," she said, but that "this shouldn't be the case."
And though ancient Babylonia is often referred to in popular culture as a "lost" world, in fact much more evidence of mathematical learning from the period exists than from ancient Greece, said Chi.
Jones of New York University believes that there is much more that could be excavated but that, of course, current conditions in Iraq are not favorable. Still, there are enough tablets in collections across the world for mathematical historians to get stuck into.
For non-mathematicians, these tablets are a fascinating document of life in Mesopotamia. Most of the problems displayed are grounded in the everyday needs of ancient Babylonians.
But some tablets show the students engaging in what Jones calls "recreational math" -- math for math's sake.
"The only point of learning to do this kind of thing is really as a mental exercise, as a way of showing how smart you are," he said.
And it seems there is still more to learn from the Babylonians. Duncan Melville is a Professor of Mathematics at St. Lawrence University in Canton, New York, whose special interest is Mesopotamian mathematics.
According to Melville, teachers can continue to learn a thing or two about the way math was taught in Mesopotamia.
"You look at the way they set up their sequences of problems and it's all very carefully graduated, from simple problems to more complicated problems," he said.
"As a teacher of mathematics, it's very interesting to see how they organized their material," he continued. "There's still interesting things to learn from cutting-edge pedagogy 4,000 years ago."
With research continuing into this strand of ancient history, it remains to be seen whether Pythagoras's theorem will come to bear the name of an old Babylonian scribe instead.
From CNN December 18, 2010
* Cuneiform tablets in New York exhibition show sophistication of Babylonian mathematicians
* Interest in this strand of history growing
(CNN) -- Over 1,000 years before Pythagoras was calculating the length of a hypotenuse, sophisticated scribes in Mesopotamia were working with the same theory to calculate the area of their farmland.
Working on clay tablets, students would "write" out their math problems in cuneiform script, a method that involved making wedge-shaped impressions in the clay with a blunt reed.
These tablets bear evidence of practical as well as more advanced theoretical math and show just how sophisticated the ancient Babylonians were with numbers -- more than a millennium before Pythagoras and Euclid were doing the same in ancient Greece.
"They are the most sophisticated mathematics from anywhere in the world at that time," said Alexander Jones, a Professor of the History of the Exact Sciences in Antiquity at New York University.
He is co-curator of "Before Pythagoras: The Culture of Old Babylonian Mathematics," an exhibition at the Institute for the Study of the Ancient World in New York.
They are the most sophisticated mathematics from anywhere in the world at that time
--Curator Alexander Jones
"This is nearly 4,000 years ago and there's no other ancient culture at that time that we know of that is doing anything like that level of work. It seems to be going beyond anything that daily life needs," he said.
Many scribes were trained in the ancient city of Nippur in what is now southern Iraq, where a large number of tablets were discovered between the mid-19th century and the 1920s.
Typical problems they worked on involved calculating the area of a given field, or the width of a trench.
These problems, says Jones, required the kind of math training taught to American Grade 10 students, but not in a format we would now recognize.
"It's not like algebra, it's all written out in words and numerals but no symbols and no times signs or equals or anything like that," he said.
This system, and the lack of recognizable Western mathematical symbols such as x and y, meant that it was several years before historians and archaeologists understood just what was represented on these tablets.
It took a young Austrian mathematician in the 1920s, named Otto Neugebauer, to crack the mathematical system and work out what the ancient Babylonians were calculating. But despite his advances, it is only recently that interest in Babylonian math has started to take hold.
"I think that before Neugebauer and even after Neugebauer, there wasn't a lot of attention placed on mathematical training in Babylon even though we have this rich cuneiform history with the tablets," said Jennifer Chi, Associate Director for Exhibitions and Public Programs at Institute for the Study of the Ancient World.
When we think of ancient mathematics, the first names that come to mind are Pythagoras and Euclid. That shouldn't be the case.
One of the aims of the institute, she says, is to find interconnections between ancient cultures as well as look at what the institute sees as under-represented ancient cultures -- and the culture of ancient Babylonian math, she says, is ripe for popular revision.
"When we think of ancient mathematics, the first names that come to mind are Pythagoras and Euclid," she said, but that "this shouldn't be the case."
And though ancient Babylonia is often referred to in popular culture as a "lost" world, in fact much more evidence of mathematical learning from the period exists than from ancient Greece, said Chi.
Jones of New York University believes that there is much more that could be excavated but that, of course, current conditions in Iraq are not favorable. Still, there are enough tablets in collections across the world for mathematical historians to get stuck into.
For non-mathematicians, these tablets are a fascinating document of life in Mesopotamia. Most of the problems displayed are grounded in the everyday needs of ancient Babylonians.
But some tablets show the students engaging in what Jones calls "recreational math" -- math for math's sake.
"The only point of learning to do this kind of thing is really as a mental exercise, as a way of showing how smart you are," he said.
And it seems there is still more to learn from the Babylonians. Duncan Melville is a Professor of Mathematics at St. Lawrence University in Canton, New York, whose special interest is Mesopotamian mathematics.
According to Melville, teachers can continue to learn a thing or two about the way math was taught in Mesopotamia.
"You look at the way they set up their sequences of problems and it's all very carefully graduated, from simple problems to more complicated problems," he said.
"As a teacher of mathematics, it's very interesting to see how they organized their material," he continued. "There's still interesting things to learn from cutting-edge pedagogy 4,000 years ago."
With research continuing into this strand of ancient history, it remains to be seen whether Pythagoras's theorem will come to bear the name of an old Babylonian scribe instead.
From CNN December 18, 2010
Thursday, December 16, 2010
Electromagnetic Energy Naval Rail Gun
(Dec. 14) -- The world's most powerful gun is one step closer to becoming the super-weapon of the future.
The Navy on Friday demonstrated a record-setting 33-megajoule shot from its developmental electromagnetic rail gun, a weapon that will be able to shoot farther than conventional guns. This weapon of the future could someday go on U.S. Navy ships, but for right now, it's a science and technology project.
Normally, a ship-based weapon would require gunpowder or a rocket boost to shoot projectiles, but the electromagnetic gun is powered by an electric pulse generated by the ship. Since the projectiles travel at speeds of more than seven times the speed of sound, they don't even require high explosives to pack a big punch: The kinetic energy of the projectile is more than enough to create a lethal effect.
Why does the Navy want it? Range and speed make the rail gun a particularly attractive weapon for the Navy, though other advantages include its accuracy and safety onboard a ship (because it doesn't require high explosives). "The 33-megajoule shot means the Navy can fire projectiles at least 110 nautical miles (126 miles), placing sailors and Marines at a safe standoff distance and out of harm's way, and the high velocities achievable are tactically relevant for air and missile defense," Rear Adm. Nevin Carr, chief of naval research, said in a release announcing the latest test.
How much does it cost? The Navy has budgeted about $250 million for the development of the prototype rail gun. It's impossible to say how much the final system would cost to buy. As with any new weapon system, the price tag is likely to be high, but advocates for the rail gun point out the projectiles would be cheaper than conventional missiles and ammunition.
When will the weapon be used on a ship? Not anytime soon. The Navy projects it won't be ready until sometime in the 2020 to 2025 time range, and that assumes the Navy pursues it beyond the prototype.
Filed under: Nation, Tech, AOL Original
The Navy on Friday demonstrated a record-setting 33-megajoule shot from its developmental electromagnetic rail gun, a weapon that will be able to shoot farther than conventional guns. This weapon of the future could someday go on U.S. Navy ships, but for right now, it's a science and technology project.
Normally, a ship-based weapon would require gunpowder or a rocket boost to shoot projectiles, but the electromagnetic gun is powered by an electric pulse generated by the ship. Since the projectiles travel at speeds of more than seven times the speed of sound, they don't even require high explosives to pack a big punch: The kinetic energy of the projectile is more than enough to create a lethal effect.
Why does the Navy want it? Range and speed make the rail gun a particularly attractive weapon for the Navy, though other advantages include its accuracy and safety onboard a ship (because it doesn't require high explosives). "The 33-megajoule shot means the Navy can fire projectiles at least 110 nautical miles (126 miles), placing sailors and Marines at a safe standoff distance and out of harm's way, and the high velocities achievable are tactically relevant for air and missile defense," Rear Adm. Nevin Carr, chief of naval research, said in a release announcing the latest test.
How much does it cost? The Navy has budgeted about $250 million for the development of the prototype rail gun. It's impossible to say how much the final system would cost to buy. As with any new weapon system, the price tag is likely to be high, but advocates for the rail gun point out the projectiles would be cheaper than conventional missiles and ammunition.
When will the weapon be used on a ship? Not anytime soon. The Navy projects it won't be ready until sometime in the 2020 to 2025 time range, and that assumes the Navy pursues it beyond the prototype.
Filed under: Nation, Tech, AOL Original
Sunday, December 5, 2010
New Life Form - Is God Dead?
AOL News Article, Dec. 5, 2010
Does a New Life Form Mean God Is Dead?
David Gibson
Religion Reporter
The discovery of what is apparently an entirely new form of life -- a bacteria based on toxic arsenic rather than phosphorus, one of the six building blocks of all life on Earth -- has set the scientific world abuzz, prompting White House inquiries to NASA and threatening to upend longstanding beliefs about biology.
But some say the announcement also signals an end to religious faith, or at least the beginning of the end, because it implies that life can spring forth unexpectedly on Earth or even on other planets, and in unexpected forms -- developments that seem to run counter to literal readings of biblical creation accounts.
"The polite thing to say is that discoveries such as this don't really impeach the credibility of established religion, but in truth of course they really do," David Niose, president of the American Humanist Association (AHA), a leading secularist organization, said of this week's revelations about the microbes discovered in Lake Mono in California.
"The fact that life can spring forth in this way from nature, taken in context with what else we've learned in recent centuries about space and time, surely makes it less plausible that the human animal is the specially favored creation of all-powerful, all-knowing divinity," Niose said.
Another shot in the Wars of Science and Religion? Maybe not.
The arsenic-based microbe discovery "sounds like a nice piece of work; we'll see where it goes from here," Brother Guy Consolmagno, a Jesuit and a planetary scientist at the Vatican Observatory, wrote in an e-mail to Politics Daily. (Yes, the Catholic Church was doing science long before Galileo.)
"But," he added, "any scientific discovery that broadens our knowledge of creation, deepens our understanding of the Creator."
Consolmagno, who a few weeks ago made news for saying he'd be delighted to find intelligent life on other planets, is typical of religious believers who don't see faith and science as natural enemies.
Even some vocal atheists who see belief and science as inevitable opponents -- with belief the problem, not the solution -- weren't buying the AHA's arguments about the discovery's importance.
"I regret to say that the American Humanists got the story wrong," PZ Myers, a biologist at the University of Minnesota and a famously trenchant critic of religion, told Politics Daily. Myers, who details his arguments at his blog, says the problem is their reading of the science.
"They say 'a new form of life has been discovered that apparently evolved outside the scope of all previously discovered life on Earth,' and this is not correct: the bacteria studied share a common ancestor with us, and the novelty of the discovery was not the organism, but that this entirely earthly organism was capable of incorporating arsenic into its chemistry. So no, their claims of its significant impact on our understanding of the history of life on Earth are overblown."
Myers does see a silver lining of sorts (at least from his non-believer's point of view) because the discovery "does represent an incremental increase in our understanding, just as science does every day."
"The point should be that the whole of science provides a direct challenge to religious belief, not that any one event is so definitive," Myers said.
Brother Guy would disagree with that assertion, but he pointed out that for the AHA and similar groups, "obviously this is no 'proof' since obviously they'd decided years ago, for whatever other reasons, that there was no God."
Faith, it seems, comes in many forms.
Niose of the American Humanist Association did concede that it is "unlikely that this discovery will change the minds of those who insist on a literal interpretation of the Bible."
"To them, the world is about 6,000 years old and evolution is a hoax, and no amount of scientific evidence will change that. For the rest of us, however, this discovery is indeed profound, and it adds to the mountains of evidence that already point to the humanistic lifestance as being our best hope."
Maybe the true test of the impact of the discovery will come in a few years time, when we can see whether there are more tourists visiting Lake Mono looking for the arsenic-eating bugs or more pilgrims checking out the full-scale replica of Noah's Ark that a well-known creationist group said this week it will build in northern Kentucky -- at a cost of $150 million, including taxpayer subsidies.
Given the success of the group's Creation Museum, which drew its millionth visitor last spring, it'd be wise not to bet against the Ark.
David Gibson »
Does a New Life Form Mean God Is Dead?
David Gibson
Religion Reporter
The discovery of what is apparently an entirely new form of life -- a bacteria based on toxic arsenic rather than phosphorus, one of the six building blocks of all life on Earth -- has set the scientific world abuzz, prompting White House inquiries to NASA and threatening to upend longstanding beliefs about biology.
But some say the announcement also signals an end to religious faith, or at least the beginning of the end, because it implies that life can spring forth unexpectedly on Earth or even on other planets, and in unexpected forms -- developments that seem to run counter to literal readings of biblical creation accounts.
"The polite thing to say is that discoveries such as this don't really impeach the credibility of established religion, but in truth of course they really do," David Niose, president of the American Humanist Association (AHA), a leading secularist organization, said of this week's revelations about the microbes discovered in Lake Mono in California.
"The fact that life can spring forth in this way from nature, taken in context with what else we've learned in recent centuries about space and time, surely makes it less plausible that the human animal is the specially favored creation of all-powerful, all-knowing divinity," Niose said.
Another shot in the Wars of Science and Religion? Maybe not.
The arsenic-based microbe discovery "sounds like a nice piece of work; we'll see where it goes from here," Brother Guy Consolmagno, a Jesuit and a planetary scientist at the Vatican Observatory, wrote in an e-mail to Politics Daily. (Yes, the Catholic Church was doing science long before Galileo.)
"But," he added, "any scientific discovery that broadens our knowledge of creation, deepens our understanding of the Creator."
Consolmagno, who a few weeks ago made news for saying he'd be delighted to find intelligent life on other planets, is typical of religious believers who don't see faith and science as natural enemies.
Even some vocal atheists who see belief and science as inevitable opponents -- with belief the problem, not the solution -- weren't buying the AHA's arguments about the discovery's importance.
"I regret to say that the American Humanists got the story wrong," PZ Myers, a biologist at the University of Minnesota and a famously trenchant critic of religion, told Politics Daily. Myers, who details his arguments at his blog, says the problem is their reading of the science.
"They say 'a new form of life has been discovered that apparently evolved outside the scope of all previously discovered life on Earth,' and this is not correct: the bacteria studied share a common ancestor with us, and the novelty of the discovery was not the organism, but that this entirely earthly organism was capable of incorporating arsenic into its chemistry. So no, their claims of its significant impact on our understanding of the history of life on Earth are overblown."
Myers does see a silver lining of sorts (at least from his non-believer's point of view) because the discovery "does represent an incremental increase in our understanding, just as science does every day."
"The point should be that the whole of science provides a direct challenge to religious belief, not that any one event is so definitive," Myers said.
Brother Guy would disagree with that assertion, but he pointed out that for the AHA and similar groups, "obviously this is no 'proof' since obviously they'd decided years ago, for whatever other reasons, that there was no God."
Faith, it seems, comes in many forms.
Niose of the American Humanist Association did concede that it is "unlikely that this discovery will change the minds of those who insist on a literal interpretation of the Bible."
"To them, the world is about 6,000 years old and evolution is a hoax, and no amount of scientific evidence will change that. For the rest of us, however, this discovery is indeed profound, and it adds to the mountains of evidence that already point to the humanistic lifestance as being our best hope."
Maybe the true test of the impact of the discovery will come in a few years time, when we can see whether there are more tourists visiting Lake Mono looking for the arsenic-eating bugs or more pilgrims checking out the full-scale replica of Noah's Ark that a well-known creationist group said this week it will build in northern Kentucky -- at a cost of $150 million, including taxpayer subsidies.
Given the success of the group's Creation Museum, which drew its millionth visitor last spring, it'd be wise not to bet against the Ark.
David Gibson »
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