Showing posts with label science. Show all posts
Showing posts with label science. Show all posts
Thursday, May 31, 2012
Ghostly Jets Haunt the Milky Way’s Black Hole
http://www.universetoday.com/95504/ghostly-jets-haunt-the-milky-ways-black-hole/ 
A ghost is haunting the Milky Way’s central black hole, revealing the galactic nucleus was likely much more active in the past than it is now. Scientists using the Fermi space telescope have found faint apparitions of what must have been powerful gamma-ray jets emanating from our galaxy’s center. “These faint jets are a ghost or after-image of what existed a million years ago,” said Meng Su, an astronomer at the Harvard-Smithsonian Center for Astrophysics (CfA), and lead author of a new paper in the Astrophysical Journal. “They strengthen the case for an active galactic nucleus in the Milky Way’s relatively recent past.” This is the first time this type of jet has been detected from the Milky Way’s black hole. Scientists know that other active galaxies have cores that glow brightly, powered by supermassive black holes swallowing material, and often spit twin jets in opposite directions. The two beams, or jets found by Fermi observations extend from the galactic center to a distance of 27,000 light-years above and below the galactic plane. The newfound jets may be related to mysterious gamma-ray bubbles that Fermi detected in 2010. Those bubbles also stretch 27,000 light-years from the center of the Milky Way. However, where the bubbles are perpendicular to the galactic plane, the gamma-ray jets are tilted at an angle of 15 degrees. This may reflect a tilt of the accretion disk surrounding the supermassive black hole. “The central accretion disk can warp as it spirals in toward the black hole, under the influence of the black hole’s spin,” explained co-author Douglas Finkbeiner of the CfA. “The magnetic field embedded in the disk therefore accelerates the jet material along the spin axis of the black hole, which may not be aligned with the Milky Way.” The two structures also formed differently. The jets were produced when plasma squirted out from the galactic center, following a corkscrew-like magnetic field that kept it tightly focused. The gamma-ray bubbles likely were created by a “wind” of hot matter blowing outward from the black hole’s accretion disk. As a result, they are much broader than the narrow jets. Both the jets and bubbles are powered by inverse Compton scattering. In that process, electrons moving near the speed of light collide with low-energy light, such as radio or infrared photons. The collision increases the energy of the photons into the gamma-ray part of the electromagnetic spectrum. The discovery leaves open the question of when the Milky Way was last active. A minimum age can be calculated by dividing the jet’s 27,000-light-year length by its approximate speed. However, it may have persisted for much longer. “These jets probably flickered on and off as the supermassive black hole alternately gulped and sipped material,” said Finkbeiner. It would take a tremendous influx of matter for the galactic core to fire up again. Finkbeiner estimates that a molecular cloud weighing about 10,000 times as much as the Sun would be required. “Shoving 10,000 suns into the black hole at once would do the trick. Black holes are messy eaters, so some of that material would spew out and power the jets,” he said. Source: CfA
Saturday, February 4, 2012
Summary: Astronomers have discovered a potentially habitable super-Earth orbiting a nearby star.
http://astrobio.net/pressrelease/4536/super-earth-detected-in-stars-habitable-zone
Super-Earth Detected in Star's Habitable Zone
Source: University of California, Santa Cruz
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New Planets
Posted: 02/02/12
The star, GJ 667C. Credit: Digitized Sky Survey
An international team of scientists has discovered a potentially habitable super-Earth orbiting a nearby star. With an orbital period of about 28 days and a minimum mass 4.5 times that of the Earth, the planet orbits within the star’s “habitable zone,” where temperatures are neither too hot nor too cold for liquid water to exist on the planet’s surface. The researchers found evidence of at least one and possibly two or three additional planets orbiting the star, which is about 22 light-years from Earth.
The team includes UC Santa Cruz astronomers Steven Vogt and Eugenio Rivera and was led by Guillem Anglada-Escudé and Paul Butler of the Carnegie Institution for Science. Their work will be published by Astrophysical Journal Letters, and the manuscript will be posted online at arxiv.org/archive/astro-ph
The host star is a member of a triple-star system and has a different makeup than our sun, with a much lower abundance of elements heavier than helium, such as iron, carbon, and silicon. This discovery indicates that potentially habitable planets can occur in a greater variety of environments than previously believed.
The Carnegie Planet Finder Spectrograph at the beginning of Summer 2008, before it was installed at the Magellan II Telescope. Credit: Carnegie Institute of Washingon
The researchers used public data from the European Southern Observatory and analyzed it with a novel data-analysis method. They also incorporated new measurements from the W. M. Keck Observatory’s High Resolution Echelle Spectrograph and the new Carnegie Planet Finder Spectrograph at the Magellan II Telescope. Their planet-finding technique involved measuring the small wobbles in a star’s motion caused by the gravitational tug of a planet.
The host star, called GJ 667C, is an M-class dwarf star. The other two stars in the triple-star system (GJ 667AB) are a pair of orange K dwarfs, with a concentration of heavy elements only 25 percent that of our sun’s. Such elements are the building blocks of terrestrial planets, so it was thought to be less likely for metal-depleted star systems to have an abundance of low-mass planets.
“This was expected to be a rather unlikely star to host planets. Yet there they are, around a very nearby, metal-poor example of the most common type of star in our galaxy,” said Vogt, a professor of astronomy and astrophysics at UCSC. “The detection of this planet, this nearby and this soon, implies that our galaxy must be teeming with billions of potentially habitable rocky planets.”
GJ 667C had previously been observed to have a super-Earth (GJ 667Cb) with a period of 7.2 days, although this finding was never published. This planet orbits so close to the star that it would be too hot for liquid water. The new study started with the aim of obtaining the orbital parameters of this super-Earth.
The team also incorporated new measurements from the High Resolution Echelle Spectrograph at the W. M. Keck Observatory, located on the island of Hawai’i. Image Credit: Pablo McLoud/WMKO
But in addition to this first candidate, the research team found the clear signal of a new planet (GJ 667Cc) with an orbital period of 28.15 days and a minimum mass of 4.5 times that of Earth. The new planet receives 90 percent of the light that Earth receives. However, because most of its incoming light is in the infrared, a higher percentage of this incoming energy should be absorbed by the planet. When both these effects are taken into account, the planet is expected to absorb about the same amount of energy from its star that the Earth absorbs from the Sun.
“This planet is the new best candidate to support liquid water and, perhaps, life as we know it,” Anglada-Escudé said.
The team found that the system might also contain a gas-giant planet and an additional super-Earth with an orbital period of 75 days. However, further observations are needed to confirm these two possibilities.
“With the advent of a new generation of instruments, researchers will be able to survey many M dwarf stars for similar planets and eventually look for spectroscopic signatures of life in one of these worlds,” said Anglada-Escudé, who was with Carnegie when he conducted the research, but has since moved on to the University of Gottingen.
Super-Earth Detected in Star's Habitable Zone
Source: University of California, Santa Cruz
print PDF Digg It
New Planets
Posted: 02/02/12
The star, GJ 667C. Credit: Digitized Sky Survey
An international team of scientists has discovered a potentially habitable super-Earth orbiting a nearby star. With an orbital period of about 28 days and a minimum mass 4.5 times that of the Earth, the planet orbits within the star’s “habitable zone,” where temperatures are neither too hot nor too cold for liquid water to exist on the planet’s surface. The researchers found evidence of at least one and possibly two or three additional planets orbiting the star, which is about 22 light-years from Earth.
The team includes UC Santa Cruz astronomers Steven Vogt and Eugenio Rivera and was led by Guillem Anglada-Escudé and Paul Butler of the Carnegie Institution for Science. Their work will be published by Astrophysical Journal Letters, and the manuscript will be posted online at arxiv.org/archive/astro-ph
The host star is a member of a triple-star system and has a different makeup than our sun, with a much lower abundance of elements heavier than helium, such as iron, carbon, and silicon. This discovery indicates that potentially habitable planets can occur in a greater variety of environments than previously believed.
The Carnegie Planet Finder Spectrograph at the beginning of Summer 2008, before it was installed at the Magellan II Telescope. Credit: Carnegie Institute of Washingon
The researchers used public data from the European Southern Observatory and analyzed it with a novel data-analysis method. They also incorporated new measurements from the W. M. Keck Observatory’s High Resolution Echelle Spectrograph and the new Carnegie Planet Finder Spectrograph at the Magellan II Telescope. Their planet-finding technique involved measuring the small wobbles in a star’s motion caused by the gravitational tug of a planet.
The host star, called GJ 667C, is an M-class dwarf star. The other two stars in the triple-star system (GJ 667AB) are a pair of orange K dwarfs, with a concentration of heavy elements only 25 percent that of our sun’s. Such elements are the building blocks of terrestrial planets, so it was thought to be less likely for metal-depleted star systems to have an abundance of low-mass planets.
“This was expected to be a rather unlikely star to host planets. Yet there they are, around a very nearby, metal-poor example of the most common type of star in our galaxy,” said Vogt, a professor of astronomy and astrophysics at UCSC. “The detection of this planet, this nearby and this soon, implies that our galaxy must be teeming with billions of potentially habitable rocky planets.”
GJ 667C had previously been observed to have a super-Earth (GJ 667Cb) with a period of 7.2 days, although this finding was never published. This planet orbits so close to the star that it would be too hot for liquid water. The new study started with the aim of obtaining the orbital parameters of this super-Earth.
The team also incorporated new measurements from the High Resolution Echelle Spectrograph at the W. M. Keck Observatory, located on the island of Hawai’i. Image Credit: Pablo McLoud/WMKO
But in addition to this first candidate, the research team found the clear signal of a new planet (GJ 667Cc) with an orbital period of 28.15 days and a minimum mass of 4.5 times that of Earth. The new planet receives 90 percent of the light that Earth receives. However, because most of its incoming light is in the infrared, a higher percentage of this incoming energy should be absorbed by the planet. When both these effects are taken into account, the planet is expected to absorb about the same amount of energy from its star that the Earth absorbs from the Sun.
“This planet is the new best candidate to support liquid water and, perhaps, life as we know it,” Anglada-Escudé said.
The team found that the system might also contain a gas-giant planet and an additional super-Earth with an orbital period of 75 days. However, further observations are needed to confirm these two possibilities.
“With the advent of a new generation of instruments, researchers will be able to survey many M dwarf stars for similar planets and eventually look for spectroscopic signatures of life in one of these worlds,” said Anglada-Escudé, who was with Carnegie when he conducted the research, but has since moved on to the University of Gottingen.
Thursday, November 3, 2011
Gamma-Ray Burst 12 Billion Years Ago Reveals Fascinating Discovery About Early Galaxies
From the Daily Galaxy
An international team of astronomers has used the brief but brilliant light of a distant gamma-ray burst as a probe to study the make-up of very distant galaxies. Surprisingly, the new observations, made with ESO’s Very Large Telescope, have revealed two galaxies in the young Universe that are richer in the heavier chemical elements than the Sun. The two galaxies may be in the process of merging. Such events in the early Universe will drive the formation of many new stars and may have been the trigger for gamma-ray bursts.
Gamma-ray bursts are the brightest explosions in the Universe. They are first spotted by orbiting observatories that detect the initial short burst of gamma rays. After their positions have been pinned down, they are then immediately studied using large ground-based telescopes that can detect the visible-light and infrared afterglows that the bursts emit over the succeeding hours and days.
One such burst, called GRB 090323, was first spotted by the NASA Fermi Gamma-ray Space Telescope. Very soon afterwards it was picked up by the X-ray detector on NASA's Swift satellite and with the GROND system at the MPG/ESO 2.2-metre telescope in Chile and then studied in great detail using ESO's Very Large Telescope (VLT) just one day after it exploded.
The VLT observations show that the brilliant light from the gamma-ray burst had passed through its own host galaxy and another galaxy nearby. These galaxies are being seen as they were about 12 billion years ago. Such distant galaxies are very rarely caught in the glare of a gamma-ray burst.
"When we studied the light from this gamma-ray burst we didn't know what we might find. It was a surprise that the cool gas in these two galaxies in the early Universe proved to have such an unexpected chemical make-up," explains Sandra Savaglio (Max-Planck Institute for Extraterrestrial Physics), lead author of the paper describing the new results. "These galaxies have more heavy elements than have ever been seen in a galaxy so early in the evolution of the Universe. We didn't expect the Universe to be so mature, so chemically evolved, so early on."
As light from the gamma-ray burst passed through the galaxies, the gas there acted like a filter, and absorbed some of the light from the gamma-ray burst at certain wavelengths. Without the gamma-ray burst these faint galaxies would be invisible. By carefully analysing the tell-tale fingerprints from different chemical elements the team was able to work out the composition of the cool gas in these very distant galaxies, and in particular how rich they were in heavy
It is expected that galaxies in the young Universe will be found to contain smaller amounts of heavier elements than galaxies at the present day, such as the Milky Way. The heavier elements are produced during the lives and deaths of generations of stars, gradually enriching the gas in the galaxies.
Astronomers can use the chemical enrichment in galaxies to indicate how far they are through their lives. But the new observations, surprisingly, revealed that some galaxies were already very rich in heavy elements less than two billion years after the Big Bang. Something unthinkable until recently.
The newly discovered pair of young galaxies must be forming new stars at a tremendous rate, to enrich the cool gas so strongly and quickly. As the two galaxies are close to each other they may be in the process of merging, which would also provoke star formation when the gas clouds collide. The new results also support the idea that gamma-ray bursts may be associated with vigorous massive star formation.
Energetic star formation in galaxies like these might have ceased early on in the history of the Universe. Twelve billion years later, at the present time, the remains of such galaxies would contain a large number of stellar remnants such as black holes and cool dwarf stars, forming a hard to detect population of "dead galaxies", just faint shadows of how they were in their brilliant youths. Finding such corpses in the present day would be a challenge.
"We were very lucky to observe GRB 090323 when it was still sufficiently bright, so that it was possible to obtain spectacularly detailed observations with the VLT. Gamma-ray bursts only stay bright for a very short time and getting good quality data is very hard. We hope to observe these galaxies again in the future when we have much more sensitive instruments, they would make perfect targets for the E-ELT," concludes Savaglio.
The Daily Galaxy via ESO
Image at top of page shows an artist's impression of two galaxies in the early universe. The brilliant explosion on the left is a gamma-ray burst. The light from the burst travels through both galaxies on its way to Earth (outside the frame to the right). Analysis of observations of the light from this gamma-ray burst made using ESO's Very Large Telescope have shown that these two galaxies are remarkably rich in heavier chemical elements.
Image Credit: ESO/L. Calçada
Posted at 01:00 AM | Permalink
An international team of astronomers has used the brief but brilliant light of a distant gamma-ray burst as a probe to study the make-up of very distant galaxies. Surprisingly, the new observations, made with ESO’s Very Large Telescope, have revealed two galaxies in the young Universe that are richer in the heavier chemical elements than the Sun. The two galaxies may be in the process of merging. Such events in the early Universe will drive the formation of many new stars and may have been the trigger for gamma-ray bursts.
Gamma-ray bursts are the brightest explosions in the Universe. They are first spotted by orbiting observatories that detect the initial short burst of gamma rays. After their positions have been pinned down, they are then immediately studied using large ground-based telescopes that can detect the visible-light and infrared afterglows that the bursts emit over the succeeding hours and days.
One such burst, called GRB 090323, was first spotted by the NASA Fermi Gamma-ray Space Telescope. Very soon afterwards it was picked up by the X-ray detector on NASA's Swift satellite and with the GROND system at the MPG/ESO 2.2-metre telescope in Chile and then studied in great detail using ESO's Very Large Telescope (VLT) just one day after it exploded.
The VLT observations show that the brilliant light from the gamma-ray burst had passed through its own host galaxy and another galaxy nearby. These galaxies are being seen as they were about 12 billion years ago. Such distant galaxies are very rarely caught in the glare of a gamma-ray burst.
"When we studied the light from this gamma-ray burst we didn't know what we might find. It was a surprise that the cool gas in these two galaxies in the early Universe proved to have such an unexpected chemical make-up," explains Sandra Savaglio (Max-Planck Institute for Extraterrestrial Physics), lead author of the paper describing the new results. "These galaxies have more heavy elements than have ever been seen in a galaxy so early in the evolution of the Universe. We didn't expect the Universe to be so mature, so chemically evolved, so early on."
As light from the gamma-ray burst passed through the galaxies, the gas there acted like a filter, and absorbed some of the light from the gamma-ray burst at certain wavelengths. Without the gamma-ray burst these faint galaxies would be invisible. By carefully analysing the tell-tale fingerprints from different chemical elements the team was able to work out the composition of the cool gas in these very distant galaxies, and in particular how rich they were in heavy
It is expected that galaxies in the young Universe will be found to contain smaller amounts of heavier elements than galaxies at the present day, such as the Milky Way. The heavier elements are produced during the lives and deaths of generations of stars, gradually enriching the gas in the galaxies.
Astronomers can use the chemical enrichment in galaxies to indicate how far they are through their lives. But the new observations, surprisingly, revealed that some galaxies were already very rich in heavy elements less than two billion years after the Big Bang. Something unthinkable until recently.
The newly discovered pair of young galaxies must be forming new stars at a tremendous rate, to enrich the cool gas so strongly and quickly. As the two galaxies are close to each other they may be in the process of merging, which would also provoke star formation when the gas clouds collide. The new results also support the idea that gamma-ray bursts may be associated with vigorous massive star formation.
Energetic star formation in galaxies like these might have ceased early on in the history of the Universe. Twelve billion years later, at the present time, the remains of such galaxies would contain a large number of stellar remnants such as black holes and cool dwarf stars, forming a hard to detect population of "dead galaxies", just faint shadows of how they were in their brilliant youths. Finding such corpses in the present day would be a challenge.
"We were very lucky to observe GRB 090323 when it was still sufficiently bright, so that it was possible to obtain spectacularly detailed observations with the VLT. Gamma-ray bursts only stay bright for a very short time and getting good quality data is very hard. We hope to observe these galaxies again in the future when we have much more sensitive instruments, they would make perfect targets for the E-ELT," concludes Savaglio.
The Daily Galaxy via ESO
Image at top of page shows an artist's impression of two galaxies in the early universe. The brilliant explosion on the left is a gamma-ray burst. The light from the burst travels through both galaxies on its way to Earth (outside the frame to the right). Analysis of observations of the light from this gamma-ray burst made using ESO's Very Large Telescope have shown that these two galaxies are remarkably rich in heavier chemical elements.
Image Credit: ESO/L. Calçada
Posted at 01:00 AM | Permalink
Friday, September 23, 2011
Particles Found to Travel Faster than Speed of Light
http://www.scientificamerican.com/article.cfm?id=particles-found-to-travel
Neutrino results challenge a cornerstone of Albert Einstein's special theory of relativity, which itself forms the foundation of modern physics.
An Italian experiment has unveiled evidence that fundamental particles known as neutrinos can travel faster than light. Other researchers are cautious about the result, but if it stands further scrutiny, the finding would overturn the most fundamental rule of modern physics—that nothing travels faster than 299,792,458 meters per second.
The experiment is called OPERA (Oscillation Project with Emulsion-tRacking Apparatus), and lies 1,400 meters underground in the Gran Sasso National Laboratory in Italy. It is designed to study a beam of neutrinos coming from CERN, Europe's premier high-energy physics laboratory located 730 kilometers away near Geneva, Switzerland. Neutrinos are fundamental particles that are electrically neutral, rarely interact with other matter, and have a vanishingly small mass. But they are all around us—the sun produces so many neutrinos as a by-product of nuclear reactions that many billions pass through your eye every second. [Click here to read more about CERN's Large Hadron Collider]
The 1,800-tonne OPERA detector is a complex array of electronics and photographic emulsion plates, but the new result is simple—the neutrinos are arriving 60 nanoseconds faster than the speed of light allows. "We are shocked," says Antonio Ereditato, a physicist at the University of Bern in Switzerland and OPERA's spokesman.
Breaking the law
The idea that nothing can travel faster than light in a vacuum is the cornerstone of Albert Einstein's special theory of relativity, which itself forms the foundation of modern physics. If neutrinos are traveling faster than light speed, then one of the most fundamental assumptions of science—that the rules of physics are the same for all observers—would be invalidated. "If it's true, then it's truly extraordinary," says John Ellis, a theoretical physicist at CERN.
Ereditato says that he is confident enough in the new result to make it public. The researchers claim to have measured the 730-kilometer trip between CERN and its detector to within 20 centimeters. They can measure the time of the trip to within 10 nanoseconds, and they have seen the effect in more than 16,000 events measured over the past two years. Given all this, they believe the result has a significance of six-sigma—the physicists' way of saying it is certainly correct. The group will present their results September 23 at CERN, and a preprint of their results will be posted on the physics website ArXiv.org.
At least one other experiment has seen a similar effect before, albeit with a much lower confidence level. In 2007, the Main Injector Neutrino Oscillation Search (MINOS) experiment in Minnesota saw neutrinos from the particle-physics facility Fermilab in Illinois arriving slightly ahead of schedule. At the time, the MINOS team downplayed the result, in part because there was too much uncertainty in the detector's exact position to be sure of its significance, says Jenny Thomas, a spokeswoman for the experiment. Thomas says that MINOS was already planning more accurate follow-up experiments before the latest OPERA result. "I'm hoping that we could get that going and make a measurement in a year or two," she says.
Reasonable doubt
If MINOS were to confirm OPERA's find, the consequences would be enormous. "If you give up the speed of light, then the construction of special relativity falls down," says Antonino Zichichi, a theoretical physicist and emeritus professor at the University of Bologna, Italy. Zichichi speculates that the "superluminal" neutrinos detected by OPERA could be slipping through extra dimensions in space, as predicted by theories such as string theory.
Neutrino results challenge a cornerstone of Albert Einstein's special theory of relativity, which itself forms the foundation of modern physics.
An Italian experiment has unveiled evidence that fundamental particles known as neutrinos can travel faster than light. Other researchers are cautious about the result, but if it stands further scrutiny, the finding would overturn the most fundamental rule of modern physics—that nothing travels faster than 299,792,458 meters per second.
The experiment is called OPERA (Oscillation Project with Emulsion-tRacking Apparatus), and lies 1,400 meters underground in the Gran Sasso National Laboratory in Italy. It is designed to study a beam of neutrinos coming from CERN, Europe's premier high-energy physics laboratory located 730 kilometers away near Geneva, Switzerland. Neutrinos are fundamental particles that are electrically neutral, rarely interact with other matter, and have a vanishingly small mass. But they are all around us—the sun produces so many neutrinos as a by-product of nuclear reactions that many billions pass through your eye every second. [Click here to read more about CERN's Large Hadron Collider]
The 1,800-tonne OPERA detector is a complex array of electronics and photographic emulsion plates, but the new result is simple—the neutrinos are arriving 60 nanoseconds faster than the speed of light allows. "We are shocked," says Antonio Ereditato, a physicist at the University of Bern in Switzerland and OPERA's spokesman.
Breaking the law
The idea that nothing can travel faster than light in a vacuum is the cornerstone of Albert Einstein's special theory of relativity, which itself forms the foundation of modern physics. If neutrinos are traveling faster than light speed, then one of the most fundamental assumptions of science—that the rules of physics are the same for all observers—would be invalidated. "If it's true, then it's truly extraordinary," says John Ellis, a theoretical physicist at CERN.
Ereditato says that he is confident enough in the new result to make it public. The researchers claim to have measured the 730-kilometer trip between CERN and its detector to within 20 centimeters. They can measure the time of the trip to within 10 nanoseconds, and they have seen the effect in more than 16,000 events measured over the past two years. Given all this, they believe the result has a significance of six-sigma—the physicists' way of saying it is certainly correct. The group will present their results September 23 at CERN, and a preprint of their results will be posted on the physics website ArXiv.org.
At least one other experiment has seen a similar effect before, albeit with a much lower confidence level. In 2007, the Main Injector Neutrino Oscillation Search (MINOS) experiment in Minnesota saw neutrinos from the particle-physics facility Fermilab in Illinois arriving slightly ahead of schedule. At the time, the MINOS team downplayed the result, in part because there was too much uncertainty in the detector's exact position to be sure of its significance, says Jenny Thomas, a spokeswoman for the experiment. Thomas says that MINOS was already planning more accurate follow-up experiments before the latest OPERA result. "I'm hoping that we could get that going and make a measurement in a year or two," she says.
Reasonable doubt
If MINOS were to confirm OPERA's find, the consequences would be enormous. "If you give up the speed of light, then the construction of special relativity falls down," says Antonino Zichichi, a theoretical physicist and emeritus professor at the University of Bologna, Italy. Zichichi speculates that the "superluminal" neutrinos detected by OPERA could be slipping through extra dimensions in space, as predicted by theories such as string theory.
Friday, September 16, 2011
Rocky, "Earth-Twin" Exo Planets May have been Born as Gas Giants
http://www.dailygalaxy.com/my_weblog/2011/09/rocky-earth-twin-exo-planets-may-have-been-born-as-gas-giants.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+TheDailyGalaxyNewsFromPlanetEarthBeyond+%28The+Daily+Galaxy%3A+News+from+Planet+Earth+%26+Beyond%29
Almost a quarter of Kepler's new found 1300 exo planets are thought to be Super-Earths. New research by Sergei Nayakshin of the University of Leicester in the United Kingdom proposes a new theory for planetary formation known as "tidal downsizing." The new study concludes that these massive rocky planets may be the result of the failed creation of Jupiter-sized gas giants.
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Image above is a Hubble Space Telescope photo of a small portion of the Orion Nebula reveals five young stars. Four are surrounded by gas and dust trapped as the stars formed, but which were left in orbit about the star. These protoplanetary disks may evolve on to agglomerate planets
Most astronomers currently believe planets are created by a method known as core accretion. Giant disks of gas circle newborn stars. Grains in these disks bond together to form larger objects known as planetesimals, which collide, creating larger and larger clumps of material. When the clumps reach a critical mass, their gravity pulls in gas from the disk around them.
In tidal downsizing, a gas disk first forms massive gas clumps farther out in space than where most of the planets discovered so far reside in their solar systems. Left to their own devices, these clumps would cool and contract into very massive (~10 Jupiter mass) planets. Nayakshin showed that during this contraction dust grains grow to large sizes and then fall to the center of the gas clump, forming a massive solid core there – the proto-rocky planet within the much more massive gas cocoon.
"Once you have a core, it may build up an atmosphere around it," Nayakshin explained. "The atmosphere is dominated by hydrogen, but it is much more chemically-rich than the primordial dust material."
The more massive the rocky core, the more massive the atmosphere around it, and it grows with time. Given time, such a mix would result in a giant gas planet with a solid core inside, for example, a super-Jupiter.
However, the surrounding disk pushes the planet in, closer to the star, and there the outer layers of the gas envelope start to be disrupted and actually consumed by the star.
Building on this theory, Nayakshin determined that Super-Earths and other terrestrial planets could, in fact, be the cores of more massive proto-planets that did not have time to mature and were instead robbed of most of their gas by their parent stars. Rocky cores and close atmospheres could survive this disruption process because they are much denser. His paper describing this mechanism appeared in the August edition of the Monthly Notices of the Royal Astronomical Society.
"The remaining core is pretty much a rocky planet, with a mass anywhere from almost zero to ten or so Earth masses," Nayakshin said.
This means the resulting planet could wind up close to their parent star - or farther away, in the area known to astronomers as the habitable zone.
Differing from star to star, the "habitable zone" is the area where water can exist as a liquid on the surface of a rocky world. Planets orbiting within this range are considered the most likely to host life.
Aaron Boley of the University of Florida says that if planets do form as described by the tidal disruption theory, then planets may be able to form in systems that are unfavorable to the core accretion mechanism, such as in disks with little dust. Although he did not work with Nayakshin, he explored a similar theory early last year.
"I like to think of the mechanisms as opposites," he said. "One is bottom up - core accretion - and the other is top down - tidal disruption."
Boley, who has done extensive research on the formation of gas giant planets and the evolution of planet-forming disks, believes that tidal disruption makes it more likely for life to evolve in a wider variety of stellar systems.
"It is another way Nature can make planets," Boley said.
As a new theory, Nayakshin admits that there are many detailed calculations left to perform. He expressed hope that other scientists would help him put his theory to the test.
In his paper, Nayakshin expressed the idea that tidal downsizing capitalized on the best of the core accretion model and competing model of gravitational instability, while neutralizing the problems in both.
Gravitational instability allows for the rapid creation of planetesimals at a distance from the star, but it doesn't allow them to migrate inward. As such, it can't account for many of the closer planets seen today.
"Tidal downsizing and core accretion are both mechanisms that can form a wide range of planets," Boley said. "They occur during different stages of a proto-planetary disk's lifetime, and are not mutually exclusive."
Core accretion has a difficult time forming planets in more distant orbits over a long period of time. Gravitational instability quickly forms them farther out, where they remain unless they can migrate inward. Tidal downsizing requires that they migrate inward fast enough to have their envelopes removed by tides from their star.
Nayakshin noted that the models contain similar physical steps, but in different proportions.
"In this sense, the final model is likely to be a composite."
Boley expressed interest in watching the new theory develop, and seeing how well it stood against up to the more popular model of core accretion.
“Progress is made in science by taking testable ideas and trying to use them until they are proved wrong,” he said.
Thursday, August 11, 2011
Thursday, July 7, 2011
Image of the Day: Saturn Agonistes --1.5-Billion Square-Mile Storm as Wide as Earth
From Daily Galaxy Blog
These false-color images from NASA's Cassini spacecraft chronicle a day in the life of a huge storm that developed from a small spot that appeared 12 weeks earlier in Saturn's northern mid-latitudes. It was the largest and most intense observed on Saturn by NASA’s Voyager or Cassini spacecraft. As seen in these Cassini images, the storm encircles the planet - whose circumference at these latitudes is 186,000 miles (300,000 kilometers). From north to south, it covers a distance of about 9,000 miles (15,000 kilometers), which is one-third of the way around the Earth.
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The storm encompasses an area of 1.5 billion square miles (4 billion square kilometers), or eight times the surface area of Earth. This storm is about 500 times the area of the biggest of the southern hemisphere storms observed by Cassini.
The highest clouds in the image are probably around 100 millibars pressure, or 60 miles (100 kilometers) above the regular undisturbed clouds. These false colors show clouds at different altitudes. Clouds that appear blue here are the highest and are semitransparent, or optically thin. Those that are yellow and white are optically thick clouds at high altitudes. Those shown green are intermediate clouds. Red and brown colors are clouds at low altitude unobscured by high clouds, and the deep blue color is a thin haze with no clouds below. The base of the clouds, where lightning is generated, is probably in the water cloud layer of Saturn's atmosphere. The storm clouds are likely made out of water ice covered by crystallized ammonia.
Taken about 11 hours -- or one Saturn day -- apart, the two mosaics below consist of 84 images each. The mosaic in the middle was taken earlier than the mosaic at the bottom. Both mosaics were captured on Feb. 26, 2011, and each of the two batches of images was taken over about 4.5 hours.
The images were taken with the Cassini spacecraft narrow-angle camera using a combination of spectral filters sensitive to wavelengths of near-infrared light, acquired at a distance of approximately 1.5 million miles (2.4 million kilometers) from Saturn and at a sun-Saturn-spacecraft angle (phase angle) of 62 degrees. Both the top and bottom images are simple cylindrical map projections, defined such that a square pixel subtends equal intervals of latitude and longitude.
Pia12826-640
These false-color images from NASA's Cassini spacecraft chronicle a day in the life of a huge storm that developed from a small spot that appeared 12 weeks earlier in Saturn's northern mid-latitudes. It was the largest and most intense observed on Saturn by NASA’s Voyager or Cassini spacecraft. As seen in these Cassini images, the storm encircles the planet - whose circumference at these latitudes is 186,000 miles (300,000 kilometers). From north to south, it covers a distance of about 9,000 miles (15,000 kilometers), which is one-third of the way around the Earth.
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Powered by Intel Xeon Processors HPC Services When You Need Them
www.PenguinComputing.com
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Advanced image processing software for aerial & satellite images. Demo
www.pcigeomatics.com
The storm encompasses an area of 1.5 billion square miles (4 billion square kilometers), or eight times the surface area of Earth. This storm is about 500 times the area of the biggest of the southern hemisphere storms observed by Cassini.
The highest clouds in the image are probably around 100 millibars pressure, or 60 miles (100 kilometers) above the regular undisturbed clouds. These false colors show clouds at different altitudes. Clouds that appear blue here are the highest and are semitransparent, or optically thin. Those that are yellow and white are optically thick clouds at high altitudes. Those shown green are intermediate clouds. Red and brown colors are clouds at low altitude unobscured by high clouds, and the deep blue color is a thin haze with no clouds below. The base of the clouds, where lightning is generated, is probably in the water cloud layer of Saturn's atmosphere. The storm clouds are likely made out of water ice covered by crystallized ammonia.
Taken about 11 hours -- or one Saturn day -- apart, the two mosaics below consist of 84 images each. The mosaic in the middle was taken earlier than the mosaic at the bottom. Both mosaics were captured on Feb. 26, 2011, and each of the two batches of images was taken over about 4.5 hours.
The images were taken with the Cassini spacecraft narrow-angle camera using a combination of spectral filters sensitive to wavelengths of near-infrared light, acquired at a distance of approximately 1.5 million miles (2.4 million kilometers) from Saturn and at a sun-Saturn-spacecraft angle (phase angle) of 62 degrees. Both the top and bottom images are simple cylindrical map projections, defined such that a square pixel subtends equal intervals of latitude and longitude.
Pia12826-640
Monday, May 16, 2011
Flippin' Planets from Life Unbounded blog
http://lifeunbounded.blogspot.com/2011/05/flippin-planets.html
A year ago it started to become clear that a significant number of exoplanetary systems harbored retrograde worlds. These planets are seen on small orbits that have the opposite sense to the spins of the stars that host them. This is a peculiar and puzzling arrangement. We've all been brought up to think of planets and stars forming out of the same proto-stellar disk of material and that angular momentum is an almost sacrosanct quantity - can't fiddle around with that. Getting planets to go in the opposite direction is quite unsettling.
Clearly the universe is having none of that silly narrow-minded thinking. However, the question has been how to produce these retrograde worlds; hot Jupiters zipping the "wrong" way around their parent stars in closely circular orbits. A new paper by Naoz and colleagues presents some intriguing and thorough calculations about a couple of phenomena that could do the trick.
They consider pairs of large, gas giant sized, planets that start out in decently large prograde orbits. For example, the inner planet may orbit at 6 astronomical units (AU) from the star, the outer planet at about 60 AU. The trick is to follow what happens if those initial orbits are highly misaligned. In other words if the orbital planes of the two planets are more than 50 degrees inclined with respect to each other. In this type of configuration long term gravitational nudging between the planets - particularly the outer one on the inner one - can result in severe changes in the ellipticity or eccentricity of the inner planet's orbit, as well as its orientation. Over a span of a few hundred thousand years the orbit can not only shift from being nearly circular to being nearly "needle like" (highly elliptical) but its orientation can change dramatically. In the most extreme instances it can quite literally flip, shifting all the way through a 90 degree inclination to more than 90 degrees - in effect going retrograde.
This flip can occur during an eccentricity spike, which I think gives us some physical insight to what happens. At the far point (apastron) of a super high eccentricity orbit the planet is going to be almost hanging in space, slowing to a near standstill before plunging back star-wards. If already on a highly inclined orbit (close to that 90 degrees) then all it will take is a little tug from the outer planet in the right direction to flip the orbit over. It's a bit like that moment of indecision teetering at the top of a snowy hill with skis attached to feet. Left to take the piste, right to go to the bar.
At the same time, an extremely elliptical orbit will bring the planet zooming in from several AU to mere tenths of an AU from the star as the planet screeches through its periastron approach. Naoz et al have computed the strength of star-planet tidal forces and the associated energy dissipation and show that the inner planet can be yanked into a tight circular orbit around the star in an incredibly brief period. A little too close to the honey pot and you get trapped. Once this happens the inner planet is totally decoupled from the outer planet, which simply cannot get its sticky gravitational mitts on the inner world any more. The end result is a close orbiting retrograde hot Jupiter.
Remarkably Naoz et al.'s models even seem to produce about the right fraction of systems in which this will happen. The only hitch is how to set up the initial configuration of planets, particularly with the outer planet on such a large orbit and with such a large mis-alignment between their orbital planes. Luckily an earlier epoch of strong planet-planet gravitational scattering from within the zone of planet formation might just do the trick.
Planetary systems are just so incredibly diverse. And, once again, we find ourselves gazing at our own system and wondering just how far we can or should take the Copernican Principle. This boring little solar system of ours may yet turn out to be a little on the special side.
POSTED BY CALEB SCHARF
A year ago it started to become clear that a significant number of exoplanetary systems harbored retrograde worlds. These planets are seen on small orbits that have the opposite sense to the spins of the stars that host them. This is a peculiar and puzzling arrangement. We've all been brought up to think of planets and stars forming out of the same proto-stellar disk of material and that angular momentum is an almost sacrosanct quantity - can't fiddle around with that. Getting planets to go in the opposite direction is quite unsettling.
Clearly the universe is having none of that silly narrow-minded thinking. However, the question has been how to produce these retrograde worlds; hot Jupiters zipping the "wrong" way around their parent stars in closely circular orbits. A new paper by Naoz and colleagues presents some intriguing and thorough calculations about a couple of phenomena that could do the trick.
They consider pairs of large, gas giant sized, planets that start out in decently large prograde orbits. For example, the inner planet may orbit at 6 astronomical units (AU) from the star, the outer planet at about 60 AU. The trick is to follow what happens if those initial orbits are highly misaligned. In other words if the orbital planes of the two planets are more than 50 degrees inclined with respect to each other. In this type of configuration long term gravitational nudging between the planets - particularly the outer one on the inner one - can result in severe changes in the ellipticity or eccentricity of the inner planet's orbit, as well as its orientation. Over a span of a few hundred thousand years the orbit can not only shift from being nearly circular to being nearly "needle like" (highly elliptical) but its orientation can change dramatically. In the most extreme instances it can quite literally flip, shifting all the way through a 90 degree inclination to more than 90 degrees - in effect going retrograde.
This flip can occur during an eccentricity spike, which I think gives us some physical insight to what happens. At the far point (apastron) of a super high eccentricity orbit the planet is going to be almost hanging in space, slowing to a near standstill before plunging back star-wards. If already on a highly inclined orbit (close to that 90 degrees) then all it will take is a little tug from the outer planet in the right direction to flip the orbit over. It's a bit like that moment of indecision teetering at the top of a snowy hill with skis attached to feet. Left to take the piste, right to go to the bar.
At the same time, an extremely elliptical orbit will bring the planet zooming in from several AU to mere tenths of an AU from the star as the planet screeches through its periastron approach. Naoz et al have computed the strength of star-planet tidal forces and the associated energy dissipation and show that the inner planet can be yanked into a tight circular orbit around the star in an incredibly brief period. A little too close to the honey pot and you get trapped. Once this happens the inner planet is totally decoupled from the outer planet, which simply cannot get its sticky gravitational mitts on the inner world any more. The end result is a close orbiting retrograde hot Jupiter.
Remarkably Naoz et al.'s models even seem to produce about the right fraction of systems in which this will happen. The only hitch is how to set up the initial configuration of planets, particularly with the outer planet on such a large orbit and with such a large mis-alignment between their orbital planes. Luckily an earlier epoch of strong planet-planet gravitational scattering from within the zone of planet formation might just do the trick.
Planetary systems are just so incredibly diverse. And, once again, we find ourselves gazing at our own system and wondering just how far we can or should take the Copernican Principle. This boring little solar system of ours may yet turn out to be a little on the special side.
POSTED BY CALEB SCHARF
Tuesday, March 22, 2011
The Universe is expanding at 73.8 +/- 2.4 km/sec/megaparsec! So there.
http://blogs.discovermagazine.com/badastronomy/2011/03/22/the-universe-is-expanding-at-73-8-2-4-kmsecmegaparsec-so-there/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+BadAstronomyBlog+%28Bad+Astronomy%29
In 1998, two teams of astronomers independently reported amazing and bizarre news: the Universal expansion known for decades was not slowing down as expected, but was speeding up. Something was accelerating the Universe.
Since then, the existence of this something was fiercely debated, but time after time it fought with and overcame objections. Almost all professional astronomers now accept it’s real, but we still don’t know what the heck is causing it. So scientists keep going back to the telescopes and try to figure it out.
[Click to galactinate, or grab the cosmic 3500 x 4000 pixel browser bruiser.]
This gorgeous image is of the nearby spiral galaxy NGC 5584, where of course "nearby" to an astronomer means 72 million light years. This galaxy is loaded with a specific type of variable star — called Cepheids — which are very important: the way they change their brightness depends on how luminous they are. Measure the change, and you measure the luminosity, and if you measure how bright they appear in the sky you get their distance. It’s a bit like judging how far away a car is by gauging how bright its headlights are. Except in this case astronomers use Hubble instead of their eyes. It’s a tad more accurate.
It so happens that in 2007, NGC 5584 was the host of a Type Ia supernova, the Golden Standard of distance indicators. These are so bright they can be seen clear across the Universe! By knowing the distance to the one in NGC 5584, we can then use that to get the distances to supernovae much, much farther away.
It’s a bootstrappy way of measuring the cosmic distance scale.
But it appears to work. By measuring the Cepheids in eight galaxies that also hosted Type 1a supernovae, astronomers (led by my old pal Adam Riess; we were grad students together when he cracked the Type 1a code that led to the discovery of the universal acceleration — which will win him the Nobel one day, I’d wager) were able to hone the distance bootstrap even better.
And now, by measuring first the Cepheids and then using them to determine the distance to far-flung supernovae, they have nailed down just how fast the Universe is expanding: 73.8 (plus or minus 2.4) km/sec/megaparsec.
OK, so what does that mean?
We see galaxies rushing away from us. Moreover, the farther away they are, the faster they appear to be moving. The rate of that expansion is what was measured. If you find a galaxy 1 megaparsec away (about 3.26 million light years), the expansion of space would carry it along at 73.8 km/sec (fast enough to cross the United States in about one minute!). A galaxy 2 megaparsecs away would be traveling away at 147.6 km/sec, and so on*.
The last time this was measured accurately, the speed was seen to be 74.2 +/- 3.6 km/sec/mpc. Note the uncertainty; both the old and new measurements overlap to within their uncertainty (which is good!), but the new one has a smaller uncertainty. In other words it’s most likely more accurate.
By knowing this number so well, it allows better understanding of how the Universe is behaving. It also means astronomers can study just how much the Universe deviates from this constant rate at large distances due to the acceleration. And that in turn allows us to throw out some ideas for what dark energy is, and entertain notions of what it might be. For example, one idea was that instead of dark energy accelerating the Universe, it was an illusion due to our region in the local Universe being unusually underdense — that would make it look like distant galaxies are receding faster than expected. However, the precision of the new measurement rules this out; the value needed by the void model would have to be much lower. So right away we know that this explanation doesn’t work, and the idea of dark energy survives another battle.
So that number of 73.8 +/- 2.4 km/sec/mpc may sound arcane and weird to you, but it is in fact the key to understanding the Universe itself. It’s amazing that so much can ride on one number… but that’s the Universe for you.
* In reality it’s a little more complicated than that. Due to gravity of galaxies and clusters, the rate of expansion doesn’t really kick in until you get out to a distance of a handful of megaparsecs. But the concept is the same.
Tuesday, March 10, 2009
Pseudosciences: the pseudoscience of sexual re.orientation
There's the pseudoscience of Astrology (I'm Cassiopeia with ascendant Quaoar), of "paranormal" studies (can you tell me WHY there aren't more telepaths or telekinetic people? After all, it would have meant a real survival advantage) of "PAST LIVES RECALLING" (I'm the reincarnation of Queen Hashepsuth, I swear!)
and there's
The pseudoscience of Sexual re-orientation
http://ahotcupofjoe.wordpress.com/2006/09/12/the-pseudoscience-of-religious-based-sexual-re-orientation/
Several religious organizations exist that claim to offer the service of “re-orientating” homosexuals back to a heterosexual sexual orientation. This “therapy” variously referred to as “conversion therapy,” “reparative therapy,” or “reorientation therapy.”
Organizations that claim to offer “therapy” to re-orientate homosexuals include the International Healing Foundation (IHF), Parents and Friends of Ex-Gays (PFOX), National Association for Research and Therapy of Homosexuals (NARTH), and Exodus International among others. One of their premises is that homosexuality is a decision that can be a habit. And, as a habit, homosexuality can be broken and gays and lesbians can be therapeutically “cured” to re-orientate them back to the “norm.”
From the IHF website, they state, “[n]o one is born with same-sex attraction; [n]o one chooses to have same-sex attraction; [c]hanging from a homosexual to a heterosexual orientation is possible!”
PFOX claims, “[n]o one is born gay. All scientific studies, including those by gay scientists, have not found any gay gene or gay brain center. Ex-gays are living proof that homosexual orientation is not fixed permanently.”
Exodus states that they “[uphold] heterosexuality as God’s creative intent for humanity, and subsequently views homosexual expression as outside of God’s will. [Exodus] cites homosexual tendencies as one of many disorders that beset fallen humanity.”
Empirical Evidence to Support the Claim of ‘Reorientation’ of Homosexuals?
Only a few studies have been conducted that even attempt to provide some empiricism with regard to the notion that gays can be ‘reorientated’ to heterosexual. Most notably was Spitzer (2003) who used self-reported informants to document at least some “minimal” change over 5 years. Pseudo-therapy groups like NARTH base much of their claims on the work of studies like Spitzer’s -and Spitzer is probably the most recent notable effort, but the pseudoscience of reparative therapy probably began with Moberly (1983), who used no study subjects at all! She based her entire book on her own opinions based on the ancient works of luminaries like Freud.
But it’s the work of Spitzer and others that NARTH would like to cite as valid reason to assume their premises are true. The primary outcome of Spitzer’s study was that, in general, some gay men and women can change their core behaviors and appear content to be heterosexual. The problem is that the very thing that a pseudoscience group like NARTH accuses gays of (pretending) is what may be happening in their ‘reorientations!’
Criticisms of ‘Reorientation’ and ‘Reparative’ Therapy of Homosexuals
The only thing that can really be said about NARTH and other reorientation groups (assuming that even some of their anecdotes are valid) is that they are successful in getting homosexuals (or bisexuals) to favor religious pretense over sexual orientation. After all: people kill for religion; die for religion; and fuck for religion. Why wouldn’t they switch genders of their sex-partners for religion?
In addition, as Carlson (2003) noted, “It may be possible that some of [Spitzer's] research participants might have a more fluid sexual orientation, such as bisexuality” (p. 427). Also, Spitzer’s investigation was heavily weighted toward highly religious Christian, Caucasian, middle-class individuals, thus ignoring the diversity of individuals who might seek conversion therapy. Overall, the research on conversion therapies is heavily weighted toward a homogeneous, predominantly White, male, Christian population. Shidlo and Schroeder’s (2002) participants were 90% male, 86% Caucasian, and of those who reported religious orientation, 89% Christian. Spitzer’s study was 97% Christian and 95% Caucasian and was predominantly middle-class and middle-aged.
Assumptions Made by re-orientation Groups like NARTH
Religious re-orientation groups assume that the causes of homosexuality are known and that homosexuality is unnatural, mentally unhealthy, and sinful and should be changed (Morrow and Beckstead 2004) Each of these is pseudoscientific when applied to the field of mental health.
Methodological problems with studies like Spitzer’s
(a) results were based on restricted, self-selected samples that represent a socially stigmatized population and thus capitalized on participants’ vested interests to manage self-impressions, promote their values and lifestyles, over report successes, and underreport failures;
(b) outcomes are ambiguous because participants’ idiosyncratic conceptualizations of sexual orientation, identity, attraction, and desire were not analyzed and research variables were not well conceptualized;
(c) some studies neglected to use fantasy and arousal to indicate sexual orientation;
(d) some results were based on therapists’ subjective impressions;
(e) comparison or control groups were not used;
(f) long-term, objective outcome results are unavailable; and
(g) dynamic factors, such as time, maturation, and contextual factors, were not analyzed to account for participants’ changes in sexuality and identity development process. Thus, the research base that supports the effectiveness of sexual reorientation is void of systematic, well-established methodologies that are needed to obtain valid scientific results (Wainberg et al. 2003 [Morrow and Beckstead 2004]).
In addition, O’Donohue and Plaud (1994) reviewed the evidence for learning and unlearning of sexual arousal responses and concluded that the empirical support for the conditioning or reconditioning of sexual arousal is weak. Barbaree, Bogaert, and Seto (1995) also concluded that substantive changes in the direction of one’s underlying sexual orientation might be difficult or impossible to achieve once established.
Tozer & Hayes (2004) further note that ‘reorientation’ therapy lacks empirical validation and also suggest that the main focus is to provide derisive messages about same-sex attractions. They found that most who seek “conversion therapy” are do so as an “expression of introjected messages about unacceptable aspects of homosexuality and an extension of one’s being in the early stages of gay or lesbian identity development.”
——————–
The “work” that groups like NARTH claim to do *is* pseudoscience since they base it on false premises and assumptions. Moreover, they use bad science and refuse to acknowledge the lack of empirical data to support their premises and assumptions. In doing so, they wrap their supernatural beliefs in a thin veil of “scientific-sounding” terminology and misquoted research of others.
If gays want to pretend to be heterosexual to fit into their other social groups and cults, I’ve no problem with that. That’s their prerogative. The response here, in this post, is to refute the unsubstantiated claims of NARTH et al, which are based on false premises and assumptions - an endeavor that can be called fraud.
What’s the Real Motivation for Re-Orientation?
Perhaps there are gays that are dissatisfied with their sexual orientation. I’m sure there are. Another flaw in Spitzer’s research, which I have not discussed yet, is that it doesn’t fully take into consideration the dissatisfaction that may exist in his study group because of the stigma and pressure that may be applied by their social group. In short, they may be victims of gay-bashing, homophobic bigots who belittle homosexuality because of religious superstitions with hate-filled rhetoric. In Shidlo and Schroeder’s sample (2002), they found that of the gays that went through so-called ‘reorientation therapy’ did so because of homophobic attitudes toward them. Among their sample were individuals who had initially sought therapy for depression and anxiety only to be instructed to attend ‘conversion therapy.’
Some participants were motivated to pursue treatment with the hope of saving their heterosexual marriage and keeping their children. Others entered conversion therapy through force and coercion. For example, some students in religious universities were told that noncompliance with the mandated treatment would be followed by academic expulsion or the termination of financial aid. One participant reported the following:
I am being forced to be in therapy [by a large religious university]. I sit there and agree with what he [the therapist] has to say to avoid confrontation. He is pushing me to marry a woman. My goal is basically just to graduate. (Shidlo and Schroeder 2002).
Of the 87% of the sample they studied (a full 176 individuals) reported that they failed to ‘convert’ back to a heterosexual identity. Only 13% perceived themselves as successful. Of that 13% (26 individuals), 6 refused to put a self-label on their sexual identity and 3 of this 6 were celibate!
This is the only study that I know of that bothers to attempt a quantitative look at so-called ‘conversion therapy.’ Clearly, such ‘therapies’ are problematic. Not only do psuedoscientific groups like NARTH fail to consider such data or discuss it with their consumers, but they flat out refuse to conduct any meaningful research of their own. Instead, they rely on one of the hallmark indicators of pseudoscience: anecdotal testimony.
Shidlo & Schroeder conclude with:
We found evidence that many consumers of failed sexual orientation therapies experienced them as harmful. Areas of perceived psychological harm included depression, suicidality, and self-esteem. In the case of aversive conditioning and covert sensitization, harm included intrusive flashback-like negative imagery that was associated with serious long-term sexual dysfunction. Areas of perceived social harm included impairment in intimate and nonintimate relationships. Some religious participants also reported experiencing spiritual harm as a result of religious therapy.
We found that some participants also reported feeling helped. For a minority (4%), conversion therapy provided help in shifting their sexual orientation. Others (9%) found help in HBM techniques and were content with being celibate or else accepted an ongoing struggle to contain their same-sex desire. Participants also reported other therapeutic benefits, including an increased sense of belonging, improved insight, improved self-esteem, improved communication skills, and relief from talking about sexuality for the first time. Surprisingly, some participants who failed to change reported that their failure had been a needed proof, which freed them to embrace their gay/lesbian identity with less guilt.
In the very same issue (October 2003) of Archives of Sexual Behavior in which Spitzer published, there were many sound criticisms of his work along with some support. In addition, Spitzer himself said (2003):
Are the participants’ self-reports of change, by-and large, credible or are they biased because of self-deception, exaggeration, or even lying? This critical issue deserves careful examination in light of the participants’ and their spouses’ high motivation to provide data supporting the value of efforts to change sexual orientation.
The only thing Spitzer demonstrated is that, given sufficient motivation, gays can at least pretend to change their sexual orientation. In his methodology, Spitzer reveals that his sample included individuals who self-reported with at least a rank of 60 with 0 being completely heterosexual and 100 being completely homosexual.
What!? 60!? So his cut-off for “gay” is someone who thinks they’re attracted to the same sex more often than not? Where is the control for the anxiety driven, depressed man or woman that is simply scared of their androgenous thoughts and occasional curiosity about the same sex? Why didn’t Spitzer study so-called ex-gays who were once completely homosexual?
Finally, the homosexual re-orientation movement was discredited by the American Psychological Association (APA) on August 11, 2006:
For over three decades the consensus of the mental health community has been that homosexuality is not an illness and therefore not in need of a cure. The APA’s concern about the positions espoused by NARTH and so-called conversation therapy is that they are not supported by the science. There is simply no sufficiently scientifically sound evidence that sexual orientation can be changed. Our further concern is that the positions espoused by NARTH and Focus on the Family create an environment in which prejudice and discrimination can flourish.
Source
References:
Barbaree, H. E., Bogaert, A. F., & Seto, M. C. (1995). Sexual reorientation therapy for pedophiles: Practices and controversies. In L. D. & R. D. McAnulty (Eds.), The psychology of sexual orientation, behavior, and identity: A handbookGreenwood.
Carlson, H. M. (2003). A methodological critique of Spitzer’s research on reparative therapy. Archives of Sexual Behavior, 32, 425-427.
Haldeman, D. C. (2001). Therapeutic antidotes: Helping gay and bisexualmen recover from conversion therapies. Journal of Gay and Lesbian Psychotherapy, 5(3-4), 117-130.
Moberly, Elizabeth (1983) Homosexuality: A New Christian Ethic. Cambridge: James Clarke Company. (pp. 357-383).Westport, CT:
Morrow, Susan L.; Beckstead, A. Lee (2004). Conversion Therapies for Same-Sex Attracted Clients in Religious Conflict: Context, Predisposing Factors, Experiences, and Implications for Therapy. The Counseling Psychologist, 32 (5), 641-650.
O’Donohue, W., & Plaud, J. J. (1994). The conditioning of human sexual arousal. Archives of Sexual Behavior, 23, 321-344.
Shidlo, A., and Schroeder, M. (2002). Changing sexual orientation: A consumers’ report. Professional Psychology: Research and Practice, 33, 249-259.
Spitzer, R. L. (2003). Can some gay men and lesbians change their sexual orientation? 200 subjects reporting a change from homosexual to heterosexual orientation. Archives of Sexual Behavior, 32, 403-417.
Tozer, E. E. & Hayes, J. A. (2004). Why do individuals seek conversion therapy? The role of religiosity, internalized homonegativity, and identity development. The Counseling Psychologist, 32(5), 716-740.
Wainberg, M. L., Bux, B., Carballo-Dieguez, A., Dowsett, G.W., Dugan, T., Forstein, M., et al. (2003). Science and the Nuremberg Code: A question of ethics and harm. Archives of Sexual Behavior, 32, 455-457.
and there's
The pseudoscience of Sexual re-orientation
http://ahotcupofjoe.wordpress.com/2006/09/12/the-pseudoscience-of-religious-based-sexual-re-orientation/
Several religious organizations exist that claim to offer the service of “re-orientating” homosexuals back to a heterosexual sexual orientation. This “therapy” variously referred to as “conversion therapy,” “reparative therapy,” or “reorientation therapy.”
Organizations that claim to offer “therapy” to re-orientate homosexuals include the International Healing Foundation (IHF), Parents and Friends of Ex-Gays (PFOX), National Association for Research and Therapy of Homosexuals (NARTH), and Exodus International among others. One of their premises is that homosexuality is a decision that can be a habit. And, as a habit, homosexuality can be broken and gays and lesbians can be therapeutically “cured” to re-orientate them back to the “norm.”
From the IHF website, they state, “[n]o one is born with same-sex attraction; [n]o one chooses to have same-sex attraction; [c]hanging from a homosexual to a heterosexual orientation is possible!”
PFOX claims, “[n]o one is born gay. All scientific studies, including those by gay scientists, have not found any gay gene or gay brain center. Ex-gays are living proof that homosexual orientation is not fixed permanently.”
Exodus states that they “[uphold] heterosexuality as God’s creative intent for humanity, and subsequently views homosexual expression as outside of God’s will. [Exodus] cites homosexual tendencies as one of many disorders that beset fallen humanity.”
Empirical Evidence to Support the Claim of ‘Reorientation’ of Homosexuals?
Only a few studies have been conducted that even attempt to provide some empiricism with regard to the notion that gays can be ‘reorientated’ to heterosexual. Most notably was Spitzer (2003) who used self-reported informants to document at least some “minimal” change over 5 years. Pseudo-therapy groups like NARTH base much of their claims on the work of studies like Spitzer’s -and Spitzer is probably the most recent notable effort, but the pseudoscience of reparative therapy probably began with Moberly (1983), who used no study subjects at all! She based her entire book on her own opinions based on the ancient works of luminaries like Freud.
But it’s the work of Spitzer and others that NARTH would like to cite as valid reason to assume their premises are true. The primary outcome of Spitzer’s study was that, in general, some gay men and women can change their core behaviors and appear content to be heterosexual. The problem is that the very thing that a pseudoscience group like NARTH accuses gays of (pretending) is what may be happening in their ‘reorientations!’
Criticisms of ‘Reorientation’ and ‘Reparative’ Therapy of Homosexuals
The only thing that can really be said about NARTH and other reorientation groups (assuming that even some of their anecdotes are valid) is that they are successful in getting homosexuals (or bisexuals) to favor religious pretense over sexual orientation. After all: people kill for religion; die for religion; and fuck for religion. Why wouldn’t they switch genders of their sex-partners for religion?
In addition, as Carlson (2003) noted, “It may be possible that some of [Spitzer's] research participants might have a more fluid sexual orientation, such as bisexuality” (p. 427). Also, Spitzer’s investigation was heavily weighted toward highly religious Christian, Caucasian, middle-class individuals, thus ignoring the diversity of individuals who might seek conversion therapy. Overall, the research on conversion therapies is heavily weighted toward a homogeneous, predominantly White, male, Christian population. Shidlo and Schroeder’s (2002) participants were 90% male, 86% Caucasian, and of those who reported religious orientation, 89% Christian. Spitzer’s study was 97% Christian and 95% Caucasian and was predominantly middle-class and middle-aged.
Assumptions Made by re-orientation Groups like NARTH
Religious re-orientation groups assume that the causes of homosexuality are known and that homosexuality is unnatural, mentally unhealthy, and sinful and should be changed (Morrow and Beckstead 2004) Each of these is pseudoscientific when applied to the field of mental health.
Methodological problems with studies like Spitzer’s
(a) results were based on restricted, self-selected samples that represent a socially stigmatized population and thus capitalized on participants’ vested interests to manage self-impressions, promote their values and lifestyles, over report successes, and underreport failures;
(b) outcomes are ambiguous because participants’ idiosyncratic conceptualizations of sexual orientation, identity, attraction, and desire were not analyzed and research variables were not well conceptualized;
(c) some studies neglected to use fantasy and arousal to indicate sexual orientation;
(d) some results were based on therapists’ subjective impressions;
(e) comparison or control groups were not used;
(f) long-term, objective outcome results are unavailable; and
(g) dynamic factors, such as time, maturation, and contextual factors, were not analyzed to account for participants’ changes in sexuality and identity development process. Thus, the research base that supports the effectiveness of sexual reorientation is void of systematic, well-established methodologies that are needed to obtain valid scientific results (Wainberg et al. 2003 [Morrow and Beckstead 2004]).
In addition, O’Donohue and Plaud (1994) reviewed the evidence for learning and unlearning of sexual arousal responses and concluded that the empirical support for the conditioning or reconditioning of sexual arousal is weak. Barbaree, Bogaert, and Seto (1995) also concluded that substantive changes in the direction of one’s underlying sexual orientation might be difficult or impossible to achieve once established.
Tozer & Hayes (2004) further note that ‘reorientation’ therapy lacks empirical validation and also suggest that the main focus is to provide derisive messages about same-sex attractions. They found that most who seek “conversion therapy” are do so as an “expression of introjected messages about unacceptable aspects of homosexuality and an extension of one’s being in the early stages of gay or lesbian identity development.”
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The “work” that groups like NARTH claim to do *is* pseudoscience since they base it on false premises and assumptions. Moreover, they use bad science and refuse to acknowledge the lack of empirical data to support their premises and assumptions. In doing so, they wrap their supernatural beliefs in a thin veil of “scientific-sounding” terminology and misquoted research of others.
If gays want to pretend to be heterosexual to fit into their other social groups and cults, I’ve no problem with that. That’s their prerogative. The response here, in this post, is to refute the unsubstantiated claims of NARTH et al, which are based on false premises and assumptions - an endeavor that can be called fraud.
What’s the Real Motivation for Re-Orientation?
Perhaps there are gays that are dissatisfied with their sexual orientation. I’m sure there are. Another flaw in Spitzer’s research, which I have not discussed yet, is that it doesn’t fully take into consideration the dissatisfaction that may exist in his study group because of the stigma and pressure that may be applied by their social group. In short, they may be victims of gay-bashing, homophobic bigots who belittle homosexuality because of religious superstitions with hate-filled rhetoric. In Shidlo and Schroeder’s sample (2002), they found that of the gays that went through so-called ‘reorientation therapy’ did so because of homophobic attitudes toward them. Among their sample were individuals who had initially sought therapy for depression and anxiety only to be instructed to attend ‘conversion therapy.’
Some participants were motivated to pursue treatment with the hope of saving their heterosexual marriage and keeping their children. Others entered conversion therapy through force and coercion. For example, some students in religious universities were told that noncompliance with the mandated treatment would be followed by academic expulsion or the termination of financial aid. One participant reported the following:
I am being forced to be in therapy [by a large religious university]. I sit there and agree with what he [the therapist] has to say to avoid confrontation. He is pushing me to marry a woman. My goal is basically just to graduate. (Shidlo and Schroeder 2002).
Of the 87% of the sample they studied (a full 176 individuals) reported that they failed to ‘convert’ back to a heterosexual identity. Only 13% perceived themselves as successful. Of that 13% (26 individuals), 6 refused to put a self-label on their sexual identity and 3 of this 6 were celibate!
This is the only study that I know of that bothers to attempt a quantitative look at so-called ‘conversion therapy.’ Clearly, such ‘therapies’ are problematic. Not only do psuedoscientific groups like NARTH fail to consider such data or discuss it with their consumers, but they flat out refuse to conduct any meaningful research of their own. Instead, they rely on one of the hallmark indicators of pseudoscience: anecdotal testimony.
Shidlo & Schroeder conclude with:
We found evidence that many consumers of failed sexual orientation therapies experienced them as harmful. Areas of perceived psychological harm included depression, suicidality, and self-esteem. In the case of aversive conditioning and covert sensitization, harm included intrusive flashback-like negative imagery that was associated with serious long-term sexual dysfunction. Areas of perceived social harm included impairment in intimate and nonintimate relationships. Some religious participants also reported experiencing spiritual harm as a result of religious therapy.
We found that some participants also reported feeling helped. For a minority (4%), conversion therapy provided help in shifting their sexual orientation. Others (9%) found help in HBM techniques and were content with being celibate or else accepted an ongoing struggle to contain their same-sex desire. Participants also reported other therapeutic benefits, including an increased sense of belonging, improved insight, improved self-esteem, improved communication skills, and relief from talking about sexuality for the first time. Surprisingly, some participants who failed to change reported that their failure had been a needed proof, which freed them to embrace their gay/lesbian identity with less guilt.
In the very same issue (October 2003) of Archives of Sexual Behavior in which Spitzer published, there were many sound criticisms of his work along with some support. In addition, Spitzer himself said (2003):
Are the participants’ self-reports of change, by-and large, credible or are they biased because of self-deception, exaggeration, or even lying? This critical issue deserves careful examination in light of the participants’ and their spouses’ high motivation to provide data supporting the value of efforts to change sexual orientation.
The only thing Spitzer demonstrated is that, given sufficient motivation, gays can at least pretend to change their sexual orientation. In his methodology, Spitzer reveals that his sample included individuals who self-reported with at least a rank of 60 with 0 being completely heterosexual and 100 being completely homosexual.
What!? 60!? So his cut-off for “gay” is someone who thinks they’re attracted to the same sex more often than not? Where is the control for the anxiety driven, depressed man or woman that is simply scared of their androgenous thoughts and occasional curiosity about the same sex? Why didn’t Spitzer study so-called ex-gays who were once completely homosexual?
Finally, the homosexual re-orientation movement was discredited by the American Psychological Association (APA) on August 11, 2006:
For over three decades the consensus of the mental health community has been that homosexuality is not an illness and therefore not in need of a cure. The APA’s concern about the positions espoused by NARTH and so-called conversation therapy is that they are not supported by the science. There is simply no sufficiently scientifically sound evidence that sexual orientation can be changed. Our further concern is that the positions espoused by NARTH and Focus on the Family create an environment in which prejudice and discrimination can flourish.
Source
References:
Barbaree, H. E., Bogaert, A. F., & Seto, M. C. (1995). Sexual reorientation therapy for pedophiles: Practices and controversies. In L. D. & R. D. McAnulty (Eds.), The psychology of sexual orientation, behavior, and identity: A handbookGreenwood.
Carlson, H. M. (2003). A methodological critique of Spitzer’s research on reparative therapy. Archives of Sexual Behavior, 32, 425-427.
Haldeman, D. C. (2001). Therapeutic antidotes: Helping gay and bisexualmen recover from conversion therapies. Journal of Gay and Lesbian Psychotherapy, 5(3-4), 117-130.
Moberly, Elizabeth (1983) Homosexuality: A New Christian Ethic. Cambridge: James Clarke Company. (pp. 357-383).Westport, CT:
Morrow, Susan L.; Beckstead, A. Lee (2004). Conversion Therapies for Same-Sex Attracted Clients in Religious Conflict: Context, Predisposing Factors, Experiences, and Implications for Therapy. The Counseling Psychologist, 32 (5), 641-650.
O’Donohue, W., & Plaud, J. J. (1994). The conditioning of human sexual arousal. Archives of Sexual Behavior, 23, 321-344.
Shidlo, A., and Schroeder, M. (2002). Changing sexual orientation: A consumers’ report. Professional Psychology: Research and Practice, 33, 249-259.
Spitzer, R. L. (2003). Can some gay men and lesbians change their sexual orientation? 200 subjects reporting a change from homosexual to heterosexual orientation. Archives of Sexual Behavior, 32, 403-417.
Tozer, E. E. & Hayes, J. A. (2004). Why do individuals seek conversion therapy? The role of religiosity, internalized homonegativity, and identity development. The Counseling Psychologist, 32(5), 716-740.
Wainberg, M. L., Bux, B., Carballo-Dieguez, A., Dowsett, G.W., Dugan, T., Forstein, M., et al. (2003). Science and the Nuremberg Code: A question of ethics and harm. Archives of Sexual Behavior, 32, 455-457.
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