Thursday, September 6, 2007
Tuesday, September 4, 2007
[Astronomy and Telescope India] Explaining Dark Energy and Universe Acceleration
21 - The 2006 Shaw Prize in Astronomy and the 2007 Gruber Cosmology Prize were awarded for the amazing discovery of the accelerating expansion of the universe, but the cause of this phenomenon is still considered a mystery. To date, the following is the only plausible explanation for this mystery that has been publicly proposed.
Observed galaxy clusters are rushing apart faster and faster thereby accelerating the expansion of the universe. If the galaxies and the stars were similarly rushing apart faster and faster, then the hypothetical concept of "dark energy" pervading all space might be valid. But this isn't the case.
The galaxy clusters are indeed rushing apart as their separation velocities are accelerating, but the separation velocities of the galaxies and of the stars are not known to be accelerating. If the hypothetical pervasive "dark energy" actually existed, all three of these types of celestial bodies would be subject to it and the galaxy clusters, galaxies, and stars, not just one of them, would be rushing apart faster and faster.
In an expanding universe, galaxy clusters are moving away from one another. When the galaxy-cluster separation velocities speed up, as in our universe, the universe is in an accelerating expansion mode. Since 1998, this has been attributed to "dark energy", called "the most profound mystery in all of science" by University of Chicago cosmologist Michael Turner.
In that year, two completed studies led by Saul Perlmutter, of the Lawrence Berkeley National Laboratory and by Brian Schmidt of the Australian National University, of astronomical events involving exploding stars (supernovae) led to the award-winning discovery that the expansion of the universe was accelerating. The cause was attributed to "dark energy", a hypothetical form of energy assumed to permeate all space and to have negative pressure resulting in a repulsive gravitational force.
In 2001, Michael Turner essentially removed the word "all" from this definition when he wrote, "Dark energy by its very nature is diffuse and a low-energy phenomenon. It probably cannot be produced at accelerators; it isn't found in galaxies or even clusters of galaxies."
Astro-cosmology author Jerome Drexler has based his accelerating-expansion theory upon Michael Turner's statement, "it isn't found in galaxies or even clusters of galaxies." That is, Drexler's criteria for the mysterious repulsive force are: it pushes galaxy clusters apart, but it doesn't push stars apart and it doesn't push galaxies apart.
Drexler's theory explains that, in a first phase, galaxy clusters, filled with relativistic dark matter protons, are separating from each other with velocities proportional to their separations. Then, when galaxy clusters' relativistic dark matter protons erode relativistic mass at a high-enough rate, via radiation of extreme ultraviolet (EUV) or soft X-ray photons, the separation velocities of galaxy clusters will increase owing to a reduction in the gravitational attraction between them and owing to the Law of Conservation of Linear Momentum.
This increases cluster-to-cluster separation and further lowers the gravitational attraction between galaxy clusters, thereby further accelerating both galaxy cluster separation and the expansion of the universe. The force causing this accelerating separation of galaxy clusters is essentially only between galaxy clusters, not between galaxies, or between stars, as will be explained. After a five-year analysis and interpretation of astronomical data, Drexler has concluded that dark matter is comprised of relativistic protons, with a relativistic mass up to ten billion times the mass of a proton at rest, accompanied by relativistic helium nuclei in a ratio of 12 to 1. This is compatible with a recent scientific paper, "Missing Mass in Collisional Debris from Galaxies" in the May 25, 2007 issue of Science Magazine, which concludes, "The most natural [dark matter] candidate is molecular hydrogen in some hard-to-trace form." (Note that relativistic protons are "hydrogen in some hard-to-trace form.")
The extragalactic magnetic fields cause the charged dark matter protons to remain within galaxy clusters and to emit radiant energy in the form of extreme ultraviolet (EUV), soft X-ray, or infrared photons.
This is called synchrotron radiation, which is photon emission from a proton in its direction of motion. Since protons in a galaxy cluster are orbiting groups of galaxies, such radiation from a galaxy cluster should be relatively isotropic with respect to the galaxy cluster's linear motion. Such dark matter protons in galaxy clusters would be emitting relatively high power synchrotron radiation, causing them to lose kinetic energy and relativistic mass continuously, as if their relativistic mass were eroding.
How can synchrotron radiation push galaxy clusters apart without pushing galaxies apart? First of all, the power of synchrotron radiation from a relativistic proton moving across a magnetic field is directly proportional to the square of the proton's energy. Secondly, the energies estimated for the dark matter protons orbiting groups of galaxies within a typical galaxy cluster would be about 30 times higher than the energies calculated for the dark matter halo protons orbiting a single spiral galaxy, such as the Milky Way.
Thus, the synchrotron radiation power per proton and relativistic mass loss rate per proton are about 900 times greater for pushing galaxy clusters apart than for pushing galaxies apart.
Another question is why the accelerating expansion did not begin until about six billion years ago, as reported by astronomers. Perhaps prior to that time the much smaller separations of galaxy clusters led to a very much higher gravitational attraction that minimized the synchrotron-radiation repulsive effect. Note that in the past 13.4 billion years galaxy-cluster separation distances have grown linearly by a factor of the order of 1000.
Drexler's theories for dark matter and accelerating expansion could be tested by NASA in 2008 when the Hubble telescope's UV sensitivity is increased by a factor of 30. The detection of EUV/UV photons or soft X-rays from dark matter of our Local Group galaxy cluster, along with no such emission from the Milky Way's halo could confirm or support Drexler's theories. This is because calculations indicate that synchrotron radiation from the Milky Way's dark matter halo should have a broad peak in the infrared while synchrotron radiation from the other dark matter particles in galaxy clusters should have a broad peak in the EUV or soft X-ray region.
Drexler authored "Comprehending and Decoding the Cosmos," published May 2006 and "How Dark Matter Created Dark Energy and the Sun," published December 2003, which explain and support the relativistic dark matter theory and cosmology. They are sold by Universal Publishers, Amazon.com, Barnes&Noble.com and other booksellers. The 2006 book is now available in over 35 astronomy or physics university libraries or astronomical observatory libraries around the world.
ABOUT THE AUTHOR: Jerome Drexler is a former NJIT Research Professor in physics at New Jersey Institute of Technology, founder, former Chairman and chief scientist of LaserCard Corp. (Nasdaq: LCRD), and former Member of the Technical Staff of Bell Laboratories. He has been granted 76 U.S. patents, honorary Doctor of Science degrees from NJIT and Upsala College, a degree of Honorary Fellow of the Technion, an Alfred P.Sloan Fellowship at Stanford University, a three-year Bell Labs graduate study fellowship, the 1990 "Inventor of the Year Award" for Silicon Valley, recognition as the inventor of the familiar "Laser Optical Storage System," and membership on the NJIT Board of Overseers.
newsblaze
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Posted By AstronomytelescopeIndia to Astronomy and Telescope India at 9/04/2007 09:19:00 AM
Observed galaxy clusters are rushing apart faster and faster thereby accelerating the expansion of the universe. If the galaxies and the stars were similarly rushing apart faster and faster, then the hypothetical concept of "dark energy" pervading all space might be valid. But this isn't the case.
The galaxy clusters are indeed rushing apart as their separation velocities are accelerating, but the separation velocities of the galaxies and of the stars are not known to be accelerating. If the hypothetical pervasive "dark energy" actually existed, all three of these types of celestial bodies would be subject to it and the galaxy clusters, galaxies, and stars, not just one of them, would be rushing apart faster and faster.
In an expanding universe, galaxy clusters are moving away from one another. When the galaxy-cluster separation velocities speed up, as in our universe, the universe is in an accelerating expansion mode. Since 1998, this has been attributed to "dark energy", called "the most profound mystery in all of science" by University of Chicago cosmologist Michael Turner.
In that year, two completed studies led by Saul Perlmutter, of the Lawrence Berkeley National Laboratory and by Brian Schmidt of the Australian National University, of astronomical events involving exploding stars (supernovae) led to the award-winning discovery that the expansion of the universe was accelerating. The cause was attributed to "dark energy", a hypothetical form of energy assumed to permeate all space and to have negative pressure resulting in a repulsive gravitational force.
In 2001, Michael Turner essentially removed the word "all" from this definition when he wrote, "Dark energy by its very nature is diffuse and a low-energy phenomenon. It probably cannot be produced at accelerators; it isn't found in galaxies or even clusters of galaxies."
Astro-cosmology author Jerome Drexler has based his accelerating-expansion theory upon Michael Turner's statement, "it isn't found in galaxies or even clusters of galaxies." That is, Drexler's criteria for the mysterious repulsive force are: it pushes galaxy clusters apart, but it doesn't push stars apart and it doesn't push galaxies apart.
Drexler's theory explains that, in a first phase, galaxy clusters, filled with relativistic dark matter protons, are separating from each other with velocities proportional to their separations. Then, when galaxy clusters' relativistic dark matter protons erode relativistic mass at a high-enough rate, via radiation of extreme ultraviolet (EUV) or soft X-ray photons, the separation velocities of galaxy clusters will increase owing to a reduction in the gravitational attraction between them and owing to the Law of Conservation of Linear Momentum.
This increases cluster-to-cluster separation and further lowers the gravitational attraction between galaxy clusters, thereby further accelerating both galaxy cluster separation and the expansion of the universe. The force causing this accelerating separation of galaxy clusters is essentially only between galaxy clusters, not between galaxies, or between stars, as will be explained. After a five-year analysis and interpretation of astronomical data, Drexler has concluded that dark matter is comprised of relativistic protons, with a relativistic mass up to ten billion times the mass of a proton at rest, accompanied by relativistic helium nuclei in a ratio of 12 to 1. This is compatible with a recent scientific paper, "Missing Mass in Collisional Debris from Galaxies" in the May 25, 2007 issue of Science Magazine, which concludes, "The most natural [dark matter] candidate is molecular hydrogen in some hard-to-trace form." (Note that relativistic protons are "hydrogen in some hard-to-trace form.")
The extragalactic magnetic fields cause the charged dark matter protons to remain within galaxy clusters and to emit radiant energy in the form of extreme ultraviolet (EUV), soft X-ray, or infrared photons.
This is called synchrotron radiation, which is photon emission from a proton in its direction of motion. Since protons in a galaxy cluster are orbiting groups of galaxies, such radiation from a galaxy cluster should be relatively isotropic with respect to the galaxy cluster's linear motion. Such dark matter protons in galaxy clusters would be emitting relatively high power synchrotron radiation, causing them to lose kinetic energy and relativistic mass continuously, as if their relativistic mass were eroding.
How can synchrotron radiation push galaxy clusters apart without pushing galaxies apart? First of all, the power of synchrotron radiation from a relativistic proton moving across a magnetic field is directly proportional to the square of the proton's energy. Secondly, the energies estimated for the dark matter protons orbiting groups of galaxies within a typical galaxy cluster would be about 30 times higher than the energies calculated for the dark matter halo protons orbiting a single spiral galaxy, such as the Milky Way.
Thus, the synchrotron radiation power per proton and relativistic mass loss rate per proton are about 900 times greater for pushing galaxy clusters apart than for pushing galaxies apart.
Another question is why the accelerating expansion did not begin until about six billion years ago, as reported by astronomers. Perhaps prior to that time the much smaller separations of galaxy clusters led to a very much higher gravitational attraction that minimized the synchrotron-radiation repulsive effect. Note that in the past 13.4 billion years galaxy-cluster separation distances have grown linearly by a factor of the order of 1000.
Drexler's theories for dark matter and accelerating expansion could be tested by NASA in 2008 when the Hubble telescope's UV sensitivity is increased by a factor of 30. The detection of EUV/UV photons or soft X-rays from dark matter of our Local Group galaxy cluster, along with no such emission from the Milky Way's halo could confirm or support Drexler's theories. This is because calculations indicate that synchrotron radiation from the Milky Way's dark matter halo should have a broad peak in the infrared while synchrotron radiation from the other dark matter particles in galaxy clusters should have a broad peak in the EUV or soft X-ray region.
Drexler authored "Comprehending and Decoding the Cosmos," published May 2006 and "How Dark Matter Created Dark Energy and the Sun," published December 2003, which explain and support the relativistic dark matter theory and cosmology. They are sold by Universal Publishers, Amazon.com, Barnes&Noble.com and other booksellers. The 2006 book is now available in over 35 astronomy or physics university libraries or astronomical observatory libraries around the world.
ABOUT THE AUTHOR: Jerome Drexler is a former NJIT Research Professor in physics at New Jersey Institute of Technology, founder, former Chairman and chief scientist of LaserCard Corp. (Nasdaq: LCRD), and former Member of the Technical Staff of Bell Laboratories. He has been granted 76 U.S. patents, honorary Doctor of Science degrees from NJIT and Upsala College, a degree of Honorary Fellow of the Technion, an Alfred P.Sloan Fellowship at Stanford University, a three-year Bell Labs graduate study fellowship, the 1990 "Inventor of the Year Award" for Silicon Valley, recognition as the inventor of the familiar "Laser Optical Storage System," and membership on the NJIT Board of Overseers.
newsblaze
Tags: dark, energy, universe, acceleration, galaxies, matter, cosmology, universe, proton, milky way
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Posted By AstronomytelescopeIndia to Astronomy and Telescope India at 9/04/2007 09:19:00 AM
Sunday, September 2, 2007
[Astronomy and Telescopes India] A giant leap: Robots or astronauts?
LONDON, England (CNN) -- Can everyone be an astronomer? It certainly seems that way, especially with some of the latest tools at our fingertips, like Google Sky, which allows Internet users to navigate through a digitized map of space. But some say virtual astronomy is not just for amateurs and should also be the way forward for professional space exploration. A future of virtual astronauts, too.
The future? The James Webb Space Telescope is the successor of Hubble.
The JWST will launch in 2013, with a collecting area six times the size of Hubble's.
Bob Park, professor of physics at the University of Maryland, believes that virtual space exploration using telerobots (which humans control from the ground) is a better solution than sending astronauts, which he calls a waste of resources. "We've gone about as far as we can with manned space missions," Park says. "We could go to Mars at enormous expense but what would a human do when he got there? We can't do much locked in a space suit. There isn't much to hear except a very low rumble from the Martian wind. The only sense that would be available to us is our eyes and we can build robots with much better eyes than humans. Already, the little rovers on Mars right now can focus in on a distant mountain or a grain of sand. We can build telescopes on our robots with any sort of visual capability that we want."
To take man to Mars? Or to take us to Mars via a robot (which we are doing already)? Park says there is little dissent in the scientific community about which is better for science, although he concedes there is an element of romance lost by using robots. "Sense of adventure is the only thing going for manned space travel," Park says. "But it's time to have a grown-up attitude to adventure. If you want adventure, go bungee jumping."
Director of the United Kingdom Astronomy Technology Centre in Edinburgh, Scotland, Ian Robson agrees that the science points us away from manned space travel. "You can always achieve more by robotic missions," Robson says. "If I had the budget, I would spend it on robotic missions. But if I was a politician I would have to think again."
Certainly, the manned space mission has been what's captured the public's imagination in the past. "The cultural experience of watching the Apollo landing was so dramatic," Robson says, "but if we all switched on our television sets today to see the first person land on Mars and career around, maybe it wouldn't have such an impact."
That could be because there are so many more ways of experiencing space exploration today, like the recently launched Google Sky, described as a 'virtual telescope'. It is the latest feature from the mapping service Google Earth but instead of focusing in on our planet, Google Sky allows Internet users to turn their zoom around and explore space, with the ability to navigate around over 100 million individual stars and 200 million galaxies. "We thought we could use the same base technology (as Google Earth) but put it in reverse and look outwards," says Ed Parsons, Google's Geospatial Technologist.
The images and information on Google Sky are all available elsewhere but their software stitches together in one place a collective knowledge, from the Sloan Digital Sky Survey, the Digital Sky Survey Consortium and NASA's Space Telescope Science Institute.
"We'll bring in imagery that may have been produced by NASA from the space telescope, from terrestrial telescopes," Parsons says, "and show you pictures of nebulae, of distant galaxies, of the planets as they move throughout the year."
Given that 250 million people have downloaded Google Earth, which was launched less than three years ago, this service also looks destined to become a popular resource. "It's a one-stop shop under a very reputable banner," says ATC's Ian Robson. "And don't forget, it's also free!"
Dr Francisco Diego, Department of Physics and Astronomy at University College London, says access to space has suddenly opened up. "There are no limits," Diego says. "When you put this in the hands of millions of people, this is public outreach for science in a way that is going to be very revolutionary."
Bob Park agrees tools like Google Sky make astronomy more accessible and that is something he believes in at all levels. "One of the things that pleases me most is how democratic this is," says Park. "When we send rovers to Mars, we can go to the web and see what the rover is seeing instead of sending inarticulate beings up there to tell us what's going on. We can see it for ourselves. Everyone can be part of that."
That's not the only argument for a future of unmanned space exploration. Park points out that the price of manned missions is staggering. "It costs more to send a human to the moon than it does to send the rovers to Mars," Park says. "If we invested the money from the manned space program into telescopes, we would be way ahead of where we are now. Our robotic missions are going great."
Park says now is the perfect time to push for a future of robots and telescopes. "I think the public is sort of tired of the manned space program and today's kids are different. They're cyber-kids. Robots are a very natural idea for kids today and we should be capitalizing on this. What we should be doing now is building far more powerful telescopes to search for life out there. That's going to tell us a lot more about ourselves."
Using robots and telescopes may not be as sexy as seeing astronauts trawling around a Martian landscape but it is generally accepted it will be better value for money. Our greatest quest -- the search for other life -- has so far been fruitless. That should continue to motivate us to keep looking upwards, whether down the barrel of a telescope or at the monitor of our home computer. Whether it will also be through the visor of a spacesuit is still to be decided.
CNN
--
Posted By AstronomytelescopeIndia to Astronomy and Telescopes India at 9/02/2007 10:17:00 PM
The future? The James Webb Space Telescope is the successor of Hubble.
The JWST will launch in 2013, with a collecting area six times the size of Hubble's. Bob Park, professor of physics at the University of Maryland, believes that virtual space exploration using telerobots (which humans control from the ground) is a better solution than sending astronauts, which he calls a waste of resources. "We've gone about as far as we can with manned space missions," Park says. "We could go to Mars at enormous expense but what would a human do when he got there? We can't do much locked in a space suit. There isn't much to hear except a very low rumble from the Martian wind. The only sense that would be available to us is our eyes and we can build robots with much better eyes than humans. Already, the little rovers on Mars right now can focus in on a distant mountain or a grain of sand. We can build telescopes on our robots with any sort of visual capability that we want."
To take man to Mars? Or to take us to Mars via a robot (which we are doing already)? Park says there is little dissent in the scientific community about which is better for science, although he concedes there is an element of romance lost by using robots. "Sense of adventure is the only thing going for manned space travel," Park says. "But it's time to have a grown-up attitude to adventure. If you want adventure, go bungee jumping."
Director of the United Kingdom Astronomy Technology Centre in Edinburgh, Scotland, Ian Robson agrees that the science points us away from manned space travel. "You can always achieve more by robotic missions," Robson says. "If I had the budget, I would spend it on robotic missions. But if I was a politician I would have to think again."
Certainly, the manned space mission has been what's captured the public's imagination in the past. "The cultural experience of watching the Apollo landing was so dramatic," Robson says, "but if we all switched on our television sets today to see the first person land on Mars and career around, maybe it wouldn't have such an impact."
That could be because there are so many more ways of experiencing space exploration today, like the recently launched Google Sky, described as a 'virtual telescope'. It is the latest feature from the mapping service Google Earth but instead of focusing in on our planet, Google Sky allows Internet users to turn their zoom around and explore space, with the ability to navigate around over 100 million individual stars and 200 million galaxies. "We thought we could use the same base technology (as Google Earth) but put it in reverse and look outwards," says Ed Parsons, Google's Geospatial Technologist.
The images and information on Google Sky are all available elsewhere but their software stitches together in one place a collective knowledge, from the Sloan Digital Sky Survey, the Digital Sky Survey Consortium and NASA's Space Telescope Science Institute.
"We'll bring in imagery that may have been produced by NASA from the space telescope, from terrestrial telescopes," Parsons says, "and show you pictures of nebulae, of distant galaxies, of the planets as they move throughout the year."
Given that 250 million people have downloaded Google Earth, which was launched less than three years ago, this service also looks destined to become a popular resource. "It's a one-stop shop under a very reputable banner," says ATC's Ian Robson. "And don't forget, it's also free!"
Dr Francisco Diego, Department of Physics and Astronomy at University College London, says access to space has suddenly opened up. "There are no limits," Diego says. "When you put this in the hands of millions of people, this is public outreach for science in a way that is going to be very revolutionary."
Bob Park agrees tools like Google Sky make astronomy more accessible and that is something he believes in at all levels. "One of the things that pleases me most is how democratic this is," says Park. "When we send rovers to Mars, we can go to the web and see what the rover is seeing instead of sending inarticulate beings up there to tell us what's going on. We can see it for ourselves. Everyone can be part of that."
That's not the only argument for a future of unmanned space exploration. Park points out that the price of manned missions is staggering. "It costs more to send a human to the moon than it does to send the rovers to Mars," Park says. "If we invested the money from the manned space program into telescopes, we would be way ahead of where we are now. Our robotic missions are going great."
Park says now is the perfect time to push for a future of robots and telescopes. "I think the public is sort of tired of the manned space program and today's kids are different. They're cyber-kids. Robots are a very natural idea for kids today and we should be capitalizing on this. What we should be doing now is building far more powerful telescopes to search for life out there. That's going to tell us a lot more about ourselves."
Using robots and telescopes may not be as sexy as seeing astronauts trawling around a Martian landscape but it is generally accepted it will be better value for money. Our greatest quest -- the search for other life -- has so far been fruitless. That should continue to motivate us to keep looking upwards, whether down the barrel of a telescope or at the monitor of our home computer. Whether it will also be through the visor of a spacesuit is still to be decided.
CNN
--
Posted By AstronomytelescopeIndia to Astronomy and Telescopes India at 9/02/2007 10:17:00 PM
[Astronomy and Telescopes India] GSLV launched successfully
SRIHARIKOTA 2 Sep: The launch of the Geosynchronous Satellite Launch Vehicle, GSLV-F04, from here on Sunday turned out to be "a sweet success," with the launch vehicle lifting off flawlessly and injecting the communication satellite, INSAT-4CR, in its pre-determined orbit.
It was a remarkable comeback for the ISRO after the failure of the GSLV on July 10, 2006. It was the third consecutive successful mission this year.
On January 10, the PSLV put in orbit a spacecraft that was brought back to earth, and on April 23, a pared down version of the PSLV put in orbit Italian satellite Agile.
"A fantastic job"
ISRO Chairman G. Madhavan Nair said the ISRO team did "a fantastic job" after the failure of the GSLV mission in 2006. He appreciated "the precision with which this mission performed the job."
B.N. Suresh, Director, Vikram Sarabhai Space Centre, Thiruvananthapuram, described the launch as "a sweet success." It showed that the GSLV was a robust vehicle, whose systems performed as expected.
As Mr. Nair described it, "from all points of view, it was a highly dramatic mission."
The INSAT-4CR, at 2,130 kg, is the heaviest satellite to be launched by the Indian Space Research Organisation (ISRO). Its transponders would be used for direct-to-home telecast, video-picture transmission, telecasting news live using a satellite and business communications..
The GSLV-F04, a three-stage vehicle, is 49 metres tall and weighs 414 tonnes. The first stage is fired by solid propellants. There are four strap-on booster motors, powered by liquid propellants, strung around the core first stage. The second stage is fired by liquid propellants. The third, uppermost stage uses cryogenic fluids — liquid hydrogen as fuel and liquid oxygen as oxidiser. The vehicle was scheduled to lift off on September 1. But the heavy downpour on August 26 played spoilsport."Every night, clouds would come in from somewhere … There will be lightning. We lost 40 hours in the countdown sequence." So the launch was postponed to 4.21 p.m. on September 2.
But 15 seconds before lift-off at 4.21 p.m., there was a problem. The signal related to the readiness of the upper, cryogenic stage did not reach the computer, which takes over the entire launch sequence 12 minutes before lift-off. So the computer halted the launch. The problem was addressed and the launch re-scheduled for 6.20 p.m.
In the twilight hour, the GSLV-F04 shot off from its second launch pad at the Satish Dhawan Space Centre and rode a ball of flame. All the three stages ignited and jettisoned into the Bay of Bengal on time. Seventeen minutes after lift-off, INSAT-4CR was injected into the geosynchronous transfer orbit at a velocity of 37,000 km an hour.
The were other heartbreaking moments. There were signal drop-outs from the tracking stations at Brunei and Biak in Indonesia, and the ISRO lost track of the vehicle. This happened on and off for three and a half minutes. But at the end of 17 minutes, jubilation filled Sriharikota.
G. Ravindranath was the Mission Director and N. Jayachandran Nair was the Vehicle Director. Prahalada Rao was the Satellite Director.
Pat for scientists
PTI reports from New Delhi:
President Pratibha Patil, Vice-President Mohd. Hamid Ansari, Prime Minister Manmohan Singh and Lok Sabha Speaker Somnath Chatterjee congratulated space scientists on the successful launch.
This successful launch further validates the immense economic and strategic importance of the country's space programme, Mr. Ansari said. Mr. Chatterjee said the successful launch "proves the point that the GSLV is a reliable vehicle."
T.S. Subramanian
The Hindu
Tags: GSLV, Madhavan nair, vikram sarabhai, director, Insat-4CR, Satish Dhawan
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Posted By auromarx to Astronomy and Telescopes India at 9/02/2007 10:11:00 PM
[Astronomy and Telescopes India] Space Race Rekindled? Russia Shoots for Moon...
The Russian space agency announced a plan to send a man to the moon by 2025, to establish a permanent base there a few years later, and possibly even send a man to Mars by 2035, in an aggressive plan reminiscent of the 1960s space race between the United States and the Soviet Union.
But Russia's plan to shoot for the stars is expensive, which is why it is looking for international assistance while relying on funding from its lucrative space tourism program.
One former American astronaut said while the Russians plan may be in motion, it is beginning from a difficult starting point.
"The Russians have some big ideas, but their space program is coming up slowly from being in a position bankruptcy," said Walter Cunningham, a former Apollo 7 astronaut.
As Russia plans out its space program, the U.S. space agency, NASA, struggles to chart its own way forward amid mounting costs and safety concerns.
History Repeating Itself
Russia's announcement has caused some to wonder if history will repeat itself.
Initially in the race for space dominance, the United States was forced to play catch up after the Soviet Union launched Sputnik, which was the first unmanned spacecraft in 1957.
Then, four years later, the Soviets sent the first man into space.
But America also made large strides in space exploration. By 1969, the country blasted ahead in the space race by placing the first man on the moon.
"That's one small step for man, one giant leap for mankind," astronaut Neil Armstrong said as he took his first steps on the moon.
Exploration Success and Implications
Even today, the Russians have yet to reach the moon. Yet, Russian President Vladimir Putin continues charting a more ambitious course for his country, including a new exploration era.
The second man to step on the moon, Buzz Aldrin, said on "Good Morning America Weekend Edition" Sunday he believes the Russian program can be successful, but said he wouldn't call it a race with America.
Aldrin, who is a proponent of space exploration, said it is important for Americans to continue their interest in the stars for future generations, despite recent high profile negative press for NASA.
"Unfortunately, our transition from Apollo took much longer than we thought," Aldrin said about Americans' declining interest in space.
But for Russia, a moon landing may not only excite citizens, but also help project military might for Russia.
With the moon and Mars in Russia's sights, some believe the two powerhouse nations once again may be in a race toward the heavens.
And other nations also have expressed interest in space exploration. Japan claimed its project is the biggest since Apollo and China said it is readying probes to study the lunar surface to plan a landing, according to The Associated Press.
abcnews
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Posted By auromarx to Astronomy and Telescopes India at 9/02/2007 10:00:00 PM
But Russia's plan to shoot for the stars is expensive, which is why it is looking for international assistance while relying on funding from its lucrative space tourism program.
One former American astronaut said while the Russians plan may be in motion, it is beginning from a difficult starting point.
"The Russians have some big ideas, but their space program is coming up slowly from being in a position bankruptcy," said Walter Cunningham, a former Apollo 7 astronaut.
As Russia plans out its space program, the U.S. space agency, NASA, struggles to chart its own way forward amid mounting costs and safety concerns.
History Repeating Itself
Russia's announcement has caused some to wonder if history will repeat itself.
Initially in the race for space dominance, the United States was forced to play catch up after the Soviet Union launched Sputnik, which was the first unmanned spacecraft in 1957.
Then, four years later, the Soviets sent the first man into space.
But America also made large strides in space exploration. By 1969, the country blasted ahead in the space race by placing the first man on the moon.
"That's one small step for man, one giant leap for mankind," astronaut Neil Armstrong said as he took his first steps on the moon.
Exploration Success and Implications
Even today, the Russians have yet to reach the moon. Yet, Russian President Vladimir Putin continues charting a more ambitious course for his country, including a new exploration era.
The second man to step on the moon, Buzz Aldrin, said on "Good Morning America Weekend Edition" Sunday he believes the Russian program can be successful, but said he wouldn't call it a race with America.
Aldrin, who is a proponent of space exploration, said it is important for Americans to continue their interest in the stars for future generations, despite recent high profile negative press for NASA.
"Unfortunately, our transition from Apollo took much longer than we thought," Aldrin said about Americans' declining interest in space.
But for Russia, a moon landing may not only excite citizens, but also help project military might for Russia.
With the moon and Mars in Russia's sights, some believe the two powerhouse nations once again may be in a race toward the heavens.
And other nations also have expressed interest in space exploration. Japan claimed its project is the biggest since Apollo and China said it is readying probes to study the lunar surface to plan a landing, according to The Associated Press.
abcnews
Tags: Moon, landing, Russia, America, Apollo, Nasa, 2025, united states, buzz aldrin, associated press
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Posted By auromarx to Astronomy and Telescopes India at 9/02/2007 10:00:00 PM
Wednesday, August 29, 2007
[Auromarx] It happens only once in a red moon
HUNDREDS of stargazers flocked to a rooftop car park in Richmond last night hoping to catch a glimpse of a red moon.
Unfortunately clouds made it almost impossible to see the rare lunar eclipse, but it didn't seem to bother the astronomy enthusiasts.
Astronomical Society of Victoria vice-president Terry Vlahos remained upbeat about the event despite the moon's virtual no-show.
"It's better than nothing," he said, as a sliver of the moon disappeared.
"I'm happy with the turnout and people seem to be having a good time. We can see Jupiter and some of the other constellations."
For almost an hour the moon teased the attentive crowd as it poked through the clouds before clear sky revealed the moon in all its red glory.
Christian Vasquez travelled from Deer Park for the lunar viewing.
"It's a bit unfortunate," he said. "But the turnout and the atmosphere has more than made up for it.
"It's great to see everyone having a good time, especially the kids."
Curator of Astronomy at Sydney's observatory, Nick Lomb, said most people in NSW had been able to see the eclipse.
"It's rare, but not as rare as a blue moon," he said.
While lunar eclipses occur at least twice a year somewhere in the world, the last time a total eclipse was visible from Australia's eastern states was in 2000.
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Posted By auromarx to Auromarx at 8/29/2007 12:21:00 AM
[Auromarx] Lunar eclipse a big draw in Bandung, Jakarta
Yuli Tri Suwarni and Adisti Sukma Sawitri, The Jakarta Post, Bandung, Jakarta
Hundreds of Bandung residents flocked to the Bosscha Observatory in Lembang, North Bandung, to catch a glimpse of the total lunar eclipse on Tuesday.
Observation activities were focussed at the Van Albada Center and aired live by TVRI state-run television station.
The eight Bosscha astronomers who conducted the observation said they were satisfied, although the telescopes were only effective 10 minutes into the peak of the total lunar eclipse at 5:37 p.m.
"We were left behind for 10 minutes because the moon was obstructed by clouds. But everything turned out well ... the weather was bright and we were very satisfied with the observations today," observatory head Taufik Hidayat told The Jakarta Post at the site Tuesday evening.
With traffic backed up one kilometer along the road leading to the observatory, astronomers were forced to share the Vixen telescope with visitors.
Observations were conducted atop the Van Albada Center by using two Celestron telescopes and one William Optics, measuring 20 cm and 7 cm in diameter respectively.
It was the second time astronomers had invited the public to an event and allowed it to broadcast live on TV, after the previous Mars full Moon phenomenon on Aug. 7 2003.
A Gegerkalong resident, Rinda, 23, came with six of her roommates by public bus to witness the spectacle.
"We're satisfied because the moon was very beautiful," said Rinda.
Meanwhile in Jakarta sky gazers could not hide their disappointment as smog clouded the rare phenomenon.
But visitors at Taman Ismail Marzuki planetarium in Central Jakarta could see the eclipse peak through four telescopes and on a big screen.
"I heard that it happens once in 18 years, so I came. Too bad there were not enough telescopes so we have to queue," said Solvi, a resident of Setiabudi, South Jakarta, who came with her five-year-old daughter Sheila.
Students in Depok, however, enjoyed the day as the Kebon Maen kindergarten, primary and junior high schools management changed their study time from the regular 8 a.m. - 11 a.m. to 3 p.m.- 8 p.m. so they could observe the total lunar eclipse.
"We implemented a contextual learning system. So the eclipse is our focus of study today," the kindergarten's curriculum supervisor Sumarti M. Thahir said, adding that the students were accompanied by astronomy experts from the University of Indonesia.
Planetarium staffed Widyaswitar said that the eclipse could help show air pollution levels in an area.
"The more red the sky is, the higher the air pollution level," he said.
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Posted By auromarx to Auromarx at 8/29/2007 12:17:00 AM
Monday, August 27, 2007
Review: Calibrating the Cosmos
Review: Calibrating the Cosmos
by Jeff Foust
Monday, August 27, 2007
Calibrating the Cosmos: How Cosmology Explains Our Big Bang Universe
by Frank Levin
Springer, 2007
hardcover, 302 pp., illus.
ISBN 0-387-30778-4
US$29.95
There is a hole in the universe. Not a black hole, mind you, but an empty space up to a billion light-years across, devoid of both visible and dark matter. That bit of vaguely disturbing news, announced by University of Minnesota astronomers last week, is hardly atypical for research on the cutting edge of astronomy. Such research involves either time and distance scales far beyond what ordinary people can easily comprehend (billions of light-years or billions of years, for example) or concepts that are utterly foreign (dark matter or dark energy). For those wishing to learn more about the universe and its origins, a good place to begin is Frank Levin's Calibrating the Cosmos.
| Calibrating the Cosmos is aimed at a particular audience: people who don't know much about cosmology, but who are relatively intelligent and motivated to learn. |
Levin starts with some basic principles regarding how distances are measured, be they on the Earth or in the universe, as well as some basics about electromagnetic radiation, then builds up the reader's knowledge about the universe and its origins. He examines some key issues in astronomy and cosmology, including the lives and deaths of stars, the expansion of the universe, and the origins and early history of the universe. Unlike many other astronomy books, there's very little in the way of colorful imagery of stars and galaxies in Calibrating the Cosmos; instead, Levin makes far more use of charts and graphs to illustrate his discussion of astronomical concepts like the Hubble Constant.
Calibrating the Cosmos is aimed at a particular audience: people who don't know much about cosmology, but who are relatively intelligent and motivated to learn. (Levin based the book on a course on cosmology he developed for adult education programs.) As a result, the book starts on some very basic foundations, but builds up quickly, and Levin is not afraid to pepper the text with relatively advanced terminology, variables, and a few equations. This is not Cosmology for Dummies, but instead a useful book for those who don't know a lot about cosmology but are interested in learning more and who don't need their education sugarcoated with a lot of pretty pictures. It won't help you understand why, for example, there's a hole a billion light-years across in the universe—not even the astronomers who found it know why it exists—but it will help you understand the significance of such discoveries.
Jeff Foust (jeff@thespacereview.com) is the editor and publisher of The Space Review. He also operates the Spacetoday.net web site and the Space Politics and Personal Spaceflight weblogs. Views and opinions expressed in this article are those of the author alone, and do not represent the official positions of any organization or company, including the Futron Corporation, the author's employer.
Tags: book, review, cosmos, universe, big bang, black hole, dark matter, billion, astronmers, jeff, space, today
Thespacereview
Thespacereview
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Posted By auromarx to Where spiritualism meets materialism at 8/27/2007 11:31:00 PM
Gaping "Hole" in the Sky Found, Expert...
There is a yawning gap of sky nearly a billion light-years across that contains no matter, a new study suggests.
But some researchers aren't buying it, in part because it would be a monumental surprise to find a void that large.
When seen on the scale of tens of millions of light-years, the universe has a foamy structure, with galaxies arranged as if on strings or sheets, with little matter in between them.
This arrangement applies to both visible matter that pumps out light, such as stars, and the mysterious dark matter, whose existence can be inferred only indirectly from how it holds galaxies together.
A "cold spot" in the universe lacks much of the normal cosmic background radiation, left over from the Big Bang, that ripples through the rest of the sky (left, with blue representing colder spots).
Researchers studied radio-wave-emitting galaxies (right) and found such sources were not responsible for the low-radiation region.
The team therefore speculates the spot is an empty hole that is devoid of both regular and dark matter—a structure completely unexpected in modern theories of the universe.
Image courtesy Rudnick et al., NRAO/AUI/NSF, NASA
But at much larger scales, about 150 million light-years and beyond, researchers had expected the universe would be more uniform—so finding a void nearly a billion light-years across was a shock.
"Not only has no one ever found a void this big, but we never even expected to find one this size," said study lead author Lawrence Rudnick of the University of Minnesota in Minneapolis.
Rudnick and colleagues Shea Brown and Liliya Williams report their findings in a paper accepted for publication in the Astrophysical Journal.
Unusual Spot of Sky
The researchers began looking at this particular spot in the sky because it already showed a strange feature.
There the cosmic microwave background radiation—low-level light left over from the birth of our universe that bathes all of space—is especially dim.
This dark patch—where the sky appears "cooler"—is known as the "WMAP cold spot," named after the Wilkinson Microwave Anisotropy Probe satellite that mapped the radiation in 2003.
Nationalgeographic
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Posted By auromarx to Where spiritualism meets materialism at 8/27/2007 11:21:00 PM
But some researchers aren't buying it, in part because it would be a monumental surprise to find a void that large.
When seen on the scale of tens of millions of light-years, the universe has a foamy structure, with galaxies arranged as if on strings or sheets, with little matter in between them.
This arrangement applies to both visible matter that pumps out light, such as stars, and the mysterious dark matter, whose existence can be inferred only indirectly from how it holds galaxies together.
A "cold spot" in the universe lacks much of the normal cosmic background radiation, left over from the Big Bang, that ripples through the rest of the sky (left, with blue representing colder spots).
Researchers studied radio-wave-emitting galaxies (right) and found such sources were not responsible for the low-radiation region.
The team therefore speculates the spot is an empty hole that is devoid of both regular and dark matter—a structure completely unexpected in modern theories of the universe.
Image courtesy Rudnick et al., NRAO/AUI/NSF, NASA
But at much larger scales, about 150 million light-years and beyond, researchers had expected the universe would be more uniform—so finding a void nearly a billion light-years across was a shock.
"Not only has no one ever found a void this big, but we never even expected to find one this size," said study lead author Lawrence Rudnick of the University of Minnesota in Minneapolis.
Rudnick and colleagues Shea Brown and Liliya Williams report their findings in a paper accepted for publication in the Astrophysical Journal.
Unusual Spot of Sky
The researchers began looking at this particular spot in the sky because it already showed a strange feature.
There the cosmic microwave background radiation—low-level light left over from the birth of our universe that bathes all of space—is especially dim.
This dark patch—where the sky appears "cooler"—is known as the "WMAP cold spot," named after the Wilkinson Microwave Anisotropy Probe satellite that mapped the radiation in 2003.
Nationalgeographic
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Posted By auromarx to Where spiritualism meets materialism at 8/27/2007 11:21:00 PM
Dark Matter Mystery Deepens In Cosmic ...
Astronomers have discovered a chaotic scene unlike any witnessed before in a cosmic "train wreck" between giant galaxy clusters. NASA's Chandra X-ray Observatory and optical telescopes revealed a dark matter core that was mostly devoid of galaxies, which may pose problems for current theories of dark matter behavior.
"These results challenge our understanding of the way clusters merge," said Dr. Andisheh Mahdavi of the University of Victoria, British Columbia. "Or, they possibly make us even reexamine the nature of dark matter itself."
There are three main components to galaxy clusters: individual galaxies composed of billions of stars, hot gas in between the galaxies, and dark matter, a mysterious substance that dominates the cluster mass and can be detected only through its gravitational effects.
Optical telescopes can observe the starlight from the individual galaxies, and can infer the location of dark matter by its subtle light-bending effects on distant galaxies. X-ray telescopes like Chandra detect the multimillion-degree gas.
A popular theory of dark matter predicts that dark matter and galaxies should stay together, even during a violent collision, as observed in the case of the so-called Bullet Cluster. However, when the Chandra data of the galaxy cluster system known as Abell 520 was mapped along with the optical data from the Canada-France-Hawaii Telescope and Subaru Telescope atop Mauna Kea, HI, a puzzling picture emerged. A dark matter core was found, which also contained hot gas but no bright galaxies.
"It blew us away that it looks like the galaxies are removed from the densest core of dark matter," said Dr. Hendrik Hoekstra, also of University of Victoria. "This would be the first time we've seen such a thing and could be a huge test of our knowledge of how dark matter behaves."
In addition to the dark matter core, a corresponding "light region" containing a group of galaxies with little or no dark matter was also detected. The dark matter appears to have separated from the galaxies.
"The observation of this group of galaxies that is almost devoid of dark matter flies in the face of our current understanding of the cosmos," said Dr. Arif Babul, University of Victoria. "Our standard model is that a bound group of galaxies like this should have a lot of dark matter. What does it mean that this one doesn't""
This multi-wavelength image shows the chaotic aftermath of the collision of at least two galaxy clusters, some of the most massive objects in the universe. X-rays from Chandra (red) show the hot gas the envelopes the clusters. The individual galaxies appear in visible-light observations (yellow and orange), which also reveal the presence of dark matter (blue) by the subtle distortions of the distant objects. The behavior of the dark matter with respect to the galaxies and hot gas in Abell 520 is very unusual. These data can be explained by changes to the current understanding of dark matter or how galaxy clusters interact when merging. (Credit: X-ray: NASA/CXC/UVic./A. Mahdavi et al. optical/lensing: CFHT/UVic./H. Hoekstra et al.)
In the Bullet Cluster, known as 1E 0657-56, the hot gas is slowed down during the collision but the galaxies and dark matter appear to continue on unimpeded. In Abell 520, it appears that the galaxies were unimpeded by the collision, as expected, while a significant amount of dark matter has remained in the middle of the cluster along with the hot gas.
Mahdavi and his colleagues have two possible explanations for their findings, both of which are uncomfortable for prevailing theories. The first option is that the galaxies were separated from the dark matter through a complex set of gravitational "slingshots." This explanation is problematic because computer simulations have not been able to produce slingshots that are nearly powerful enough to cause such a separation.
The second option is that dark matter is affected not only by gravity, but also by an as-yet-unknown interaction between dark matter particles. This exciting alternative would require new physics and could be difficult to reconcile with observations of other galaxies and galaxy clusters, such as the aforementioned Bullet Cluster.
In order to confirm and fully untangle the evidence for the Abell 520 dark matter core, the researchers have secured time for new data from Chandra plus the Hubble Space Telescope. With the additional observations, the team hopes to resolve the mystery surrounding this system.
These results are scheduled to appear in the October 20th issue of The Astrophysical Journal. Other members of the research team included David Balam (University of Victoria) and Peter Capak (California Institute of Technology).
Note: This story has been adapted from a news release issued by Chandra X-ray Center.
Sciencedaily
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Posted By auromarx to Where spiritualism meets materialism at 8/27/2007 11:12:00 PM
Race Is on to Detect Dark Matter
LOS ANGELES -
In deep underground laboratories around the globe, a high-tech race is on to spot dark matter, the invisible cosmic glue that's believed to keep galaxies from spinning apart.
Whoever discovers the nature of dark matter would solve one of modern science's greatest mysteries and be a shoo-in for the Nobel Prize. Yet it's more than just a brainy exercise. Deciphering dark matter - along with a better understanding of another mysterious force called dark energy - could help reveal the fate of the universe.
Previous hunts for the hypothetical matter have turned up nothing, but that has not deterred some two dozen research teams from plumbing the darkness of idled mines and tunnel shafts for a fleeting glimpse.
Dark-matter detecting machines today are more powerful than previous generations, but even the best has failed so far to catch a whiff of the stuff. Many teams are now building bigger detectors or toying with novel technologies to aid in the hunt.
"We're in the golden age of dark matter search," said Sean Carroll, a California Institute of Technology theoretical physicist who has no role in the experiments. "It's looking good for some breakthroughs to happen."
Scientists admittedly are still in the dark about dark matter. The prevailing theory is that it's made up of tiny, exotic particles left over from the Big Bang some 13.7 billion years ago. Dark matter, thought to make up a quarter of the universe's mass, gets its name because it doesn't give off light or heat. Astronomers know it exists because of its gravitational tug-of-war with stars and galaxies.
Knowing that dark matter exists is a far cry from knowing what it is. Most experiments are searching for theoretical particles called WIMPS - or weakly interacting massive particles - the leading dark-matter candidate.
The underground custom-built machines are all waiting for the rare moment when a WIMP hits the atomic nucleus and causes an elastic recoil. Experiments have to run below ground to prevent cosmic rays from interfering with the results.
Dark matter researcher Neil Spooner of Sheffield University in England sums it up this way: "You have a needle in a haystack and you're trying to remove the hay. You need better technology to pull out the event you're looking for and reject the rubbish."
Subterranean experiments are humming in an idled iron mine in Minnesota and in caverns in Canada, England, France, Italy, Japan and Russia. Last month, the National Science Foundation chose the defunct Homestake gold mine in South Dakota to be the site of one of the largest and deepest labs of its kind in the world - bigger than six Empire State Buildings stacked below ground.
The competition is cutthroat and physicists spar over which technology works best.
The front-runner for the past several years, called CDMS for cryogenic dark matter search, uses ultracold silicon and germanium crystals each the size of a hockey puck to sift out telltale vibrations of a WIMP collision. Newer contraptions use noble gas such as xenon or emerging technologies like superheated liquid bubble chambers.
"There's no perfect dark matter experiment or detector. All of them have their quirks and limitations," said Juan Collar, a particle physicist at the University of Chicago and part of a team called COUPP.
Scientists realize they may be in for a reality check.
"It's possible that no matter how big of an experiment you build, you may not find anything," said Steve Ahlen of Boston University, who along with collaborators from the Massachusetts Institute of Technology and Brandeis University, is building a prototype that will be placed underground next year in a yet to be determined location.
There have been false alarms. In 2000, Italian scientists working in an underground lab near Italy's Gran Sasso mountain range claimed to have detected a dark matter signal. But no one has been able to reproduce the result and the claim is not widely recognized in the scientific community. The Italian researchers have since been working on a second-generation detector and expect to present new results next year.
This spring, a rival group led by Columbia University's Elena Aprile, who also works in Gran Sasso, shocked her peers by announcing at a science meeting that her liquid gas project called XENON10 is more sensitive and rejects more background noise than the CDMS detector.
"The more sensitivity you have, the closer you get to the truth," Aprile said.
CDMS spokesman Bernard Sadoulet of the University of California, Berkeley, said it helps to have more than one technology searching for dark matter to cross-check results. He added that his team has been taking data with its scaled-up detector since last year and expects to regain the sensitivity lead.
The quest for dark matter dates back to the 1930s when Swiss astronomer Fritz Zwicky of Caltech, peering through his telescope, determined that there's missing mass in the universe by observing celestial motions. The idea took a while to catch on, but is now the subject of an intense underground hunt.
Dark matter detectors are expensive to build and even pricier to upgrade and operate. Many projects are funded by a mix of sources. For example, the National Science Foundation has invested about $21 million since fiscal year 2000 on six projects including CDMS and XENON10.
Scientists are also searching for dark matter in space. NASA next year plans to launch the GLAST telescope to study gamma ray bursts that may be created by dark matter collisions. And it's possible researchers will create dark matter in the lab - like at the Large Hadron Collider buried beneath the Swiss-French border - even before they confirm it in the cosmos or under ground.
Not all dark matter searches are betting their money on WIMPS.
The Axion Dark Matter Experiment at Lawrence Livermore National Laboratory has been searching for another theoretical particle called axions. The first phase of the project ended in 2003 with no signal. It recently got the green light from the Energy Department to upgrade the experiment.
Just how long the dark matter hunt will go on is anybody's guess.
"The crystal ball is fuzzy," said physicist Leslie Rosenberg, a co-spokesman of the axion project, adding that, "The nature of dark matter will be revealed."
Forbes
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Posted By auromarx to Where spiritualism meets materialism at 8/27/2007 11:06:00 PM
In deep underground laboratories around the globe, a high-tech race is on to spot dark matter, the invisible cosmic glue that's believed to keep galaxies from spinning apart.
Whoever discovers the nature of dark matter would solve one of modern science's greatest mysteries and be a shoo-in for the Nobel Prize. Yet it's more than just a brainy exercise. Deciphering dark matter - along with a better understanding of another mysterious force called dark energy - could help reveal the fate of the universe.
Previous hunts for the hypothetical matter have turned up nothing, but that has not deterred some two dozen research teams from plumbing the darkness of idled mines and tunnel shafts for a fleeting glimpse.
Dark-matter detecting machines today are more powerful than previous generations, but even the best has failed so far to catch a whiff of the stuff. Many teams are now building bigger detectors or toying with novel technologies to aid in the hunt.
"We're in the golden age of dark matter search," said Sean Carroll, a California Institute of Technology theoretical physicist who has no role in the experiments. "It's looking good for some breakthroughs to happen."
Scientists admittedly are still in the dark about dark matter. The prevailing theory is that it's made up of tiny, exotic particles left over from the Big Bang some 13.7 billion years ago. Dark matter, thought to make up a quarter of the universe's mass, gets its name because it doesn't give off light or heat. Astronomers know it exists because of its gravitational tug-of-war with stars and galaxies.
Knowing that dark matter exists is a far cry from knowing what it is. Most experiments are searching for theoretical particles called WIMPS - or weakly interacting massive particles - the leading dark-matter candidate.
The underground custom-built machines are all waiting for the rare moment when a WIMP hits the atomic nucleus and causes an elastic recoil. Experiments have to run below ground to prevent cosmic rays from interfering with the results.
Dark matter researcher Neil Spooner of Sheffield University in England sums it up this way: "You have a needle in a haystack and you're trying to remove the hay. You need better technology to pull out the event you're looking for and reject the rubbish."
Subterranean experiments are humming in an idled iron mine in Minnesota and in caverns in Canada, England, France, Italy, Japan and Russia. Last month, the National Science Foundation chose the defunct Homestake gold mine in South Dakota to be the site of one of the largest and deepest labs of its kind in the world - bigger than six Empire State Buildings stacked below ground.
The competition is cutthroat and physicists spar over which technology works best.
The front-runner for the past several years, called CDMS for cryogenic dark matter search, uses ultracold silicon and germanium crystals each the size of a hockey puck to sift out telltale vibrations of a WIMP collision. Newer contraptions use noble gas such as xenon or emerging technologies like superheated liquid bubble chambers.
"There's no perfect dark matter experiment or detector. All of them have their quirks and limitations," said Juan Collar, a particle physicist at the University of Chicago and part of a team called COUPP.
Scientists realize they may be in for a reality check.
"It's possible that no matter how big of an experiment you build, you may not find anything," said Steve Ahlen of Boston University, who along with collaborators from the Massachusetts Institute of Technology and Brandeis University, is building a prototype that will be placed underground next year in a yet to be determined location.
There have been false alarms. In 2000, Italian scientists working in an underground lab near Italy's Gran Sasso mountain range claimed to have detected a dark matter signal. But no one has been able to reproduce the result and the claim is not widely recognized in the scientific community. The Italian researchers have since been working on a second-generation detector and expect to present new results next year.
This spring, a rival group led by Columbia University's Elena Aprile, who also works in Gran Sasso, shocked her peers by announcing at a science meeting that her liquid gas project called XENON10 is more sensitive and rejects more background noise than the CDMS detector.
"The more sensitivity you have, the closer you get to the truth," Aprile said.
CDMS spokesman Bernard Sadoulet of the University of California, Berkeley, said it helps to have more than one technology searching for dark matter to cross-check results. He added that his team has been taking data with its scaled-up detector since last year and expects to regain the sensitivity lead.
The quest for dark matter dates back to the 1930s when Swiss astronomer Fritz Zwicky of Caltech, peering through his telescope, determined that there's missing mass in the universe by observing celestial motions. The idea took a while to catch on, but is now the subject of an intense underground hunt.
Dark matter detectors are expensive to build and even pricier to upgrade and operate. Many projects are funded by a mix of sources. For example, the National Science Foundation has invested about $21 million since fiscal year 2000 on six projects including CDMS and XENON10.
Scientists are also searching for dark matter in space. NASA next year plans to launch the GLAST telescope to study gamma ray bursts that may be created by dark matter collisions. And it's possible researchers will create dark matter in the lab - like at the Large Hadron Collider buried beneath the Swiss-French border - even before they confirm it in the cosmos or under ground.
Not all dark matter searches are betting their money on WIMPS.
The Axion Dark Matter Experiment at Lawrence Livermore National Laboratory has been searching for another theoretical particle called axions. The first phase of the project ended in 2003 with no signal. It recently got the green light from the Energy Department to upgrade the experiment.
Just how long the dark matter hunt will go on is anybody's guess.
"The crystal ball is fuzzy," said physicist Leslie Rosenberg, a co-spokesman of the axion project, adding that, "The nature of dark matter will be revealed."
Forbes
Tags: race, dark matter, cosmic glue, california, institute, technology, galaxies, cdms, cern, berkeley
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Posted By auromarx to Where spiritualism meets materialism at 8/27/2007 11:06:00 PM
Friday, August 24, 2007
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