Astronomers have recorded heavenly music bellowed out by the Sun's atmosphere.
Snagging orchestra seats for this solar symphony would be fruitless, however, as the frequency of the sound waves is below the human hearing threshold. While humans can make out sounds between 20 and 20,000 hertz, the solar sound waves are on the order of milli-hertz--a thousandth of a hertz.
The study, presented this week at the Royal Astronomical Society's National Astronomy Meeting in Lancashire, England, reveals that the looping magnetic fields along the Sun's outer regions, called the corona, carry magnetic sound waves in a similar manner to musical instruments such as guitars or pipe organs.
Making music
Robertus von Fay-Siebenburgen of the Solar Physics and Space Plasma Research Center at the University of Sheffield and his colleagues combined information gleaned from sun-orbiting satellites with theoretical models of solar processes, such as coronal mass ejections.
They found that explosive events at the Sun's surface appear to trigger acoustic waves that bounce back and forth between both ends of the loops, a phenomenon known as a standing wave.
"These magnetic loops are analogous to a simple guitar string," von Fay-Siebenburgen explained. "If you pluck a guitar string, you will hear the music."
In the cosmic equivalent of a guitar pick, so-called microflares at the base of loops could be plucking the magnetic loops and setting the sound waves in motion, the researchers speculate. While solar flares are the largest explosions in the solar system, microflares are a million times smaller but much more frequent; both phenomena are now thought to funnel heat into the Sun's outer atmosphere.
The acoustic waves can be extremely energetic, reaching heights of tens of miles, and can travel at rapid speeds of 45,000 to 90,000 miles per hour. "These [explosions] release energy equivalent to millions of hydrogen bombs," von Fay-Siebenburgen said.
"These energies are plucking these magnetic strings or standing pipes, which set up standing waves--exactly the same waves you see on a guitar string," von Fay-Siebenburgen told SPACE.com. The "sound booms" decay to silence in less than an hour, dissipating in the hot solar corona.
Solar physics
The musical finding could help explain why the Sun's corona is so hot.
While the Sun's surface is a steamy 10,000 degrees Fahrenheit (5,538 degrees Celsius), plasma gas in the corona soars to more than 100 times hotter.
"How can the atmosphere above the surface of the Sun be hotter if nuclear fusion happens inside the Sun?" von Fay-Siebenburgen said. If astronomers can get a clearer picture of what's going on inside these magnetic loops in the Sun's atmosphere, they have a better chance of finding the answer.
Another recent study using images from Hinode's telescope revealed twisted magnetic fields along the Sun's surface, which store huge amounts of energy. The magnetic fields can snap like a rubber band; when they do, they might release energy that could heat up the corona or power solar eruptions and coronal mass ejections, the researchers say.
Video: Sun Storms
Images: Solar Flares
Twisted Solution to Sun's Mystery Heat
Original Story: Sun's Atmosphere Sings
Visit SPACE.com and explore our huge collection of Space Pictures, Space Videos, Space Image of the Day, Hot Topics, Top 10s, Multimedia, Trivia, Voting and Amazing Images. Follow the latest developments in the search for life in our universe in our SETI: Search for Life section. Join the community, sign up for our free daily email newsletter, listen to our Podcasts, check out our RSS feeds and other Reader Favorites today!
Jeanna BrynerStaff WriterSPACE.com
Friday, April 20, 2007
Friday, April 06, 2007
Mystery of Greek Amphitheater's Amazing Sound Finally Solved
Cut the chatter! The ancient mystery surrounding the great acoustics of the theater at Epidaurus in Greece has been solved.
The theater, dating to the 4th century B.C. and arranged in 55 semi-circular rows, remains the great masterwork of Polykleitos the Younger. Audiences of up to an estimated 14,000 have long been able to hear actors and musicians—unamplified—from even the back row of the architectural masterpiece.
How this sonic quality was achieved has been the source of academic and amateur speculation, with some theories suggesting that prevailing winds carried sounds or masks amplified voices.
It's in the seats
Now, researchers at the Georgia Institute of Technology have discovered that the limestone material of the seats provide a filtering effect, suppressing low frequencies of voices, thus minimizing background crowd noise. Further, the rows of limestone seats reflect high-frequencies back towards the audience, enhancing the effect.
Researcher Nico Declercq, a mechanical engineer, initially suspected that the slope of the theater had something to do with the effect.
“When I first tackled this problem, I thought that the effect of the splendid acoustics was due to surface waves climbing the theater with almost no damping,” Declercq said. “While the voices of the performers were being carried, I didn’t anticipate that the low frequencies of speech were also filtered out to some extent.”
However, experiments with ultrasonic waves and numerical models indicated that frequencies up to 500 hertz (cycles per second) were lowered, and frequencies higher than 500 hertz went undiminished, he said.
Acoustic traps
The corrugations on the surface of the seats act as natural acoustic traps. Though this effect would seem to also remove the low frequencies from the actors' voices, listeners actually fill in the missing portion of the audio spectrum through a phenomenon known as virtual pitch. The human brain reconstructs the missing frequencies, producing the virtual pitch phenomenon, as in listening to someone speaking on a telephone with no low end.
The findings are detailed in the April issue of the Journal of the Acoustics Society of America.
Amazingly, the Greek builders of the theater did not themselves understand the principles that led to the exceptional audibility of sound from the stage.
Attempts to recreate the Epidaurus design never quite matched the original. Later seating arrangements featured other materials, such as wood for the benches, an approach which may have ultimately derailed the design duplication effort.
Music Tickles Strong Memories
Singing Sand Dunes: The Mystery of Desert Music
Top 10 Ancient Capitals
Original Story: Mystery of Greek Amphitheater's Amazing Sound Finally Solved
Tom ChaoLiveScience Staff WriterLiveScience.com
The theater, dating to the 4th century B.C. and arranged in 55 semi-circular rows, remains the great masterwork of Polykleitos the Younger. Audiences of up to an estimated 14,000 have long been able to hear actors and musicians—unamplified—from even the back row of the architectural masterpiece.
How this sonic quality was achieved has been the source of academic and amateur speculation, with some theories suggesting that prevailing winds carried sounds or masks amplified voices.
It's in the seats
Now, researchers at the Georgia Institute of Technology have discovered that the limestone material of the seats provide a filtering effect, suppressing low frequencies of voices, thus minimizing background crowd noise. Further, the rows of limestone seats reflect high-frequencies back towards the audience, enhancing the effect.
Researcher Nico Declercq, a mechanical engineer, initially suspected that the slope of the theater had something to do with the effect.
“When I first tackled this problem, I thought that the effect of the splendid acoustics was due to surface waves climbing the theater with almost no damping,” Declercq said. “While the voices of the performers were being carried, I didn’t anticipate that the low frequencies of speech were also filtered out to some extent.”
However, experiments with ultrasonic waves and numerical models indicated that frequencies up to 500 hertz (cycles per second) were lowered, and frequencies higher than 500 hertz went undiminished, he said.
Acoustic traps
The corrugations on the surface of the seats act as natural acoustic traps. Though this effect would seem to also remove the low frequencies from the actors' voices, listeners actually fill in the missing portion of the audio spectrum through a phenomenon known as virtual pitch. The human brain reconstructs the missing frequencies, producing the virtual pitch phenomenon, as in listening to someone speaking on a telephone with no low end.
The findings are detailed in the April issue of the Journal of the Acoustics Society of America.
Amazingly, the Greek builders of the theater did not themselves understand the principles that led to the exceptional audibility of sound from the stage.
Attempts to recreate the Epidaurus design never quite matched the original. Later seating arrangements featured other materials, such as wood for the benches, an approach which may have ultimately derailed the design duplication effort.
Music Tickles Strong Memories
Singing Sand Dunes: The Mystery of Desert Music
Top 10 Ancient Capitals
Original Story: Mystery of Greek Amphitheater's Amazing Sound Finally Solved
Tom ChaoLiveScience Staff WriterLiveScience.com
Friday, March 23, 2007
France opens secret UFO files covering 50 years
PARIS (AFP) - France became the first country to open its files on UFOs Thursday when the national space agency unveiled a website documenting more than 1,600 sightings spanning five decades.
The online archives, which will be updated as new cases are reported, catalogues in minute detail cases ranging from the easily dismissed to a handful that continue to perplex even hard-nosed scientists.
"It is a world first," said Jacques Patenet, the aeronautical engineer who heads the office for the study of "non-identified aerospatial phenomena."
Known as OVNIs in French, UFOs have always generated intense interest along with countless conspiracy theories about secretive government cover-ups of findings deemed too sensitive or alarming for public consumption.
"Cases such as the lady who reported seeing an object that looked like a flying roll of toilet paper" are clearly not worth investigating, said Patenet.
But many others involving multiple sightings -- in at least one case involving thousands of people across France -- and evidence such as burn marks and radar trackings showing flight patterns or accelerations that defy the laws of physics are taken very seriously.
A phalanx of beefy security guards formed a barrier in front of the space agency (CNES) headquarters where the announcement was made, "to screen out uninvited UFOlogists," an official explained.
Of the 1,600 cases registered since 1954, nearly 25 percent are classified as "type D", meaning that "despite good or very good data and credible witnesses, we are confronted with something we can't explain," Patenet said.
On January 8, 1981 outside the town of Trans-en-Provence in southern France, for example, a man working in a field reported hearing a strange whistling sound and seeing a saucer-like object about 2.5 meters (eight feet) in diameter land in his field about 50 meters (yards) away.
A dull-zinc grey, the saucer took off, he told police, almost immediately, leaving burn marks.
Investigators took photos, and then collected and analyzed samples, and to this day no satisfactory explanation has been made.
The nearly 1,000 witness who said they saw flashing lights in the sky on November 5, 1990, by contrast, had simply seen a rocket fragment falling back into earth's atmosphere.
Patenet's answer to questions about evidence of life beyond Earth was sure to inflame the suspicions of those convinced the government is holding back: "We do not have the least proof that extra-terrestrials are behind the unexplained phenomena."
But then he added: "Nor do we have the least proof that they aren't."
The CNES fields between 50 and 100 UFO reports ever year, usually written up by police. Of these, 10 percent are the object of on-site investigations, Patenet said.
Other countries collect data more or less systematically about unidentified flying objects, notably in Britain and in the United States, where information can be requested on a case-by-case basis under the Freedom of Information Act.
"But we decided to do it the other way around and made everything available to the public," Patenet said.
The aim was to make it easier for scientists and other UFO buffs to access the data for research.
The website itself -- which crashed host servers hours after it was unveiled due to heavy traffic -- is extremely well organized and complete, even including scanned copies of police reports.
To visit the website: www.cnes-geipan.fr.
by Marlowe Hood
The online archives, which will be updated as new cases are reported, catalogues in minute detail cases ranging from the easily dismissed to a handful that continue to perplex even hard-nosed scientists.
"It is a world first," said Jacques Patenet, the aeronautical engineer who heads the office for the study of "non-identified aerospatial phenomena."
Known as OVNIs in French, UFOs have always generated intense interest along with countless conspiracy theories about secretive government cover-ups of findings deemed too sensitive or alarming for public consumption.
"Cases such as the lady who reported seeing an object that looked like a flying roll of toilet paper" are clearly not worth investigating, said Patenet.
But many others involving multiple sightings -- in at least one case involving thousands of people across France -- and evidence such as burn marks and radar trackings showing flight patterns or accelerations that defy the laws of physics are taken very seriously.
A phalanx of beefy security guards formed a barrier in front of the space agency (CNES) headquarters where the announcement was made, "to screen out uninvited UFOlogists," an official explained.
Of the 1,600 cases registered since 1954, nearly 25 percent are classified as "type D", meaning that "despite good or very good data and credible witnesses, we are confronted with something we can't explain," Patenet said.
On January 8, 1981 outside the town of Trans-en-Provence in southern France, for example, a man working in a field reported hearing a strange whistling sound and seeing a saucer-like object about 2.5 meters (eight feet) in diameter land in his field about 50 meters (yards) away.
A dull-zinc grey, the saucer took off, he told police, almost immediately, leaving burn marks.
Investigators took photos, and then collected and analyzed samples, and to this day no satisfactory explanation has been made.
The nearly 1,000 witness who said they saw flashing lights in the sky on November 5, 1990, by contrast, had simply seen a rocket fragment falling back into earth's atmosphere.
Patenet's answer to questions about evidence of life beyond Earth was sure to inflame the suspicions of those convinced the government is holding back: "We do not have the least proof that extra-terrestrials are behind the unexplained phenomena."
But then he added: "Nor do we have the least proof that they aren't."
The CNES fields between 50 and 100 UFO reports ever year, usually written up by police. Of these, 10 percent are the object of on-site investigations, Patenet said.
Other countries collect data more or less systematically about unidentified flying objects, notably in Britain and in the United States, where information can be requested on a case-by-case basis under the Freedom of Information Act.
"But we decided to do it the other way around and made everything available to the public," Patenet said.
The aim was to make it easier for scientists and other UFO buffs to access the data for research.
The website itself -- which crashed host servers hours after it was unveiled due to heavy traffic -- is extremely well organized and complete, even including scanned copies of police reports.
To visit the website: www.cnes-geipan.fr.
by Marlowe Hood
Tuesday, March 20, 2007
Mathematicians solve E8 structure
WASHINGTON (AFP) - After four years of intensive collaboration, 18 top mathematicians and computer scientists from the United States and Europe have successfully mapped E8, one of the largest and most complicated structures in mathematics, scientists said late Sunday.
Jeffrey Adams, project leader and mathematics professor at the University of Maryland said E8 was discovered over a century ago, in 1887, and until now, no one thought the structure could ever be understood.
"This groundbreaking achievement is significant both as an advance in basic knowledge, as well as a major advance in the use of large scale computing to solve complicated mathematical problems," Adams said.
He added that the mapping of E8 may well have unforeseen implications in mathematics and physics which won't be evident for years to come.
E8 belongs to so-called Lie groups that were invented by a 19th century Norwegian mathematician, Sophus Lie, to study symmetry.
The theory holds that underlying any symmetrical object, such as a sphere, is a Lie group.
Balls, cylinders or cones are familiar examples of symmetric three-dimensional objects.
However, mathematicians study symmetries in higher dimensions. In fact, E8 itself is 248-dimensional.
Today string theorists search for a theory of the universe by looking at E8 X E8.
The scientists said the magnitude of the E8 calculation invited comparison with the
Human Genome Project.
While the human genome, which contains all the genetic information of a cell, is less than a gigabyte in size, the result of the E8 calculation, which contains all the information about E8, is 60 gigabytes in size, they said.
This is enough to store 45 days of continuous music in MP3-format. If written out on paper, the answer would cover an area the size of Manhattan.
Jeffrey Adams, project leader and mathematics professor at the University of Maryland said E8 was discovered over a century ago, in 1887, and until now, no one thought the structure could ever be understood.
"This groundbreaking achievement is significant both as an advance in basic knowledge, as well as a major advance in the use of large scale computing to solve complicated mathematical problems," Adams said.
He added that the mapping of E8 may well have unforeseen implications in mathematics and physics which won't be evident for years to come.
E8 belongs to so-called Lie groups that were invented by a 19th century Norwegian mathematician, Sophus Lie, to study symmetry.
The theory holds that underlying any symmetrical object, such as a sphere, is a Lie group.
Balls, cylinders or cones are familiar examples of symmetric three-dimensional objects.
However, mathematicians study symmetries in higher dimensions. In fact, E8 itself is 248-dimensional.
Today string theorists search for a theory of the universe by looking at E8 X E8.
The scientists said the magnitude of the E8 calculation invited comparison with the
Human Genome Project.
While the human genome, which contains all the genetic information of a cell, is less than a gigabyte in size, the result of the E8 calculation, which contains all the information about E8, is 60 gigabytes in size, they said.
This is enough to store 45 days of continuous music in MP3-format. If written out on paper, the answer would cover an area the size of Manhattan.
Sunday, March 18, 2007
Giant Pool of Water Ice at Mars' South Pole
Mars is unlikely to sport beachfront property anytime soon, but the planet has enough water ice at its south pole to blanket the entire planet in more than 30 feet of water if everything thawed out.
With a radar technique, astronomers have penetrated for the first time about 2.5 miles (nearly four kilometers) beneath the south pole's frozen surface. The data showed that nearly pure water ice lies beneath.
Discovered in the early 1970s, layered deposits of ice and dust cap the North and South Poles of Mars. Until now, the deposits have been difficult to study closely with existing telescopes and satellites. The current advance comes from a probe of the deposits using an instrument aboard the Mars Express orbiter.
"This is the first time that a ground-penetrating system has ever been used on Mars," said the new radar study's lead author, Jeffrey Plaut of NASA's Jet Propulsion Laboratory. "All the other instruments used to study the surface of Mars in the past really have only been sensitive to what occurs at the very surface."
(NASA's Mars Odyssey spacecraft also carries instruments designed, among other things, to probe beneath icy polar surfaces.)
Deep probe
Plaut and his colleagues probed the deposits with radar echo sounding, typically used on Earth to study the interiors of glaciers. The instrument, called the Mars Advanced Radar for Subsurface and Ionospheric Sounding, or MARSIS, beams radio waves which penetrate the planet's surface and bounce off features having different electrical properties.
The reflected beams revealed that 90 percent or more of the frozen polar material is pure water ice, sprinkled with dust particles. The scientists calculated that the water would form a 36-foot-deep ocean of sorts if spread over the Martian globe.
"It's the best evidence that's been obtained to date for that thickness," said Ken Herkenhoff, a planetary geologist at the U.S. Geological Survey in Flagstaff, Ariz., who studies the Martian polar regions. He was not involved in the current study.
Scientists have long known that Mars' north polar cap is a massive storehouse of water ice, and the current research team says they will use their radar technique to refine past estimates of its thickness and make-up.
Missing water
"These polar ice deposits are by far the largest reservoir of water or water ice that we know of on Mars," Plaut said.
That's a lot of water, but not enough to account for the flowing streams thought to meander along Mars' surface in the past.
"There's evidence that about 10 times or maybe even 100 times that much water has flowed across the surface of Mars to carve the various channels, the outflow valleys and other features we see in the images and topography data," Plaut told SPACE.com.
So where's the rest of the water? One idea is that a subterranean plumbing system once ferried loads of water beneath the Martian surface. Plaut said his team also will search for underground pools with the radar technique.
Underground Plumbing System Discovered on Mars
New View of Ancient Mars Water System
Martian beach
A Martian water-world is unlikely in the near future, but astronomers have solid evidence that billions of years ago water flowed over the Martian surface. And recently, evidence has pointed to a warming trend as Mars emerges from an "ice age."
Scientists think variations in Mars' orbit and tilt drive the planet's climate over time, though a few astronomers have speculated about how the Sun's activity could be partly to blame for warming on several planets.
Sun Blamed for Warming of Earth and Other Worlds
In addition to warming from the atmosphere, ice-thawing heat could come from the core of Mars, analogous to the plumes of heat that cause volcanic eruptions on Earth. But evidence from the new radar study suggests the Martian crust is icy cold and rigid.
Mars Madness: A Multimedia Adventure
Top 10 Best Mars Images Ever
Video: A Wet Modern Mars?
Images: Ice on Mars
All About Mars
Original Story: Giant Pool of Water Ice at Mars' South Pole
Visit SPACE.com and explore our huge collection of Space Pictures, Space Videos, Space Image of the Day, Hot Topics, Top 10s, Multimedia, Trivia, Voting and Amazing Images. Follow the latest developments in the search for life in our universe in our SETI: Search for Life section. Join the community, sign up for our free daily email newsletter, listen to our Podcasts, check out our RSS feeds and other Reader Favorites today!
Jeanna BrynerStaff WriterSPACE.com
With a radar technique, astronomers have penetrated for the first time about 2.5 miles (nearly four kilometers) beneath the south pole's frozen surface. The data showed that nearly pure water ice lies beneath.
Discovered in the early 1970s, layered deposits of ice and dust cap the North and South Poles of Mars. Until now, the deposits have been difficult to study closely with existing telescopes and satellites. The current advance comes from a probe of the deposits using an instrument aboard the Mars Express orbiter.
"This is the first time that a ground-penetrating system has ever been used on Mars," said the new radar study's lead author, Jeffrey Plaut of NASA's Jet Propulsion Laboratory. "All the other instruments used to study the surface of Mars in the past really have only been sensitive to what occurs at the very surface."
(NASA's Mars Odyssey spacecraft also carries instruments designed, among other things, to probe beneath icy polar surfaces.)
Deep probe
Plaut and his colleagues probed the deposits with radar echo sounding, typically used on Earth to study the interiors of glaciers. The instrument, called the Mars Advanced Radar for Subsurface and Ionospheric Sounding, or MARSIS, beams radio waves which penetrate the planet's surface and bounce off features having different electrical properties.
The reflected beams revealed that 90 percent or more of the frozen polar material is pure water ice, sprinkled with dust particles. The scientists calculated that the water would form a 36-foot-deep ocean of sorts if spread over the Martian globe.
"It's the best evidence that's been obtained to date for that thickness," said Ken Herkenhoff, a planetary geologist at the U.S. Geological Survey in Flagstaff, Ariz., who studies the Martian polar regions. He was not involved in the current study.
Scientists have long known that Mars' north polar cap is a massive storehouse of water ice, and the current research team says they will use their radar technique to refine past estimates of its thickness and make-up.
Missing water
"These polar ice deposits are by far the largest reservoir of water or water ice that we know of on Mars," Plaut said.
That's a lot of water, but not enough to account for the flowing streams thought to meander along Mars' surface in the past.
"There's evidence that about 10 times or maybe even 100 times that much water has flowed across the surface of Mars to carve the various channels, the outflow valleys and other features we see in the images and topography data," Plaut told SPACE.com.
So where's the rest of the water? One idea is that a subterranean plumbing system once ferried loads of water beneath the Martian surface. Plaut said his team also will search for underground pools with the radar technique.
Underground Plumbing System Discovered on Mars
New View of Ancient Mars Water System
Martian beach
A Martian water-world is unlikely in the near future, but astronomers have solid evidence that billions of years ago water flowed over the Martian surface. And recently, evidence has pointed to a warming trend as Mars emerges from an "ice age."
Scientists think variations in Mars' orbit and tilt drive the planet's climate over time, though a few astronomers have speculated about how the Sun's activity could be partly to blame for warming on several planets.
Sun Blamed for Warming of Earth and Other Worlds
In addition to warming from the atmosphere, ice-thawing heat could come from the core of Mars, analogous to the plumes of heat that cause volcanic eruptions on Earth. But evidence from the new radar study suggests the Martian crust is icy cold and rigid.
Mars Madness: A Multimedia Adventure
Top 10 Best Mars Images Ever
Video: A Wet Modern Mars?
Images: Ice on Mars
All About Mars
Original Story: Giant Pool of Water Ice at Mars' South Pole
Visit SPACE.com and explore our huge collection of Space Pictures, Space Videos, Space Image of the Day, Hot Topics, Top 10s, Multimedia, Trivia, Voting and Amazing Images. Follow the latest developments in the search for life in our universe in our SETI: Search for Life section. Join the community, sign up for our free daily email newsletter, listen to our Podcasts, check out our RSS feeds and other Reader Favorites today!
Jeanna BrynerStaff WriterSPACE.com
EU site to offer extreme weather data
VIENNA, Austria - It looks like a color-coded terror alert scale — and meteorologically speaking, that's exactly what it is. With climate change making conditions more unpredictable, national weather services from across the European Union have joined forces to create http://www.meteoalarm.eu — a new Web site providing up-to-the-minute information on "extreme weather" across the continent.
The initiative, managed by Austria's Central Institute for Meteorology and Geodynamics, is designed to give Europeans a single source for details on flash floods, severe thunderstorms, gale-force winds, heat waves, blizzards and other violent weather that poses a threat to life or property.
It also issues 24- and 48-hour warnings for heavy fog, extreme cold, forest fires and "coastal events" such as high waves or severe tides.
"In one glance you will be able to see where in Europe the weather might become dangerous," organizers said Saturday in a statement.
The service is similar to the United States' National Weather Service, which posts on its Web site conditions, warnings and forecasts for all 50 states.
Although the European site officially will launch in Madrid, Spain, on March 23 — World Meteorological Day — it is already live on the Web in test form.
Under the new pan-European warning system, white means missing or insufficient data; green means no imminent threat; yellow signifies potentially dangerous weather; orange warns of dangerous conditions; and red means very dangerous, "exceptionally intense" weather.
Pictograms and photographs showing lightning bolts, churning floodwaters and other catastrophic scenes also pop up "to make the general public more conscious or aware" of a particular threat, the organizers said.
Users click on maps to get details on current conditions or forecasts of violent weather for the next day. There are also links to a country's national weather service.
The Network of European Meteorological Services includes 20 countries and covers land stretching from Portugal to Sweden. Not every nation in the region is contributing, but the site hopes to bring others online eventually.
The Web site "pulls together all the warnings from the official national weather services," said Michael Staudinger of the Vienna weather institute.
It seemed to be accurate on Saturday, at least for Vienna, which was buffeted by gale-force winds gusting to 50 mph. The system churned out a yellow high-wind warning for the area and provided details in German and English.
By WILLIAM J. KOLE, Associated Press Writer
The initiative, managed by Austria's Central Institute for Meteorology and Geodynamics, is designed to give Europeans a single source for details on flash floods, severe thunderstorms, gale-force winds, heat waves, blizzards and other violent weather that poses a threat to life or property.
It also issues 24- and 48-hour warnings for heavy fog, extreme cold, forest fires and "coastal events" such as high waves or severe tides.
"In one glance you will be able to see where in Europe the weather might become dangerous," organizers said Saturday in a statement.
The service is similar to the United States' National Weather Service, which posts on its Web site conditions, warnings and forecasts for all 50 states.
Although the European site officially will launch in Madrid, Spain, on March 23 — World Meteorological Day — it is already live on the Web in test form.
Under the new pan-European warning system, white means missing or insufficient data; green means no imminent threat; yellow signifies potentially dangerous weather; orange warns of dangerous conditions; and red means very dangerous, "exceptionally intense" weather.
Pictograms and photographs showing lightning bolts, churning floodwaters and other catastrophic scenes also pop up "to make the general public more conscious or aware" of a particular threat, the organizers said.
Users click on maps to get details on current conditions or forecasts of violent weather for the next day. There are also links to a country's national weather service.
The Network of European Meteorological Services includes 20 countries and covers land stretching from Portugal to Sweden. Not every nation in the region is contributing, but the site hopes to bring others online eventually.
The Web site "pulls together all the warnings from the official national weather services," said Michael Staudinger of the Vienna weather institute.
It seemed to be accurate on Saturday, at least for Vienna, which was buffeted by gale-force winds gusting to 50 mph. The system churned out a yellow high-wind warning for the area and provided details in German and English.
By WILLIAM J. KOLE, Associated Press Writer
Wednesday, March 07, 2007
Scientists study Earth's missing crust
SANTA CRUZ DE TENERIFE, Canary Islands - British scientists have embarked on a mission to study a huge area on the Atlantic seabed where the Earth's crust is mysteriously missing and instead is covered with dark green rock from deep inside the planet.
The 12-member expedition to take an unprecedented peek at Earth's mantle left the Canary Islands on Monday with a new high-tech vessel and a robotic device named Toby that will dig up rock samples at the site and film what it sees.
The main site — there is at least one other in roughly the same area and a third is suspected — is about three miles below the surface of the Atlantic and located about 2,000 nautical miles southwest of the Canaries.
It is part of a globe-spanning ridge of undersea volcanos, the kind of structure that forms when Atlantic tectonic plates separate and lava surges upward to fill the gap in the Earth's crust.
But that apparently did not happen this time. Where there should be a four-mile-thick layer of crust, there is instead that much mantle — the very dense, dark green rock that makes up the deep inner layer of the Earth.
Scientists have seen chunks of mantle that have been spewed up with lava, but never such a large, exposed stretch.
"It is like a window into the interior of the Earth," Bramley Murton, a geophysicist who is taking part in the six-week mission, said Tuesday from the research ship RRS James Cook as it headed to the site, still five days away.
This exposed layer is irregularly shaped, about 30 miles long and perhaps that distance or more at its widest. It was detected about five years ago with sonar from a surface vessel.
There are two main theories as to what happened, Murton said: A fault ripped away huge chunks of crust, or in an area of crust-forming volcanoes, this area was mysteriously devoid of that outer material, Murton said.
Roger Searle of Durham University, one of the lead researchers, said the study aims to provide insight on everything from the chemistry of oceans to the mechanisms of how the Earth behaves under so much water.
The robotic device will land on the exposed mantle, deploy a drill, and dig into the rock to bring back samples.
The project is being financed by Britain's National Environment Research Council and the Department of trade and Industry's Large Scientific Facilities Fund.
By JUAN MANUEL PARDELLAS, Associated Press Writer
The 12-member expedition to take an unprecedented peek at Earth's mantle left the Canary Islands on Monday with a new high-tech vessel and a robotic device named Toby that will dig up rock samples at the site and film what it sees.
The main site — there is at least one other in roughly the same area and a third is suspected — is about three miles below the surface of the Atlantic and located about 2,000 nautical miles southwest of the Canaries.
It is part of a globe-spanning ridge of undersea volcanos, the kind of structure that forms when Atlantic tectonic plates separate and lava surges upward to fill the gap in the Earth's crust.
But that apparently did not happen this time. Where there should be a four-mile-thick layer of crust, there is instead that much mantle — the very dense, dark green rock that makes up the deep inner layer of the Earth.
Scientists have seen chunks of mantle that have been spewed up with lava, but never such a large, exposed stretch.
"It is like a window into the interior of the Earth," Bramley Murton, a geophysicist who is taking part in the six-week mission, said Tuesday from the research ship RRS James Cook as it headed to the site, still five days away.
This exposed layer is irregularly shaped, about 30 miles long and perhaps that distance or more at its widest. It was detected about five years ago with sonar from a surface vessel.
There are two main theories as to what happened, Murton said: A fault ripped away huge chunks of crust, or in an area of crust-forming volcanoes, this area was mysteriously devoid of that outer material, Murton said.
Roger Searle of Durham University, one of the lead researchers, said the study aims to provide insight on everything from the chemistry of oceans to the mechanisms of how the Earth behaves under so much water.
The robotic device will land on the exposed mantle, deploy a drill, and dig into the rock to bring back samples.
The project is being financed by Britain's National Environment Research Council and the Department of trade and Industry's Large Scientific Facilities Fund.
By JUAN MANUEL PARDELLAS, Associated Press Writer
Sunday, March 04, 2007
World watches 1st total lunar eclipse in 3 years
LONDON - The moon darkened, reddened, and turned shades of gray and orange Saturday night during the first total lunar eclipse in nearly three years, thrilling stargazers and astronomers around the world.
The Earth’s shadow took over six hours to crawl across the moon’s surface, eating it into a crescent shape before engulfing it completely in a spectacle at least partly visible on every continent.
About a dozen amateur astronomers braved the cold and mud outside the Croydon Observatory in southeast London to watch the start of the eclipse.
“It’s starting to go!” said Alex Gikas, 8, a Cub Scout who was studying for his astronomy badge. “I’ve never seen anything like it before. I’m really excited.”
By the time greatest eclipse, shortly after 5:44 p.m. EST, the light of the full moon was replaced by near-total obscurity.
“It was really very dark,” said Paul Harper, Chairman of the Croydon Astronomical Society, who estimated that moon had lost over four-fifths of its luminosity. “It was quite a nice one.”
Lunar eclipses occur when Earth passes between the sun and the moon, an uncommon event because the moon spends most of its time either above or below the plane of Earth’s orbit.
Sunlight still reaches the moon during total eclipses, but it is refracted through Earth’s atmosphere, bathing the moon in an eerie crimson light.
Mike Ealay, a 60-year-old architect who wandered over to the observatory to watch the eclipse, said the red color of the moon made it look like a close-up version of Mars.
“I think it’s quite exciting. It’s like having the red planet on your doorstep,” he said.
Despite cloudy conditions over much of Europe, a variety of Webcasts carried the event live, and astronomers urged the public not to miss out on the spectacle.
“It’s not an event that has any scientific value, but it’s something everybody can enjoy,” said Robert Massey, of Britain’s Royal Astronomical Society.
The moon’s red blush faded as it began moving out of Earth’s shadow just after 8 p.m. EST. The eclipse ended a little more than hour later.
Residents of east Asia saw the eclipse cut short by moonset, while those in the eastern parts of North and South America had the moon already partially or totally eclipsed by the time it rose over the horizon in the evening.
While eastern Australia, Alaska and New Zealand missed Saturday’s show, they will have front row seats to the next total lunar eclipse, on Aug. 28.
© 2007 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
The Earth’s shadow took over six hours to crawl across the moon’s surface, eating it into a crescent shape before engulfing it completely in a spectacle at least partly visible on every continent.
About a dozen amateur astronomers braved the cold and mud outside the Croydon Observatory in southeast London to watch the start of the eclipse.
“It’s starting to go!” said Alex Gikas, 8, a Cub Scout who was studying for his astronomy badge. “I’ve never seen anything like it before. I’m really excited.”
By the time greatest eclipse, shortly after 5:44 p.m. EST, the light of the full moon was replaced by near-total obscurity.
“It was really very dark,” said Paul Harper, Chairman of the Croydon Astronomical Society, who estimated that moon had lost over four-fifths of its luminosity. “It was quite a nice one.”
Lunar eclipses occur when Earth passes between the sun and the moon, an uncommon event because the moon spends most of its time either above or below the plane of Earth’s orbit.
Sunlight still reaches the moon during total eclipses, but it is refracted through Earth’s atmosphere, bathing the moon in an eerie crimson light.
Mike Ealay, a 60-year-old architect who wandered over to the observatory to watch the eclipse, said the red color of the moon made it look like a close-up version of Mars.
“I think it’s quite exciting. It’s like having the red planet on your doorstep,” he said.
Despite cloudy conditions over much of Europe, a variety of Webcasts carried the event live, and astronomers urged the public not to miss out on the spectacle.
“It’s not an event that has any scientific value, but it’s something everybody can enjoy,” said Robert Massey, of Britain’s Royal Astronomical Society.
The moon’s red blush faded as it began moving out of Earth’s shadow just after 8 p.m. EST. The eclipse ended a little more than hour later.
Residents of east Asia saw the eclipse cut short by moonset, while those in the eastern parts of North and South America had the moon already partially or totally eclipsed by the time it rose over the horizon in the evening.
While eastern Australia, Alaska and New Zealand missed Saturday’s show, they will have front row seats to the next total lunar eclipse, on Aug. 28.
© 2007 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.
Monday, February 26, 2007
Population Density of Madagascar
Source: UNOSAT
Reuters and AlertNet are not responsible for the content of this article or for any external internet sites. The views expressed are the author's alone.
Reuters and AlertNet are not responsible for the content of this article or for any external internet sites. The views expressed are the author's alone.
Tropical Cyclone Gamede Track As of 26 February 2007 This map illustrates the approximate population density (2004) for Madagascar, which is currently threatened by tropical cyclone Gamede. Map Scale 1:4,200,000 for A3 Print Projection: Lambert Conformal Conic Datum: WGS-84 Population Data: Landscan 2004 Storm Data: GDACS, WMO GIS Data: SALB, NGA, UNEP, GEBCO Map Production: UNOSAT (26 February 2007)
Madagascar - Tropical Cyclone Gamede Track As of 26 February 2007
This map illustrates the approximate population density (2004) for Madagascar, which is currently threatened by tropical cyclone Gamede. Map Scale 1:4,200,000 for A3 Print Projection: Lambert Conformal Conic Datum: WGS-84
Thursday, February 22, 2007
Distant planets: Warm, weird, waterless
WASHINGTON - The first "sniffs of air" of two huge far-away planets reveal that they seem to be missing water, a surprising finding amid weather unlike any planets in our solar system with blast furnace-like gusts amid supersonic winds.
The absence of water from the atmosphere of both these Jupiter-sized gaseous bodies upsets one of the most basic assumptions of astronomy.
One of the researchers, Harvard University astronomy professor David Charbonneau, called the planets "very different beasts ... unlike any other planets in the solar system."
So far, scientists have found 213 planets outside our solar system — they are called exoplanets. But only eight or nine are in the right orbit and location for the type of study reported by three teams using NASA's Spitzer Space Telescope.
The closest of the two planets studied, HD 189733b, is 360 trillion miles from Earth in the constellation Vulpecula. The other planet, HD 209458b, is about 900 trillion miles away in the constellation Pegasus and it has a strange cloud of fine silicate particles. Two different research teams studied it.
The two suns the planets orbit closely have hydrogen and oxygen, the stable building blocks of water. The planets' atmospheres — examined for the first time using light spectra to determine the air's chemical composition — are supposed to be made up of the same thing, good old H2O.
"We had expected this tremendous signature of water ... and it wasn't there," said Carl Grillmair of the California Institute of Technology and Spitzer Science Center. He and Charbonneau studied the closer of the two planets, and their work is being published online in The Astrophysical Journal Letters.
Our own solar system has two planets without water in the atmosphere, Grillmair noted: Mercury, which doesn't have an atmosphere, and Venus, which is a different type of planet from the huge gaseous ones that would be expected to have the components of water in the air.
But consider the atmosphere on the second of the two exoplanets, the one 900 trillion miles away: "Weather today on 209458 is hot, dry, probably cloudy with a chance of wind," study team leader Mark Swain of NASA's Jet Propulsion Lab said in a Wednesday teleconference.
How hot? Try 1,500 degrees Fahrenheit. How windy? Somewhere between 500 and 2,000 mph.
Another research team found indications that the atmosphere has grains of silicon-oxygen compounds. That team, led by L. Jeremy Richardson of NASA's Goddard Space Flight Center in Maryland, is reporting its research in Thursday's issue of Nature.
But the key finding is dry.
"In NASA's search for life beyond Earth, the mantra has been to follow the water," said Carnegie Institution of Washington astronomer Alan Boss, who wasn't involved in any of the research.
Scientists say it's possible the water is hiding beneath dust clouds or that all the airborne water molecules are the same temperature, making it impossible to see using an infrared spectrograph. Or maybe it's just not there and astronomers have to go back to the drawing board when it comes to these alien planets.
"The very fact that we've been surprised here is a wake-up call. We obviously need to do some more work," Grillmair said.
Charbonneau said these surprising "sniffs of air from an alien world" tell astronomers not to be so Earth-centric in thinking about other planets. "We're limited by our imagination in thinking about the different avenues that these atmospheres take place in," he said.
Swain called the results "a very important stepping stone for our ultimate goal of characterizing planets around other stars where life could exist."
___
On the Net:
Spitzer Space Telescope: http://www.spitzer.caltech.edu/
Nature: http://www.nature.com.
The Astrophysical Journal Letters: http://www.journals.uchicago.edu/ApJ/rapid.html
By SETH BORENSTEIN, AP Science Writer
The absence of water from the atmosphere of both these Jupiter-sized gaseous bodies upsets one of the most basic assumptions of astronomy.
One of the researchers, Harvard University astronomy professor David Charbonneau, called the planets "very different beasts ... unlike any other planets in the solar system."
So far, scientists have found 213 planets outside our solar system — they are called exoplanets. But only eight or nine are in the right orbit and location for the type of study reported by three teams using NASA's Spitzer Space Telescope.
The closest of the two planets studied, HD 189733b, is 360 trillion miles from Earth in the constellation Vulpecula. The other planet, HD 209458b, is about 900 trillion miles away in the constellation Pegasus and it has a strange cloud of fine silicate particles. Two different research teams studied it.
The two suns the planets orbit closely have hydrogen and oxygen, the stable building blocks of water. The planets' atmospheres — examined for the first time using light spectra to determine the air's chemical composition — are supposed to be made up of the same thing, good old H2O.
"We had expected this tremendous signature of water ... and it wasn't there," said Carl Grillmair of the California Institute of Technology and Spitzer Science Center. He and Charbonneau studied the closer of the two planets, and their work is being published online in The Astrophysical Journal Letters.
Our own solar system has two planets without water in the atmosphere, Grillmair noted: Mercury, which doesn't have an atmosphere, and Venus, which is a different type of planet from the huge gaseous ones that would be expected to have the components of water in the air.
But consider the atmosphere on the second of the two exoplanets, the one 900 trillion miles away: "Weather today on 209458 is hot, dry, probably cloudy with a chance of wind," study team leader Mark Swain of NASA's Jet Propulsion Lab said in a Wednesday teleconference.
How hot? Try 1,500 degrees Fahrenheit. How windy? Somewhere between 500 and 2,000 mph.
Another research team found indications that the atmosphere has grains of silicon-oxygen compounds. That team, led by L. Jeremy Richardson of NASA's Goddard Space Flight Center in Maryland, is reporting its research in Thursday's issue of Nature.
But the key finding is dry.
"In NASA's search for life beyond Earth, the mantra has been to follow the water," said Carnegie Institution of Washington astronomer Alan Boss, who wasn't involved in any of the research.
Scientists say it's possible the water is hiding beneath dust clouds or that all the airborne water molecules are the same temperature, making it impossible to see using an infrared spectrograph. Or maybe it's just not there and astronomers have to go back to the drawing board when it comes to these alien planets.
"The very fact that we've been surprised here is a wake-up call. We obviously need to do some more work," Grillmair said.
Charbonneau said these surprising "sniffs of air from an alien world" tell astronomers not to be so Earth-centric in thinking about other planets. "We're limited by our imagination in thinking about the different avenues that these atmospheres take place in," he said.
Swain called the results "a very important stepping stone for our ultimate goal of characterizing planets around other stars where life could exist."
___
On the Net:
Spitzer Space Telescope: http://www.spitzer.caltech.edu/
Nature: http://www.nature.com.
The Astrophysical Journal Letters: http://www.journals.uchicago.edu/ApJ/rapid.html
By SETH BORENSTEIN, AP Science Writer
Monday, February 19, 2007
U.N. urged to take action on asteroid threat
SAN FRANCISCO (Reuters) - An asteroid may come uncomfortably close to Earth in 2036 and the
United Nations' name=c1> SEARCHNews News Photos Images Web' name=c3> United Nations should assume responsibility for a space mission to deflect it, a group of astronauts, engineers and scientists said on Saturday.
Astronomers are monitoring an asteroid named Apophis, which has a 1 in 45,000 chance of striking Earth on April 13, 2036.
Although the odds of an impact by this particular asteroid are low, a recent congressional mandate for
NASA' name=c1> SEARCHNews News Photos Images Web' name=c3> NASA to upgrade its tracking of near-Earth asteroids is expected to uncover hundreds, if not thousands of threatening space rocks in the near future, former astronaut Rusty Schweickart said.
"It's not just Apophis we're looking at. Every country is at risk. We need a set of general principles to deal with this issue," Schweickart, a member of the Apollo 9 crew that orbited the earth in March 1969, told an American Association for the Advancement of Science conference in San Francisco.
Schweickart plans to present an update next week to the U.N. Committee on Peaceful Uses of Outer Space on plans to develop a blueprint for a global response to an asteroid threat.
The Association of Space Explorers, a group of former astronauts and cosmonauts, intends to host a series of high-level workshops this year to flesh out the plan and will make a formal proposal to the U.N. in 2009, he said.
Schweickart wants to see the United Nations adopt procedures for assessing asteroid threats and deciding if and when to take action.
The favored approach to dealing with a potentially deadly space rock is to dispatch a spacecraft that would use gravity to alter the asteroid's course so it no longer threatens Earth, said astronaut Ed Lu, a veteran of the
International Space Station' name=c1> SEARCHNews News Photos Images Web' name=c3> International Space Station.
The so-called Gravity Tractor could maintain a position near the threatening asteroid, exerting a gentle tug that, over time, would deflect the asteroid.
An asteroid the size of Apophis, which is about 460 feet
long, would take about 12 days of gravity-tugging, Lu added.
Mission costs are estimated at $300 million.
Launching an asteroid deflection mission early would reduce the amount of energy needed to alter its course and increase the chances of a successful outcome, Schweickart said.
NASA says the precise effect of a 460-foot (140-meter) object hitting the Earth would depend on what the asteroid was made of and the angle of impact.
Paul Slovic, president of Oregon-based Decision Research, which studies judgment, decision-making and risk analysis, said the asteroid could take out an entire city or region.
By Irene Klotz
United Nations' name=c1> SEARCHNews News Photos Images Web' name=c3> United Nations should assume responsibility for a space mission to deflect it, a group of astronauts, engineers and scientists said on Saturday.
Astronomers are monitoring an asteroid named Apophis, which has a 1 in 45,000 chance of striking Earth on April 13, 2036.
Although the odds of an impact by this particular asteroid are low, a recent congressional mandate for
NASA' name=c1> SEARCHNews News Photos Images Web' name=c3> NASA to upgrade its tracking of near-Earth asteroids is expected to uncover hundreds, if not thousands of threatening space rocks in the near future, former astronaut Rusty Schweickart said.
"It's not just Apophis we're looking at. Every country is at risk. We need a set of general principles to deal with this issue," Schweickart, a member of the Apollo 9 crew that orbited the earth in March 1969, told an American Association for the Advancement of Science conference in San Francisco.
Schweickart plans to present an update next week to the U.N. Committee on Peaceful Uses of Outer Space on plans to develop a blueprint for a global response to an asteroid threat.
The Association of Space Explorers, a group of former astronauts and cosmonauts, intends to host a series of high-level workshops this year to flesh out the plan and will make a formal proposal to the U.N. in 2009, he said.
Schweickart wants to see the United Nations adopt procedures for assessing asteroid threats and deciding if and when to take action.
The favored approach to dealing with a potentially deadly space rock is to dispatch a spacecraft that would use gravity to alter the asteroid's course so it no longer threatens Earth, said astronaut Ed Lu, a veteran of the
International Space Station' name=c1> SEARCHNews News Photos Images Web' name=c3> International Space Station.
The so-called Gravity Tractor could maintain a position near the threatening asteroid, exerting a gentle tug that, over time, would deflect the asteroid.
An asteroid the size of Apophis, which is about 460 feet
long, would take about 12 days of gravity-tugging, Lu added.
Mission costs are estimated at $300 million.
Launching an asteroid deflection mission early would reduce the amount of energy needed to alter its course and increase the chances of a successful outcome, Schweickart said.
NASA says the precise effect of a 460-foot (140-meter) object hitting the Earth would depend on what the asteroid was made of and the angle of impact.
Paul Slovic, president of Oregon-based Decision Research, which studies judgment, decision-making and risk analysis, said the asteroid could take out an entire city or region.
By Irene Klotz
Monday, February 12, 2007
Dark Matter's Link to Brilliant Galaxies Confirmed
A new cosmic map confirms a close relationship between galaxies with supermassive black holes at their centers and the distribution of the invisible dark matter in the early universe.
Video: Black Holes: Warping Time & Space
Quasars are incredibly bright objects located at the center of galaxies and thought to be powered by gas falling into enormous black holes up to a billion times the mass of the sun. Although smaller than our solar system, a single quasar can outshine an entire galaxy of a hundred billion stars.
Compared to normal galaxies, quasars are extremely rare, about 200 million light years or more apart from one another on average. The new map was created using the Sloan Digital Sky Survey (SDSS-II) and includes more than 4,000 quasars, some as far as 11 billion light years away. The universe is estimated to be only about 14 billion years old.
The new map [image] reveals a close relationship between quasars and dark matter, as predicted from theory.
'By measuring the clustering of quasars, we can learn about the dark matter halos in which they sit, and we find that they live in these very rare and very massive dark matter halos in the early universe,' said study team member Michael Strauss of Princeton University.
The new map will be detailed in an upcoming issue of The Astronomical Journal.
Dark matter is a mysterious hypothetical substance that does not interact with light photons and is thus invisible to current detection instruments. Scientists estimate that only about one-sixth of the matter in the universe is visible, while the rest is dark matter.Current theories predict that matter-both the dark and visible variety-was smoothly distributed in the early universe, and that over time, it became more concentrated.
'Dark matter halos are a dime a dozen in the present day universe, but in the young universe, they were really quite rare,' Strauss said.
It was in these rare spots of concentrated dark matter that the first massive galaxies and quasars formed.
'The quasars themselves are sort of a signpost to those very massive [dark matter] halos, and our work makes that a little more clear,' Strauss told SPACE.com.
Avi Loeb, an astronomer at Harvard University who was not involved in the study, says the new findings could help answer a major question in cosmology: How did the first quasars form at all?
'How did black holes grow to a billion times the mass of the sun when the universe was only a tenth of its current age?' Loeb said. 'The SDSS measurements will help us answer this question.'
Twinkle, Twinkle, Little Quasar
Understanding Dark Matter and Light Energy
Astronomers Create 3D Map of Dark Matter
Dark Matter Exposed: Animation Offers Clues to Cosmic Mystery
Original Story: Dark Matter's Link to Brilliant Galaxies Confirmed
Visit SPACE.com and explore our huge collection of Space Pictures, Space Videos, Space Image of the Day, Hot Topics, Top 10s, Multimedia, Trivia, Voting and Amazing Images. Follow the latest developments in the search for life in our universe in our SETI: Search for Life section. Join the community, sign up for our free daily email newsletter, listen to our Podcasts, check out our RSS feeds and other Reader Favorites today!
Ker ThanStaff WriterSPACE.com
Video: Black Holes: Warping Time & Space
Quasars are incredibly bright objects located at the center of galaxies and thought to be powered by gas falling into enormous black holes up to a billion times the mass of the sun. Although smaller than our solar system, a single quasar can outshine an entire galaxy of a hundred billion stars.
Compared to normal galaxies, quasars are extremely rare, about 200 million light years or more apart from one another on average. The new map was created using the Sloan Digital Sky Survey (SDSS-II) and includes more than 4,000 quasars, some as far as 11 billion light years away. The universe is estimated to be only about 14 billion years old.
The new map [image] reveals a close relationship between quasars and dark matter, as predicted from theory.
'By measuring the clustering of quasars, we can learn about the dark matter halos in which they sit, and we find that they live in these very rare and very massive dark matter halos in the early universe,' said study team member Michael Strauss of Princeton University.
The new map will be detailed in an upcoming issue of The Astronomical Journal.
Dark matter is a mysterious hypothetical substance that does not interact with light photons and is thus invisible to current detection instruments. Scientists estimate that only about one-sixth of the matter in the universe is visible, while the rest is dark matter.Current theories predict that matter-both the dark and visible variety-was smoothly distributed in the early universe, and that over time, it became more concentrated.
'Dark matter halos are a dime a dozen in the present day universe, but in the young universe, they were really quite rare,' Strauss said.
It was in these rare spots of concentrated dark matter that the first massive galaxies and quasars formed.
'The quasars themselves are sort of a signpost to those very massive [dark matter] halos, and our work makes that a little more clear,' Strauss told SPACE.com.
Avi Loeb, an astronomer at Harvard University who was not involved in the study, says the new findings could help answer a major question in cosmology: How did the first quasars form at all?
'How did black holes grow to a billion times the mass of the sun when the universe was only a tenth of its current age?' Loeb said. 'The SDSS measurements will help us answer this question.'
Twinkle, Twinkle, Little Quasar
Understanding Dark Matter and Light Energy
Astronomers Create 3D Map of Dark Matter
Dark Matter Exposed: Animation Offers Clues to Cosmic Mystery
Original Story: Dark Matter's Link to Brilliant Galaxies Confirmed
Visit SPACE.com and explore our huge collection of Space Pictures, Space Videos, Space Image of the Day, Hot Topics, Top 10s, Multimedia, Trivia, Voting and Amazing Images. Follow the latest developments in the search for life in our universe in our SETI: Search for Life section. Join the community, sign up for our free daily email newsletter, listen to our Podcasts, check out our RSS feeds and other Reader Favorites today!
Ker ThanStaff WriterSPACE.com
Wednesday, February 07, 2007
Eternal embrace? Couple still hugging 5,000 years on
Archaeologists in Italy have discovered a couple buried 5,000 to 6,000 years ago, hugging each other.
ROME (Reuters) - Call it the eternal embrace.
ROME (Reuters) - Call it the eternal embrace.
Wednesday, January 17, 2007
Nuclear, climate perils push Doomsday Clock ahead
WASHINGTON (Reuters) - The scientists who mind the Doomsday Clock moved it two minutes closer to midnight on Wednesday -- symbolizing the annihilation of civilization and adding the perils of global warming for the first time.
The Bulletin of the Atomic Scientists, which created the Doomsday Clock in 1947 to warn the world of the dangers of nuclear weapons, advanced the clock to five minutes until midnight. It was the first adjustment of the clock since 2002.
"We stand at the brink of a second nuclear age," the bulletin's board of directors said in a statement.
They pointed North Korea's first nuclear test, Iran's nuclear ambitions, U.S. flirtation with "bunker buster" nuclear bombs, the continued presence of 26,000 American and Russian nuclear weapons and inadequate security for nuclear materials.
But the scientists also said destruction of human habitats wreaked by climate change brought on by human activities is a growing danger.
"Global warming poses a dire threat to human civilization that is second only to nuclear weapons," they said.
The announcement was made in news conferences in London and Washington.
"We foresee great peril if governments and societies do not take action now to render nuclear weapons obsolete and to prevent further climate change," theoretical physicist Stephen Hawking of the University of Cambridge, a member of the bulletin's board of sponsors, told reporters in London.
'VILLAGE IDIOTS'
Cambridge astrophysicist Martin Rees added that while the Cold War confrontation between two nuclear-armed superpowers is over, the world is closer than ever to having nuclear bombs used in a localized war or by terrorists in a city center.
"A global village will have its village idiots," Rees said.
Kennette Benedict, the bulletin's executive director, dismissed the notion that by touting the threat posed by global warming, the scientists had diluted their message about the nuclear peril.
Many scientists predict dire consequences from global warming, including higher sea levels that over time could swamp coastal regions, more severe storms and worse wildfires. Human activities like burning of fossil fuels contribute to warming, they contend.
Physicist Lawrence Krauss of Case Western Reserve University in Cleveland said if humankind fails to change course on global warming, "there's a great possibility that the Earth in the year 2100 will only dimly resemble our planet today -- and as it has existed over the past 500,000 years."
The bulletin's scientists moved the clock two minutes forward in 2002, to seven minutes until midnight, following the September 11, 2001, attacks on the United States.
The bulletin was founded in 1945 by University of Chicago scientists who had worked on developing the first nuclear bomb, and it is now overseen by some of the world's most prominent scientists.
The bulletin created the clock in 1947, two years after the United States ushered in the nuclear age by dropping atomic bombs on two Japanese cities at the end of World War Two, to symbolize the urgent nuclear dangers confronting the world.
It now stands at the closest to midnight since 1984, when it was three minutes to midnight amid a deepening Cold War.
It has been adjusted 18 times in 60 years. It was set as close as two minutes to midnight in 1953 after the United States and Soviet Union tested hydrogen bombs, and as far as 17 minutes to midnight in 1991 at the Cold War's end.
By Will Dunham Wed Jan 17, 2:22 PM ET
The Bulletin of the Atomic Scientists, which created the Doomsday Clock in 1947 to warn the world of the dangers of nuclear weapons, advanced the clock to five minutes until midnight. It was the first adjustment of the clock since 2002.
"We stand at the brink of a second nuclear age," the bulletin's board of directors said in a statement.
They pointed North Korea's first nuclear test, Iran's nuclear ambitions, U.S. flirtation with "bunker buster" nuclear bombs, the continued presence of 26,000 American and Russian nuclear weapons and inadequate security for nuclear materials.
But the scientists also said destruction of human habitats wreaked by climate change brought on by human activities is a growing danger.
"Global warming poses a dire threat to human civilization that is second only to nuclear weapons," they said.
The announcement was made in news conferences in London and Washington.
"We foresee great peril if governments and societies do not take action now to render nuclear weapons obsolete and to prevent further climate change," theoretical physicist Stephen Hawking of the University of Cambridge, a member of the bulletin's board of sponsors, told reporters in London.
'VILLAGE IDIOTS'
Cambridge astrophysicist Martin Rees added that while the Cold War confrontation between two nuclear-armed superpowers is over, the world is closer than ever to having nuclear bombs used in a localized war or by terrorists in a city center.
"A global village will have its village idiots," Rees said.
Kennette Benedict, the bulletin's executive director, dismissed the notion that by touting the threat posed by global warming, the scientists had diluted their message about the nuclear peril.
Many scientists predict dire consequences from global warming, including higher sea levels that over time could swamp coastal regions, more severe storms and worse wildfires. Human activities like burning of fossil fuels contribute to warming, they contend.
Physicist Lawrence Krauss of Case Western Reserve University in Cleveland said if humankind fails to change course on global warming, "there's a great possibility that the Earth in the year 2100 will only dimly resemble our planet today -- and as it has existed over the past 500,000 years."
The bulletin's scientists moved the clock two minutes forward in 2002, to seven minutes until midnight, following the September 11, 2001, attacks on the United States.
The bulletin was founded in 1945 by University of Chicago scientists who had worked on developing the first nuclear bomb, and it is now overseen by some of the world's most prominent scientists.
The bulletin created the clock in 1947, two years after the United States ushered in the nuclear age by dropping atomic bombs on two Japanese cities at the end of World War Two, to symbolize the urgent nuclear dangers confronting the world.
It now stands at the closest to midnight since 1984, when it was three minutes to midnight amid a deepening Cold War.
It has been adjusted 18 times in 60 years. It was set as close as two minutes to midnight in 1953 after the United States and Soviet Union tested hydrogen bombs, and as far as 17 minutes to midnight in 1991 at the Cold War's end.
By Will Dunham Wed Jan 17, 2:22 PM ET
Friday, January 05, 2007
Lost lakes of Titan are found at last
Lakes of methane have been spotted on Saturn's largest moon, Titan, boosting the theory that this strange, distant world bears beguiling similarities to Earth, according to a new study.
ADVERTISEMENT
Titan has long intrigued space scientists, as it is the only moon in the Solar System to have a dense atmosphere -- and its atmosphere, like Earth's, mainly comprises nitrogen.
Titan's atmosphere is also rich in methane, although the source for this vast store of hydrocarbons is unclear.
Methane, on the geological scale, has a relatively limited life. A molecule of the compound lasts several tens of millions of years before it is broken up by sunlight.
Given that Titan is billions of years old, the question is how this atmospheric methane gets to be renewed. Without replenishment, it should have disappeared long ago.
A popular hypothesis is that it comes from a vast ocean of hydrocarbons.
But when the US spacecraft Cassini sent down a European lander, Huygens, to Titan in 2005, the images sent back were of a rugged landscape veiled in an orange haze.
There were indeed signs of methane flows and methane precipitation, but nothing at all that pointed to any sea of the stuff.
But a flyby by Cassini on July 22 last year has revealed, thanks to a radar scan, 75 large, smooth, dark patches between three and 70 kilometers across (two and 42 miles) across that appear to be lakes of liquid methane, scientists report on Thursday.
They believe the lakes prove that Titan has a "methane cycle" -- a system that is like the water cycle on Earth, in which the liquid evaporates, cools and condenses and then falls as rain, replenishing the surface liquid.
As on Earth, Titan's surface methane may well be supplemented by a "table" of liquid methane that seeps through the rock, the paper suggests.
Some of the methane lakes seem only partly filled, and other depressions are dry, which suggests that, given the high northerly latitudes where they were spotted, the methane cycle follows Titan's seasons.
In winter, the lakes expand, while in summer, they shrink or dry up completely -- again, another parallel with Earth's hydrological cycle.
The study, which appears on Thursday in the British weekly journal Nature, is headed by Ellen Stofan of Proxemy Research in Virginia and University College London.
Titan and Earth are of course very different, especially in their potential for nurturing life. Titan is frigid, dark and, as far as is known, waterless, where as Earth is warm, light and has lots of liquid water.
But French astrophysicist Christophe Sotin says both our planet and Titan have been sculpted by processes that, fundamentally, are quite similar.
The findings "add to the weight of evidence that Titan is a complex world in which the interaction between the inner and outer layers is controlled by processes similar to those that must have dominated the evolution of any Earth-like planet," Sotin said in a commentary.
"Indeed, as far as we know," Sotin added, "there is only one planetary body that displays more dynamism than Titan. Its name is Earth."
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Titan has long intrigued space scientists, as it is the only moon in the Solar System to have a dense atmosphere -- and its atmosphere, like Earth's, mainly comprises nitrogen.
Titan's atmosphere is also rich in methane, although the source for this vast store of hydrocarbons is unclear.
Methane, on the geological scale, has a relatively limited life. A molecule of the compound lasts several tens of millions of years before it is broken up by sunlight.
Given that Titan is billions of years old, the question is how this atmospheric methane gets to be renewed. Without replenishment, it should have disappeared long ago.
A popular hypothesis is that it comes from a vast ocean of hydrocarbons.
But when the US spacecraft Cassini sent down a European lander, Huygens, to Titan in 2005, the images sent back were of a rugged landscape veiled in an orange haze.
There were indeed signs of methane flows and methane precipitation, but nothing at all that pointed to any sea of the stuff.
But a flyby by Cassini on July 22 last year has revealed, thanks to a radar scan, 75 large, smooth, dark patches between three and 70 kilometers across (two and 42 miles) across that appear to be lakes of liquid methane, scientists report on Thursday.
They believe the lakes prove that Titan has a "methane cycle" -- a system that is like the water cycle on Earth, in which the liquid evaporates, cools and condenses and then falls as rain, replenishing the surface liquid.
As on Earth, Titan's surface methane may well be supplemented by a "table" of liquid methane that seeps through the rock, the paper suggests.
Some of the methane lakes seem only partly filled, and other depressions are dry, which suggests that, given the high northerly latitudes where they were spotted, the methane cycle follows Titan's seasons.
In winter, the lakes expand, while in summer, they shrink or dry up completely -- again, another parallel with Earth's hydrological cycle.
The study, which appears on Thursday in the British weekly journal Nature, is headed by Ellen Stofan of Proxemy Research in Virginia and University College London.
Titan and Earth are of course very different, especially in their potential for nurturing life. Titan is frigid, dark and, as far as is known, waterless, where as Earth is warm, light and has lots of liquid water.
But French astrophysicist Christophe Sotin says both our planet and Titan have been sculpted by processes that, fundamentally, are quite similar.
The findings "add to the weight of evidence that Titan is a complex world in which the interaction between the inner and outer layers is controlled by processes similar to those that must have dominated the evolution of any Earth-like planet," Sotin said in a commentary.
"Indeed, as far as we know," Sotin added, "there is only one planetary body that displays more dynamism than Titan. Its name is Earth."
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