Earth Will Survive After All, Physicists Say
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By DENNIS OVERBYE
Published: June 21, 2008
That black hole that was going to eat the Earth? Forget about it, and keep making the mortgage payments — those of you who still have them.
A new particle accelerator, the Large Hadron Collider scheduled to go into operation this fall outside Geneva, is no threat to the Earth or the universe, according to a new safety review approved Friday by the governing council of the European Organization for Nuclear Research, or Cern, which is building the collider.
“There is no basis for any concerns about the consequences of new particles or forms of matter that could possibly be produced by the LHC,” five physicists who comprised the safety assessment group wrote in their report. Whatever the collider will do, they said, Nature has already done many times over.
The report is available at http://lsag.web.cern.ch/lsag/LSAG-Report.pdf.
The physicists, who labored anonymously for the last year and a half, are John Ellis, Michelangelo Mangano, Gian Giudice and Urs Wiedemann, of Cern, and Igor Tkachev, of the Institute for Nuclear Research in Moscow. In a press release, Cern’s director general Robert Aymar said, “With this report, the Laboratory has fulfilled every safety and environmental evaluation necessary to ensure safe operation of this exciting new research facility.”
It is full speed ahead, they say, on the new machine, which is designed to accelerate protons, the building blocks of ordinary matter, to energies of 7 trillion electron volts and then bang them together to produce tiny primordial fireballs, miniature versions of the Big Bang. Physicists will comb the detritus from those fireballs in search of forces and particles and even new laws of nature that might have prevailed during the first trillionth of a second of time.
Some critics have argued, however, that Cern has ignored or downplayed the risk that the collider could produce a black hole that would swallow the Earth, or that it could create some other dangerous particle.
The safety group, however, pointed out that cosmic rays have produced equivalently energetic collisions with the Earth and other objects in the cosmos over and over again. “This means that Nature has already completed about 1031 LHC experimental programs since the beginning of the Universe,” they write. But the stars and galaxies endure.
The new report, which is an update and expansion of a previous 2003 report, pays particular attention to the issue of black holes, which could be produced according to some speculative variations of the already speculative string theory. Could one eat the Earth? These same theories predict that the black holes would immediately disintegrate, the authors say. But if stable black holes could somehow be produced, they would also have been produced by cosmic ray collisions.
The report draws heavily on a dense 96-page analysis by Steven B. Giddings of the University of California, Santa Barbara, and Dr. Mangano, which will be available on the physics archive on Monday. In that paper, Dr. Giddings and Dr. Mangano conclude, “Indeed, conservative arguments based on detailed observations and the best-available scientific knowledge, including solid astronomical data, conclude, from multiple perspectives, that there is no risk of any significance whatsoever from such black holes.”
The difference between these two ways of making black holes is that the ones from cosmic rays would be going near the speed of light and would shoot through the Earth with no effect, while collider black holes would be at rest relative to the Earth and could be captured. But if such black holes from cosmic rays existed, the physicists concluded, dense cinders like neutron stars or white dwarfs would capture them and get eaten. But that doesn’t happen; such objects continue to exist.
The safety report was itself reviewed and approved by another panel of scientists outside Cern. And so, after 14 years and $8 billion, the future of physics is almost here.
Cern’s engineers are in the process of cooling the superconducting magnets that power the protons around their 17-mile racetrack down to within 3 degrees Fahrenheit of absolute zero. They are on track, they say to begin circulating protons in the machine in August and to begin colliding them a couple of months later.
Because the engineers have not yet finished “training” the magnets to carry the currents necessary to propel the protons to full energy, the plan is for the colliding protons to have 5 trillion electron volts apiece initially, still five times more energetic than physicists have achieved before.
In the winter, when Cern traditionally shuts down for a period, the magnets will be trained for the full energy. In the spring the collider will start up again with 14-trillion volt collisions. And physicists can finally stop holding their breaths.
An earlier version of this article misstated the number of authors of the report. There are five, not four. Gian Giudice of Cern is also an author.
Sunday, June 22, 2008
Sunday, June 15, 2008
Christian Theologians Prepare for Extraterrestrial Life
Home > Technology & Science
Christian Theologians Prepare for Extraterrestrial Life
By BRANDON KEIM
June 15, 2008
Little green men might shock the secular public. But the Catholic Church would welcome them as brothers.
Alien
(Getty Images)
That's what Vatican chief astronomer and papal science adviser Gabriel Funes explained in a recent article in L'Osservatore Romano, the newsletter of the Vatican Observatory (translated here). His conclusion might surprise nonbelievers. After all, isn't this the same church that imprisoned Galileo for saying that the Earth revolves around the sun? Doesn't the Bible say that God created man -- not little green men -- in his image?
Indeed, many observers assert that aliens would be bad for believers. Jill Tarter, director of the Center for SETI Research, once wrote that finding intelligent other-worldly life "will be inconsistent with the existence of God or at least organized religions." But such predictions tend to come from outside Christianity. From within, theologians have debated the implications of alien contact for centuries. And if one already believes in angels, no great leap of faith is required to accept the possibility of other extraterrestrial intelligences.
Since God created the universe, theologians say, he would have created aliens, too. And far from being weakened by contact, Christianity would adapt. Its doctrines would be interpreted anew, the aliens greeted with open -- and not necessarily Bible-bearing -- arms.
"The main question is, 'Would religion survive this contact?'" said NASA chief historian Steven J. Dick, author of The Biological Universe. "Religion hasn't gone away after Copernican theory, after Darwin. They've found ways to adapt, and they'll find a way if this happens, too," Dick says.
The central conundrum posed to Christianity by alien contact would involve the Incarnation -- the arrival of Jesus Christ as God's representative on Earth, his crucifixion and the absolution of humanity's sins through his forgiveness.
"It would still be true -- but if there are other races and intelligences, then what is the meaning of this visit to our race at that time?" asked Vatican astronomer Guy Consolmagno, who in 2005 penned the booklet Intelligent Life in the Universe?
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Christian Theologians Prepare for Extraterrestrial Life
By BRANDON KEIM
June 15, 2008
Little green men might shock the secular public. But the Catholic Church would welcome them as brothers.
Alien
(Getty Images)
That's what Vatican chief astronomer and papal science adviser Gabriel Funes explained in a recent article in L'Osservatore Romano, the newsletter of the Vatican Observatory (translated here). His conclusion might surprise nonbelievers. After all, isn't this the same church that imprisoned Galileo for saying that the Earth revolves around the sun? Doesn't the Bible say that God created man -- not little green men -- in his image?
Indeed, many observers assert that aliens would be bad for believers. Jill Tarter, director of the Center for SETI Research, once wrote that finding intelligent other-worldly life "will be inconsistent with the existence of God or at least organized religions." But such predictions tend to come from outside Christianity. From within, theologians have debated the implications of alien contact for centuries. And if one already believes in angels, no great leap of faith is required to accept the possibility of other extraterrestrial intelligences.
Since God created the universe, theologians say, he would have created aliens, too. And far from being weakened by contact, Christianity would adapt. Its doctrines would be interpreted anew, the aliens greeted with open -- and not necessarily Bible-bearing -- arms.
"The main question is, 'Would religion survive this contact?'" said NASA chief historian Steven J. Dick, author of The Biological Universe. "Religion hasn't gone away after Copernican theory, after Darwin. They've found ways to adapt, and they'll find a way if this happens, too," Dick says.
The central conundrum posed to Christianity by alien contact would involve the Incarnation -- the arrival of Jesus Christ as God's representative on Earth, his crucifixion and the absolution of humanity's sins through his forgiveness.
"It would still be true -- but if there are other races and intelligences, then what is the meaning of this visit to our race at that time?" asked Vatican astronomer Guy Consolmagno, who in 2005 penned the booklet Intelligent Life in the Universe?
two more pages
NEXT >
Monday, June 9, 2008
Weight of the Milky Way
Discovery of the Week
What the Milky Way Weighs
How much does our galaxy weigh? About half as much as astronomers once thought. Or so says a recent study by an international team of stellar scientists. According to their calculations, the Milky Way's mass is equal to that of about 1 trillion suns. Previous studies had put our galaxy's bulk at roughly 2 trillion suns.
Friends, remember: this bonus issue is just a taste of what our members get every weekday. To feed your brain for life, just click below and . . .
Why the wide discrepancy? Well, you can't just plop a galaxy onto a scale. To estimate the Milky Way's mass, researchers measure the speeds of stars and dwarf galaxies that orbit its main disk in a "galactic halo." But they don't always agree about which stars' speeds to measure--or about other factors that could affect the speeds they see.
As one researcher notes, "the total mass of the galaxy is hard to measure because we're stuck in the middle of it." Still, the new study has at least one big advantage over previous ones. Thanks to better technology, it started from a much larger sample of stars.
Of course, even on the newer, slimmer estimate, our little corner of the universe is mind-bogglingly big. To try to get a sense for just how big it is, let's survey the Milky Way by some other astronomical numbers.
The Milky Way's Astronomical Numbers
100,000 - Diameter of the Milky Way, in light-years. It's also around 1,000 light-years thick, and that's just the main stellar disk. One light-year is a little less than 6 trillion miles (10 trillion km), so we're talking about a very big disk. In fact, if our solar system was just the size of a coin in your pocket, the Milky Way would still be the size of the United States.
26,000 - Distance from our solar system to the Milky Way's center, in light-years. Astronomers think our solar system completes an orbit around the galaxy's center once every 225 to 250 million years. That means it was just one "galactic year" ago when the dinosaurs began to appear on Earth.
2.6 million - Low-end estimate of the number of suns it would take to equal the mass of the supermassive black hole that lurks at our galaxy's center. The sun is roughly 333,000 times more massive than Earth. So, it would take at least 858 billion Earths to equal that black hole's mass. Of course, no one can see the black hole. But astronomers theorize that such massive monsters lurk at the hearts of most galaxies.
200-400 billion - Number of stars in the Milky Way. That number is staggering enough. But consider this. Most astronomers say there are at least 100 billion other galaxies out beyond ours. Big as it is, our little corner of the universe really is just that. The Milky Way is but a drop in the bucket.
--Steve Sampson
What the Milky Way Weighs
How much does our galaxy weigh? About half as much as astronomers once thought. Or so says a recent study by an international team of stellar scientists. According to their calculations, the Milky Way's mass is equal to that of about 1 trillion suns. Previous studies had put our galaxy's bulk at roughly 2 trillion suns.
Friends, remember: this bonus issue is just a taste of what our members get every weekday. To feed your brain for life, just click below and . . .
Why the wide discrepancy? Well, you can't just plop a galaxy onto a scale. To estimate the Milky Way's mass, researchers measure the speeds of stars and dwarf galaxies that orbit its main disk in a "galactic halo." But they don't always agree about which stars' speeds to measure--or about other factors that could affect the speeds they see.
As one researcher notes, "the total mass of the galaxy is hard to measure because we're stuck in the middle of it." Still, the new study has at least one big advantage over previous ones. Thanks to better technology, it started from a much larger sample of stars.
Of course, even on the newer, slimmer estimate, our little corner of the universe is mind-bogglingly big. To try to get a sense for just how big it is, let's survey the Milky Way by some other astronomical numbers.
The Milky Way's Astronomical Numbers
100,000 - Diameter of the Milky Way, in light-years. It's also around 1,000 light-years thick, and that's just the main stellar disk. One light-year is a little less than 6 trillion miles (10 trillion km), so we're talking about a very big disk. In fact, if our solar system was just the size of a coin in your pocket, the Milky Way would still be the size of the United States.
26,000 - Distance from our solar system to the Milky Way's center, in light-years. Astronomers think our solar system completes an orbit around the galaxy's center once every 225 to 250 million years. That means it was just one "galactic year" ago when the dinosaurs began to appear on Earth.
2.6 million - Low-end estimate of the number of suns it would take to equal the mass of the supermassive black hole that lurks at our galaxy's center. The sun is roughly 333,000 times more massive than Earth. So, it would take at least 858 billion Earths to equal that black hole's mass. Of course, no one can see the black hole. But astronomers theorize that such massive monsters lurk at the hearts of most galaxies.
200-400 billion - Number of stars in the Milky Way. That number is staggering enough. But consider this. Most astronomers say there are at least 100 billion other galaxies out beyond ours. Big as it is, our little corner of the universe really is just that. The Milky Way is but a drop in the bucket.
--Steve Sampson
Monday, June 2, 2008
Tiniest extrasolar planet found
Tiniest extrasolar planet found
By Paul Rincon
Science reporter, BBC News
The planet may be orbiting a "failed star" called a brown dwarf
Astronomers have sighted the smallest extrasolar planet yet orbiting a normal star - a distant world just three times the size of our own.
Discovering a planet with a similar mass to that of Earth is considered the "holy grail" of research into planets that lie outside our Solar System.
It is vital because researchers want to find other worlds that could host life.
The planet orbits a star which is itself of such low mass it may in fact be a "failed star", or brown dwarf.
Astronomers found the new world using a technique called gravitational microlensing. This takes advantage of the fact that light is bent as the rays pass close to a massive object, like a star.
The planet, called MOA-2007-BLG-192Lb, is about 3.3 times the size of Earth. Some researchers have suggested the planet could have a thick atmosphere and have even speculated there could be a liquid ocean on its surface.
Internal heat coming from within the planet could be warming up the surface
Nicholas Rattenbury, University of Manchester
Nasa's planned James Webb Space Telescope, due to launch in 2013, could search for signatures of life on Earth-mass planets orbiting low-mass stars in the vicinity of the Sun.
A smaller planet than this one has been found orbiting a pulsar, a spinning neutron star which produces powerful beams of radiation.
Lead author David Bennett, from the University of Notre Dame, commented: "This is leading the way to finding lower mass planets, including Earth-mass planets, by microlensing.
He added: "It also encourages astronomers who search for planets in the habitable zones of very low-mass stars."
Water world?
The planet orbits its host star, or brown dwarf, with an orbital radius similar to that of Venus. But the host is likely to be between 3,000 and one million times fainter than the Sun, so the top of the planet's atmosphere is likely to be colder than Pluto. It would also be extremely dim if one were to stand on its surface.
Nicholas Rattenbury, a co-author from the University of Manchester and Jodrell Bank, told BBC News: "Our best ideas about how planets form suggests the planet could have quite a thick atmosphere. This atmosphere could act like a big blanket, keeping the planet warm.
"So even though there's very little energy coming from its host star, hitting the planet and warming it up that way, internal heat coming from within the planet could be warming up the surface.
"This has led to some speculation that there could, possibly, be a liquid ocean on the surface of this planet. The reason why that's exciting, is one of the properties we'd like to have on a habitable planet is liquid water on the surface."
MOA-2007-BLG-192Lb was found with the new MOA-II telescope at New Zealand's Mount John Observatory.
The technique employed to find the new planet uses the gravitational field of a star like a lens - magnifying the light from a distant background star. This effect occurs only when the two stars are in almost perfect alignment.
Astronomers are able to detect planets orbiting the lens star if the light from the background star is warped by one or more planets.
The team's measurements cannot distinguish whether the planet's host is a brown dwarf or a very low-mass hydrogen burning star called a red dwarf.
Paul.Rincon-INTERNET@bbc.co.uk
By Paul Rincon
Science reporter, BBC News
The planet may be orbiting a "failed star" called a brown dwarf
Astronomers have sighted the smallest extrasolar planet yet orbiting a normal star - a distant world just three times the size of our own.
Discovering a planet with a similar mass to that of Earth is considered the "holy grail" of research into planets that lie outside our Solar System.
It is vital because researchers want to find other worlds that could host life.
The planet orbits a star which is itself of such low mass it may in fact be a "failed star", or brown dwarf.
Astronomers found the new world using a technique called gravitational microlensing. This takes advantage of the fact that light is bent as the rays pass close to a massive object, like a star.
The planet, called MOA-2007-BLG-192Lb, is about 3.3 times the size of Earth. Some researchers have suggested the planet could have a thick atmosphere and have even speculated there could be a liquid ocean on its surface.
Internal heat coming from within the planet could be warming up the surface
Nicholas Rattenbury, University of Manchester
Nasa's planned James Webb Space Telescope, due to launch in 2013, could search for signatures of life on Earth-mass planets orbiting low-mass stars in the vicinity of the Sun.
A smaller planet than this one has been found orbiting a pulsar, a spinning neutron star which produces powerful beams of radiation.
Lead author David Bennett, from the University of Notre Dame, commented: "This is leading the way to finding lower mass planets, including Earth-mass planets, by microlensing.
He added: "It also encourages astronomers who search for planets in the habitable zones of very low-mass stars."
Water world?
The planet orbits its host star, or brown dwarf, with an orbital radius similar to that of Venus. But the host is likely to be between 3,000 and one million times fainter than the Sun, so the top of the planet's atmosphere is likely to be colder than Pluto. It would also be extremely dim if one were to stand on its surface.
Nicholas Rattenbury, a co-author from the University of Manchester and Jodrell Bank, told BBC News: "Our best ideas about how planets form suggests the planet could have quite a thick atmosphere. This atmosphere could act like a big blanket, keeping the planet warm.
"So even though there's very little energy coming from its host star, hitting the planet and warming it up that way, internal heat coming from within the planet could be warming up the surface.
"This has led to some speculation that there could, possibly, be a liquid ocean on the surface of this planet. The reason why that's exciting, is one of the properties we'd like to have on a habitable planet is liquid water on the surface."
MOA-2007-BLG-192Lb was found with the new MOA-II telescope at New Zealand's Mount John Observatory.
The technique employed to find the new planet uses the gravitational field of a star like a lens - magnifying the light from a distant background star. This effect occurs only when the two stars are in almost perfect alignment.
Astronomers are able to detect planets orbiting the lens star if the light from the background star is warped by one or more planets.
The team's measurements cannot distinguish whether the planet's host is a brown dwarf or a very low-mass hydrogen burning star called a red dwarf.
Paul.Rincon-INTERNET@bbc.co.uk
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