Stand Down: Black Holes Won't Destroy Earth

Jeanna Bryner, Senior Writer, LiveScience.com

The world's largest, most powerful particle smasher

probably won't generate any planet-gobbling black holes,

according to a new analysis.

That's contrary to suggestions in a news article

Wednesday that invoked a possible doomsday scenario

and said black holes created by the collider could stick

around longer than predicted.

The Large Hadron Collider (LHC), a 17-mile (27-kilometer)

circular tunnel running 300 feet (91 meters) underground

at the European Center for Nuclear Research (CERN)

near Geneva, is expected to recreate the conditions that

occurred a fraction of a second after the Big Bang, the

theoretical instant in which the universe was born from an

incredibly small point.

By smashing protons together at nearly the speed of light, 

the LHC could help to solve mysteries about the origin of

mass and the reasons for more matter than antimatter in

the universe.

(The LHC was shut down last year after a helium leak was

discovered within days of its initial powering up. The

machine is scheduled to re-start again some time this

year, according to CERN.)

Scientists have speculated the proton-to-proton collisions

could possibly generate microscopic black holes. These

black holes would be orders of magnitude smaller and less

massive than the gravity wells produced by the collapse

of stars and known to exist in the universe, said Howard

Gordon of Brookhaven National Laboratory in New York,

who also works at the LHC.

Even still, fears arose in the past few years that the LHC

could churn out a black hole that would gobble up

everything in sight, including our planet.

Why the fears? "I think it's the confusion between the

massive black holes in the universe and these

microscopic black holes that possibly could get created,"

Gordon told LiveScience. "It's a difference in scale."

Black-hole model

The new analysis, detailed online at ArXiv.org, a

repository for new research papers, suggests again that

the LHC probably can't generate a catastrophic black

hole.

Gordon said the analysis is based on a theoretical model

and that further research is needed to confirm the results.

Roberto Casadio of the University of Bologna in Italy and

his University of Alabama colleagues Benjamin Harms and

Sergio Fabi based their theoretical model on the so-called

Randall-Sundrum brane-world scenario, in which the four-

dimensional universe is embedded within a five-

dimensional space.

"All we're doing is taking a model of our space-time, where

we live, and exploring the consequences," Harms said

during a telephone interview. "And our exploration shows

that black holes could not grow large enough to become

catastrophic in the sense that they could do damage to

the Earth or anything in the Earth."

He added, "What we found was that if black holes are

created at the LHC, they would not be able to grow to

catastrophic size because the accretion rate is simply not

great enough to offset the evaporation rate."

In fact, the model showed that once a black hole is

created by the LHC (if that were to happen), the only way

to get the black hole to grow would be "to extend the size

of one of the parameters in our model beyond a physically

accepted value," so beyond what is physically possible.

And then, such a black hole would evaporate, and

essentially vanish, within one-trillionth to one-millionth of a

second, the model showed. While the black holes might

not truly vanish, their masses would become so small they

would have no effect on Earth.

One small caveat is that the results only apply to Earth

because they depend partly on the density of material

through which the black holes are traveling.

Creating black holes

"Large Hadron Collider had a tremendous amount of

publicity last year because of the black hole

speculations," Gordon said, adding, "We don't know for

sure we're even going to see black holes in the Large

Hadron Collider."

Here's the logic behind the LHC generating microscopic

black holes:

Various models of the universe suggest extra dimensions

(other than those of space and time) exist and are folded

up into sizes ranging from that of a proton to as big as a

fraction of a millimeter. The models go on to suggest that

at distances comparable to such sizes, gravity becomes

far stronger. If this is true, the collider could smash

enough energy together to generate gravitational

collapses that produce black holes.

Researchers have calculated that under such scenarios,

the accelerator could create a microscopic black hole

anywhere from every second to every day.

Harmless black holes

Physicists have repeatedly said that fears about these

artificial black holes are "groundless."

For instance, microscopic black holes would probably lose

more mass than they absorb and so would evaporate

immediately.

Say a black hole was created and that black hole was

stable. "Then their interactions would be very weak. They

would pass harmlessly into space. They would vanish,"

Gordon said, referring to stable black holes with no

electrical charge.

In addition, as CERN scientists have pointed out, Earth is

bathed with cosmic rays powerful enough to create black

holes, and the planet hasn't been destroyed yet.

At the end of the day, Gordon said, the LHC is safe and

so are we.

"We're expecting the discoveries at the Large Hadron

Collider to be significant and exciting, but we are pretty

sure that the collider is safe and will not be causing any

trouble to people living on Earth," Gordon said.

·           Will the Large Hadron Collider Destroy Earth? 

·           Despite Rumors, Black Hole Factory Will Not Destroy Earth 

·           Search for Magical Dark Matter Gets Real 

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Small accidents mean big trouble for supercollider

By ALEXANDER G. HIGGINS

GENEVA - Scientists expect startup glitches in the massive, complex machines they use to smash atoms.

But the unique qualities of the world's largest particle collider mean that the meltdown of a small electrical connection could delay its groundbreaking research until next year, scientists said Sunday.

Because the Large Hadron Collider operates at near absolute zero -- colder than outer space -- the damaged area must be warmed to a temperature where humans can work. That takes about a month. Then it has to be re-chilled for another month.

As a result, the equipment may not be running again before the planned shutdown of the equipment for the winter to reduce electricity costs. That means Friday's meltdown could end up putting off high-energy collisions of particles -- the machine's ultimate objective -- until 2009.

"Hopefully we'll come online and go quickly to full energy a few months into 2009 so in the long term, this may not end up being such a large delay in the physics program," Seth Zenz, a graduate student from the University of California, wrote on the site of the U.S. physicists working at the European Organization for Nuclear Research, or CERN.

"It's obviously a short-term disappointment, though, and a lost opportunity," he wrote.

CERN spokesman James Gillies said the repair operation will last until close to the usual winter shutdown time at the end of November. There has been some discussion that the new equipment could operate through the winter, but no decision has been made, he said.

The melting of the wire connecting two magnets Friday would have taken only a couple of days to repair on smaller, room-temperature accelerators that have been in use for decades, Gillies said.

Gillies said particle accelerators using superconducting equipment at Fermilab outside Chicago and at Brookhaven National Laboratory in New York state had similar problems starting up, but have been operating smoothly since then.

"Once they settled in they seem to be pretty stable," Gillies said.

At the Sept. 10 launch of the collider, beams of protons from the nuclei of atoms were fired first at the speed of light in a clockwise direction though a fire-hose-sized tube in the tunnel. Then proton beams were fired in the counterclockwise tube.

Jos Engelen, CERN's chief scientific officer and deputy director-general, said the startup showed that the LHC can handle complex operations.

"We have encountered a weakness in one particular connection during very final hardware commissioning," Engelen told The Associated Press by e-mail. "It is tough, but it can happen. We will make the repair and resume the very successful operation of the accelerator."

A transformer failed outside the cold zone about 36 hours after the collider's launch. That was repaired and the machine was ready again a week after it was shut down.

But the goal of the LHC -- shattering protons to reveal more about how the tiniest particles were first created -- was still weeks away because the equipment has to be gradually brought to the higher energies possible at full power.

"This was the last circuit of the LHC to be tested at high current before operations," Gillies said. "There are an awful lot of these connections between wires in the machine. They all have to be very well done so that they don't stop superconducting, and what appears to have happened is that this connection stopped being superconducting."

Superconductivity -- the ability to conduct electricity without any resistance in some metals at low temperatures -- allows for much greater efficiency in operating the electromagnets that guide the proton beams.

Without the superconducting, resistance builds up in the wires, causing them to overheat, he explained.

"That's what we think happened," Gillies said. "This piece of wire heated up, melted, and that led to a mechanical failure."

Gillies said experts have already gone down into the 27-kilometer (17-mile) circular tunnel under the Swiss-French border to inspect the damage.

"By Monday I suspect we'll know more," he said.

Gillies said there is plenty for scientists at CERN to do between now and the startup of experiments, including studying cosmic rays that pass through collider's massive detectors.

Associated Press writer Patrick McGroarty in Berlin contributed to this report.

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Scientists beaming after test of big atom smasher (LHC成功完成第一個測試)

By ALEXANDER G. HIGGINS, Associated Press Writer

GENEVA - A small blip on a computer screen sent champagne corks popping among physicists in Switzerland. Near Chicago, researchers at a "pajama party" who watched via satellite let out an early morning cheer.

The blip was literally of cosmic proportions, representing a new tool to probe the birth of the universe.

The world's largest atom smasher passed its first test Wednesday as scientists said their powerful tool is almost ready to reveal how the tiniest particles were first created after the "big bang," which many theorize was the massive explosion that formed the stars, planets and everything.

Rivals and friends turned out in the wee hours at Fermilab in Batavia, Ill., in pajamas to watch the event by a special satellite connection. Joining in from around the world were other physicists -- many of whom may one day work on the new Large Hadron Collider.

Tension mounted in the five control rooms at CERN, the European Organization for Nuclear Research, as scientists huddled around computer screens. After a few trial runs, they fired a beam of protons clockwise around the 17-mile tunnel of the collider deep under the rolling fields along the Swiss-French border. Then they succeeded in sending another beam in the opposite, counterclockwise direction.

The physicists celebrated with champagne when the white dots flashed on the blue screens of the control room, showing a successful crossing of the finish line on the $10 billion machine under planning since 1984.

"The first technical challenge has been met," said a jubilant Robert Aymar, director-general of CERN. "What you have just seen is the result of 20 years of effort. It all went like clockwork. Now it's for the physicists to show us what they can do.

"They are ready to go for discoveries," Aymar said. "Man has always shown he wants to know where he comes from and where he will go, where the universe comes from and where it will go. So here we're looking at essential questions for mankind."

The beams will gradually be filled with more protons and fired at near the speed of light in opposite directions around the tunnel, making 11,000 circuits a second. They will travel down the middle of two tubes about the width of fire hoses, speeding through a vacuum that is colder than outer space. At four points in the tunnel, the scientist will use giant magnets to cross the beams and cause protons to collide. The collider's two largest detectors -- essentially huge digital cameras weighing thousands of tons -- are capable of taking millions of snapshots a second.

It is likely to be several weeks before the first significant collisions.

The CERN experiments could reveal more about "dark matter," antimatter and possibly hidden dimensions of space and time. It could also find evidence of a hypothetical particle -- the Higgs boson -- which is sometimes called the "God particle" because it is believed to give mass to all other particles, and thus to matter that makes up the universe.

...

Its start came over the objections of some who feared the collision of protons could eventually imperil the Earth by creating micro black holes -- subatomic versions of collapsed stars whose gravity is so strong they can suck in planets and other stars.

...

The project organized by the 20 European member nations of CERN has attracted researchers from 80 nations. Some 1,200 are from the United States, an observer country that contributed $531 million. Japan, Canada, Russia and India -- also observers -- are other major contributors.

Some scientists have been waiting for 20 years to use the LHC.

...

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