A Primer on the Great Proton Smashup

By DENNIS OVERBYE
Published: April 2, 2010

For those whose physics knowledge was a bit rusty, the news about the Large Hadron Collider, the world's biggest physics machine, might have been puzzling.



Yes, the collider finally crashed subatomic particles into one another last week, but why, exactly, is that important? Here is a primer on the collider - with just enough information, hopefully, to impress guests at your next cocktail party.

Let’s be basic. What does a particle physicist do?

Particle physicists have one trick that they do over and over again, which is to smash things together and watch what comes tumbling out.

What does it mean to say that the collider will allow physicists to go back to the Big Bang? Is the collider a time machine?

Physicists suspect that the laws of physics evolved as the universe cooled from billions or trillions of degrees in the first moments of the Big Bang to superfrigid temperatures today (3 degrees Kelvin) — the way water changes from steam to liquid to ice as temperatures decline. As the universe cooled, physicists suspect, everything became more complicated. Particles and forces once indistinguishable developed their own identities, the way Spanish, French and Italian diverged from the original Latin.

By crashing together subatomic particles — protons — physicists create little fireballs that revisit the conditions of these earlier times and see what might have gone on back then, sort of like the scientists in Jurassic Park reincarnating dinosaurs.

The collider, which is outside Geneva, is 17 miles around. Why is it so big?

Einstein taught us that energy and mass are equivalent. So, the more energy packed into a fireball, the more massive it becomes. The collider has to be big and powerful enough to pack tremendous amounts of energy into a proton.

Moreover, the faster the particles travel, the harder it is to bend their paths in a circle, so that they come back around and bang into each other. The collider is designed so that protons travel down the centers of powerful electromagnets that are the size of redwood trunks, which bend the particles’ paths into circles, creating a collision. Although the electromagnets are among the strongest ever built, they still can’t achieve a turning radius for the protons of less than 2.7 miles.

All in all, the bigger the accelerator, the bigger the crash, and the better chance of seeing what is on nature’s menu.

What are physicists hoping to see?

According to some theories, a whole list of items that haven’t been seen yet — with names like gluinos, photinos, squarks and winos — because we haven’t had enough energy to create a big enough collision.

Any one of these particles, if they exist, could constitute the clouds of dark matter, which, astronomers tell us, produce the gravity that holds galaxies and other cosmic structures together.

Another missing link of physics is a particle known as the Higgs boson, after Peter Higgs of the University of Edinburgh, which imbues other particles with mass by creating a cosmic molasses that sticks to them and bulks them up as they travel along, not unlike the way an entourage forms around a rock star when they walk into a club.

Have scientists ever seen dark matter?

It’s invisible, but astronomers have deduced from their measurements of galactic motions that the visible elements of the cosmos, like galaxies, are embedded in huge clouds of it.

Will physicists see these gluinos, photinos, squarks and winos?

There is no guarantee that any will be discovered, which is what makes science fun, as well as nerve-racking.

So how much energy do you need to create these fireballs?

At the Large Hadron Collider, that energy is now 3.5 trillion electron volts per proton — about as much energy as a flea requires to do a pushup. That may not sound like much, but for a tiny proton, it is a lot of energy. It is the equivalent of a 200-pound man bulking up by 700,000 pounds.

What’s an electron volt?

An electron volt is the amount of energy an electron would gain passing from the negative to the positive side of a one-volt battery. It is the basic unit of energy and of mass preferred by physicists.

When protons collide, is there a big bang?

There is no sound. It’s not like a bomb exploding.

In previous trials, there was an actual explosion.

All that current is dangerous. During the testing of the collider in September 2008, the electrical connection between a pair of the giant magnets vaporized. There are thousands of such connections in the collider, many of which are now believed to be defective. As a result the collider can only run at half-power for the next two years.

Could the collider make a black hole and destroy the Earth?

The collider is not going to do anything that high-energy cosmic rays have not done repeatedly on Earth and elsewhere in the universe. There is no evidence that such collisions have created black holes or that, if they have, the black holes have caused any damage. According to even the most speculative string theory variations on black holes, the Large Hadron Collider is not strong enough to produce a black hole.

Too bad, because many physicists would dearly like to see one.

This article has been revised to reflect the following correction:


Correction: April 11, 2010

Because of an editing error, an article last Sunday about the Large Hadron Collider referred incorrectly to the cooling effect of the Big Bang. It was the universe — not the Earth — that the Big Bang caused to coolfrom billions or trillions of degrees to superfrigid temperatures today.
A version of this article appeared in print on April 4, 2010, on page WK3 of the New York edition.

European Collider Begins Its Subatomic Exploration

In a control room, a scientist toasted the start of the Large Hadron Collider outside Geneva on Tuesday.
By DENNIS OVERBYE
Published: March 30, 2010

PASADENA, Calif. — After 16 years and $10 billion — and a long morning of electrical groaning and sweating — there was joy in the meadows and tunnels of the Swiss-French countryside Tuesday: the world’s biggest physics machine, the Large Hadron Collider, finally began to make subatomic particles collide.

After two false starts due to electrical failures, protons that were whipped to more than 99 percent of the speed of light and to record-high energy levels of 3.5 trillion electron volts apiece raced around a 17-mile underground magnetic track outside Geneva a little after 1 p.m. local time. They crashed together inside apartment-building-size detectors designed to capture every evanescent flash and fragment from microscopic fireballs thought to hold insights into the beginning of the universe.

The soundless blooming of proton explosions was accompanied by the hoots and applause of scientists crowded into control rooms at CERN, the European Organization for Nuclear Research, which built the collider. The relief spread to bleary-eyed gatherings of particle physicists around the world, who have collectively staked the future of their profession on the idea that the collider will eventually reveal new secrets of the universe.

Among their top goals are finding the identity of the dark matter that shapes the visible cosmos and the strange particle known as the Higgs boson, which is thought to imbue other particles with mass. Until now, these have been tantalizingly out of reach.

“We’re expecting some answers,” said David Politzer, a Nobel laureate and professor at the California Institute of Technology, where a conference room overflowed with Los Angeles-area physicists attending a midnight remote viewing, with refreshments including matzos, chips and pizza.

Rolf-Dieter Heuer, director general of CERN, speaking from Japan, said the new collider “opens a new window of discovery and it brings, with patience, new knowledge of the universe and the microcosm.”

“It shows what one can do in bringing forward knowledge,” he said, adding, “It will also bring out an army of children and young people who will get into the private sector and academia.”

“We are all proud and so happy,” Fabiola Gianotti, a spokeswoman for CERN, said of one of the giant particle detectors at the collider, known as Atlas.

Guido Tonelli, spokesman for a rival detector called C.M.S., said, “We are really starting physics.”

The success in producing proton collisions represents a remarkable comeback for CERN, but the lab is still only halfway back to where it wanted to be. Only a year and a half ago, the first attempt to start the collider ended with an explosion that left part of its tunnel enveloped in frigid helium gas and soot when an electrical connection between two of the powerful magnets that steer the protons vaporized.

A subsequent investigation revealed that the collider was riddled with thousands of such joints, a result of what Lucio Rossi, head of magnets at CERN, said was a “lack of adequate risk analysis,” in a recent report in the online journal Superconductor Science and Technology. As a result, the collider, which was designed to accelerate protons to seven trillion electron volts, then smash them together to reveal particles and forces that reigned during the first trillionth of a second of time as we know it, can only be safely run for now at half power.

CERN physicists say that operating the collider for a year and a half at this energy level should allow them to gather enough data to start catching up with its American rival, the trillion-electron-volt Tevatron at the Fermi National Accelerator Laboratory in Illinois. The Tevatron is smaller but has been running for years and thus has a head start in data. After that, the CERN machine will be shut down for a year so that the connections can be rebuilt.

Particle colliders get their oomph from Einstein’s equation of mass and energy. The more energy — denoted in the physicists’ currency of choice, electron volts — that these machines can pack into their little fireballs, the farther back in time they can go, closer and closer to the Big Bang, and the smaller and smaller are the things they can see.

The first modern accelerator was the cyclotron, built by Ernest Lawrence at the University of California, Berkeley, in the 1930s. An early version was a foot in diameter and accelerated protons to energies of 1.25 million electron volts.

Over the last century, universities and then nations leapfrogged each other, building bigger machines to peer deeper into the origins of the universe. But the race ended in 1993, when Congress canceled the Superconducting Supercollider, a 54-mile, 20 trillion-electron-volt machine being built underneath Waxahachie, Tex., after its projected cost ballooned to $11 billion.

The following year, CERN approved its own big collider. CERN, a 20-nation consortium that grew from the ashes of World War II, has provided a template for other pan-European organizations like the European Space Agency and the European Southern Observatory. With a budget and dues established by treaty, the organization enjoys a long-term stability that is the envy of American labs. Last winter, Europe took the lead for good when test collisions at the Hadron collider achieved energies of 1.18 trillion electron volts.

The collider first ramped up its beams to 3.5 trillion electron volts two weeks ago, but the engineers took pains to prevent them from colliding so as not to steal the thunder from what was billed as First Physics Day on Tuesday.

Because of the defective joints and some mysteriously underperforming magnets, it will still be three years at least before CERN’s collider runs at or near full strength. According to theoretical models, that would stretch out the time it should take to achieve the collider’s main goals, like producing the Higgs boson and testing more exotic ideas like extra dimensions.

Until then, the Tevatron will chase CERN for big goals like the Higgs boson, physicists say. The CERN experimenters will spend the next four to six months learning how their detectors work and rediscovering known physics. Then, anything is possible.

“It’s very exciting because we are entering a new energy range,” said Harvey Newman, a Caltech professor who works on the C.M.S. experiment. “We’re looking at all kinds of exotic things,” he said, including signs of extra dimensions. The possibilities begin between the middle and end of this year.”

Michael Barnett, a physicist from the Lawrence Berkeley National Laboratory, said that he had worked on an experiment for the Superconducting Supercollider for 10 years until the project was canceled by Congress, and later spent 16 years on the Atlas experiment at the CERN collider.

“We are on this planet and in this universe a short time,” he wrote in an e-mail message. “The dreams of a lifetime are waiting, and hopefully not much longer.”

Correction: An earlier version of this article incorrectly identified Fabiola Gianotti as a spokesman for CERN. She is a spokeswoman.

Five laws of human nature

New scientist Revue, 17 December 2009 by Michael Marshall

http://www.newscientist.com/article/dn18301-five-laws-of-human-nature.html

You're so predictable.

Offended? We're used to the idea that nature is governed by laws that spell out how things work. But the idea that human nature is governed by such laws raises hackles. Perhaps because of this, they have often been proposed with tongue in cheek – which makes it all the more disconcerting when they turn out to be backed up by evidence.

One such law is the Peter principle, which states that in any organisation "people reach the level of their own incompetence". As we report this week, physics-based simulations suggest that this is more than just a cynical snipe at our bosses' competence. And that means we might have to rethink our ideas about who to promote to what jobs.

So what other laws of human nature might we have to reluctantly accept? Here are five that may – or may not – govern our lives.

Parkinson's law
Why is there always so much work to do? Anyone searching for an explanation might find one in Parkinson's law. Civil servant, historian and theorist Cyril Northcote Parkinson suggested in a 1955 article that work expands to fill the time available for its completion – backed up with statistical evidence drawn from his historical research. More recent mathematical analyses have lent support to the idea.

Parkinson also came up with the "law of triviality", which states that the amount of time an organisation spends discussing an issue is inversely proportional to its importance. He argued that nobody dares to expound on important issues in case they're wrong – but everyone is happy to opine at length about the trivial.

This in turn may be a result of Sayre's law, which states that in any dispute, the intensity of feeling is inversely proportional to the value of the stakes at issue.

Parkinson also proposed a coefficient of inefficiency, which attempts to define the maximum size a committee can reach before it becomes unable to make decisions. His suggestion that it lay "somewhere 19.9 and 22.4" has stood the test of time: more recent research suggests that committees cannot include many more than 20 members before becoming utterly hapless.

Student syndrome
"If it weren't for the last minute, I wouldn't get anything done." So said an anonymous wit, and none but the most ferociously well-organised can disagree.

In fact, procrastination is a major problem for some people, especially those who are easily distracted or are uncertain of their ability to complete a task.

One of the most well-known examples of vigorous procrastination is student syndrome. As anyone who has ever been (or known) a student will know, it is standard practice to apply yourself to a task only at the last possible moment before the deadline.

Student syndrome is so common that some experts in project management recommend not assigning long periods of time to particular tasks, because the people who are supposed to do them will simply wait until just before the deadline to start work, and the project will overrun anyway (International Journal of Project Management, vol 18, p 173).

Some of the blame for student syndrome may be laid at the feet of the planning fallacy: the tendency for people to underestimate how long it will take to do something.

If you often get caught out by how long things take, we recommend considering Hofstadter's law, coined by the cognitive scientist Douglas Hofstadter: "It always takes longer than you expect, even when you take into account Hofstadter's law."

Pareto principle
The rich have a lot more money than you. That might sound like a statement of the obvious, but you may be surprised by just how much richer than you they are. In fact, in most countries 80 per cent of the wealth is owned by just 20 per cent of the population.

This was first spotted by the economist Vilfredo Pareto in the early 20th century, and it seems to be a universal rule in societies – although the precise nature of the distribution has been revised over the years.

But the Pareto principle is not just about money. For most systems, 80 per cent of events are triggered by just 20 per cent of the causes. For instance, 20 per cent of the users of a popular science website are responsible for 80 per cent of the page clicks.

Businesses often use the Pareto principle as a rule of thumb, for instance deciding to do the most important 20 per cent of a job in order to get 80 per cent of the reward.

Salem hypothesis
First proposed by Bruce Salem on the discussion site Usenet, the Salem hypothesis claims that "an education in the engineering disciplines forms a predisposition to [creationist] viewpoints". This was rephrased somewhat by P. Z. Myers as "creationists with advanced degrees are often engineers".

Is there any evidence to back this up, or is it just a gratuitous slander against engineers? A 1982 article in the Proceedings of the Iowa Academy of Science suggested that many leading creationists trained as engineers, notably Henry Morris, one of the authors of the key creationist book The Genesis Flood. But the article did not present any figures.

More recently, Diego Gambetta and Steffen Hertog have noted a preponderance of engineers among Islamic extremist groups. They suggested that engineers may be at greater risk of being recruited by such groups than other graduates.

Obviously creationism is not the same thing as violent activism, but Gambetta and Hertog's analysis may be useful nevertheless because they discuss the engineering mindset in some detail. They show, for instance, that engineers are more likely to be religious than other graduates (PDF).

None of this is anywhere near enough to prove the Salem hypothesis, but it does provide some intriguing circumstantial evidence.

Maes-Garreau law
Everyone loves predicting the future, and some make a career out of it. These futurists often present detailed, authoritative claims about what is going to happen, though their success rate isn't always exemplary.

A common theme in futurist predictions is that revolutionary technology of one sort or another is just around the corner, and that this technology will allow people to live forever. This can mean physical immortality or some more abstracted technique like downloading one's personality into a computer. The "singularity", which Ray Kurzweil says will arrive "by 2045 or thereabouts", is a prime example.

And thus we come to the Maes-Garreau law, which states that any such prediction about a favourable future technology will fall just within the expected lifespan of the person making it.

Pattie Maes, a researcher at the Massachusetts Institute of Technology, observed in the late 1980s that many of her male colleagues were interested in these ideas, and tabulated when they expected the miracle technology to arrive. Sure enough, she found that the dates they predicted for the singularity were always on or around their 70th birthdays.

She mentioned her findings in a talk, but did not write them up. Subsequently, the journalist Joel Garreau made similar observations in his book Radical Evolution, which looked at the implications of such "transhumanist" ideas.

The Maes-Garreau law was finally coined, and given its name, by Wired editor Kevin Kelly. Kelly informally repeated Maes's analysis, confirming her findings. He then defined the "Maes-Garreau point" as the latest possible date a prediction can come true and still remain in the lifetime of the person making it.