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This subject has been mentioned in a few other threads, but as it should provide a wealth of new data and theories in physics I feel it deserves a thread of its own.
The Big Bang: atom-smaching could uncover truth
Last Updated: 12:01am GMT 25/03/
Scientists hope that a new atom-smashing machine will allow them to replicate the beginning of the universe and uncover truths about how it works, says Graham Farmalo
In a few months' time, the world's most powerful atom-smasher will be switched on at the CERN laboratory near Geneva.
Scientists hope the new machine will further their understanding of the fundamental laws that underlie the workings of the universe - "to know the mind of God", in Stephen Hawking's arresting phrase.
Plans are afoot at Radio 4 to mark the event by devoting programming to particle physics, broadcasting from the lab throughout the day on which the physicists switch on their new toy, the biggest scientific instrument ever built.
It will enable them to recreate - fleetingly - the state of the universe during the early stages of the Big Bang. Quite how early beggars belief: a millionth of a millionth of a second after the beginning of time.
One of the leading theorists of the younger generation, Nima Arkani-Hamed of the Institute for Advanced Study at Princeton, summarises the excitement: "We have been waiting for a generation for the new machine to turn on. Our world view is set to change dramatically, and we can't wait to get started."
The machine is known as the Large Hadron Collider, or LHC (hadron is the technical name of the class of sub-atomic particles to which protons belong).
The LHC will do something essentially very simple: record what happens when protons are smashed together.
This way of finding out about Nature might seem crude, but there is no alternative: protons, each about a tenth of a thousandth as wide as an atom, are much too small to see, cut up or probe in any other way.
This strategy of arranging brutal, sub-atomic smash-ups has paid handsome dividends over the past three-quarters of a century.
Its first great success was the talk of the country in 1932 when the Cambridge experimenters John Cockcroft and Ernest Walton split the atom by firing protons into the core of lithium atoms, producing atoms of a different type, helium.
In a piece of nuclear alchemy, they had turned one type of chemical element into another.
Science has come a long way since then. Cockcroft and Walton's particle accelerator was a pea-shooter compared with the LHC, which delivers protons with 10 million times the energy.
The particle beams in the new collider circulate in a tunnel 17 miles long, about 100m below the Swiss-French border. The collisions take place in huge detectors, one of them called Atlas, so vast it would only just fit inside Westminster Abbey.
Some 10,000 physicists and engineers from 100 countries are working on the £4.4 billion machine. For every adult in the UK, the annual cost of contributing to the project is about the price of one pint of beer.
So is it worth it? Yes - because the LHC will probe more deeply into the heart of atoms than ever before, 10 times more deeply than any previous machine.
To do this, its operators have to assemble batches of particles, each consisting of hundreds of billions of protons, and accelerate them to within a gnat's whisker of the speed of light, while subtly tweaking the motion of each batch so that it keeps to the right path.
In the tunnel - the largest fridge in the world, colder than outer space - two batches will circulate in opposite directions, ready to meet in virtually head-on collisions. Forty million such collisions will take place every second, generating a spray of hundreds or even thousands of particles.
The conditions then will be just as they were 13.7 billion years ago, at the start of the Big Bang.
This, inevitably, will produce a lot of data - indeed, the experiments will fill some 600 stacks of CDs, each of them as high as the Eiffel Tower. The data processing, to be carried out by researchers all over the world, is one of the biggest challenges computer scientists have ever tackled.
What do they expect to find when they begin poring over the results, probably early next year?
They would certainly like to improve their current theory about the forces that bind together the particles in every atom. Known as the Standard Model, this is one of the triumphs of 20th-century science and fits in with the results of all experiments ever done on sub-atomic particles.
The problem is that no one has ever observed a crucial ingredient, the Higgs particle, whose existence goes some way to explain why atoms contain particles that have weight. With confirmation or refutation of the Higgs impending, some theoreticians are getting cold feet and supporting other ideas.
This is partly because the Standard Model is far from perfect. For theorists, too much in it is arbitrary. Nobody, for example, understands the masses of Nature's fundamental particles and why the force of gravity is so weak compared with the other forces.
Some researchers have a new, improved model up their sleeve, based on a special kind of symmetry known as supersymmetry, which might exist at the heart of Nature.
If this is correct, there is a symmetry between the two basic classes of sub-atomic particle - ones with whole-number spins (such as the particle of light) and ones that are multiples of a half (such as the electron).
According to the equations of this symmetry, the Standard Model remains intact, but there also follow a host of new predictions, for example the existence of a slew of hitherto undiscovered particles, often called supersymmetric particles, or "sparticles".
Since supersymmetry was first mooted 30 years ago, the idea has been a favourite among particle physicists. But experimenters have found no evidence to support it - indeed, some theorists have come to doubt whether the idea is correct after all.
Perhaps all the doubts will be swept away by a menagerie of new particles when the LHC is switched on - and perhaps some of them will help account for the "dark matter" that astronomers cannot see, although they can detect its existence via the gravitational forces it exerts on other particles.
Quite a bit of this matter needs to be accounted for - about 10 thousand trillion trillion trillion tonnes.
It is also possible, as Nima Arkani-Hamed suspects, that evidence might be found for new dimensions of space and time. Perhaps the longest shot of all, though, is that the LHC will come up with results that support string theory.
According to this idea, the universe is not made of tiny, point-like particles but of tiny, vibrating pieces of string, each about a millionth of a billionth of a billionth of a billionth of a centimetre long.
Many of the world's leading theorists are working flat out on this mathematically beautiful theory, but it has yet to make a prediction confirmed by experiment.
When physicists were planning the LHC, they designed it so that, according to the predictions of the best and most promising theories, it would have enough energy to explore plenty of new ground in our understanding of the way the universe ticks.
It could be that this ground is arid and the physicists find nothing exciting.
But the mood among theorists is upbeat: most are convinced that Nature is going to show that they've been on the right lines all along. In any event, the experiments will soon be marking the theoreticians' cards, as they learn how well they've done their job of being God's mindreaders.
THE 'BIG BANGER IN NUMBERS
Scheduled to begin operation in May, the Large Hadron Collider (LHC) will produce close to one per cent of all digital data generated on the planet. The amount stored every year by each of the big experiments would fill about 100,000 DVDs.
The LHC operates at a temperature colder than that found in outer space - about 240C colder than a domestic freezer.
The vacuum inside the LHC beam pipe is so good that there is actually 10 times more atmosphere on the Moon.
The filament making up the LHC's superconducting cable is about a tenth of the width of a human hair. If you could lay all the filament end to end, it would stretch to the Sun and back five times.
LHC protons at full energy will travel within 0.0000001 per cent of the speed of light.
An LHC beam has the total energy of a 400-tonne train travelling at 150kph. Each proton has about the energy of motion of a flea.
The Sun never sets on the LHC collaborations - members come from all seven continents except Antarctica.
The magnet system of one of the detectors contains more iron than the Eiffel Tower.
Big Bang, an exhibition about the LHC produced by the Science Museum and supported by the Science and Technology Facilities Research Council, is at Glasgow Science Centre until June 23. It will be at the World Museum, Liverpool, from June 28 until September 22.
For more information on LHC visit www.lhc.ac.uk
http://www.telegraph.co.uk/earth/main.j ... xml&page=1
The Big Bang: atom-smaching could uncover truth
Last Updated: 12:01am GMT 25/03/
Scientists hope that a new atom-smashing machine will allow them to replicate the beginning of the universe and uncover truths about how it works, says Graham Farmalo
In a few months' time, the world's most powerful atom-smasher will be switched on at the CERN laboratory near Geneva.
Scientists hope the new machine will further their understanding of the fundamental laws that underlie the workings of the universe - "to know the mind of God", in Stephen Hawking's arresting phrase.
Plans are afoot at Radio 4 to mark the event by devoting programming to particle physics, broadcasting from the lab throughout the day on which the physicists switch on their new toy, the biggest scientific instrument ever built.
It will enable them to recreate - fleetingly - the state of the universe during the early stages of the Big Bang. Quite how early beggars belief: a millionth of a millionth of a second after the beginning of time.
One of the leading theorists of the younger generation, Nima Arkani-Hamed of the Institute for Advanced Study at Princeton, summarises the excitement: "We have been waiting for a generation for the new machine to turn on. Our world view is set to change dramatically, and we can't wait to get started."
The machine is known as the Large Hadron Collider, or LHC (hadron is the technical name of the class of sub-atomic particles to which protons belong).
The LHC will do something essentially very simple: record what happens when protons are smashed together.
This way of finding out about Nature might seem crude, but there is no alternative: protons, each about a tenth of a thousandth as wide as an atom, are much too small to see, cut up or probe in any other way.
This strategy of arranging brutal, sub-atomic smash-ups has paid handsome dividends over the past three-quarters of a century.
Its first great success was the talk of the country in 1932 when the Cambridge experimenters John Cockcroft and Ernest Walton split the atom by firing protons into the core of lithium atoms, producing atoms of a different type, helium.
In a piece of nuclear alchemy, they had turned one type of chemical element into another.
Science has come a long way since then. Cockcroft and Walton's particle accelerator was a pea-shooter compared with the LHC, which delivers protons with 10 million times the energy.
The particle beams in the new collider circulate in a tunnel 17 miles long, about 100m below the Swiss-French border. The collisions take place in huge detectors, one of them called Atlas, so vast it would only just fit inside Westminster Abbey.
Some 10,000 physicists and engineers from 100 countries are working on the £4.4 billion machine. For every adult in the UK, the annual cost of contributing to the project is about the price of one pint of beer.
So is it worth it? Yes - because the LHC will probe more deeply into the heart of atoms than ever before, 10 times more deeply than any previous machine.
To do this, its operators have to assemble batches of particles, each consisting of hundreds of billions of protons, and accelerate them to within a gnat's whisker of the speed of light, while subtly tweaking the motion of each batch so that it keeps to the right path.
In the tunnel - the largest fridge in the world, colder than outer space - two batches will circulate in opposite directions, ready to meet in virtually head-on collisions. Forty million such collisions will take place every second, generating a spray of hundreds or even thousands of particles.
The conditions then will be just as they were 13.7 billion years ago, at the start of the Big Bang.
This, inevitably, will produce a lot of data - indeed, the experiments will fill some 600 stacks of CDs, each of them as high as the Eiffel Tower. The data processing, to be carried out by researchers all over the world, is one of the biggest challenges computer scientists have ever tackled.
What do they expect to find when they begin poring over the results, probably early next year?
They would certainly like to improve their current theory about the forces that bind together the particles in every atom. Known as the Standard Model, this is one of the triumphs of 20th-century science and fits in with the results of all experiments ever done on sub-atomic particles.
The problem is that no one has ever observed a crucial ingredient, the Higgs particle, whose existence goes some way to explain why atoms contain particles that have weight. With confirmation or refutation of the Higgs impending, some theoreticians are getting cold feet and supporting other ideas.
This is partly because the Standard Model is far from perfect. For theorists, too much in it is arbitrary. Nobody, for example, understands the masses of Nature's fundamental particles and why the force of gravity is so weak compared with the other forces.
Some researchers have a new, improved model up their sleeve, based on a special kind of symmetry known as supersymmetry, which might exist at the heart of Nature.
If this is correct, there is a symmetry between the two basic classes of sub-atomic particle - ones with whole-number spins (such as the particle of light) and ones that are multiples of a half (such as the electron).
According to the equations of this symmetry, the Standard Model remains intact, but there also follow a host of new predictions, for example the existence of a slew of hitherto undiscovered particles, often called supersymmetric particles, or "sparticles".
Since supersymmetry was first mooted 30 years ago, the idea has been a favourite among particle physicists. But experimenters have found no evidence to support it - indeed, some theorists have come to doubt whether the idea is correct after all.
Perhaps all the doubts will be swept away by a menagerie of new particles when the LHC is switched on - and perhaps some of them will help account for the "dark matter" that astronomers cannot see, although they can detect its existence via the gravitational forces it exerts on other particles.
Quite a bit of this matter needs to be accounted for - about 10 thousand trillion trillion trillion tonnes.
It is also possible, as Nima Arkani-Hamed suspects, that evidence might be found for new dimensions of space and time. Perhaps the longest shot of all, though, is that the LHC will come up with results that support string theory.
According to this idea, the universe is not made of tiny, point-like particles but of tiny, vibrating pieces of string, each about a millionth of a billionth of a billionth of a billionth of a centimetre long.
Many of the world's leading theorists are working flat out on this mathematically beautiful theory, but it has yet to make a prediction confirmed by experiment.
When physicists were planning the LHC, they designed it so that, according to the predictions of the best and most promising theories, it would have enough energy to explore plenty of new ground in our understanding of the way the universe ticks.
It could be that this ground is arid and the physicists find nothing exciting.
But the mood among theorists is upbeat: most are convinced that Nature is going to show that they've been on the right lines all along. In any event, the experiments will soon be marking the theoreticians' cards, as they learn how well they've done their job of being God's mindreaders.
THE 'BIG BANGER IN NUMBERS
Scheduled to begin operation in May, the Large Hadron Collider (LHC) will produce close to one per cent of all digital data generated on the planet. The amount stored every year by each of the big experiments would fill about 100,000 DVDs.
The LHC operates at a temperature colder than that found in outer space - about 240C colder than a domestic freezer.
The vacuum inside the LHC beam pipe is so good that there is actually 10 times more atmosphere on the Moon.
The filament making up the LHC's superconducting cable is about a tenth of the width of a human hair. If you could lay all the filament end to end, it would stretch to the Sun and back five times.
LHC protons at full energy will travel within 0.0000001 per cent of the speed of light.
An LHC beam has the total energy of a 400-tonne train travelling at 150kph. Each proton has about the energy of motion of a flea.
The Sun never sets on the LHC collaborations - members come from all seven continents except Antarctica.
The magnet system of one of the detectors contains more iron than the Eiffel Tower.
Big Bang, an exhibition about the LHC produced by the Science Museum and supported by the Science and Technology Facilities Research Council, is at Glasgow Science Centre until June 23. It will be at the World Museum, Liverpool, from June 28 until September 22.
For more information on LHC visit www.lhc.ac.uk
http://www.telegraph.co.uk/earth/main.j ... xml&page=1
