Science Notebook

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So how are things with the Large Hadron Collider?

October 11th, 2008 · by Carol Ferndale · No Comments

Following the successful circulation of first beam in the LHC on 10 September, the world’s largest and most complex scientific instrument is now on stand-by. A fault in one of its eight sectors is under investigation, and this requires the warming up the sector from a staggering -271 Celsius right up to room temperature. To achieve this will actually take several weeks, then the repair can be done and the whole sector cooled down again. By the time the repair is done it will be November and CERN’s entire research infrastructure, including all its particle accelerators and experiments, will be shut down for annual maintenance until spring 2009, which is when the LHC will most likely be able to restart, and all the exciting stuff will begin.

And in case you were wondering how the phenomenal amount of data generated by the LHC will be dealt with, the Worldwide LHC Computing Grid, which involves more than 140 computer centres in 33 countries, will be managing and analysing more than 15 million Gigabytes of data every year, which will be produced from the hundreds of millions of subatomic collisions that will take place inside the LHC every second.

“The Worldwide LHC Computing Grid is a vital pillar of the LHC project,” said Jos Engelen, chief scientific officer for the LHC project. “It is an absolute necessity for analysis of the LHC data. It is the result of a ‘silent revolution’ in large scale computing over the last five years.”

The Worldwide LHC Computing Grid relies on dedicated optical fibre networks to distribute data from CERN, to eleven major computer centres in Europe, North America and Asia. From these, data is dispatched to more than 140 centres around the world. Together, these distributed computers provide the power to manage the LHC’s data.

→ No CommentsTags: CERN · IT · LHC · Physics

China’s first spacewalk

September 27th, 2008 · by Carol Ferndale · 1 Comment

In the wake of a superb hosting of the Olympics, China has wowed the world again by achieving the first spacewalk ever made by a Chinese person. In orbit 213 miles above the earth today Colonel Zhai Zhigang took a walk in space.

The official commentary declared it to be “a small step by Col. Zhai Zhigang, but a historical leap in China’s space dreams”, in a carefully phrased echo of what Neil Armstrong said when he became the first human to set foot on the Moon.

China is a latecomer to the space race, but this achievement certainly shows the world that China is a serious player, and that the Middle Kingdom has the ability to achieve its high ambitions. The fact that all of this has been shown live on TV is indicative of China’s increasing confidence.

The Chinese Shenzhou VII spacecraft blasted off at 9:07 p.m. on Thursday 25th September, 2008, carrying three Chinese astronauts into space on a three-day mission which is China’s third manned space mission in five years.

In recent years the Chinese government has spent billions of dollars creating a space program that may well enable China to establish a space station by 2020, and eventually even put a man on the moon.

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Postcards from the edge - scientists to study near-death experiences

September 21st, 2008 · by Carol Ferndale · 1 Comment

Near-death Experience Illustration. Jesse Krauß, Wikimedia Commons

Scientists are to investigate those near-death experiences, where people talk about floating out of their body, while remaining attached by some kind of umbilical cord, and floating off towards a bright light, bumping into long-dead relatives along the way, before the doctors, with the aid of modern technology, manage to get everything going again and you land all neat into your body ready to live a little longer.

The odd thing about all these accounts is that people appear to be describing very similar experiences. Might it not just be that they have all been reading the same sort of paranormal related literature? Or could it just be that when the body is packing in there are effects on the brain which produce this type of illusion in everyone? Or could there really be something to it? Scientists at the University of Southampton have decided to try and shed a little light on this, and have designed a new experiment to examine near-death experiences in heart attack survivors, which will actually be the largest ever international study into this type of experience, and will involve 1,500 heart attack patients.

Postcards are going to be placed on shelves above the patients’ beds, positioned in such a way that the images on the cards can only be seen from above. Patients who have cardiac arrests will then be asked to recall any memories of the time of the arrest.

The study is led by Dr Sam Parnia, an expert in the field of consciousness during clinical death, and the study will be carried out in the UK, mainland Europe and North America.

“Contrary to popular perception,” says Dr Parnia, “death is not a specific moment. It is a process that begins when the heart stops beating, the lungs stop working and the brain ceases functioning – a medical condition termed cardiac arrest, which from a biological viewpoint is synonymous with clinical death.
“During a cardiac arrest, all three criteria of death are present. There then follows a period of time, which may last from a few seconds to an hour or more, in which emergency medical efforts may succeed in restarting the heart and reversing the dying process. What people experience during this period of cardiac arrest provides a unique window of understanding into what we are all likely to experience during the dying process.”

During the study, doctors will also use sophisticated technology to study the brain and consciousness during cardiac arrest. At the same time, they will test the validity of out of body experiences and claims of being able to ‘see’ and ‘hear’ during cardiac arrest.

It will be interesting to see if there really is anything to the similar stories that have been told about these near-death out-of-body experiences.

→ 1 CommentTags: Biology · Medicine · Paranormal

Celebration at CERN as the Large Hadron Collider gets going

September 11th, 2008 · by Carol Ferndale · 1 Comment

Part of the LHC. Wikimedia Commons

Yesterday was a great day for physics as the most powerful particle accelerator ever, the Large Hadron Collider (LHC) at CERN, (European Organization for Nuclear Research), was switched on for the first time, with the initial beams of protons making their way around the great circular tunnel lying under the French-Swiss border. This huge physics experiment, now charmingly named by the media “the Big Bang experiment”, has been some fifteen years in the making, and has involved more than 8,000 scientists from around 85 countries, at a cost of around $10 billion.

The LHC has been constructed in the existing 27 km ring-shaped Large Electron-Positron collider tunnel, has 8,000 superconducting magnets, and will achieve proton beam energies of 7 TeV (teraelectronvolts). In terms of particle physics, this is the highest energy ever achieved by a machine, and will recreate the conditions a few moments after the Big Bang, producing the smallest particles humans have ever come across.

Energy is really what it’s all about - physicists believe that significant new discoveries are to be made in the region of around 1 TeV, known as the terascale. The protons will be collided head-on at a rate of 30-million collisions per second, each of which will generate thousands of particles travelling at close to the speed of light. These experiments may well help to solve some of the major puzzles about the composition of matter and energy in the universe, by allowing physicists to probe the shortest distances and the highest energies ever looked at.

How does the LHC work?

The 8,000 magnets are chilled by liquid helium to less than two kelvin, which makes them superconducting, and these steer and focus the beams of protons, that will differ in speed from light speed by only a breathtaking millionth of a percent. At impressive speeds such as this, each proton will have 7 TeV of energy, which, bearing in mind E = mc2, is 7,000 times more energy than a proton would have at rest.

The protons will travel in bunches, each bunch the size of a needle and composed of some 100 billion protons. At four locations around the 27km ring, these bunches will pass through one another, producing collisions. These collisions, or “events”, will actually occur between the particles that make up the protons, known as quarks and gluons, and will release at most about a seventh of the energy available in the parent protons, or about 2 TeV.

Desperately seeking the Higgs boson

So what will the study of these collisions tell us? Well, one of the first things that physicists will be seeking will be confirmation of the currently accepted theory of particle physics, known as the Standard Model. But there is one missing piece of this jigsaw puzzle, and that is a particle known as the Higgs boson, which gives particles the property of mass. Being the last remaining undiscovered piece of the current theory of matter, the Higgs boson, also dubbed “the God particle”, has become the most highly sought after item of particle physics. Actually finding the Higgs boson would be a tremendous step forward in the search for the Grand Unified Theory, which would be a unification of three of the fundamental forces of nature: electromagnetism, the strong nuclear force and the weak nuclear force. Finding the Higgs boson and learning something about its properties could also explain why gravitation is so mysteriously weak compared to the other three forces.

Going beyond the Standard Model

The current Standard Model of particle physics does begin to fall apart when things are probed much beyond the range of the current particle accelerators, suggesting that we need a more sophisticated theory to take its place. So the high levels of energy achieved by the LHC will hopefully lead the way to a theory beyond the Standard Model.

New forces and symmetries

The LHC may actually help us to find new forces of nature which could also reveal new symmetries within nature. For example, the idea of supersymmetry is a symmetry that suggests that elementary particles have superpartners that differ by half a unit of spin, meaning that for every type of boson there is a corresponding type of fermion, and vice versa. If supersymmetry were found to exist close to the terascale, it would provide answers to a number of questions relating to Grand Unified Theory, supersymmetric quantum field theory, and string theory.

Unlocking the secrests of dark matter

Yet another exciting possibility is that work with the new LHC could lead to the discovery of the particle or particles that make up that mysterious stuff known as dark matter, that amazingly actually seems to make up most of the material in the universe, if its apparent gravitational effects on visible matter are anything to go by. It has been suggested that this dark matter could be made up of hypothetical things called strangelets which would be a bound state of equal numbers of up, down and strange quarks.

Magnetic monopoles

Another novelty that will be researched with the collider is the idea of a magnetic monopole, a magnet with only one pole, which, as yet, has never been found. Back in 1931 Paul Dirac got people thinking about magnetic monopoles by mentioning them in relation to the quantization of electric charge. Current ideas suggest that while they could exist, they would have to be so massive that they might never be observed in practice.

The creation of black holes?

The remote possibility that the LHC might create a minuscule black hole has even caused some to take out a lawsuit against CERN, and caused people to panic about yesterday being the end of the world. Thankfully not.

A micro black hole is a tiny black hole, and Stephen Hawking has theorised that these micro black holes, due to quantum effects, evaporate by the emission of particles, with smaller black holes evaporating faster, and finally exploding in a burst of particles. Some say that the Large Hadron Collider might produce one of these micro black holes, but it is thought that this is really unlikely because the LHC, despite its impressive size, is not actually big enough to do this. To create a micro black hole with currently-available materials would require a circular accelerator roughly one thousand light years in diameter.

New dimensions

There are other possibilities besides these, including the exciting possibility that the collider might reveal hidden spacetime dimensions.

The LHC will be shut down over the winter for further fine tuning, and serious new physics will most likely not emerge until 2009. Whatever happens the LHC is bound to turn up something new, so physicists can look forward to some really exciting advances next year.

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