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Hadron Collider to be closed
THIS UNIVERSE |
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Hadron Collider to be closed THE world’s single most complicated and expensive scientific experiment, designed to discover the “God particle” and recreate the conditions that existed at the dawn of creation, will be switched off for a year to correct a design problem that could break it apart if it ran on full power. Scientists in charge of the Large Hadron Collider (LHC) in Geneva announced yesterday that the machine will only be able to run on half energy before it is temporarily shut down in two years’ time. Its full operating capacity designed to probe the frontiers of science will not be achieved until at least 2013 - several years later than planned. However, the European Centre for Nuclear Research (Cern), which operates the £2.6bn atom-smasher on the Franco-Swiss border, said that the additional costs of correcting the problem in the machine’s copper sheaths or “stabilisers” would come out of its existing budget and it would not be asking for any additional funding from contributing countries, including Britain. On 19 September 2008, the LHC had to be shut down just days after it was switched on for the first time because of an electrical fault that led to helium gas being accidentally released into the machine’s underground tunnel. The fault took £25m to fix but Cern’s engineers found that further work on the copper stabilisers designed to soak up spare electrical current from the supercooled magnets was needed before the machine could go to full energy. “I wouldn’t call it a design flaw. It is just that some of the copper stabilisers are not up to the quality needed to go to the full energy level,” said Steve Myers, director of accelerators and technology at Cern. As a compromise to the particle physicists eager to begin work on the fundamental forces of nature at the heart of the atomic nucleus, the Cern authorities decided to run the machine on half energy for the next two years in the hope that this would provide enough experimental data for them to begin to make discoveries in esoteric fields such as supersymmetry and dark matter. However, the revelation that the problems at the LHC are going to delay its full potential for several more years is unlikely to soothe the growing discontent among scientists in other disciplines who feel that “big physics” gets more than its fair share of funding, especially when savage spending cuts are being planned in other areas of science back home. Even nuclear physicists are beginning to feel envious of the funding given to their colleagues in particle physics. “What we pay to Cern just eats into other projects. There is a feeling that it gets a disproportionate amount of funding,” said Jim Al-Khalili, professor of physics at Surrey University. Britain has so far paid about £500m total towards the LHC, which is one of the most ambitious science experiments. Its objective is to collide two beams of subatomic protons circulating in opposite directions at 99.9999991 per cent of the speed of light. By crashing the beams together at such high energy levels, scientists hope to break apart the sub-atomic constituents of matter and recreate the conditions that occurred less than a billionth of a second after the Big Bang some 13.7bn years ago. However, the engineering difficulties involved in the experiment are uniquely difficult. The 27km tunnel that houses the atom smasher had to be so precisely aligned that it was no greater than one tenth of a millimetre out and the giant, superconducting magnets that accelerate the proton beams have to be held together with a force that can resist 500 tons per square metre, equivalent to one full-throttle jumbo jet pushing on each square metre. Dr Myers said that following the emergency shutdown in September 2008, engineers found that the joints holding the copper stabilisers were not strong enough to withstand the full energy levels of the machine, designed to run at a maximum level of 14TeV (14 million million electron Volts). “The joints were not made to a sufficient standard. We learnt how to correct the problem as a result of the 2008
accident,” he said. So instead of running at 14TeV the machine will be run at about half this level, which is still four times higher than the energy of any previous subatomic collider, he said. Within the next few weeks, each beam of the LHC is scheduled to reach 3.5 TeV and when they collide the resulting energy of 7TeV is expected to be high enough to produce findings that could open new avenues, such as the possible discovery of supersymmetry - subatomic particles thought to be created at the beginning of the Universe but have never been seen. At these energy levels it might also be possible to find the elusive Higgs boson, or “God particle”, which could explain why matter has mass and hence lead to a greater understanding of the force of gravity, which operates over the vast distances of space. But many particle physicists believe that it will be necessary to go to much higher energy levels to find the Higgs, and make the sort of discoveries that could lead to the fabled “theory of everything”, a unified theory to explain and bring together all the disparate forces of nature, from the small-scale nuclear forces within the atomic nucleus to the force of gravity operating at the level of stars and
galaxies. — By arrangement with
The Independent |
Why “sunshine” vitamin D is crucial LONDON: Vitamin D is vital in activating human defences and low levels suffered by around half the world’s population may mean their immune systems’ killer T cells are poor at fighting infection, scientists said on Sunday. The findings by Danish researchers could help the fight against infectious diseases and global epidemics, they said, and could be particularly useful in the search for new vaccines. UK risks losing innovation edge LONDON: Britain risks decades of slow economic decline unless it invests heavily in research, which at the moment is one of the country’s few genuine areas of economic competitive advantage, leading scientists said on Tuesday. The Royal Society, an influential science academy whose members include more than 60 Nobel laureates, said Britain’s current technological advantage could be wiped out by the United States, China, India, France and Germany, who it said had “ramped up spending in science to boost their economies.” Experiment may reveal dark universe GENEVA: Dark matter, which scientists believe makes up 25 percent of the universe but whose existence has never been proven, could be detected by the giant particle collider at CERN, the research center’s head said Monday. Rolf-Dieter Heuer told a news conference some evidence for the matter may emerge even in the shorter term from mega-power particle collisions aimed at recreating conditions at the “Big Bang” birth of the universe some 13.7 billion years ago. SpaceX aborts rocket engine test CAPE CANAVERAL, Florida:
Space Exploration Technologies aborted a test firing of its Falcon 9 rocket on Tuesday, in what was to be a key milestone in its quest to fly cargo-and eventually astronauts-to the International Space Station. The test was aborted two seconds before engine ignition at the privately owned company’s Cape Canaveral, Florida, launch site, where the Falcon 9 rocket is being prepared for a company-sponsored demonstration flight this spring.
— Reuters |
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THIS UNIVERSE A rainbow consists of seven
colours with violet at bottom and red at the top which is in
accordance with fact that violet has maximum refractive index due to
which it deviates the most. However, on close observation we will find
that there is also a fainter rainbow on the outer side of main
rainbow. It also contains same colours but in reverse order. Why is it
so? Your observation is correct. One does often see a second rainbow outside the normal one, when there is enough clarity in the atmosphere. To understand the reason for this let us go over the sequence of events which produce the primary rainbow: The light from the sun enters a droplet of water hanging in the air. It is refracted and dispersed. At some angle the direction of light inside is such that it suffers a total internal reflection at the back of the droplet. This light then comes backward and re-emerges from the droplet in our direction, suffering yet another deviation and dispersion. Most of the light is at the angle of minimum deviation. This angle is about 42 degrees with respect to the direction from the sun to the back of our head. This is the angle at which we see the primary rainbow, produced through cooperation of millions upon millions of water droplets. Let us now understand why some times we see another rainbow outside the primary one. This can be seen in situations when there is special clarity of the air. It is easy to imagine that the bundle of rays emerging after the first internal reflection at the back of the droplet might be reflected back into the droplet at the front surface and then come back and out after still another deflection and dispersal. This then could form a fainter rainbow out side the normal rainbow. Clearly the sequence of colours in this would be reversed. Why are we told not to sit on the top of a bus? If lot of people sit on top of the bus the centre of mass of the loaded bus becomes higher. This might affect the stability of the bus while take sharp turns — the bus would be in danger of overturning. There is, in addition, the fact that during a bumpy bus ride you might fall off the roof. Better stay inside — preferably sitting if there is room to sit. Why there are stones beneath the railway tracks? Why these stones are removed at regular intervals and put there again after removing the dust, grass, etc? The stones are there to provide ballast on the sleepers that bind the rails. This keeps them from moving due to the rocking and turning of the train. Of and on they are replaced and gathered together to ensure that they are on firm ground and mud has not formed underneath that might make the base of the rails slippery.
Readers wanting to ask Prof Yash Pal a
question can e-mail him at palyash.pal@gmail.com |
