Monday, June 30, 2008
The machine has been called the largest scientific experiment in history It straddles the French and Swiss border and is buried 330 feet underground. Scientists will hunt for signs of invisible "dark matter" and "dark energy" The safety of the powerful collider has been debated for years
MEYRIN, Switzerland (AP) -- The most powerful atom-smasher ever built could make some bizarre discoveries, such as invisible matter or extra dimensions in space, after it is switched on in August. This collider, called the largest scientific experiment in history, is expected to begin test runs in August. But some critics fear the Large Hadron Collider could exceed physicists' wildest conjectures: Will it spawn a black hole that could swallow Earth? Or spit out particles that could turn the planet into a hot dead clump? Ridiculous, say scientists at the European Organization for Nuclear Research, known by its French initials CERN -- some of whom have been working for a generation on the $5.8 billion collider, or LHC. "Obviously, the world will not end when the LHC switches on," said project leader Lyn Evans. David Francis, a physicist on the collider's huge ATLAS particle detector, smiled when asked whether he worried about black holes and hypothetical killer particles known as strangelets. "If I thought that this was going to happen, I would be well away from here," he said.
The collider basically consists of a ring of supercooled magnets 17 miles in circumference attached to huge barrel-shaped detectors. The ring, which straddles the French and Swiss border, is buried 330 feet underground.
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The machine, which has been called the largest scientific experiment in history, isn't expected to begin test runs until August, and ramping up to full power could take months. But once it is working, it is expected to produce some startling findings.
Scientists plan to hunt for signs of the invisible "dark matter" and "dark energy" that make up more than 96 percent of the universe, and hope to glimpse the elusive Higgs boson, a so-far undiscovered particle thought to give matter its mass. The collider could find evidence of extra dimensions, a boon for superstring theory, which holds that quarks, the particles that make up atoms, are infinitesimal vibrating strings. The theory could resolve many of physics' unanswered questions, but requires about 10 dimensions -- far more than the three spatial dimensions our senses experience. The safety of the collider, which will generate energies seven times higher than its most powerful rival, at Fermilab near Chicago, has been debated for years. The physicist Martin Rees has estimated the chance of an accelerator producing a global catastrophe at one in 50 million -- long odds, to be sure, but about the same as winning some lotteries. By contrast, a CERN team this month issued a report concluding that there is "no conceivable danger" of a cataclysmic event. The report essentially confirmed the findings of a 2003 CERN safety report, and a panel of five prominent scientists not affiliated with CERN, including one Nobel laureate, endorsed its conclusions. Critics of the LHC filed a lawsuit in a Hawaiian court in March seeking to block its startup, alleging that there was "a significant risk that ... operation of the Collider may have unintended consequences which could ultimately result in the destruction of our planet. One of the plaintiffs, Walter L. Wagner, a physicist and lawyer, said Wednesday CERN's safety report, released June 20, "has several major flaws," and his views on the risks of using the particle accelerator had not changed. On Tuesday, U.S. Justice Department lawyers representing the Department of Energy and the National Science Foundation filed a motion to dismiss the case. The two agencies have contributed $531 million to building the collider, and the NSF has agreed to pay $87 million of its annual operating costs. Hundreds of American scientists will participate in the research. The lawyers called the plaintiffs' allegations "extraordinarily speculative," and said "there is no basis for any conceivable threat" from black holes or other objects the LHC might produce. A hearing on the motion is expected in late July or August. In rebutting doomsday scenarios, CERN scientists point out that cosmic rays have been bombarding the earth, and triggering collisions similar to those planned for the collider, since the solar system formed 4.5 billion years ago. And so far, Earth has survived. "The LHC is only going to reproduce what nature does every second, what it has been doing for billions of years," said John Ellis, a British theoretical physicist at CERN. Critics like Wagner have said the collisions caused by accelerators could be more hazardous than those of cosmic rays. Both may produce micro black holes, subatomic versions of cosmic black holes -- collapsed stars whose gravity fields are so powerful that they can suck in planets and other stars. But micro black holes produced by cosmic ray collisions would likely be traveling so fast they would pass harmlessly through the earth. Micro black holes produced by a collider, the skeptics theorize, would move more slowly and might be trapped inside the earth's gravitational field -- and eventually threaten the planet. Ellis said doomsayers assume that the collider will create micro black holes in the first place, which he called unlikely. And even if they appeared, he said, they would instantly evaporate, as predicted by the British physicist Stephen Hawking. As for strangelets, CERN scientists point out that they have never been proven to exist. They said that even if these particles formed inside the Collider they would quickly break down. When the LHC is finally at full power, two beams of protons will race around the huge ring 11,000 times a second in opposite directions. They will travel in two tubes about the width of fire hoses, speeding through a vacuum that is colder and emptier than outer space. Their trajectory will be curved by supercooled magnets -- to guide the beams around the rings and prevent the packets of protons from cutting through the surrounding magnets like a blowtorch. The paths of these beams will cross, and a few of the protons in them will collide, at a series of cylindrical detectors along the ring. The two largest detectors are essentially huge digital cameras, each weighing thousands of tons, capable of taking millions of snapshots a second. Each year the detectors will generate 15 petabytes of data, the equivalent of a stack of CDs 12 miles tall. The data will require a high speed global network of computers for analysis. Wagner and others filed a lawsuit to halt operation of the Relativistic Heavy Ion Collider, or RHIC, at the Brookhaven National Laboratory in New York state in 1999. The courts dismissed the suit. The leafy campus of CERN, a short drive from the shores of Lake Geneva, hardly seems like ground zero for doomsday. And locals don't seem overly concerned. Thousands attended an open house here this spring. "There is a huge army of scientists who know what they are talking about and are sleeping quite soundly as far as concerns the LHC," said project leader Evans.
Copyright 2008 The Associated Press.
CNN website:http://www. cnn. com/2008/TECH/06/30/doomsdaycollider. ap/index. html
Sunday, June 15, 2008
The prospect of all-female conception
Friday, 13 April 2007
Women might soon be able to produce sperm in a development that could allow lesbian couples to have their own biological daughters, according to a pioneering study published today.
Scientists are seeking ethical permission to produce synthetic sperm cells from a woman's bone marrow tissue after showing that it possible to produce rudimentary sperm cells from male bone-marrow tissue.
The researchers said they had already produced early sperm cells from bone-marrow tissue taken from men. They believe the findings show that it may be possible to restore fertility to men who cannot naturally produce their own sperm.
But the results also raise the prospect of being able to take bone-marrow tissue from women and coaxing the stem cells within the female tissue to develop into sperm cells, said Professor Karim Nayernia of the University of Newcastle upon Tyne.
Creating sperm from women would mean they would only be able to produce daughters because the Y chromosome of male sperm would still be needed to produce sons. The latest research brings the prospect of female-only conception a step closer.
"Theoretically is it possible," Professor Nayernia said. "The problem is whether the sperm cells are functional or not. I don't think there is an ethical barrier, so long as it's safe. We are in the process of applying for ethical approval. We are preparing now to apply to use the existing bone marrow stem cell bank here in Newcastle. We need permission from the patient who supplied the bone marrow, the ethics committee and the hospital itself."
If sperm cells can be developed from female bone-marrow tissue they will be matured in the laboratory and tested for their ability to penetrate the outer "shell" of a hamster's egg - a standard fertility test for sperm.
"We want to test the functionality of any male and female sperm that is made by this way," Professor Nayernia said. But he said there was no intention at this stage to produce female sperm that would be used to fertilise a human egg, a move that would require the approval of the Human Fertilisation and Embryology Authority.
The immediate aim is to see if female bone marrow can be lured into developing into the stem cells that can make sperm cells. The ultimate aim is to discover if these secondary stem cells can then be made into other useful tissues of the body, he said.
The latest findings, published in the journal Reproduction: Gamete Biology, show that male bone marrow can be used to make the early "spermatagonial" stem cells that normally mature into fully developed sperm cells.
"Our next goal is to see if we can get the spermatagonial stem cells to progress to mature sperm in the laboratory and this should take around three to five years of experiments," Professor Nayernia said.
Last year, Professor Nayernia led scientists at the University of Gottingen in Germany who became the first to produce viable artificial sperm from mouse embryonic stem cells, which were used to produce seven live offspring.
His latest work on stem cells derived from human bone marrow suggests that it could be possible to develop the techniques to help men who cannot produce their own sperm naturally.
"We're very excited about this discovery, particularly as our earlier work in mice suggests that we could develop this work even further," Professor Nayernia said.
Whether the scientists will ever be able to develop the techniques to help real patients - male or female - will depend on future legislation that the Government is preparing as a replacement to the existing Human Fertilisation and Embryology Act.
A White Paper on genetics suggested that artificial gametes produced from the ordinary "somatic" tissue of the body may be banned from being used to fertilise human eggs by in vitro fertilisation.
Making babies without men - a literary view
Aristophanes (c. 411BC)
After 21 years of war, the women of Athens, led by Lysistrata, take matters into their own hands. Lysistrata suggests every wife and mistress should refuse all sexual favours until peacetime. Before long it proves effective, peace is concluded and the play ends with festivities.
Charlotte Perkins Gilman (1914)
On the eve of the First World War, an isolated society entirely comprising Aryan women is discovered by three male explorers. The women reproduce asexually and live in an ideal society without war and domination. This feminist utopia is a 20th-century vehicle for Gilman's then-unconventional views of male and female behaviour, motherhood, individuality, and sexuality. It is said to be based on Gilman's version of utopia through Aryan separatism.
Philip Wylie (1978)
At four minutes and 52 seconds past four one afternoon, the world shatters into two parallel universes as men vanish from women and women from men. With families and loved ones separated from one another, life continues very differently as an explosion of violence sweeps one world while stability and peace break down in the other.
Doris Lessing (2007)
In her novel, which has made this year's International Man Booker shortlist, Lessing portrays a group of near-amphibious women who have no need of men, known as Squirts, as they are impregnated by the wind, wave or moon. But this is no feminist utopia: the women behave brutally, mutilating male babies before placing them on a rock for eagles to devour. The eagles turn out to be the men's allies, transporting the babies to the forest where they are suckled by does. Lessing reveals she was inspired by a scientific claim that "the primal human stock was probably female, and that males came along later, as a kind of cosmic afterthought".