Archive for March, 2013

Why does Easter move around so much?

March 30, 2013 1 comment

The Economist explains – March 28th 2013.    Find Article Here:-

THIS year Easter falls on March 31st for adherents to the various branches of Western Christianity, and on May 5th for Eastern Christianity. In both cases the date of Easter can vary by more than a month, falling between March 22nd and April 25th for the Western church, and between April 4th and May 8th for the Eastern church. This in turn determines the dates of public holidays, school holidays and the timings of school terms in many countries. Why does Easter move around so much?

According to the Bible, Jesus held the Last Supper with his disciples on the night of the Jewish festival of Passover, died the next day (Good Friday) and rose again on the third day (the following Sunday). The beginning of Passover is determined by the first full moon after the vernal equinox, which can occur on any day of the week. To ensure that Easter occurs on a Sunday, the Council of Nicaea therefore ruled in 325AD that Easter would be celebrated on the Sunday after the first full moon on or after the vernal equinox. But there’s a twist: if the full moon falls on a Sunday, then Passover begins on a Sunday, so Easter is then delayed by a week to ensure that it still occurs after Passover. To further confuse matters, the council fixed the date of the vernal equinox at March 21st, the date on which it occurred in 325AD (though it now occurs on March 20th), and introduced a set of tables to define when the full moon occurs that do not quite align with the actual astronomical full moon (which means that, in practice, Easter can actually occur before Passover).

The earliest possible date for Easter occurs when the notional full moon falls on March 21st itself, in a year in which March 21st falls on a Saturday. Easter is then celebrated on Sunday March 22nd, a rare event that last happened in 1818 and will next take place in 2285. The latest possible date for Easter occurs when there is a full moon on March 20th, so that the first full moon after March 21st falls a lunar month or 29 days later, on April 18th. If April 18th falls on a Sunday, then the special Sunday rule applies, and Easter is celebrated the following Sunday, or April 25th. This last happened in 1943, and will next happen in 2038. There is therefore a 35-day window in which Easter can fall, depending on the timing of the full moon relative to March 21st. Eastern Christianity applies the same basic rule but uses the older Julian calendar, which is currently 13 days behind the Gregorian calendar, giving a different range of possible dates. This can pose problems.

There have been various proposals to change the way the date of Easter is calculated. At a meeting held in Aleppo in 1997, representatives of several churches proposed that a new system be adopted from 2001, relying on actual astronomical observations rather than tables to define the dates of the vernal equinox and the full moon. This would have ensured that Easter occurred on the same day for both branches of the church. But the proposal was not adopted. In 1928 Britain’s parliament passed a law, which has not been implemented, that would define Easter as the Sunday after the second Saturday in April. Another proposal would define Easter as the second Sunday in April. Several churches, including the Catholic church, say they are open to the idea of setting the date of Easter in this way, so that its date varies by no more than a week. But until there is widespread agreement, its date will continue to jump around within a five-week window.


U.S. To Bury Almost All Existing Used Nuclear Fuel; Recycling Deferred At Least 20 Years.

March 30, 2013 1 comment

By Jeff McMahon 28th January 2013.    Find Article Here:-

There’s little hope that the 70,000 metric tons of used nuclear fuel dispersed across the United States will ever be recycled, according to a recent study by Oak Ridge National Laboratory—so nearly all existing waste will go into the earth.

In a study completed late last year, Oak Ridge officials determined that the U.S. is at least 20 years away from large-scale reprocessing of used nuclear fuel, if it decides to pursue such technologies. By then, they estimate, nuclear plants will have generated another 40,000 metric tons of spent fuel.

LUBMIN, GERMANY - JUNE 08:  Workers look down ...
Castor containers filled with spent nuclear fuel rods from decomissioned nuclear power plants at a temporary waste depository in Germany (Image credit: Getty Images via @daylife)
“Based on the technical assessment, about 68,450 (metric tons) or about 98 percent of the total current inventory by mass, can proceed to permanent disposal without the need to ensure retrievability for reuse or research purposes,” Oak Ridge officials conclude in a report issued late last year.The remaining 2 percent should be reserved for research into storage and reprocessing technologies, the report advised.

The Oak Ridge report came to light this month when it was cited by the Department of Energy in a document revealing DOE’s plan to seek a new permanent geologic waste depository. The country’s previous depository, Yucca Mountain, was defunded by Congress and the Obama Administration in 2011.

The United States long opposed the reprocessing of used nuclear fuel because of terrorism and proliferation concerns, but DOE began researching new reprocessing technologies in 2005, and the Obama Administration has remained open to new technologies.

In 2009, Energy Secretary Steven Chu told Congress “there is research that has to be done, again, because reprocessing has the potential for greatly reducing both the amount and lifetime of the waste and to extend the nuclear fuel.”

At the time—before meltdowns and hydrogen explosions damaged spent fuel pools at Fukushima—the U.S. appeared more open to recycling processes like those employed in France.

After Fukushima, The Blue Ribbon Commission on America’s Nuclear Future, co-chaired by Chu, adopted more cautious language about recycling: “no currently available or reasonably foreseeable reactor and fuel cycle technology developments—including advances in reprocessing and recycling technologies—have the potential to fundamentally alter the waste management challenges the nation confronts over at least the next several decades, if not longer.”

But neither the Blue Ribbon report nor the administration’s response close the door to reprocessing, calling it “premature for the United States to commit, as a matter of policy, to ‘closing’ the nuclear fuel cycle given the large uncertainties that exist about the merits and commercial viability of different fuel cycle and technology options.”

Although reprocessing offers some benefits over long-term storage, few anti-nuclear activists embrace it.

Recycling is a euphemism for reprocessing which is one of the worst polluters of the atmosphere and the ocean, and is a direct conduit to proliferation,” said Mali Martha Lightfoot, executive director of the Helen Caldicott Foundation. “It is not really a solution to anything except how can the industry get more of our money. It also ups the ante for reactor accident danger, as in the case of Fukushima, because MOX fuel has plutonium in it.”

Mixed-oxide or MOX fuel is recycled from nuclear warheads.

The United States’ current inventory of domestic used nuclear fuel “is massive, diverse, dispersed, and increasing,” according to the Oak Ridge report. Stored at 79 temporary sites in 34 states, it represents”a total of about 23 billion curies of long-lived radioactivity.”

Biological computer that ‘lives’ inside the body comes one step closer as scientists make transistor out of DNA and RNA.

By Steve Connor March 28th 2013.    Find Article Here:-

Finding could lead to new biodegradable devices based on living cells that are capable of detecting changes in the environment.

Scientists believe they are close to building the first truly biological computer made from the organic molecules of life and capable of working within the living cells of organisms ranging from microbes to man.

The researchers said that they have made a transistor – the critical switch at the heart of all computers – from DNA and RNA, the two biological molecules that store the information necessary for living things to replicate and grow.

Silicon transistors control the direction of flow of electrical impulses within computer chips, but the biological transistor controls the movement of an enzyme called RNA polymerase along a strand of the DNA molecule, the scientists said.

Ultimately, the aim is to use the biological transistors – called transcriptors – to make simple but extremely small biological computers that could be programmed to monitor and perhaps affect the functioning of the living cells in which they operate, researchers said.

It could lead to new biodegradable devices based on living cells that are capable of detecting changes in the environment, or intelligent microscopic vehicles for delivering drugs within the body, or a biological monitor for counting number of times a human cell divides so that the device could destroy the cell if it became cancerous, the scientists said.

“Biological computers can be used to study and reprogram living systems, monitor environments and improve cellular therapeutics,” said Drew Endy, assistant professor of bioengineering at Stanford University in California, who led the study published in the journal Science.

Last year, Professor Endy announced new ways of using biological molecules to store information and to transmit data from one cell to another. The latest study adds the third critical component of computing – a biological transistor that acts as a “logic gate” to determine whether a biochemical question is true or false.

Logic gates are critical for a computer to function properly. In a biological setting the use of logical data processing is almost as limitless as its use in conventional electronic computing, said Jerome Bonnet, a bioengineer within the Endy laboratory, and the lead author of the study.

“You could test whether a given cell had been exposed to any number of external stimuli – the presence of glucose and caffeine for instance. [Logic] gates would allow you to make the determination and store that information so you could easily identify those which had been exposed and which had not,” Dr Bonnet said.

Biological computers have been the dream of electronic engineers for decades because they open the possibility of a new generation of ultra-small, ultra-fast devices that could be incorporated into the machinery of living organisms.

“For example, suppose we could partner with microbes and plants to record events, natural or otherwise, and convert this information into easily observed signals. That would greatly expand our ability to monitor the environment,” Professor Endy said.

“So the future of computing need not only be a question of putting people and things together with ubiquitous silicon computers. The future will be much richer if we can imagine new modes of computing in new places and with new materials – and then find ways to bring those new modes to life,” he said.

Cancer Pandemic: Reaping the Seeds of Nuke Tests.

By John LaForge Global Research, March 28th, 2013.    Find Article Here:-
America's Covert War Against Iran. Do 'All Options' Mean Nukes?

The warnings about fallout from nuclear tests six decades ago often noted that cancers from the radiation would probably not begin appearing in large numbers for many years. But that time is now – and medical experts are wondering whether the surge in some cancers is a result.

Back in the 1950s and 1960s, the Atomic Energy Commission doused the entire United States with thyroid cancer-causing iodine-131 — and 300 other radioisotopes — by exploding atomic and hydrogen bombs above ground. To protect the dirty, secretive, militarized bomb-building industry, the government chose to warn the photographic film industry about the radioactive fallout patterns, but not the general public.

In 1951, the Eastman Kodak Company had threatened a federal lawsuit over the nuclear fallout that was fogging its bulk film shipments. Film was not packed in bubble wrap then, but in corn stalks that were sometimes being fallout-contaminated.

Image: During nuclear bomb drills in the 1950s, school children were ordered to hide under their desks.

By agreeing to warn Kodak, etc., the AEC and the bomb program avoided the public uproar — and the bomb testing program’s possible cancellation — that a lawsuit would have precipitated. The settlement kept the deadliness of the fallout hidden from farmers and the public, even though the government well knew that fallout endangered all the people it was supposed to be defending.

This staggering revelation was heralded on Sept. 30, 1997, in the New York Times headline, “U.S. Warned Film Plants, Not Public, About Nuclear Fallout.” The article began, “[W]hile the Government reassured the public that there was no health threat from atmospheric nuclear tests…” The fallout’s radioactive iodine-131delivered thyroid doses to virtually all 160 million people in the U.S. at the time.

According to the Institute for Energy and Environmental Research (IEER) in Takoma Park, Maryland, which discovered the cover-up, children were especially affected and received higher doses because they generally consumed more milk than adults and since their thyroids are smaller and growing more rapidly. The “milk pathway” moves radioiodine from grass, to cows, to milk with extreme efficiency — a fact known to the government as early as 1951.

Ingested iodine-131 concentrates in the thyroid gland where it can cause cancer. Average doses to children averaged between 6 and 14 rad, with some as high as 112 rad. Prior to 1997, the government claimed that thyroid doses to children were 15 to 70 times less.

Every Corner of the U.S.

My friend Steve O’Neil of Duluth, Minnesota, who was born in 1951, has been a public spirited political activist all of his adult life, an advocate for the homeless and a campaigner against the causes of homelessness.

As a St. Louis County Commissioner in his third term, Steve made headlines this month by announcing that he has been attacked by an aggressive form of thyroid cancer. Steve is not alone in his affliction — more than 60,000 thyroid cancers will be spotted this year in the U.S. Tens of thousands of them have been caused by our government’s nuclear weapons establishment.

The National Cancer Institute disclosed in 1997 that some 75,000 thyroid cancer cases can be expected in the U.S. from just 90 — out of a total of 235 — above-ground bomb tests and that 10 percent of them will be fatal. That year, the NCI said, about 70 percent of the thyroid cancers caused by iodine-131 fallout from those 90 tests had not yet been diagnosed but would appear years or decades later.

The 14-year NCI study also said the 90 bomb blasts produced more than 100 times the radioactive iodine-131 than the government had earlier claimed. The NCI estimated that they dispersed “about 150 million curies of iodine-131, mainly in the years 1952, 1953, 1955, and 1957.”

The study reported that all 160 million people in the country at the time were exposed to the iodine-131 (the only isotope out of more than 300 that were dispersed by the bomb blasts that it studied). Children under 15, like Steve O’Neil and all the Baby Boomers, were particularly at risk. High doses of fallout were spread nation-wide. Wind patterns and local rainfall caused “hot spots” from Montana and Idaho to South Dakota, Minnesota, Missouri and beyond.

In 1962, according to IEER, officials in Utah and Minnesota diverted possibly contaminated milk from the market when iodine-131 levels exceeded radiation guidelines set by the Federal Radiation Council (FRC). The FRC reacted harshly and declared that it did “not recommend such actions.” The FRC also announced that its radiation guidelines should not be applied to bomb test fallout because “any possible health risk which may be associated with exposures even many times above the guide levels would not result in a detectable increase in the incidence of disease.”

IEER’s scientists condemned this fabulously implausible assurance, writing: “Since thyroid cancers can develop many years after radiation exposure and are therefore not immediately detectable, this reassurance was highly misleading.”

Tip of Cancer Iceberg

The National Cancer Institute’s 1997 study said about 16,000 cases of thyroid cancer were diagnosed in the U.S. annually, and that 1,230 would die from the disease. This estimate turned out to be a gross under-statement.

Today the NCI reports that 60,220 new cases of thyroid cancer will be diagnosed in the U.S. this year, and that 1,850 of them will be fatal. The thyroid cancer “balloon” is with us because the nuclear weapons complex under Presidents Dwight Eisenhower and John F. Kennedy attacked the very people it was said to be defending. Yet, it gets worse.

The UN Scientific Committee on the Effects of Atomic Radiation says that iodine-131 doses comprise only two percent of the overall radiation dose from weapons testing. Ninety-eight percent of our fallout dose is from 300 other isotopes produced by the Bomb.

It is not idle speculation to suggest that the cancer pandemic afflicting the people of the U.S. has been caused by our own government’s deliberately secret and viciously reckless weapons program.

John LaForge works for Nukewatch, a nuclear watchdog group in Wisconsin, edits its Quarterly newsletter, and is syndicated through PeaceVoice.

Benefit cuts and rhetoric undermine a bastion of civilised society.

The Guardian, Wednesday 27th March 2013.   Find Article Here:-

As the UK’s leading experts on social policy and the welfare state, we urge the government to reconsider the benefit cuts scheduled for 1 April and to ensure that no further public spending cuts are targeted on the poorest in our society. We have two major concerns.

First, as the government’s own impact assessment has demonstrated, the 1% uprating in the Welfare Benefits Up-rating Act will have a disproportionate effect on the poorest. Families with children will be particularly hard hit, pushing a further 200,000 children into poverty. In addition, those with low to middle earnings and single-earner households will be caught by the 1% limit on tax credit rates. These new cuts come on top of the cumulative impact of previous tax, benefit and public expenditure cuts which have already meant the equivalent to a loss of around 38% of net income for the poorest tenth of households and only 5% for the richest tenth.

Second, the welfare state is one of the hallmarks of a civilised society. All developed countries have them and the less developed ones are striving to establish their own. Welfare states depend on a fair collection and redistribution of resources, which in turn rests upon the maintenance of trust between different sections of society and across generations. Misleading rhetoric concerning those who have to seek support from the welfare state, such as the contrast between “strivers” and “shirkers”, risks undermining that trust and, with it, one of the key foundations of modern Britain.

In fact the divisions are not so simple. For example, the borderline between low and no pay is fluid. Families move in and out of work and in and out of poverty. Around one in six of economically active people have claimed jobseeker’s allowance at least once in the last two years (almost 5 million people). The record level of youth unemployment accounts for most of those households where no one has ever worked. Around 6.5 million people are underemployed and want to work more. The 50% rise in families receiving working tax credits since 2003 reflects the 20% increase in the working poor, as one in five women and one in seven men earn less than £7 per hour. Now the majority of children and working-age adults in poverty live in working, not workless, households.

In the interests of fairness and to protect the poorest, as well as to avoid the risk of undermining the consensus on the British welfare state, the government should increase taxation progressively on the better off, those who can afford to pay (including ourselves), rather than cutting benefits for the poorest.
Professor Peter Alcock University of Birmingham
Professor SJ Banks University of Durham
Professor Marion Barnes University of Brighton
Professor Saul Becker University of Nottingham
Professor Tim Blackman Open University
Professor Hugh Bochel University of Lincoln
Professor John Clarke Open University
Professor Gary Craig University of Durham
Professor Guy Daly Derby University
Professor Alan Deacon University of Leeds
Professor Bob Deacon University of Sheffield
Professor Nicholas Deakin
Professor V Drennan Kingston University
Professor Hartley Dean LSE
Professor Simon Duncan University of Bradford
Professor Peter Dwyer University of Salford
Professor RS Edwards University of Southampton
Professor Nick Ellison University of Leeds
Professor Norman Ginsburg London Metropolitan University
Professor Ian Gough LSE
Professor Caroline Glendinning University of York
Professor Paul Higgs UCL
Professor Michael Hill
Professor Julian LeGrand LSE
Professor Ruth Lister University of Loughborough
Professor Linda McKie University of Durham
Professor John Macnicol LSE
Professor Nigel Malin University of Sunderland
Professor Nicholas Mayes London School of Hygiene and Tropical Medicine
Professor Jane Millar University of Bath
Professor Michael Noble University of Oxford
Professor JS O’Connor University of Ulster
Professor Jan Pahl University of Kent
Professor J Parker University of Bournemouth
Professor S Peckham University of Kent
Professor Lucinda Platt Institute of Education
Professor Randall Smith University of Bristol
Professor Tess Ridge University of Bath
Professor D Robinson Sheffield Hallam University
Professor Karen Rowlingson University of Birmingham
Professor Kirstein Rummery Stirling University
Professor Adrian Sinfield University of Edinburgh
Professor Peter Taylor-Gooby University of Kent
Professor Alan Walker University of Sheffield
Professor Carol Walker University of Lincoln
Professor Robert Walker University of Oxford
Professor Jane Wheelock University of Newcastle
Professor John Veit-Wilson University of Newcastle
Professor Fiona Williams University of Leeds
Professor Nicola Yeates Open University

• I was very worried to read that some councils in England will be replacing crisis loans for people experiencing a financial emergency with food vouchers (Report, 27 March). Not only is this deeply stigmatising for people who are already extremely vulnerable, it also doesn’t take into account why they might need the emergency funds. A broken boiler or higher than expected fuel bill are often enough to push people into poverty, and forcing them to go to charity-run food banks for handouts is a Dickensian act.

Oxfam works in many of the world’s poorest countries, where cash transfers are forming the basis of an increasing volume of humanitarian aid. In some countries that face chronic food shortages, cash transfer programmes have proven to be more efficient and effective than repeated emergency food aid. It is astounding that we would take such a backward step here in the UK and pick apart the safety net that the social fund was designed to provide.

We commend the scheme Manchester city council is running, to offer people low-interest loans through a credit union rather than food vouchers, and believe all councils should be taking this more humane approach.
Chris Johnes
Director of UK poverty, Oxfam

Benefit cuts putting 200,000 UK children in poverty must be stopped, experts say.

By and March 27th 2013.    Find Full Article Here:-

Letter signed by more than 50 social policy professors warns poorest tenth of households lose equivalent of 38% income.

Benefit cuts child poverty

Benefit cuts and welfare reforms will undermine public support for the welfare state, experts warn.
Photograph: Jeff J Mitchell/Getty Images

Senior welfare experts have urged the government to reconsider benefit cuts coming into force next week that will disproportionately hit the poorest families and push a further 200,000 children into poverty.

In an open letter to David Cameron, published in the Guardian, more than 50 social policy professors warn that the welfare reforms, coupled with previous tax, benefit and public expenditure cuts, will result in the poorest tenth of households losing the equivalent of around 38% of their income.

They say the changes will undermine public support for the welfare state – which they call “one of the hallmarks of a civilised society”.

“Welfare states depend on a fair collection and redistribution of resources, which in turn rests upon the maintenance of trust between different sections of society and across generations.

“Misleading rhetoric concerning those who have to seek support from the welfare state, such as the contrast between ‘strivers’ and ‘shirkers’, risks undermining that trust and, with it, one of the key foundations of modern Britain.”

The letter argues that such rhetoric does not reflect the reality of a UK where families move fluidly in and out of work and in and out of poverty.

It adds: “In the interests of fairness and to protect the poorest, as well as to avoid the risk of undermining the consensus on the British welfare state, we urge you to increase taxation progressively on the better off, those who can afford to pay (including ourselves), rather than cutting benefits for the poorest.”

The letter follows growing concern among charities, campaigners and local authorities about the combined impact on vulnerable individuals and households of welfare changes and cuts to local authority budgets.

A separate report compiled by academics from six UK universities concludes that Britain’s poorest are worse off today than they were at the height of the cuts imposed by Margaret Thatcher’s Conservative government in 1983.

The Poverty and Exclusion project reports that 33% of British households lacked at least three basic living necessities in 2012, compared with 14% in 1983. These include living in adequately heated homes, eating healthily, and owning basic clothing items such as properly fitting shoes.

“Despite the fact that the UK is a much wealthier country, levels of deprivation are going back to the levels found 30 years ago,” says the report, titled The Impoverishment of The UK.

Some of the findings are featured in an ITV Tonight programme titled Breadline Britain on Thursday evening.

The report found:

• Around 4 million adults and almost 1 million children lack at least one basic item of clothing, such as a warm winter coat, while 3 million adults of working age (including over a fifth of those looking for work) cannot afford appropriate clothes for a job interview.

• Roughly 4 million children and adults are not fed properly judged against what most people consider to be a minimally acceptable diet – meaning they do not eat three meals a day, including fresh fruit, meat, fish and vegetables. Over a quarter of all adults skimped on meals so others in their households could eat.

• One-third of all adults can’t afford to pay unexpected costs of £500 (such as if a cooker breaks down), 31% can’t afford to save at least £20 a month, and 1 million children can’t afford to join sports training or drama clubs.

• About 11 million people cannot afford adequate housing conditions and nearly one in ten households are unable to afford to fully heat their home.

The project measures who and how many people fall below what the majority agree are “necessities for life” in the UK today. The list of necessities also includes consumer items such as a washing machine and a telephone, and social activities like visiting friends and family in hospital.

“The results present a remarkably bleak portrait of life in the UK today and the shrinking opportunities faced by the bottom third of UK society,” said the head of the project, Professor David Gordon of Bristol University. “Moreover this bleak situation will get worse as benefit levels fall in real terms, real wages continue to decline and living standards are further squeezed.”

Silk Road: the online drug marketplace that officials seem powerless to stop.

By 22nd March 2013.    Find Full Article and Video Here:-

Authorities around the world know about the website, but closing it is another matter – partly because it uses Bitcoins.

Silk Road

The Silk Road online marketplace, which lists more than 10,000 items, 7,000 of which are drugs.

Mark Johnson* rifles through his mail as he gets home from work. Among the usual bills is a small padded envelope. Though it doesn’t have his name on, it’s the package he’s most interested in: inside lie two grams of, he hopes, relatively pure MDMA.

Johnson has no idea who has sent him the envelope: he has never met his dealer, and never will. The delivery was facilitated through a website called Silk Road, an underground eBay-like site which has become the core marketplace for buying and selling drugs online – and despite law enforcement authorities across the world being fully aware of its operation they have, so far, been powerless to stop it.

The site has been shrouded in secrecy even since it was founded in February 2011, but research due to be formally published later this year tracked its growth during six months of last year. Over those months, sales on the site doubled, hitting $1.7m a month.

Johnson, a TV executive, is one of those contributing to those monthly takings. Describing himself as “not excited or impressed by drugs per se”, but “interested” in them, he explains how he came to the Silk Road.

“I heard about it at a party, from the type of guy you only ever meet at parties,” he said. “I missed the last train. I might as well go hard. His brown envelope proved to be a veritable party bag, reminiscent of Hunter S Thompson. Where had he found all this? The Silk Road.”

Link to video: Bitcoin: the fastest growing currency in the world

Johnson said his view was that Silk Road was a site for connoisseurs: an easy way to track down better quality – not cheap – drugs. The site “isn’t easy to use”, but doesn’t require particular expertise: “If you can set up a direct debit and follow a recipe for risotto then you’ll work it out.”

Once you’re in, it works much like eBay: sellers’ reputations are verified through feedback, building trust. Money is typically held in an escrow (a trusted middleman) until delivery, with missing packages qualifying for partial refunds.

In all, he concludes, the quality is more consistent, the sale is safer, and the experience better than trying to find a street dealer. Johnson even claims the site helps combat addiction.

“There are some highly addictive and dangerous substances available on Silk Road, so instant access wouldn’t be advisable,” he concludes. “You must undertake the purchase soberly, with plenty of occasions to confirm your intentions.”

Silk Road today lists more than 10,000 items, 7,000 of which are drugs, with erotica, books and fake IDs among the rest. Notably missing are weapons of any sort (a sister site selling weapons shut due to lack of demand last year) and child pornography, both of which are banned.

Dr Nicolas Christin, who researched the site, believes Silk Road is far bigger today than it was in July 2012 when his fieldwork ended. “It’s not a matter of the police locking a few guys up to end this,” he said. “It is very distributed: we are looking at more than 600 sellers each month.”

How has a marketplace with millions of pounds of revenue survived the long arm of the law? The answer, according to its users, lies in the way it is structured.

Silk Road is no secret to law enforcement, who know where to find it online – indeed, shortly after the site’s existence was first reported in 2011, the senior US senator Chuck Schumer vowed to shut it down.

“It’s a certifiable one-stop shop for illegal drugs that represents the most brazen attempt to peddle drugs online that we have ever seen,” he said.

The site continued uninterrupted, thanks to two technological innovations that make it all but impregnable.

The first is that Silk Road runs as a “hidden service” on a popular internet anonymising tool known as Tor. This makes identifying the physical location of the computers operating the marketplace – or anyone visiting it – all but impossible.

The legitimate uses of Tor make disrupting the service morally difficult: it is a staple of activists avoiding internet censorship or government crackdowns the world over, including in China, Iran and Syria. Indeed, a large proportion of Tor’s funding comes – albeit indirectly – from the US state department‘s internet freedom budget.

In his paper, Christin raised the possibility that authorities might instead try to disrupt Silk Road’s other protection: its use of the anonymous, stateless, encrypted online currency known as Bitcoin. But that’s a task that’s only getting harder.

Bitcoins are a currency controlled by no government, no company, and no group, but rather by maths: a series of complex cryptographic calculations rule how many Bitcoins are in existence and how many are traded.

Silk Road is probably the biggest use of the currency, followed by an unregulated online gambling site known as Satoshidice.

But more mainstream services are adopting the currency: the blogging platform WordPress accepts Bitcoins, as does the social news site Reddit. WikiLeaks opened up to Bitcoin when the mainstream banking system blockaded the site.

At the currency’s birth, Bitcoins were almost worthless – five cents each. Today, a single Bitcoin trades at $70 (£46) – and the total value of all the world’s Bitcoins has topped $800m (£500m). On the face of it, this makes Bitcoin the fastest-growing currency in the world.

Bitcoin creators

Mihai Alisie, editor of Bitcoin Magazine, and Amir Taaki, a Bitcoin developer and activist, in a squat in London. Photograph: Linda Nylind for the Guardian