Police hold man on suspicion of stealing five tonnes of ice from a glacier in Patagonia to sell as designer ice cubes for cocktails

• In pictures: The world's melting glaciers

Climate change sceptics have acquired a new explanation for why glaciers are retreating: it's not global warming, it's theft.

Police in Chile have arrested a man on suspicion of stealing five tonnes of ice from the Jorge Montt glacier in the Patagonia region to sell as designer ice cubes in bars and restaurants.

Local media reported that last Friday police intercepted a refrigerated truck with an estimated £3,900 worth of illicit ice allegedly bound for whiskies, rums and cocktails in the capital Santiago.

Authorities have accused the driver of theft and are considering adding violation of national monuments to the charge sheet.

Scientists say Jorge Montt, part of the Bernardo O'Higgins national park, is retreating by half a mile a year, making it one of the world's fastest shrinking glaciers.

Environmentalists have cited it as evidence that man-made climate change is warming the planet. Sceptics have cited other explanations for retreating glaciers, but theft – until now – was not one of them. It may be the only case in which both sides agree human activity was to blame.

British diplomats accuse Argentina of attempting to isolate Falklands Islands by pressuring Chile to end Port Stanley flights

British diplomats have accused Argentina of plotting an economic blockade of the Falklands amid fears that Buenos Aires is attempting to stop all flights from Chile reaching the islands.

The government of Cristina Fernández de Kirchner has publicly threatened to halt the weekly flight operated by a Chilean-owned airline between Punta Arenas and Port Stanley.

It is the islands' only air link with South America and their main connection with the outside world. British officials believe the service will disappear in an attempt by Argentina to make the Falklands too expensive for Britain to maintain.

"If the LAN Chile flight is cancelled it would be pretty difficult to resist the already credible thesis that there is an economic blockade of the civilian population of the Falklands," said a senior British diplomat in the region on Wednesday.

The move, which diplomats predicted would come soon, would further isolate the disputed island chain and ratchet up tension with London on the eve of the 30th anniversary of the war between Argentina and Britain.

British officials said that if LAN resisted, Argentina would simply ban the use of its airspace.

Fernández signalled the escalation in a speech to the UN last September, when she said Buenos Aires might block the flights, negotiated during a thaw in relations in 1999, if David Cameron's government refused to discuss sovereignty of the islands – which Argentina refers to as Las Malvinas. "We'll wait a little longer, but otherwise we'll be forced to review the standing provisional agreements," she said.

Cameron has continued to refuse to hold talks and recently angered the Argentinian government by accusing it of "colonialism" in its campaign to win back the islands. Argentina says Britain stole the territory, 300 miles off its south Atlantic coast, in 1833.

Argentinian commentators reported last week that Buenos Aires was squeezing LAN, a view which is shared by British officials. The cancellation of the route would leave the Falklands entirely dependent on the twice-weekly 8,000-mile military flight from London via Ascension Island, a volcanic island near the equator.

Barry Elsby, a member of the Falkland Islands' legislative assembly, said: "This has been rumbling for many months. It's a possibility we live with on a daily basis. It would be sad, especially for the Chileans who work and live here, because they would have to leave. And it would be a shame for a nation like Chile to be dictated to."

Instead of a 560-mile flight home to southern Chile, the islands' estimated 250 Chileans would have to travel via London.

Elsby said relatives of Argentina's 600 war dead would also suffer by losing cemetery visits. Once a month the LAN flights stop in Rio Gallegos, Argentina.

He played down the economic and political implications of the 3,000-strong population losing its main link to the outside world. "It would be an inconvenience but nothing that would harm the Falklands," he said.

Others have been less sanguine and warned of damage to tourism and exports.

The row puts LAN, which has one of the region's biggest fleets of aircraft, and Chile's conservative president, Sebastián Piñera, in an awkward position. Neither can be seen to bow to a neighbour's bullying, but there is commercial pressure for an accommodation.

The Falkland Islands flights are a profitable but tiny part of operations for LAN, which requires Argentinian co-operation for much of its international business. The airline, which Piñera part-owned before becoming president, has been unsuccessfully seeking permission from Argentina for a Buenos Aires to Miami flight.

Argentina has cancelled landing rights at Aeroparque, the capital's domestic airport, for LAN's flights from the Chilean capital, Santiago, and São Paulo, Brazil. It has transferred these to Ezeiza, the city's international airport, a major drawback for LAN because it is farther outside the city and deters potential passengers. Chilean commentators speculated this was done to gain leverage over the airline.

Fernández is understood to have raised the issue of Falklands flights with Piñera during a UN meeting in New York last September. She was expected to do so again earlier this month in Santiago, but the visit was pushed back because of her thyroid treatment.

A Chilean military court sentenced a police officer to 541 days in prison for attacking a news photographer.

But the journalist, Víctor Salas of the EFE agency, said he would appeal in order to seek a harsher sentence against the officer, Iván Barría Álvarez.

Salas was attacked while covering a protest in the coastal city of Valparaíso in May 2008. According to EFE, Álvarez struck Salas in the right eye. Despite several operations, he has not recovered total vision.

In the latest press freedom index published by Reporters Without Borders, Chile was ranked at 80th due in large part to the high number of journalists arrested during the country's student protests.

Source: Knight Centre

At 2,500m up in the northern Atacama desert in Chile, Paranal is no place for human beings to live for long periods: dry, dusty and almost lifeless. But it is perfect for watching the skies. At night, the bone dry air means the Very Large Telescope (VLT) can track and measure stars, black holes and planets with exquisite precision using its four individual observatories.

In this podcast Alok Jha describes his visit to the Atacama Large Millimetre/Submillimetre Array (Alma) which is also now taking shape in the desert. When complete in 2013, this collection of 66 carbon-fibre radio antennae, each 12m wide, will open astronomers' eyes to the half of the universe that has, until now, been hidden to modern optical telescopes.

Alma will detect radiation similar to microwaves, around 1,000 times longer than the light we see with our eyes – but easily absorbed by water in the atmosphere.

The music for the show was composed by Iain Chambers.

Subscribe for free via iTunes to ensure every episode gets delivered. (Here is the non-iTunes URL feed).

Follow the podcast on our Science Weekly Twitter feed and receive updates on all breaking science news stories from Guardian Science.

Email scienceweeklypodcast@gmail.com.

Guardian Science is now on Facebook. You can also join our Science Weekly Facebook group.

We're always here when you need us. Listen back through our archive.

Alma, a super-sensitive radio telescope 5,000m above sea level in Chile, will detect a new galaxy every three minutes

Spend a few days with astronomers at the world's most sophisticated telescopes in the mountains of Chile, and your skin will begin to feel different. Cheeks become stretched a little tighter; hands and lips get chapped. It seems to make little difference how much water you drink. Spend a few weeks here and, the astronomers will tell you, the headaches and dizziness start. "You really feel it when you've been here a long time," says Jonathan Smoker, an astronomer at the European Southern Observatory (ESO) at Mount Paranal in northern Chile. "Sometimes my hands start to bleed because it's so dry here."

The scientists and technicians who work here are not allowed to stay on the mountain for more than 14 days at a time. After that, they have to go down to sea level to recuperate. At 2,500m up in the northern Atacama desert, Paranal is no place for human beings to live for long periods: dry, dusty and devoid of much life. But it is perfect for watching the skies: at night, the bone dry air means the Very Large Telescope (VLT) can track and measure stars, black holes and planets with exquisite precision using its four individual observatories. At the heart of each observatory is an 8m-wide mirror made from a single piece of polished glass, the exact shape of which changes 100 times per second to counteract, in real time, the distorting effects of the air on the starlight that it is trying to detect.

The VLT, opened in 1998, was the first telescope to image an exoplanet and it has made significant contributions to our understanding of the giant black hole at the centre of the Milky Way. But it is not the most extreme of the telescopes ESO operates. The VLT has recently been joined in Chile by an even bigger, even more sensitive telescope: the Atacama Large Millimetre/Submillimetre Array (Alma). When complete in 2013, this collection of 66 carbon-fibre radio antennae, each 12m wide, will open astronomers' eyes to the half of the universe that has, until now, been hidden to modern optical telescopes.

Alma will detect radiation similar to microwaves, around 1,000 times longer than the light we see with our eyes – but easily absorbed by water in the atmosphere. So astronomers picked the Chajnantor plateau, 5,000m up on the Andes, near the border with Bolivia, to build their new array. It is one of the driest places in the world, and the air contains half the oxygen of that at sea level. At this height, Alma will be able to produce pin-sharp images of the parts of the universe shrouded by dust.

"When a star forms, it forms in cold, dusty gas clouds," says John Richer of the University of Cambridge and a project scientist for Alma. "The moment it's formed it's shrouded in this dusty material, out of which only half of the light from a typical star escapes. Many other stars are formed in very dense clouds and their light is completely absorbed by the dust in these clouds."

These soot-like clouds of dust, which are also the birthplace of galaxies in the early universe and planets – including our own – obscure stars from modern optical and infrared equipment, such as the VLT and the Hubble Space Telescope. While the dust hides the stars, however, it also gets heated by the starlight to a few degrees above absolute zero (-273C). The dust then emits radiation of its own at sub-millimetre wavelengths, which can be detected on Earth. When it is fully operational in 2013, Alma will provide such an increase in sensitivity over current instruments that it will find a previously unseen galaxy every three minutes.

The dishes themselves will be controlled by shifts of astronomers from an operations support facility (OSF), a collection of offices and workshops located more than 2,000m below the Chajnantor plateau. Here, visitors are given a chance to acclimatise to the thin air before the slow drive up to the higher-altitude site.

On the half-hour journey up the mountains, the vegetation changes with every 500m or so of altitude, as the microclimate gets colder and wetter. Around the OSF, scrub and small cactuses can grow. At 3,000m, giant cactuses dominate the terrain, surrounded by dense, rounded shrubs with long spines that are known locally as the "mother-in-law's cushion". Higher up, the spiny plants give way to larger bushes and grasslands.

At 5,000m, the Mars-like terrain can support no life. The mountains are featureless save for small rocks that litter the surface and patches of ice and snow left after from the recent winter.

By the start of 2012, the first 30 of the Alma dishes had already been installed and most are operational. Every few minutes, the white discs rotate and angle in unison towards some unseen target. By 2013, Alma will have all of its carbon-fibre antennas, which can be arranged in countless configurations, up to 10 miles apart across the mountains, depending on the measurements astronomers want to make. When the submillimetre light from distant galaxies and dust clouds has made its way across the universe and reached the Alma antennas, it goes through a carefully engineered obstacle course to ensure it is measured with maximum precision.

The carbon-fibre dishes are linked, via optical fibres, to a building a few hundred metres away and the incoming light waves are first sent to an instrument known as the correlator. Here, thousands of microprocessors mark each incoming light wave with a timestamp, accurate to picoseconds, to ensure all the light from a single source can be reunited later in the detectors.

To get that precision, the scientists have to allow for even the tiniest fluctuations in length of the optical fibres, which can expand and contract due to temperature fluctuations around them. The fibres are buried a metre underground but, where they emerge to connect to the antennas and computers at either end, they are exposed to the air and prone to changes. Any differences are minuscule – millimetres – but over the course of a 20km fibre this expansion and contraction will affect the arrival time of the light pulses at the correlator by a few femtoseconds (10^-15 of a second).

The engineers came up with a neat solution: a series of machines called the line-length correctors. These contain small coils of optical fibre connected to pistons. As the light from the distant galaxy comes in, computers use the pistons to stretch the fibre just enough to compensate for the thermal changes in the main fibre earlier on. "It actually keeps the fibre in exactly the same length, it makes sure that you get the same number of wavelengths of light all the way out and back again," says Richard Hills, project scientist at Alma.

This delicate attention means that all the different antennas, though miles apart on the plateau, work as a single telescope. The technique of combining signals from several receivers, known as interferometry, means astronomers can get all the benefits of a much larger telescope without having to build it. Combining data from 66 Alma antennas will produce the sensitivity of a telescope with a diameter of 14,000m.

The correlator passes its perfectly timed light down the corridor to a second refrigerated room which then compares signals from each antenna at each specific point in time. It looks for signals that appear to come from the same source in the sky, picking out the light from galaxies or dust clouds from the background hum of the universe.

"What arrives at each telescope are these very, very faint signals but also coming from each telescope is the emission from the microwave background, from the atmosphere, the noise that's generated in the telescope and receivers themselves," says Hills. "Those are a hundred or a thousand or, in the case of a really faint object, a million times stronger than what we're actually looking for. But they will be random noise, whereas the signals that have come from our distant galaxy will be the same, buried in that noise. We have to look for the correlation, the bits of that signal that are the same."

Individual data from each antenna, around 120 gigabits per second, are compared to the other antennas. "Because the signals from different places in the sky arrive with slightly different times, that's what enables you to tell where in the image each individual object is," says Hill. "Not only do we have to compare each sample, we have to compare the ones at slightly different times as well. The net result is that the amount of arithmetic you need to do in this comes up to more than 10¹⁶ operations per second. A fast PC does 2GHz, that's 2x10⁹. It's 10 million times your PC in terms of processing power."

In October last year, Alma released its first scientific image, taken by measurements from 16 of the dishes then installed on the Chajnantor site. It showed the violent swirls of the Antennae galaxies, a pair of distorted spiral galaxies that are in the process of colliding about 70m light years from Earth.

Though Alma is not yet complete, ESO already has plans to build the next generation of telescope. The European Extremely Large Telescope (ELT) will be situated near the main VLT observatory site at Paranal. The ink on the contracts is barely dry – the agreement from the Chilean government to bequeath the site at the top of Mount Armazones was only granted a few weeks ago. There is no road to the site yet, and getting to the summit of the 3,000m peak from the nearest highway means a bone-shaking drive that kicks up thick clouds of dust from the desert.

The ELT will have a much greater collecting power than the telescopes on Paranal thanks to a primary mirror of almost 40m. Building this €1bn telescope will take at least a decade and require new technology – no one knows how to build a 40m mirror from a single block of glass (never mind transport it safely through the desert), so it will be composed of 1,000 smaller hexagonal segments. The main mirror will reflect the ancient starlight it detects onto a 4m-wide secondary mirror before it goes on to hit the detectors. Collecting more light will enable it to resolve more detail than anything before it — ELT will be able to take pictures of exoplanets directly, for example, and even work out what chemical elements are present in their atmospheres. It will see farther out into deep space (and therefore further back in time towards the beginning of the universe) and explore the nature of dark energy and dark matter. Most important, says ESO's Gonzalo Argando, is the unexpected, "the things astronomers are not even able to guess today and that can reshape astronomy as we know it".

An Earth-like planet with Earth-like conditions and which may even support life is tantalising for scientific as well as cultural reasons. Michael Sterzik, deputy director of Paranal observatory, said characterising the properties of an exoplanet's atmosphere would be a major hit for the ELT. He is acutely aware how such a discovery would appeal directly to the public, something ESO does its best to highlight when accounting for the big costs of modern astronomy, money that has to come from increasingly cash-strapped governments. The ELT might well be the last major telescope funded for some decades, as the world focuses instead on getting itself out of financial trouble. But it might also be the one that detects the first signs that we are not alone in the universe.

"People are really excited and want to know more about their origins and the origins of the universe," says Sterzik. "I'm very optimistic that funding will continue to be able to yield these facilities that help to answer the fundamental questions of mankind."