Category: OCR Physics A – H158 H558
Permanent link to this article: https://www.animatedscience.co.uk/2013/liquid-metal-inter-atomic-distance-shown-to-contract-on-heating-surprisingly-national-academy-of-sciences
Jul 04 2013
French nuclear tests ‘showered vast area of Polynesia with radioactivity’
French nuclear tests ‘showered vast area of Polynesia with radioactivity’
Declassified papers show extent of plutonium fall-out from South Pacific tests of 60s and 70s was kept hidden, says French paper
The papers, seen by the French paper Le Parisien, reportedly reveal that plutonium fallout hit the whole of French Polynesia, a much broader area than France had previously admitted. Tahiti, above, the most populated island, was exposed to 500 times the maximum accepted levels of radiation. The impact spread as far as the tourist island, Bora Bora.
Thousands of veterans, families and civilians still fighting for compensation over health issues have insisted France now reveals the full truth about the notorious tests whose impact was kept secret for decades.
From 1960 to 1996, France carried out 210 nuclear tests, 17 in the Algerian Sahara and 193 in French Polynesia in the South Pacific, symbolised by the images of a mushroom cloud over the Mururoa atoll. For decades, France argued that the controlled explosions were clean.Jacques Chirac, the French president, controversially resumed nuclear atoll explosions in the South Pacific shortly after being elected in 1995.
Le Parisien said the documents “lifted the lid on one of the biggest secrets of the French army”. It said papers showed that on 17 July 1974, a test exposed Tahiti to 500 times the maximum allowed level of plutonium fallout.
Bruno Barillot, who has investigated the impacts of the nuclear tests for the Polynesian government, complained of the high levels of thyroid cancers and leukaemia in Polynesia. He said the declassified documents revealed Tahiti had “literally been showered with plutonium for two days” during the Mururoa test; from the outset France knew the impact spread further than it publicly admitted. But of the 2,050 pages declassified, 114 remained blacked out.
Richard Oldham, a member of the Polynesia nuclear workers’ association Mururoa e Tatou, told Radio New Zealand International : “It’s the right for our future generations to know what has happened in this country.”
In 2006 a French medical research body found nuclear testing had caused an increase in cancer on the nearest inhabited islands. The French judiciary began investigating health implications. It was not until 2010 that France acknowledged that there could be a compensation process for veterans and civilians. But that is complex and limited to a small geographical area and certain ailments.
About 150,000 veterans and civilians worked on, or were present during, nuclear tests, including 127,000 in Polynesia. But of 800 dossiers, only 11 people have received compensation.
Troops who worked on the tests have described a staggering lack of precaution for workers. During the Mururoa tests in French Polynesia in the late 1960s, one veteran described how he was stationed in shorts and a T-shirt on a boat only about 15 miles from the explosion before having to sail immediately to the area of the vast mushroom cloud to examine the damage.
Others on different tests wore shorts and had no sunglasses; they were told simply to shield their eyes and turn their backs at the time of the explosion.
Permanent link to this article: https://www.animatedscience.co.uk/2013/french-nuclear-tests-showered-vast-area-of-polynesia-with-radioactivity
Apr 12 2013
New Scientist: Drone-wrecking laser gun to sail on US warship. https://www.goo.gl/mag/zHCXYPj
Permanent link to this article: https://www.animatedscience.co.uk/2013/new-scientist-drone-wrecking-laser-gun-to-sail-on-us-warship
Feb 19 2013
Has Dark Matter Finally Been Found? Big News Coming Soon. https://www.goo.gl/mag/6pMDilc
If we can work this out then we can start to think about the end of the universe and also what is going to happen in the meantime 🙁
Permanent link to this article: https://www.animatedscience.co.uk/2013/has-dark-matter-finally-been-found-big-news-coming-soon
Aug 22 2012
Star is caught devouring planet (from the BBC)
Astronomers have found evidence for a planet being devoured by its star, yielding insights into the fate that will befall Earth in billions of years.
The team uncovered the signature of a planet that had been “eaten” by looking at the chemistry of the host star.
They also think a surviving planet around this star may have been kicked into its unusual orbit by the destruction of a neighbouring world.
Details of the work have been published in Astrophysical Journal Letters.
The US-Polish-Spanish team made the discovery when they were studying the star BD+48 740 – which is one of a stellar class known as red giants. Their observations were made with the Hobby Eberly telescope, based at the McDonald Observatory in Texas.
Rising temperatures near the cores of red giants cause these elderly stars to expand in size, a process which will cause any nearby planets to be destroyed.
“A similar fate may await the inner planets in our solar system, when the Sun becomes a red giant and expands all the way out to Earth’s orbit some five billion years from now,” said co-author Prof Alexander Wolszczan from Pennsylvania State University in the US.
The first piece of evidence for the missing planet comes from the star’s peculiar chemical composition.
Spectroscopic analysis of BD+48 740 revealed that it contained an abnormally high amount of lithium, a rare element created primarily during the Big Bang 14 billion years ago.
Lithium is easily destroyed in stars, so its high abundance in this ageing star is very unusual.
“Theorists have identified only a few, very specific circumstances, other than the Big Bang, under which lithium can be created in stars,” Prof Wolszczan explained.
“In the case of BD+48 740, it is probable that the lithium production was triggered by a mass the size of a planet that spiralled into the star and heated it up while the star was digesting it.”
The second piece of evidence discovered by the astronomers is the highly elliptical orbit of a newly discovered planet around the red giant star. The previously undetected world is at least 1.6 times as massive as Jupiter.
Co-author Andrzej Niedzielski of Nicolaus Copernicus University in Torun, Poland, said that orbits as eccentric as this one are uncommon in planetary systems around evolved stars.
“In fact, the BD+48 740 planet’s orbit is the most elliptical one detected so far,” he added.
Because gravitational interactions between planets are often responsible for such peculiar orbits, the astronomers suspect that the dive of the missing planet toward its host star before it became a giant could have given the surviving massive planet a burst of energy.
This boost would have propelled it into its present unusual orbit.
Team member Eva Villaver of the Universidad Autonoma de Madrid in Spain commented: “Catching a planet in the act of being devoured by a star is an almost improbable feat to accomplish because of the comparative swiftness of the process, but the occurrence of such a collision can be deduced from the way it affects the stellar chemistry.
“The highly elongated orbit of the massive planet we discovered around this lithium-polluted red giant star is exactly the kind of evidence that would point to the star’s recent destruction of its now-missing planet.”
Permanent link to this article: https://www.animatedscience.co.uk/2012/star-is-caught-devouring-a-planet