Category: GCSE Physics

‘Critical phase’ for fusion dream

‘Critical phase’ for fusion dream http://www.bbc.co.uk/news/science-environment-23408073

Permanent link to this article: https://animatedscience.co.uk/2013/critical-phase-for-fusion-dream

Neutron starbursts can forge gold

Neutron starbursts can forge gold http://www.bbc.co.uk/news/science-environment-23361153

New evidence has been uncovered of a rare cosmic event that is proposed as a source of heavy elements such as gold. Observations from the Hubble Space Telescope appear to show a distant collision between two neutron stars – the remnants of massive supernovae. Astronomers suggest that such collisions are responsible for ultra-short bursts of gamma rays occasionally seen across the Universe. The work is described in a paper on the pre-print server Arxiv.org.

Although rare, neutron star collisions would generate the enormous fluxes of neutrons needed to make elements heavier than iron, like platinum, lead and gold, by rapid neutron capture. Prof Edo Berger and colleagues from Harvard University analysed Hubble observations of a short burst of gamma rays, lasting only one fifth of a second, seen from a galaxy 3.9 billion light years away. The infrared afterglow of this burst of gamma-ray light appears to show the characteristics expected during radioactive decay of atomic nuclei generated in a neutron star collision.

This sort of event emits light with an intensity that lies between normal star light and that of a supernova, and the term “kilonova” has been coined to describe it. They appear to be around 1,000 times rarer than supernova explosions, and occur when the remnants of two supernovae collide.

If confirmed, the result represents the first observation of a neutron star collision, and provides an explanation for the rapid “R-process” of atom-building that must generate the heavy elements on the periodic table, such as gold and platinum. Neutron stars are incredibly dense and massive. As well as bursts of light, when they collide they are also expected to send gravity “shock waves” through the Universe. Experiments in America and Europe are now focussed on measuring such waves, and combined with the type of events seen by Hubble in the last month this will provide a further confirmation of neutron star collision. Astronomers are now testing the conclusions of the Harvard group with further detailed analysis of the Hubble data.

Permanent link to this article: https://animatedscience.co.uk/2013/neutron-starbursts-can-forge-gold

French nuclear tests ‘showered vast area of Polynesia with radioactivity’

French nuclear tests ‘showered vast area of Polynesia with radioactivity’

http://gu.com/p/3h3kf

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

Tahiti, Polynesia

Tahiti, above, was exposed to 500 times the accepted maximum radiation level from nuclear tests in the 20th century, reports Le Parisien. French nuclear tests in the South Pacific in the 1960s and 1970s were far more toxic than has been previously acknowledged and hit a vast swath of Polynesia with radioactive fallout, according to newly declassified ministry of defence documents which have angered veterans and civilians’ groups.

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://animatedscience.co.uk/2013/french-nuclear-tests-showered-vast-area-of-polynesia-with-radioactivity

Debut for thermal invisibility cloak

Debut for thermal invisibility cloak http://www.bbc.co.uk/news/science-environment-22462853

Permanent link to this article: https://animatedscience.co.uk/2013/debut-for-thermal-invisibility-cloak

Carbon dioxide passes symbolic mark

Carbon dioxide passes symbolic mark http://www.bbc.co.uk/news/science-environment-22486153

Permanent link to this article: https://animatedscience.co.uk/2013/carbon-dioxide-passes-symbolic-mark

World’s oldest and stickiest lab study ready for drop of excitement

World’s oldest and stickiest lab study ready for drop of excitement

http://gu.com/p/3fedf

Permanent link to this article: https://animatedscience.co.uk/2013/worlds-oldest-and-stickiest-lab-study-ready-for-drop-of-excitement

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