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Monthly Archives: June 2016

Four elements have new names announced following their recognition last December.

The International Union of Pure and Applied Chemistry officially recognized elements 113, 115, 117, and 118, filling out the seventh row of the periodic table. As is the traditional in chemistry, the naming rights go to the discoverers: scientists at RIKEN in Wako, Japan, named element 113, and a Russian-U.S. collaboration named the others.

These elements are not found in nature as they are all short-lived and highly radioactive. They were all created in high-energy physics laboratories where lighter nuclei were smashed into one another and scientists looked for signature radioactive decays that should come from the new elements.

0608176_ec_periodictable

Credit: E. Otwell

 

Element 113 is “nihonium”, chemical symbol Nh. Its name comes from the Japanese word “Nihon,” (tr: Land of the Rising Sun), a name for Japan.

Element 115 is “moscovium,” chemical symbol Mc, after the Moscow region, home to the Joint Institute for Nuclear Research, where the element was discovered in collaboration with researchers at Lawrence Livermore National Laboratory in California and Oak Ridge National Laboratory in Tennessee.

Element 117 is “tennessine,” chemical symbol Ts, after the home state of Oak Ridge, Vanderbilt University and the University of Tennessee. (Livermorium, Lv, is already element 116.)

Element 118 is “oganesson,” chemical symbol Og, after the Russian physicist Yuri Oganessian, who contributed to the discovery of several superheavy elements.

The proposed names are expected to be confirmed in November, following a period of public consultation.

Links: IUPAC press release; NY Times coverage; Nature news.

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An article in the New York Times by Dennis Overbye gives the latest chapter in Stephen Hawking’s saga concerning whether the properties of matter that has fallen into a black hole are lost forever, or whether there is a way out.

Forty years ago, Hawking showed theoretically that black holes were not ‘eternal prisons’ but could leak radiation. There ensued a long-running debate about whether this radiation retained any information or attributes of the original matter. If it does not, this violates a tenet of modern physics, that it is always possible, in theory, to reverse time. This became known as the ‘information paradox’ and was the subject of a famous bet between Hawking and Caltech professor John Preskill. (Hawking conceded defeat 10 years ago, admitting that advances in string theory, had left no room in the universe for information loss.)

In a paper published to be published this week in Physical Review Letters, Hawking and his colleagues Andrew Strominger (Harvard) and Malcolm Perry (Cambridge) announce they have found a clue pointing the way out of black holes. They new results undermine John Wheeler’s famous notion that black holes have “no hair” — that they are shorn of the essential properties of the things they have consumed.

Looked at from the right vantage point — from a far distance in time, technically known as “null infinity” — black holes might not be not be bald at all. A tell-tale pattern of light rays bordering the event horizon contains information about what has passed through. This has been dubbed in their paper a “soft hair” theory.

For a more complete description of this story, see the full NYT article.

In a subsequent article, Dennis Overbye answers questions on black holes submitted by his readers.

 

From a UC Berkeley press release, June 2, 2016:

Astronomers have obtained the most precise measurement yet of how fast the universe is expanding at the present time, and it doesn’t agree with predictions based on other data and our current understanding of the physics of the cosmos. The discrepancy – the universe is now expanding 9 percent faster than expected – means either that measurements of the cosmic microwave background radiation are wrong, or that some unknown physical phenomenon is speeding up the expansion of space, the astronomers say.

“If you really believe our number – and we have shed blood, sweat and tears to get our measurement right and to accurately understand the uncertainties – then it leads to the conclusion that there is a problem with predictions based on measurements of the cosmic microwave background radiation, the leftover glow from the Big Bang,” said The Cosmos author Alex Filippenko, a co-author of a paper announcing the discovery. “Maybe the universe is tricking us, or our understanding of the universe isn’t complete.”

The cause could be the existence of another, unknown particle – perhaps an often-hypothesized fourth flavor of neutrino – or that the influence of dark energy (which accelerates the expansion of the universe) has increased over the 13.8 billion year history of the universe. Or perhaps Einstein’s general theory of relativity, the basis for the Standard Model, is slightly wrong.

“This surprising finding may be an important clue to understanding those mysterious parts of the universe that make up 95 percent of everything and don’t emit light, such as dark energy, dark matter and dark radiation,” said Nobel Laureate Adam Riess, the leader of the study. Riess is a former UC Berkeley post-doctoral fellow who worked with Filippenko. The results, using data from the Hubble Space Telescope and the Keck I telescope in Hawaii, will appear in an upcoming issue of The Astrophysical Journal.

Links: UC Berkeley press release with more details of the measurements; Hubble press release; the ApJ paper;