23/09/2013, 19:20
Fonte: http://www.sciencedaily.com/releases/2010/04/100406181611.htm
Nuclear Missing Link Created at Last: Superheavy Element 117
Apr 7, 2010 - An international team of scientists from Russia and the United States,
including two Department of Energy national laboratories and two universities,
has created the newest superheavy element, element 117.
"The discovery of element 117 is the culmination of a decade-long journey to expand the periodic table and write the next chapter in heavy element research," said Academician Yuri Oganessian, scientific leader of the Flerov Laboratory of Nuclear Reactions at JINR and spokesperson for the collaboration.
The lifetime of element 117,
which has now been created in the lab for the first time,
confirms that superheavy elements lie in an island of stability on the periodic table.
The island of stability is a term in nuclear physics that refers to the possible existence of a region beyond the current periodic table where new superheavy elements with special numbers of neutrons and protons would exhibit increased stability. Such an island would extend the periodic table to even heavier elements and support longer isotopic lifetimes to enable chemistry experiments.
Element 117 was the only missing element in row seven of the periodic table. On course to the island of stability, researchers initially skipped element 117 due to the difficulty in obtaining the berkelium target material. The observed decay patterns in the new isotopes from this experiment, as close as researchers have ever approached the island of stability, continue a general trend of increasing stability for superheavy elements with increasing numbers of neutrons in the nucleus. This provides strong evidence for the existence of the island of stability.
"It fills in the gap and gets us incrementally closer than element 116 -- on the edge of the island of stability," said Ken Moody, one of the LLNL collaborators and a long term veteran of superheavy element research. "The experiments are getting harder, but then I thought we were done 20 years ago."
This discovery brings the total to six new elements discovered by the Dubna-Livermore team (113, 114, 115, 116, 117, and 118)
Since 1940, 26 new elements beyond uranium have been added to the periodic table.
"These new elements expand our understanding of the universe and provide important tests of nuclear theories," said Vanderbilt University Professor of physics Joe Hamilton.
"The existence of the island of stability, a pure theoretical notion in the 1960s, offers the possibility of further expansion of the periodic table with accompanying scientific breakthroughs in the physics and chemistry of the heaviest elements."
23/09/2013, 23:46
24/09/2013, 13:33
25/09/2013, 13:12
25/09/2013, 18:21
25/09/2013, 22:40
Aztlan ha scritto:
Quindi la domanda rimane:
Lazar ha anticipato scoperte "non prevedibili" (per capirci)
o solo quelle di cui si parla in questo topic, che erano basate su teorie di cui nell' ambito scientifico già si parlava da decenni
26/09/2013, 00:28
26/09/2013, 01:33
Aztlan ha scritto:
La sintetizzazione non era prevedibile in quanto non vi era la tecnologia e si riteneva impossibile pure in futuro,
o perchè si riteneva non potesse esistere l' elemento?
Comprendi da te l' importanza della differenza tra le due.
26/09/2013, 13:08
26/09/2013, 22:07
27/09/2013, 15:51
27/09/2013, 16:00
30/09/2013, 14:08
30/09/2013, 14:12
30/09/2013, 17:24
MarcoFranceschini ha scritto:
E' molto semplice, esiste come sostengo da tempo una biforcazione che porta a due paradigmi di scienza con avanzamenti, metodi e modi diversi.
Il più grande è quello canonico a cui la maggioranza delle persone possono accedere...l'altro quello minoritario (forse) va avanti con una sua logica, con un proprio obbiettivo e soprattutto è parecchi anni avanti a ciò che è disponibile ai più.
Lazar stava riportando i risultati raggiunti dalla scienza "parallela"...
Marco71.