How Much Mass Makes a Black Hole? Astronomers Challenge Current Theories

How Much Mass Makes a Black Hole? Astronomers Challenge Current Theories: "(PhysOrg.com) -- Using ESO's Very Large Telescope, European astronomers have for the first time demonstrated that a magnetar -- an unusual type of neutron star -- was formed from a star with at least 40 times as much mass as the Sun. The result presents great challenges to current theories of how stars evolve, as a star as massive as this was expected to become a black hole, not a magnetar. This now raises a fundamental question: just how massive does a star really have to be to become a black hole?"

Portugueses descobrem gene associado à enxaqueca

Portugueses descobrem gene associado à enxaqueca: "Investigadores portugueses descobriram que a causa das enxaquecas está nos genes, uma descoberta que poderá abrir as portas a novas terapêuticas para esta doença incapacitante, que afecta mais de uma em cada..."

Experiments offer tantalizing clues as to why matter prevails in the universe

Experiments offer tantalizing clues as to why matter prevails in the universe: "A large collaboration of physicists working at the Fermilab Tevatron particle collider has discovered evidence of an explanation for the prevalence of matter over antimatter in the universe. They found that colliding protons in their experiment produced short-lived B meson particles that almost immediately broke down into debris that included slightly more matter than antimatter. The two types of matter annihilate each other, so most of the material coming from these sorts of decays would disappear, leaving an excess of regular matter behind."

Researchers find function of proteins that can enhance the progression of viruses and cancer cells

Researchers find function of proteins that can enhance the progression of viruses and cancer cells: "In a discovery that has implications for developing treatments against cancer and potentially deadly viruses, researchers at SUNY Downstate Medical Center have discovered the function of proteins that can enhance the progression of certain viruses and cancer cells. Their findings were published in the journal Genes and Development."

Fermi detects 'shocking' surprise from supernova's little cousin

Fermi detects 'shocking' surprise from supernova's little cousin: "Astronomers using NASA's Fermi Gamma-ray Space Telescope have detected gamma-rays from a nova for the first time, a finding that stunned observers and theorists alike. The discovery overturns the notion that novae explosions lack the power to emit such high-energy radiation."

Citizen scientists discover rotating pulsar

Citizen scientists discover rotating pulsar: "Idle computers are the astronomers' playground: three citizen scientists -- an American couple and a German -- have discovered a new radio pulsar hidden in data gathered by the Arecibo Observatory. This is the first deep-space discovery by Einstein@Home, which uses donated time from the home and office computers of 250,000 volunteers from 192 different countries. This is the first genuine astronomical discovery by a public volunteer distributed computing project."

ALERTA: espectáculo de estrelas cadentes. As Perseidas são esta noite!

ALERTA: espectáculo de estrelas cadentes. As Perseidas são esta noite!: "O pico da chuva de estrelas Perseidas será esta noite. Não faltarão estrelas cadentes no céu. Cerca de uma por minuto. Leiam todas as informações que precisam saber, nestes sites: - astroPT: post deste ano com informações sobre esta chuva de estrelas e como observar. - astroPT: post do ano passado, com gráficos e vídeos. [...]"

Dark-matter search plunges physicists to new depths

Dark-matter search plunges physicists to new depths: "Physicists are taking their attempt to unmask the secret identity of dark matter into a Canadian mine more than a mile underground. They are deploying a 4-kilogram bubble chamber at SNOLab, which is part of the Sudbury Neutrino Observatory in Ontario, Canada. A second 60-kilogram chamber will follow later this year."

Identificadas células no combate à rejeição de órgãos

Identificadas células no combate à rejeição de órgãos: "Um grupo de investigadores portugueses identificou células capazes de controlar a acção excessiva do sistema imunitário e que podem ser aplicadas no combate à rejeição de órgãos após transplante."

Rubik's Cube - God's Number is 20

A team of researchers has shown recently that every position of the Rubik's Cube™ can be solved in 20 moves or less. The team members are Morley Davidson, a mathematician from Kent State University, John Dethridge, an engineer at Google in Mountain View, Herbert Kociemba, math teacher from Darmstadt, Germany, and Tomas Rokicki, a programmer from Palo Alto, California.

The best solution know to date was Tomas Rokicki solution. He announced in August 2008 that he had a proof that the Rubik's Cube™ could be solved in 22 moves or less.

A Rubik's Cube™ has 43,252,003,274,489,856,000 positions. To help solving this problem, the team asked Google to donate the idle computer time from their computer systems, and it took a few weeks to get the solution. The time needed to solve the problem was equivalent to 35 years of CPU time in a desktop computer.

More information about Rubik's Cube™ solution in the cube20.org site.

ALPHA freezes antiprotons

ALPHA freezes antiprotons: "

Laboratories like CERN can routinely produce many different types of antiparticles. In 1995, the PS210 experiment formed the first antihydrogen atoms and a few years later, in 2002, ATRAP and ATHENA were already able to produce several thousand of them. However, no experiment in the world has succeeded in ‘trapping’ these anti-atoms in order to study them. This is the goal of the ALPHA experiment, which has recently managed to cool down the antiprotons to just a few Kelvin. This represents a major step towards trapping the anti-atom, thus opening a new avenue into the investigation of antimatter properties.

Members of the ALPHA collaboration working on the apparatus in the Antiproton Decelerator experimental hall at CERN.

Just like the atom, the anti-atom is neutral. Unlike the atom, the anti-atom is made up of antiprotons (as opposed to protons in the atom) and positrons (as opposed to electrons). In order to thoroughly study the properties of the anti-atoms, scientists need to have them trapped for a reasonable amount of time (up to one second). The ALPHA experiment, installed at CERN’s Antiproton Decelerator (AD), has recently reached an important milestone by cooling antiprotons to just a few Kelvin. “This is the first time that a cloud of antiprotons has been cooled to such low temperatures”, explains Jeffrey Hangst, ALPHA’s spokesperson. “The next step will be to mix the cool antiprotons with positrons and form cold antihydrogen atoms that can stay trapped and can then be studied”.

The technique used by the ALPHA collaboration to cool down the antiprotons is borrowed from the neutral atom physics field and is called ‘evaporative cooling’. “You have to imagine your antiprotons contained in a bowl – in our case this is an electrostatic well. Initially, antiprotons move about quite a lot because they have quite a high energy. If you lower one side of the bowl, the hot ones will come out while the others will continue to interact. They end up with a lower temperature than they had before the hot ones escaped. You keep doing it: you let the hot ones escape while those remaining in the bowl come to a lower temperature thermal equilibrium”, says Jeffrey. Although this process leads to a heavy loss of antiprotons in the sample, the overall probability of forming antihydrogen atoms that can be trapped increases drastically.

The AD machine produces antiprotons at an energy of 5.3 MeV that corresponds to about 6x10¹⁰ Kelvin. Using the ‘evaporative cooling’ technique, the ALPHA collaboration managed to cool the antiprotons down to a temperature of 9 Kelvin, increasing the probability of trapping the anti-atoms by a factor of 100 with respect to other cooling techniques. “In order to achieve this temperature of just a few Kelvin, we need to carefully control the voltage in our trap with a precision of the order of a millivolt. Indeed, a potential change of 1 V is equivalent to a temperature change of more than 11000 K! The electric noise in the system must be kept very low to avoid heating up the antiprotons. The whole cooling process takes tens of seconds to complete”, explains Jeffrey.

The ALPHA collaboration is now working to integrate this technique into the main experiment. Trapping antihydrogen will be the next step, which will hopefully happen by the end of the year.
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UE autoriza importação de milho transgénico sem consultar estados

UE autoriza importação de milho transgénico sem consultar estados: "Poderá ter sido uma questão de necessidade mas, no passado dia 28 de Julho, a União Europeia (UE) autorizou a importação de mais seis variedades de milho geneticamente modificado, destinados à alimentação... "

Greenland glacier calves island four times the size of Manhattan

Greenland glacier calves island four times the size of Manhattan: "A researcher reports that an 'ice island' four times the size of Manhattan has calved from Greenland's Petermann Glacier. The last time the Arctic lost such a large chunk of ice was in 1962."

ALERTA: Fantástico Espectáculo nos Céus esta noite!!!

ALERTA: Fantástico Espectáculo nos Céus esta noite!!!: "Notícia de Última Hora!! Lembram-se deste nosso post sobre a mancha solar 1092? Essa mancha solar produziu erupções solares no dia 1 de Agosto. Essas erupções solares expelem grandes quantidades de plasma (átomos ionizados). Uma dessas erupções vem na nossa direcção (na direcção da Terra). Vai chegar cá esta 3ª feira à noite. Assim, esta [...]"