Lightweight Black Hole
Saint-Sauves-d'Auvergne via Armand Guillaumin
Archaeologists have started an underwater detection project after villagers in eastern China’s Jiangxi Province found the head of a Buddha statue emerging from the surface of a local reservoir.
The head was spotted at Hongmen Reservoir, Nancheng County in the city of Fuzhou, at the end of last year when a hydropower gate renovation project lowered water levels in the reservoir by more than 10 meters.
Judging from the head design, the statue was carved during the Ming Dynasty (1368-1644), said Xu Changqing, head of the provincial research institute of archaeology.
He said that the researchers had also found rectangular holes carved on the cliff, obvious marks of architecture, which meant that a temple could have existed there. Read more.
NGC 7129
The Boatyard at Saint Mammes by Alfred Sisley
Size: 38.8x56 cm
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The eight planets of our solar system image credits: [x]
A team led by Roberto Mignani from INAF Milan (Italy) and from the University of Zielona Gora (Poland), used ESO’s Very Large Telescope (VLT) at the Paranal Observatory in Chile to observe the neutron star RX J1856.5-3754, about 400 light-years from Earth [1].
Despite being amongst the closest neutron stars, its extreme dimness meant the astronomers could only observe the star with visible light using the FORS2 instrument on the VLT, at the limits of current telescope technology.
Neutron stars are the very dense remnant cores of massive stars – at least 10 times more massive than our Sun – that have exploded as supernovae at the ends of their lives. They also have extreme magnetic fields, billions of times stronger than that of the Sun, that permeate their outer surface and surroundings.
These fields are so strong that they even affect the properties of the empty space around the star. Normally a vacuum is thought of as completely empty, and light can travel through it without being changed. But in quantum electrodynamics (QED), the quantum theory describing the interaction between photons and charged particles such as electrons, space is full of virtual particles that appear and vanish all the time. Very strong magnetic fields can modify this space so that it affects the polarisation of light passing through it.
Mignani explains: “According to QED, a highly magnetised vacuum behaves as a prism for the propagation of light, an effect known as vacuum birefringence.”
Among the many predictions of QED, however, vacuum birefringence so far lacked a direct experimental demonstration. Attempts to detect it in the laboratory have not yet succeeded in the 80 years since it was predicted in a paper by Werner Heisenberg (of uncertainty principle fame) and Hans Heinrich Euler.
“This effect can be detected only in the presence of enormously strong magnetic fields, such as those around neutron stars. This shows, once more, that neutron stars are invaluable laboratories in which to study the fundamental laws of nature.” says Roberto Turolla (University of Padua, Italy).
After careful analysis of the VLT data, Mignani and his team detected linear polarisation – at a significant degree of around 16% – that they say is likely due to the boosting effect of vacuum birefringence occurring in the area of empty space surrounding RX J1856.5-3754 [2].
Vincenzo Testa (INAF, Rome, Italy) comments: “This is the faintest object for which polarisation has ever been measured. It required one of the largest and most efficient telescopes in the world, the VLT, and accurate data analysis techniques to enhance the signal from such a faint star.”
“The high linear polarisation that we measured with the VLT can’t be easily explained by our models unless the vacuum birefringence effects predicted by QED are included,” adds Mignani.
“This VLT study is the very first observational support for predictions of these kinds of QED effects arising in extremely strong magnetic fields,” remarks Silvia Zane (UCL/MSSL, UK).
Mignani is excited about further improvements to this area of study that could come about with more advanced telescopes: “Polarisation measurements with the next generation of telescopes, such as ESO’s European Extremely Large Telescope, could play a crucial role in testing QED predictions of vacuum birefringence effects around many more neutron stars.”
“This measurement, made for the first time now in visible light, also paves the way to similar measurements to be carried out at X-ray wavelengths,” adds Kinwah Wu (UCL/MSSL, UK).
This research was presented in the paper entitled “Evidence for vacuum birefringence from the first optical polarimetry measurement of the isolated neutron star RX J1856.5?3754”, by R. Mignani et al., to appear in Monthly Notices of the Royal Astronomical Society.
European Southern Observatory
“In 1967, a radio source emitting regular, 0.04-second long pulses every 1.3373 seconds was found for the first time using a scintillation array. After the “noise” explanation was ruled out, the next thing people turned towards were intelligent extraterrestrials. There was no natural mechanism in existence that would have explained it at that time, so turning to aliens was logical, if ultimately incorrect.”
Observations that surprise us, of a phenomenon we weren’t expecting and don’t have an explanation for, are some of the most exciting things we can encounter in astronomy. In 1967, regularly pulsing radio sources, discovered without any expectation, provided exactly that. It wasn’t noise; it was definitely a robust, repeatable observation; so what was it? While our imaginations might have run to aliens initially, further developments quickly showed that this was a ball of rapidly rotating neutrons, more massive than even the Sun but only a few kilometers in diameter. These pulsars, as they’re now know, are ubiquitous and come about from the corpses of core-collapse supernova. Could this be a harbinger of what we can expect from the ‘alien megastructure’ controversy?
Come find out how the first ‘false alien’ signal from astronomy opened up a whole new field of science for us to investigate!
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Space station flyover of Gulf of Aden and Horn of Africa
European Space Agency astronaut Samantha Cristoforetti took this photograph from the International Space Station and posted it to social media on Jan. 30, 2015. Cristoforetti wrote, “A spectacular flyover of the Gulf of Aden and the Horn of Africa. #HelloEarth”
Image credit: NASA/ESA/Samantha Cristoforetti
My wife has never had a cat/kitten so I got her one. This is… - (Source: http://www.miniurls.co/lJTF)
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CYGNSS rockets into orbit atop Pegasus
The first Cygnus launch from Cape Canaveral in nearly 10 years successfully placed NASA’s eight CYGNSS satellite into orbits Thursday, December 15. Pegasus, attached to the belly of Orbital ATK’s L-1011 Stargazer aircraft, lifted off from Cape Canaveral Air Force Station’s Skid Strip runway at 7:38am EDT. After reaching an altitude of 39,000 feet and within the 10 by 40 mile launch box, Pegasus was commanded for release, falling away from the mothership at 8:37am. Less than five seconds later, the first stage ignited, beginning a 14-minute climb to orbit for Pegasus and the eight CYGNSS satellites.
CYGNSS, short for Cyclone Global Navigation Satellite System, will use high-fidelity GPS signals to help forecasters better measure and predict hurricanes. In honor of the storm recently affecting the space coast, the Pegasus rocket launching CYGNSS was named Matthew. This was the 43rd launch of the Pegasus rocket, which made history in 1990 as the world’s first successfully-launched commercially-developed rocket vehicle. It remains the only air-launched rocket system in operation. CYGNSS was originally scheduled for launch Monday, but a faulty hydraulic pump in the rocket’s release mechanism promoted a delay into today. P/C: NASA.