Rue Mosnier Decorated With Flags By Edouard Manet

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PEOPLE OF THE ANCIENT WORLD: Lucius Verus (Marcus Aurelius’ Co-Emperor) 

LUCIUS Verus (161-169 CE) was Marcus Aurelius’ adopted brother and co-emperor, a man whose time on the throne is overshadowed by the reign of the last of the Five Good Emperors.

 In the final years of the Pax Romana, a period of almost two centuries of relative peace and stability following the rule of Augustus, a young Stoic philosopher, Marcus Aurelius, came to the throne in 161 CE, and for the first time in the empire’s short history he chose to have someone rule at his side; his adopted brother Lucius Verus.

The future emperor Lucius Ceionius Commodus was born in 130 CE and raised in Rome, the eldest son of the one-time consul Lucius Aelius Caesar.

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Article by Donald L. Wasson on AHE

First signs of weird quantum property of empty space?

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

NGC 7129

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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.

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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

Celestial nomad takes centre stage

In this new ESO image, nightfall raises the curtain on a theatrical display taking place in the cloudless skies over La Silla.

In a scene humming with activity, the major players captured here are Comet Lovejoy, glowing green in the centre of the image; the Pleiades above and to the right; and the California Nebula, providing some contrast in the form of a red arc of gas directly to the right of Lovejoy.

A meteor adds its own streak of light to the scene, seeming to plunge into the hazy pool of green light collecting along the horizon.

The telescopes of La Silla provide an audience for this celestial performance, and a thin shroud of low altitude cloud clings to the plain below the observatory streaked by the Panamericana Highway.

Comet Lovejoy’s long tail is being pushed away from the comet by the solar wind. Carbon compounds that have been excited by ultraviolet radiation from the Sun give it its striking green hue.

This is the first time the comet has passed through the inner Solar System and ignited so spectacularly in over 11 000 years. Its highly elliptical orbit about the Sun — adjusted slightly due to meddling planets — means that it will not grace our skies for another 8000 years once it has rounded the Sun and begun its lonely voyage back into the cold outer regions of the Solar System.

Image credit: P. Horálek/ESO

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Archaeologists Discover Unknown Fortress Walls, Byzantine Gold Coin

Two unknown fortress walls and three unknown fortress towers as well as a 14th century Byzantine gold coin have been discovered by archaeologists during the 2016 excavations of the major medieval fortress of Rusocastro in today’s Southeast Bulgaria.

The Rusocastro Fortress is best known for the Battle of Rusocastro in 1332 AD. It was the last big military victory of the medieval Bulgarian Empire before it was conquered by the invading Ottoman Turks at the end of the 14th century.

It was also the last major battle of the seven-century-long Bulgarian-Byzantine Wars for domination of the Balkan Peninsula (lasting from the 7th until the 14th century), which ended when, weakened by their hostilities against one another, among other factors, Bulgaria and Byzantium were both conquered by the Ottoman Turkish invaders at the end of the 14th and the beginning of the 15th century. Read more.

Rhodochrosite with Quartz - Uchucchacua Mine, Lima Department, Peru

Anahita and Ishtar: Connections to the Planet Venus

Anahita was a goddess associated with water, fertility, wisdom, warfare, and eventually the planet Venus. During the Achaemenid dynasty in Persia, she became incorporated into the Zoroastrian religion as a Yazata, a type of minor divinity. Her association with warfare and the planet Venus was not very prominent before the Achaemenid Period, leading some to conclude that her cult and persona may have become influenced by the goddess Ishtar. In becoming associated with Ishtar, she may have taken on the characteristics of a Venus god/Venus goddess, a type of god which appears to occur across cultures associated with the planet Venus.  

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The Boatyard at Saint Mammes by Alfred Sisley

Size: 38.8x56 cm