Anahita And Ishtar: Connections To The Planet Venus

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

Dancer with a Fan by Edgar Degas

Medium: pastel

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A giant predatory lizard swam in Antarctic seas near the end of the dinosaur age http://www.geologypage.com/2016/11/giant-predatory-lizard-swam-antarctic-seas-near-end-dinosaur-age.html

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Dancers in Light Blue (Rehearsing in the Dance Studio) by Edgar Degas

Medium: oil on canvas

Nice

Scans of the inside covers of Strang’s Calculus, which you can legally-download for free here from the MIT website. This is my all-time favorite math or physics textbook. Scanned it so I could cut and paste it into my new sketchbook, wanna try and make a ~cool artistic~ reference poster out of it, ‘cuz I’ve been real into that idea since I took notes about rings for the algebra midterm on a big piece of watercolor paper.

NGC 7129

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Интересно

Ancient rocks hold evidence for life before oxygen http://www.geologypage.com/2016/11/ancient-rocks-hold-evidence-life-oxygen.html

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

The Pork Butcher by Camille Pissarro

Size: 66x54 cm Medium: oil on canvas