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The Boatyard at Saint Mammes by Alfred Sisley

Size: 38.8x56 cm

2017 January 14

Stardust in the Perseus Molecular Cloud Image Credit & Copyright: Lorand Fenyes

Explanation: Clouds of stardust drift through this deep skyscape. The cosmic scene spans nearly 2 degrees across the Perseus molecular cloud some 850 light-years away. A triangle of dusty nebulae reflecting light from embedded stars is captured in the telescopic field of view. With a characteristic bluish color reflection nebula NGC 1333 is at left, vdB13 at bottom right, and rare yellowish reflection nebula vdB12 lies at the top. Stars are forming in the Perseus molecular cloud, though most are obscured at visible wavelengths by the pervasive dust. Still, hints of contrasting red emission from Herbig-Haro objects, the jets and shocked glowing gas emanating from recently formed stars, are evident in NGC 1333. At the estimated distance of the molecular cloud, legs of the triangle formed by the reflection nebulae would be about 20 light-years long.

∞ Source: apod.nasa.gov/apod/ap170114.html

Fright Night, The Witches Hour & The Darkest Hour by DVerissimo - Like it? Find out more and buy HERE (t-shirts, phone & laptop cases, prints, pillows, stickers, mugs, calendars, etc…)

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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

Dancer with a Fan by Edgar Degas

Medium: pastel

😊

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.

😊

Holiday Lights from the Universe

Although there are no seasons in space, some cosmic vistas invoke thoughts of a frosty winter landscape. Here are a few stellar images of holiday wonderlands from across the galaxy…

Located in our galaxy about 5,500 light years from Earth, this region is actually a “cluster of clusters,” containing at least three clusters of young stars, including many hot, massive, luminous stars.

The outstretched “wings” of this nebula looks like a soaring, celestial snow angel. Twin lobes of super-hot gas, glowing blue in this image, stretch outward from the central star. This hot gas creates the “wings” of our angel. A ring of dust and gas orbiting the star acts like a belt, clinching the expanding nebula into an “hourglass” shape.

At this time of year, holiday parties often include festive lights. When galaxies get together, they also may be surrounded by a spectacular light show. This pair of spiral galaxies has been caught in a grazing encounter. This region has hosted three supernova explosions in the past 15 years and has produced one of the most bountiful collections of super-bright X-ray lights known.

What do the following things have in common: a cone, the fur of a fox and a Christmas tree? Answer: they all occur in the constellation of the unicorn (Monoceros). Pictured as a star forming region, the complex jumble of cosmic gas and dust is about 2,700 light-years away.

Resembling festive lights on a holiday wreath, this Hubble Space Telescope image of a nearby spiral galaxy is an iconic reminder of the impending season. Bright knots of glowing gas light up the spiral arms, indicating a rich environment of star formation.

The Hubble Space Telescope captured two festive-looking nebulas, situated so as to appear as one. Intense radiation from the brilliant central stars is heating hydrogen in each of the nebulas, causing them to glow red…like a holiday light.

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this atmospheric phenomenon is known as a circumhorizontal arc, which occurs when the sun is at least 58° above the horizon and the hexagonal ice crystals which form cirrus clouds become horizontally aligned.                     

(photos x, x, x, x, x, x, x. see also: more circumhorizontal arcs, asperatus clouds, mammatus clouds, polar stratospheric clouds and cloud iridescence)

Egypto-Phoenician Silver Swivel Ring, C. 1000 BC

The thick solid silver shank tapering at the terminal and holding a solid silver scarab engraved with the falcon Horus in the center with the “Ames Scepter” and a protective Uraeus on either side, all standing on the Neb (Lord) sign.