ASTRONOMY - Thor's Helmet

 2024 January 9

Thor's Helmet
Image Credit & Copyright: Ritesh Biswas

Explanation: Thor not only has his own day (Thursday), but a helmet in the heavens. Popularly called Thor's Helmet, NGC 2359 is a hat-shaped cosmic cloud with wing-like appendages. Heroically sized even for a Norse god, Thor's Helmet is about 30 light-years across. In fact, the cosmic head-covering is more like an interstellar bubble, blown with a fast wind from the bright, massive star near the bubble's center. Known as a Wolf-Rayet star, the central star is an extremely hot giant thought to be in a brief, pre-supernova stage of evolution. NGC 2359 is located about 15,000 light-years away toward the constellation of the Great Overdog. This remarkably sharp image is a mixed cocktail of data from narrowband filters, capturing not only natural looking stars but details of the nebula's filamentary structures. The star in the center of Thor's Helmet is expected to explode in a spectacular supernova sometime within the next few thousand years.

ASTRONOMY - The Phases of Venus

 2024 January 8

The Phases of Venus
Image Credit & License: Stéphane Gonzales

Explanation: Venus goes through phases. Just like our Moon, Venus can appear as a full circular disk, a thin crescent, or anything in between. Venus, frequently the brightest object in the post-sunset or pre-sunrise sky, appears so small, however, that it usually requires binoculars or a small telescope to clearly see its current phase. The featured time-lapse sequence was taken over the course of six months in 2015 from Surgères, Charente-Maritime, France, and shows not only how Venus changes phase, but changes angular size as well. When Venus is on the far side of the Sun from the Earth, it appears angularly smallest and nearest to full phase, while when Venus and Earth are on the same side of the Sun, Venus appears larger, but as a crescent. This month Venus rises before dawn in waxing gibbous phases.

LE JARDIN MERVEILLEUX DES EPICES - La badiane, une épice étoilée

Le goût de la badiane est incontestablement anisé. C'est d'ailleurs pour cela -- et pour sa forme particulière -- que l'on appelle aussi la badiane, anis étoilé. Mais attention, à ne pas confondre ce fruit du badianier de Chine avec la badiane japonaise. Cette dernière en effet est une plante toxique.

On attribue à la badiane toute une série de propriétés médicinales. Elle est ainsi reconnue pour ses propriétés antivirales. Consommée en infusion ou ajoutée aux plats ou aux desserts, la badiane aiderait également à atténuer les troubles gastro-intestinaux. Elle agirait aussi sur la fatigue physique et l'anxiété. 

© Daria-Yakovleva, Pixabay, CC0 Creative Commons ; Daderot, Wikimedia Commons, CC0 Creative Commons

FuturaSciences

ASTRONOMY - The Cat's Eye Nebula in Optical and X-ray

 2024 January 7

The Cat's Eye Nebula in Optical and X-ray
Image Credit: NASA, ESA, Hubble Legacy Archive; Chandra X-ray Obs.;
Processing & Copyright: Rudy Pohl

Explanation: To some it looks like a cat's eye. To others, perhaps like a giant cosmic conch shell. It is actually one of the brightest and most highly detailed planetary nebula known, composed of gas expelled in the brief yet glorious phase near the end of life of a Sun-like star. This nebula's dying central star may have produced the outer circular concentric shells by shrugging off outer layers in a series of regular convulsions. The formation of the beautiful, complex-yet-symmetric inner structures, however, is not well understood. The featured image is a composite of a digitally sharpened Hubble Space Telescope image with X-ray light captured by the orbiting Chandra Observatory. The exquisite floating space statue spans over half a light-year across. Of course, gazing into this Cat's Eye, humanity may well be seeing the fate of our sun, destined to enter its own planetary nebula phase of evolution ... in about 5 billion years.

ASTRONOMY - The Snows of Churyumov-Gerasimenko

 2024 January 6

The Snows of Churyumov-Gerasimenko
Images Credit: ESA, Rosetta, MPS, OSIRIS; UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA;
Animation: Jacint Roger Perez

Explanation: You couldn't really be caught in this blizzard while standing by a cliff on periodic comet 67P/Churyumov-Gerasimenko. Orbiting the comet in June of 2016, the Rosetta spacecraft's narrow angle camera did record streaks of dust and ice particles similar to snow as they drifted across the field of view close to the camera and above the comet's surface. Still, some of the bright specks in the scene are likely due to a rain of energetic charged particles or cosmic rays hitting the camera, and the dense background of stars in the direction of the constellation of the Big Dog (Canis Major). In the video, the background stars are easy to spot trailing from top to bottom. The stunning movie was constructed from 33 consecutive images taken over 25 minutes while Rosetta cruised some 13 kilometers from the comet's nucleus. In September 2016, the nucleus became the final resting place for the Rosetta spacecraft after its mission was ended with a successful controlled impact on 67P/Churyumov-Gerasimenko.

LE JARDIN MERVEILLEUX DES EPICES - Les baies roses

En France, seuls les fruits de Piper nigrum peuvent être appelés poivre. C'est pourquoi le poivre rose, issu de Schinus terebinthifolius, est plutôt connu sous le nom de baies roses. Cela n'enlève rien au côté poivré de cet exhausteur de goût très particulier. En plus d'être joli à voir dans une assiette, il lui donnera en effet un goût un brin sucré et anisé.

Originaires d'Amérique du Sud, les baies roses sont réputées présenter des propriétés anti-inflammatoires, antiseptiques et antispasmodiques. Ainsi, sous forme d'huile essentielle, notamment, elles peuvent aider à calmer les douleurs rhumatismales et articulaires, mais aussi les affections de voies respiratoires et les troubles intestinaux. Mais consommées en trop grande quantité, les baies roses deviennent toxiques et provoquent des maux d'estomac.

© 5ph, Fotolia ; Dinesh Valke, Wikimedia, CC by-SA 2.0

FuturaSciences

ASTRONOMY - Trapezium: At the Heart of Orion

 2024 January 5

Trapezium: At the Heart of Orion
Image Credit & Copyright: Fred Zimmer, Telescope Live

Explanation: Near the center of this sharp cosmic portrait, at the heart of the Orion Nebula, are four hot, massive stars known as the Trapezium. Gathered within a region about 1.5 light-years in radius, they dominate the core of the dense Orion Nebula Star Cluster. Ultraviolet ionizing radiation from the Trapezium stars, mostly from the brightest star Theta-1 Orionis C powers the complex star forming region's entire visible glow. About three million years old, the Orion Nebula Cluster was even more compact in its younger years and a dynamical study indicates that runaway stellar collisions at an earlier age may have formed a black hole with more than 100 times the mass of the Sun. The presence of a black hole within the cluster could explain the observed high velocities of the Trapezium stars. The Orion Nebula's distance of some 1,500 light-years would make it one of the closest known black holes to planet Earth.

ASTRONOMY - Zeta Oph: Runaway Star

 2024 January 4

Zeta Oph: Runaway Star
Image Credit: NASA, JPL-Caltech, Spitzer Space Telescope

Explanation: Like a ship plowing through cosmic seas, runaway star Zeta Ophiuchi produces the arcing interstellar bow wave or bow shock seen in this stunning infrared portrait. In the false-color view, bluish Zeta Oph, a star about 20 times more massive than the Sun, lies near the center of the frame, moving toward the left at 24 kilometers per second. Its strong stellar wind precedes it, compressing and heating the dusty interstellar material and shaping the curved shock front. What set this star in motion? Zeta Oph was likely once a member of a binary star system, its companion star was more massive and hence shorter lived. When the companion exploded as a supernova catastrophically losing mass, Zeta Oph was flung out of the system. About 460 light-years away, Zeta Oph is 65,000 times more luminous than the Sun and would be one of the brighter stars in the sky if it weren't surrounded by obscuring dust. The image spans about 1.5 degrees or 12 light-years at the estimated distance of Zeta Ophiuchi. In January 2020, NASA placed the Spitzer Space Telescope in safe mode, ending its 16 successful years of exploring the cosmos.

BIOMIMETISME - Innovations inspirées par la Nature - Quand les termites inspirent les architectes

Les termitières peuvent atteindre plusieurs mètres de haut et abriter plusieurs milliers d'insectes. Les espèces qui vivent dans les pays chauds, comme en Namibie par exemple, doivent faire face à un challenge de taille : ne pas mourir de chaud. Les termites font alors preuve d'une grande intelligence lors de la construction de leur foyer. Elles creusent de longues galeries qui relient entre elles des loges. Ces galeries débouchent sur l'extérieur et permettent alors à l'air de circuler dans toute la termitière et de la ventiler. Quand il fait 40 °C à l'extérieur, la température au sein de la termitière ne dépasse pas 30 °C. L'air chaud est constamment évacuer vers l'extérieur tandis que l'air à l'intérieur de la construction garde une température acceptable.

Il n'y a pas que les termites qui souffrent de la chaleur et ont besoin ventilation, les humains aussi. Des architectes ont construit au Zimbwawe un immeuble inspiré des termitières qui ne possède pas d'air conditionné puisqu'il s'autoventile. Le Eastgate Center est pourvu d'une multitude d'ouvertures sur l'extérieur qui permet à l'air chaud de s'évacuer. Résultat, sans climatisation, la température ne dépasse jamais 27 °C.

© W. Bulach, Wikimedia Commons, CC by-sa 4.0

FuturaSciences

ASTRONOMY - A SAR Arc from New Zealand

 2024 January 3

A SAR Arc from New Zealand
Image Credit & Copyright: Tristian McDonald; Text: Tiffany Lewis (Michigan Tech U.)

Explanation: What is that unusual red halo surrounding this aurora? It is a Stable Auroral Red (SAR) arc. SAR arcs are rare and have only been acknowledged and studied since 1954. The featured wide-angle photograph, capturing nearly an entire SAR arc surrounding more common green and red aurora, was taken earlier this month from Poolburn, New Zealand, during an especially energetic geomagnetic storm. Why SAR arcs form remains a topic of research, but is likely related to Earth's protective magnetic field, a field created by molten iron flowing deep inside the Earth. This magnetic field usually redirects incoming charged particles from the Sun's wind toward the Earth's poles. However, it also traps a ring of ions closer to the equator, where they can gain energy from the magnetosphere during high solar activity. The energetic electrons in this ion ring can collide with and excite oxygen higher in Earth's ionosphere than typical auroras, causing the oxygen to glow red. Ongoing research has uncovered evidence that a red SAR arc can even transform into a purple and green STEVE.