Urs Leutenegger : MAGIC NEOWISE (Science & Technology - Astronomy picture of the day)

2020 July 24
MAGIC NEOWISE
Image Credit & Copyright: Urs Leutenegger

Explanation: The multi-mirror, 17 meter-diameter MAGIC telescopes reflect this starry night sky from the Roque de los Muchachos European Northern Observatory on the Canary Island of La Palma. MAGIC stands for Major Atmospheric Gamma Imaging Cherenkov and the telescopes can see the brief flashes of optical light produced in particle air showers as high-energy gamma rays impact the Earth's upper atmosphere. On July 20, two of the three telescopes in view were looking for gamma rays from the center of our Milky Way galaxy. In reflection they show the bright stars of Sagittarius and Scorpius near the galactic center to the southeast. Beyond the segmented-mirror arrays, above the northwest horizon and below the Big Dipper is Comet NEOWISE. NEOWISE stands for Near Earth Object Wide-field Infrared Survey Explorer. That's the Earth-orbiting satellite used to discover the comet designated C/2020 F3, but you knew that.

Korii : Les médicaments anti-âge (Science & Technologie - Santé/Médecine)

Une première vague de médicaments anti-âge est entrée dans sa phase de test sur des êtres humains. Ils ne vous feront –pour l'instant– pas vivre plus longtemps mais cibleront des problèmes de santé spécifiques liés à l'âge. Appelés les «sénolytiques», ces traitements suppriment certaines cellules que l'on accumule avec le temps.

De premiers résultats ont été observés sur des cas d'arthrites dégénératives, et d'autres molécules pourraient s'intéresser aux maladies des yeux, des poumons ou encore à Parkinson et Alzheimer.

Zixuan Lin : The Structured Tails of Comet NEOWISE - (Science & Technology - Astronomy picture of the day)

2020 July 23
The Structured Tails of Comet NEOWISE
Image Credit & Copyright: Zixuan Lin (Beijing Normal U.)

Explanation: What is creating the structure in Comet NEOWISE's tails? Of the two tails evident, the blue ion tail on the left points directly away from the Sun and is pushed out by the flowing and charged solar wind. Structure in the ion tail comes from different rates of expelled blue-glowing ions from the comet's nucleus, as well as the always complex and continually changing structure of our Sun's wind. Most unusual for Comet C/2020 F3 (NEOWISE), though, is the wavy structure of its dust tail. This dust tail is pushed out by sunlight, but curves as heavier dust particles are better able to resist this light pressure and continue along a solar orbit. Comet NEOWISE's impressive dust-tail striations are not fully understood, as yet, but likely related to rotating streams of sun-reflecting grit liberated by ice melting on its 5-kilometer wide nucleus. The featured 40-image conglomerate, digitally enhanced, was captured three days ago through the dark skies of the Gobi Desert in Inner Mongolia, China. Comet NEOWISE will make it closest pass to the Earth tomorrow as it moves out from the Sun. The comet, already fading but still visible to the unaided eye, should fade more rapidly as it recedes from the Earth.

Nasa : La Terre vue de l'Espace - "Les dunes en étoile du Grand Erg Oriental, en Algérie" - (Science & Technologie)

Dans le désert du Sahara algérien, le Grand Erg Oriental se caractérise par ses dunes en étoile de forme pyramidale qui sont façonnées par des vents dont l'orientation ne cesse de changer. Ainsi, d'est en été, les vents tournent en ouest une fois l'hiver venu. C'est la combinaison de ces vents changeant avec les spécificités géographiques de cette région et les tempêtes qui la traversent qui façonnent ces dunes en étoile.

Cette image satellite a été obtenue en associant de la lumière proche infrarouge et visible. Le sable est de couleur ocre, les ombres sont noires ou grises. Les zones bleutées représentent des roches évaporites.

© Nasa

Science & Technologie - La Terre vue de l'Espace : Eruption du mont Saint Helens

Photo prise le 8 mars 2005, une semaine après l'éruption de poussière et de vapeur. La dernière éruption depuis ce réveil du mont Saint Helens datait alors de septembre 2004. La végétation est en vert et la neige en bleu.

© Nasa/GSFC/METI/ERSDAC/JAROS et U.S./Japan Aster Science Team

NASA : Iron in the Butterfly Nebula (Science & Technology - Astronomy picture of the day)

2020 July 21
Iron in the Butterfly Nebula
Image Credit: NASA, ESA, Hubble; Processing & License: Judy Schmidt

Explanation: Can stars, like caterpillars, transform themselves into butterflies? No, but in the case of the Butterfly Nebula -- it sure looks like it. Though its wingspan covers over 3 light-years and its estimated surface temperature exceeds 200,000 degrees, C, the dying central star of NGC 6302, the featured planetary nebula, has become exceptionally hot, shining brightly in visible and ultraviolet light but hidden from direct view by a dense torus of dust. This sharp close-up was recorded by the Hubble Space Telescope and is reprocessed here to show off the remarkable details of the complex planetary nebula, highlighting in particular light emitted by iron, shown in red. NGC 6302 lies about 4,000 light-years away in the arachnologically correct constellation of the Scorpion (Scorpius). Planetary nebulas evolve from outer atmospheres of stars like our Sun, but usually fade in about 20,000 years.

Somak Raychaudhury : Eclipse under the Bamboo (Science & Technology - Astronomy picture of the day)

                   Eclipse under the Bamboo
Image Credit & Copyright: Somak Raychaudhury (Inter-University Centre for Astronomy & Astrophysics)

Explanation: Want to watch a solar eclipse safely? Try looking down instead of up, though you might discover you have a plethora of images to choose from. For example, during the June 21st solar eclipse this confusing display appeared under a shady bamboo grove in Pune, India. Small gaps between close knit leaves on the tall plants effectively created a network of randomly placed pinholes. Each one projected a separate image of the eclipsed Sun. The snapshot was taken close to the time of maximum eclipse in Pune when the Moon covered about 60 percent of the Sun's diameter. But an annular eclipse, the Moon in silhouette completely surrounded by a bright solar disk at maximum, could be seen along a narrow path where the Moon's dark shadow crossed central Africa, south Asia, and China.

Tom Masterson : Finding NEOWISE - Science & Technology - Astronomy picture of the day

Finding NEOWISE
Image Credit & Copyright: Tom Masterson

Explanation: If you can see the stars of the Big Dipper, you can find comet NEOWISE in your evening sky tonight. After sunset look for the naked-eye comet below the bowl of the famous celestial kitchen utensil of the north and above your northwestern horizon. You're looking for a fuzzy 'star' with a tail, though probably not so long a tail as in this clear sky snapshot taken from Los Padres National Forest in California on the evening of July 16. Recent photographs of C/2020 F3 (NEOWISE) often show this comet's broad dust tail and fainter but separate ion tail extending farther than the eye can follow. Skygazers around the world have been delighted to find NEOWISE, surprise visitor from the outer Solar System.

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