Autor: Rafael Bustamante

Malagueño desde que abrí los ojos, allá por mayo del 71, he procurado desde entonces que nada me los cierre. Tengo la suerte de trabajar como neurólogo en el hospital de mi tierra, donde trato de aliviar, en la medida en que la naturaleza y la ciencia me permiten, las dolencias de mis conciudadanos y de nuestros visitantes, cuando se encuentran en el trance vital de alguna enfermedad neurológica que amenaza su bienestar. Cuando la amenazada es la sociedad, por otro tipo de procesos mórbidos, cuento con mi opinión, podrá juzgarse si acertada o no, pero siempre sincera.

Salt Pepper and Ice

There’s a «camera» comet now moving across the sky. Just a bit too dim to see with the unaided eye, Comet 21P / Giacobini-Zinner has developed a long tail that makes it a good sight for binoculars and sensitive cameras. The movement of the Comet 21P on the sky was captured last week in the featured time-lapse video compressing 90 minutes into about 2.5 seconds. What might seem odd is that the 21P’s tail is not following the comet’s movement. This is because comet tails always point away from the Sun, and the comet was not moving toward the Sun during the period photographed. Visible far in the background on the upper left is the Salt & Pepper star cluster, M37, while the bright red star V440 Auriga is visible just about the frame’s center. This 2-km ball of dust-shedding ice passed its nearest to the Sun and Earth only last week and is now fading as it crosses into southern skies. Comet 21P should remain visible, however, and photogenic to stabilized cameras, for another month or so. [via NASA] https://ift.tt/2xljwOS

Cosmic Collision Forges Galactic Ring

How could a galaxy become shaped like a ring? The rim of the blue galaxy pictured on the right is an immense ring-like structure 150,000 light years in diameter composed of newly formed, extremely bright, massive stars. That galaxy, AM 0644-741, is known as a ring galaxy and was caused by an immense galaxy collision. When galaxies collide, they pass through each other — their individual stars rarely come into contact. The ring-like shape is the result of the gravitational disruption caused by an entire small intruder galaxy passing through a large one. When this happens, interstellar gas and dust become condensed, causing a wave of star formation to move out from the impact point like a ripple across the surface of a pond. The likely intruder galaxy is on the left of this combined image from Hubble (visible) and Chandra (X-ray) space telescopes. X-ray light is shown in pink and depicts places where energetic black holes or neutron stars, likely formed shortly after the galaxy collision, reside. [via NASA] https://ift.tt/2MFwI60

Tuiteando al vuelo, September 15, 2018 at 12:57PM

La inmensa mayoría de las revisiones anuales por especialistas hospitalarios son innecesarias. Además perjudican la atención a otros pacientes que sí necesitan la consulta y devalúan injustamente la labor del médico de familia. Fdo. Un especialista hospitalario. https://t.co/w2zGltYt43

https://platform.twitter.com/widgets.js

Mont Blanc, Meteor, and Milky Way

Snowy Mont Blanc is near the center of this atmospheric night skyscape. But high, thin clouds fogged the skies at the photographer’s location, looking south toward Europe’s highest peak from the southern Swiss Alps. Still, the 13 second exposure finds the faint star fields and dark rifts of the Milky Way above the famous white mountain. Bloated by the mist, bright planet Saturn and Antares (right), alpha star of Scorpius, shine through the clouds to flank the galaxy’s central bulge. The high-altitude scene is from the rewarding night of August 12/13, so it also includes the green trail of a Perseid meteor shooting along the galactic plane. [via NASA] https://ift.tt/2xegZGt

Tuiteando al vuelo, September 14, 2018 at 08:59PM

Franco se ha enterado de lo de la exhumación, se ha escapado del valle y ha resucitado en el gobierno vasco.
https://t.co/SFwQSlDk4S

Ice Halos at Yellowknife

You’ve probably seen a circle around the Sun before. More common than rainbows, ice halos, like a 22 degree circular halo for example, can be easy to spot, especially if you can shade your eyes from direct sunlight. Still it’s rare to see such a diverse range of ice halos, including sundogs, tangent, infralateral, and Parry arcs, all found in this snapshot from planet Earth. The picture was quickly taken in the late morning of September 4 from Yellowknife, Northwest Territories, Canada. The beautiful patterns are generated as sunlight (or moonlight) is reflected and refracted in six-sided water ice crystals in Earth’s atmosphere. Of course, atmospheric ice halos in the skies of other worlds are likely to be different. [via NASA] https://ift.tt/2MumLIF

Comet, Clusters, and Nebulae

Bright enough for binocular viewing Comet 21P / Giacobini-Zinner stands out, even in this deep telephoto mosaic of the star cluster and nebula rich constellation Auriga the Charioteer. On the night of September 9 its greenish coma and diffuse tail contrast with the colorful stars and reddish emission nebulae in the almost 10 degree field of view along the Milky Way. The comet was near its perihelion and closest approach to Earth, about 200 light-seconds away. Riding across the distant background just above the comet’s tail are well-known Auriga star clusters M38 (left of center) and M36 (toward the right) about 4,000 light-years away. At the top left, emission region IC 405 is only 1,500 light-years distant, more dramatically known as the Flaming Star Nebula. To its right lies IC 410, 12,000 light-years away and famous for its star-forming cosmic tadpoles. A child of our Solar System Giacobini-Zinner is a periodic comet orbiting the Sun once every 6.5 years, and the parent body of October’s Draconids meteor shower. [via NASA] https://ift.tt/2x93nLD

Tuiteando al vuelo, September 12, 2018 at 09:49PM

Sea donde sea, sea cuando sea, hay que tener memoria del terror. No para buscar venganza, sino para alcanzar justicia y para evitar que vuelva a pillar desprevenidos a los inocentes. Este hilo me ha helado el corazón, pero a veces es necesario sentir ese pavoroso frío. https://t.co/AjF2E6sZS2

https://platform.twitter.com/widgets.js

Lunations

Our Moon’s appearance changes nightly. As the Moon orbits the Earth, the half illuminated by the Sun first becomes increasingly visible, then decreasingly visible. The featured video animates images taken by NASA’s Moon-orbiting Lunar Reconnaissance Orbiter to show all 12 lunations that appear this year, 2018. A single lunation describes one full cycle of our Moon, including all of its phases. A full lunation takes about 29.5 days, just under a month (moon-th). As each lunation progresses, sunlight reflects from the Moon at different angles, and so illuminates different features differently. During all of this, of course, the Moon always keeps the same face toward the Earth. What is less apparent night-to-night is that the Moon’s apparent size changes slightly, and that a slight wobble called a libration occurs as the Moon progresses along its elliptical orbit. [via NASA] https://ift.tt/2x1jU52