Monday, October 31, 2016

NASA’S SDO CATCHES A LUNAR TRANSIT


On Oct. 30, 2016, NASA’s Solar Dynamics Observatory, or SDO, experienced a partial solar eclipse in space when it caught the moon passing in front of the sun. The lunar transit lasted one hour, between 3:56 p.m. and 4:56 p.m. EDT, with the moon covering about 59 percent of the sun at the peak of its journey across the face of the sun. The moon’s shadow obstructs SDO’s otherwise constant view of the sun, and the shadow’s edge is sharp and distinct, since the moon has no atmosphere which would distort sunlight.





On Oct. 30, 2016, NASA’s Solar Dynamics Observatory, or SDO, experienced a partial solar eclipse in space when it caught the moon passing in front of the sun. The lunar transit lasted one hour, between 3:56 p.m. and 4:56 p.m. EDT, with the moon covering about 59 percent of the sun at the peak of its journey across the face of the sun.
Credits: NASA’s Goddard Space Flight Center/SDO/Joy Ng



From SDO’s point of view, the sun appears to be shaking slightly – but not because the solar observatory was spooked by this near-Halloween sight. Instead, the shaking results from slight adjustments in SDO’s guidance system, which normally relies upon viewing the entire sun to center the images between exposures. SDO captured these images in extreme ultraviolet light, a type of light invisible to human eyes. The imagery here is colorized in red.



Related Links

NASA's SDO website


NASA's eclipses and transits website





VIEW FROM ABOVE SATURN



Saturn appears as a serene globe amid tranquil rings in this view from NASA's Cassini spacecraft. In reality, the planet's atmosphere is an ever-changing scene of high-speed winds and evolving weather patterns, punctuated by occasional large storms (see PIA14901). The rings, consist of countless icy particles, which are continually colliding. Such collisions play a key role in the rings' numerous waves and wakes, which are the manifestation of the subtle influence of Saturn's moons and, indeed, the planet itself.

The long duration of the Cassini mission has allowed scientists to study how the atmosphere and rings of Saturn change over time, providing much-needed insights into this active planetary system.

The view looks toward the sunlit side of the rings from about 41 degrees above the ring plane. The image was taken with the Cassini spacecraft wide-angle camera on July 16, 2016 using a spectral filter which preferentially admits wavelengths of near-infrared light centered at 752 nanometers.

The view was acquired at a distance of approximately 1 million miles (2 million kilometers) from Saturn. Image scale is 68 miles (110 kilometers) per pixel.

The Cassini mission is a cooperative project of NASA, ESA (the European Space Agency) and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini

The Cassini imaging team homepage is at http://ciclops.org.



Image Credit: NASA/JPL-Caltech/Space Science Institute


GHOST AURORA OVER CANADA Image Credit & Copyright: Yuichi Takasaka



What does this aurora look like to you? While braving the cold to watch the skies above northern Canada early one morning in 2013, a most unusual aurora appeared. The aurora definitely appeared to be shaped like something , but what? Two ghostly possibilities recorded by the astrophotographer were "witch" and "goddess of dawn", but please feel free to suggest your own Halloween-enhanced impressions. Regardless of fantastical pareidolic interpretations, the pictured aurora had a typical green color and was surely caused by the scientifically commonplace action of high energy particles from space interacting with oxygen in Earth's upper atmosphere. In the image foreground, at the bottom, is a frozen Alexandra Falls, while evergreen trees cross the middle.


EN HALLOWEEN DE ESTE AÑO 2016, PARA SER ORIGINALES, NO VAMOS A PRESENTAR UNA HISTORIA DE FANTASMAS, SINO QUE POR EL CONTRARIO, VAMOS A DESMITIFICAR UNA DE ELLAS.


Firmat es una ciudad del departamento General López, provincia de Santa Fe, Argentina, que adquirió notoriedad hace unos años por una hamaca que misteriosamente se movía sola.







Se presentaron diversas explicaciones sobre el origen de este fenómeno, algunas bastantes ridículas como que el movimiento se debía a un fantasma que la empleaba para hamacarse.

Aquí vamos a ensayar una nueva explicación sobre el tema.

Según nuestro punto de vista, el movimiento se producía por la unión de dos fenómenos físicos, por una parte tenemos lo que se denomina calle de vórtices de Von Karman y por otra, la resonancia.

De acuerdo a las geometría que presenta un objeto y a la velocidad del viento que incide sobre el mismo, se puede generar una sucesión de vórtices que se desprenden de dicho objeto, esta sucesión de vórtices recibe el nombre de calle de vórtices de Von Karman.



Calle de vórtices de Von Karma




Calle de vórtices de Von Karman generada por la interacción del viento con la isla de Jan Mayen ( noruega ).
Imagen Nasa.


En el siguiente video se puede observar la formación de una calle de vórtices de Von Karman.




Al desprenderse estos vórtices del cuerpo que estamos considerando generan fuerzas sobre el mismo, si la frecuencia de formación de vórtices, se corresponde con la frecuencia natural de oscilación del cuerpo, este último puede llegar a adquirir un movimiento de gran amplitud respecto a su posición de equilibrio.


Al final del siguiente video se puede apreciar el resultado que se obtiene cuando la frecuencia con la que se generan los vórtices se ajusta a la frecuencia natural de oscilación de un determinado sistema.





Si alguien puede llegar a tener dudas sobre el movimiento de la hamaca por efecto del viento, lo invitamos a ver el siguiente video, van a ser testigos de lo que le sucede al puente de arcos de Alconétar, que atraviesa el río Tajo cerca de la frontera entre España y Portugal, en la provincia de Cáceres ( escuchen el sonido del viento presente ).

El arco de acero del puente ha entrado en resonancia con una calle de vórtices de Von Kárman, por tal motivo se mueve como se observa en el video, si los vórtices pueden mover esta estructura gigante como esta, que problema pueden tener en mover la famosa hamaca embrujada.




En el video que presentamos a continuación vemos a la famosa hamaca, en primer lugar queremos hacer notar el sonido que produce el viento, el verdadero responsable y no un fantasma juguetón, del movimiento observado, en segundo lugar presten atención al comienzo del video, de la serie de hamacas que se encuentran en segundo plano, también se están moviendo con bastante amplitud, parece ser que nuestro fantasma trajo a un grupo de amigos ( amigos fantasmas, por supuesto ), para que se hamaquen con el.


En un momento dado, uno de los que están filmando, detiene  la hamaca fantasmal, fíjense que todas las hamacas del grupo presentan en un principio, pequeñas oscilaciones, pero solo la del fantasma, adquiere con el tiempo, un movimiento de gran amplitud, esto se debe a que, si bien la calle de vórtices de Von Karman se está generando en todas las hamacas, por razones constructivas, solo la hamaca mágica entra en resonancia con los vórtices.






No me vengan con fantasmas ni Von Karman, 
el que movía la hamaca era yo.








Info: Licenciado en Física José Luis Lomáscolo
( Museo Experimental de Ciencias )

Compaginación: Esmeralda Sosa 
 ( Técnica - Planetario Ciudad de Rosario )






.. Mil Gracias Cachitus ! ..


..  y en agradecimiento a Cachitus van RECETAS " DE MIEDO " para Celebrar HALLOWEEN ..

.. No te comas TODO JUNTO Cachitus ! ..









HALLOWEEN AND THE GHOST HEAD NEBULA Image Credit: Mohammad Heydari-Malayeri (Observatoire de Paris) et al., ESA, NASA





Halloween's origin is ancient and astronomical. Since the fifth century BC, Halloween has been celebrated as a cross-quarter day, a day halfway between an equinox (equal day / equal night) and a solstice (minimum day / maximum night in the northern hemisphere). With a modern calendar however, even though Halloween occurs tomorrow, the real cross-quarter day will occur next week. Another cross-quarter day is Groundhog Day. Halloween's modern celebration retains historic roots in dressing to scare away the spirits of the dead. Perhaps a fitting tribute to this ancient holiday is this view of the Ghost Head Nebula taken with the Hubble Space Telescope. Similar to the icon of a fictional ghost, NGC 2080 is actually a star forming region in the Large Magellanic Cloud, a satellite galaxy of our own Milky Way Galaxy. The Ghost Head Nebula spans about 50 light-years and is shown in representative colors.



COMET C/2015 V2 (JOHNSON) Taken by Dr Paolo Candy on October 30, 2016 @ Ci.A.O. Cimini Astronomical Observatory - Italy





In a splendid morning-night, we shot a genuine photo to this comet in a thick field of galaxies in Ursae Maioris.
The comet show a pointed coma and a slanting tail. We hope this comet will be a visible to nacked eye next months before its perielium in Giune 2017!

NIkon Nikkor 600mm F/4 ED-IF STL 6303E LRGB 10 min tot exp Bin 2 30 Oct 2016 04:58 UT


WAVELENGTH COMPARISON



The difference in features that are visible in different wavelengths of extreme ultraviolet light can be stunning as we see when we compare very large coronal holes, easily seen in the AIA 171 image (colorized bronze) yet hardly perceptible in the AIA 304 image (colorized red). Both were taken at just about the same time (Oct. 27, 2016). Coronal holes are areas of open magnetic field that carry solar wind out into space. In fact, these holes are currently causing a lot of geomagnetic activity here on Earth. The bronze image wavelength captures material that is much hotter and further up in the corona than the red image. The comparison dramatizes the value of observing the sun in multiple wavelengths of light. Credit: Solar Dynamics Observatory, NASA.






Friday, October 28, 2016

HUBBLE ADMIRES A YOUTHFUL GLOBULAR STAR CLUSTER



Globular clusters offer some of the most spectacular sights in the night sky. These ornate spheres contain hundreds of thousands of stars, and reside in the outskirts of galaxies. The Milky Way contains over 150 such clusters — and the one shown in this NASA/ESA Hubble Space Telescope image, named NGC 362, is one of the more unusual ones.

As stars make their way through life they fuse elements together in their cores, creating heavier and heavier elements — known in astronomy as metals — in the process. When these stars die, they flood their surroundings with the material they have formed during their lifetimes, enriching the interstellar medium with metals. Stars that form later therefore contain higher proportions of metals than their older relatives.

By studying the different elements present within individual stars in NGC 362, astronomers discovered that the cluster boasts a surprisingly high metal content, indicating that it is younger than expected. Although most globular clusters are much older than the majority of stars in their host galaxy, NGC 362 bucks the trend, with an age lying between 10 and 11 billion years old. For reference, the age of the Milky Way is estimated to be above 13 billion years.

This image, in which you can view NGC 362’s individual stars, was taken by Hubble’s Advanced Camera for Surveys (ACS).

Text credit: European Space Agency
Image credit: ESA/Hubble& NASA


HAUNTING THE CEPHEUS FLARE Image Credit & Copyright: Thomas Lelu




Spooky shapes seem to haunt this jeweled expanse, drifting through the night in the royal constellation Cepheus. Of course, the shapes are cosmic dust clouds faintly visible in dimly reflected starlight. Far from your own neighborhood on planet Earth, they lurk along the plane of the Milky Way at the edge of the Cepheus Flare molecular cloud complex some 1,200 light-years away. Over 2 light-years across and brighter than the other ghostly apparitions, vdB 141 or Sh2-136 is also known as the Ghost Nebula, seen at the right of the starry field of view. Within the nebula are the telltale signs of dense cores collapsing in the early stages of star formation.