sábado, 4 de junho de 2016

As Nuvens de Magalhães, nossas vizinhas


Olá!


As Nuvens de Magalhães nos trazem imensa felicidade
por morarmos no hemisfério sul e podermos, então,
usufruir da maravilhosa observação a olho nu
dessas Nuvens que não são nuvens e sim galáxias
e que escondem um verdadeiro mundo de tesouros....  
Tesouros que vão sendo, vagarosamente,
descobertos e trazidos ao nosso conhecimento!


Uma das minhas grandes alegrias em morar na roça
e buscando céus mais escuros e transparentes,
é poder observar a olho nu
as Nuvens Pequena e Grande de Magalhães.


Aqui na roça, um antigo caseiro meu
dizia que estas duas "Nuvens"
são as mulas do presépio do Menino Jesus...


Não importa o que se pense sobre estas Nuvens
- que quase sempre nos engana, parecendo nuvens mesmo! -,
porque o importante é que elas a nós se apresentam enfeitando os céus do sul...,
e fazem isso de maneira tão simples, quase humilde!


Quer dizer,
as nuvens que nomeamos de Nuvens e que sabemos serem Galáxias
parecem esconder (assim como as nuvens escondem)
um mundo de maravilhas.... , 
porém apenas se apresentando
 enquanto nuvens, simples nuvens, simples quase-enganos.



Com um abraço estrelado,
Janine Milward



Stellarium

Stellarium



http://en.wikipedia.org/wiki/Magellanic_Clouds#mediaviewer/File:Magellanic_Clouds_%E2%80%95_Irregular_Dwarf_Galaxies.jpg
Magellanic Clouds ― Irregular Dwarf Galaxies

ESO/S. Brunier - ESO


AS NUVENS DE MAGALHÃES




Wonder and Mystery above the Very Large Telescopes 
Credit: Yuri Beletsky (ESO)







http://apod.nasa.gov/apod/image/1105/vltsky_beletsky_3114.jpg
Wonder and Mystery above the Very Large Telescopes 

Credit: Yuri Beletsky (ESO) 





http://en.wikipedia.org/wiki/Zone_of_Avoidance#mediaviewer/File:Milky_Way_infrared.jpg
Milky Way infraredPublic Domain
The Milky Way creates a Zone of Avoidance for local observers




http://en.wikipedia.org/wiki/Milky_Way#mediaviewer/File:5_Local_Galactic_Group_(ELitU).png
5 Local Galactic Group (ELitU)CC BY-SA 3.0

Andrew Z. Colvin - Own work





http://en.wikipedia.org/wiki/Magellanic_Clouds#mediaviewer/File:Magellanic_Clouds_%E2%80%95_Irregular_Dwarf_Galaxies.jpg
Magellanic Clouds ― Irregular Dwarf Galaxies
ESO/S. Brunier - ESO


As Nuvens de Magalhães

Existem duas pequenas nuvens esfumaçadas que pareciam ser fragmentos da Via Láctea e que formam um quase triangulo com o pólo sul celestial.  Estas nuvens foram primeiramente descritas pelo navegante português Fernando de Magalhães, no começo do século dezesseis.  Porém, somente nos anos de 1920, os astrônomos determinaram que as Nuvens de Magalhães são galáxias, irregulares, pequena e próximas.

As Nuvens de Magalhães são ligadas entre si e à nossa Galáxia não somente pela força de gravidade mas também pela ponte gigantesca de hidrogênio neutro e frio.  O brilho azulado das Nuvens de Magalhães revelam a presença de um imenso número de estrelas jovens, quentes e gigantes muito luminosas.

Se pudéssemos olhar para nossa Galáxia de um ponto externo à mesma, veríamos três pequenos e próximos satélites (galáxias-satélites), as Nuvens de Magalhães.  Um sistema similar acontece com a Galáxia de ndrômeda, onde podemos observar várias pequenas galáxias satélites.


- 6a. Edição do Atlas Celeste
de autoria de Ronaldo Rogério de Freitas Mourão,
Editora Vozes, Petrópolis, ano de 1986






http://en.wikipedia.org/wiki/Large_Magellanic_Cloud#mediaviewer/File:Large_and_small_magellanic_cloud_from_new_zealand.jpg
Large and small magellanic cloud from new zealand
Markrosenrosen - Own work





The Magellanic Clouds have been known since the first millennium in Western Asia. The first preserved mention of the Large Magellanic Cloud is by the Persian astronomer Al Sufi.[4][5] In 964, in his Book of Fixed Stars, he called it al-Bakr ("the Sheep") "of the southern Arabs"; he noted that the Cloud is not visible from northern Arabia and Baghdad, but can be seen at the strait of Bab el Mandeb (12°15' N), which is the southernmost point of Arabia.[2]
In Europe, the Clouds were first observed by Italian explorers Peter Martyr d'Anghiera and Andrea Corsali at the end of the 15th century. Subsequently, they were reported byAntonio Pigafetta, who accompanied the expedition of Ferdinand Magellan on its circumnavigation of the world in 1519-1522.[2] However, naming the clouds after Magellan did not become widespread until much later. In Bayer's Uranometria they are designated as nubecula major and nubecula minor.[6] In the 1756 star map of the French astronomer Lacaille, they are designated as le Grand Nuage and le Petit Nuage ("the Large Cloud" and "the Small Cloud").[7]
In Sri Lanka, from ancient times, these clouds have been referred to as the 'Maha Mera Paruwathaya' meaning "the great mountain", as they look like the peaks of a distant mountain range.


In the southern hemisphere, the Magellanic clouds have long been included in the lore of native inhabitants, including south sea islanders and indigenous AustraliansPersian astronomer Al Sufi labelled the larger of the two clouds as Al Bakr, the White Ox. European sailors may have first noticed the clouds during the Middle Ages when they were used for navigation.Portuguese and Dutch sailors called them the Cape Clouds, a name that was retained for several centuries. During the circumnavigation of the Earth by Ferdinand Magellan in 1519–22, they were described by Antonio Pigafetta as dim clusters of stars.[8] In Johann Bayer's celestial atlas Uranometria, published in 1603, he named the smaller cloud, Nubecula Minor.[9]In Latin, Nubecula means a little cloud.[10]
Between 1834 and 1838, John Frederick William Herschel made observations of the southern skies with his 14-inch (36 cm) reflector from the Royal Observatory at the Cape of Good Hope. While observing the Nubecula Minor, he described it as a cloudy mass of light with an oval shape and a bright center. Within the area of this cloud he catalogued a concentration of 37 nebulae and clusters.[11]
In 1891, Harvard College Observatory opened an observing station at Arequipa in Peru. Between 1893 and 1906, under the direction of Solon Bailey, the 24-inch (610 mm) telescope at this site was used to survey photographically both the Large and Small Magellanic Clouds.[12] Henrietta Swan Leavitt, an astronomer at the Harvard College Observatory, used the plates from Arequipa to study the variations in relative luminosity of stars in the SMC. In 1908, the results of her study were published, which showed that a type of variable star called a "cluster variable", later called a Cepheid variable after the prototype star Delta Cephei, showed a definite relationship between the variability period and the star's luminosity.[13] This important period-luminosity relation allowed the distance to any other cepheid variable to be estimated in terms of the distance to the SMC. Hence, once the distance to the SMC was known with greater accuracy, Cepheid variables could be used as a standard candle for measuring the distances to other galaxies.[14]
Using this period-luminosity relation, in 1913 the distance to the SMC was first estimated by Ejnar Hertzsprung. First he measured thirteen nearby cepheid variables to find the absolute magnitude of a variable with a period of one day. By comparing this to the periodicity of the variables as measured by Leavitt, he was able to estimate a distance of 10,000 parsecs (30,000 light years) between the Sun and the SMC.[15] This later proved to be a gross underestimate of the true distance, but it did demonstrate the potential usefulness of this technique.[16]
Announced in 2006, measurements with the Hubble Space Telescope suggest the Large and Small Magellanic Clouds may be moving too fast to be orbiting the Milky Way.[17]


Veja o Vídeo:
https://www.youtube.com/watch?v=53yokIKAnDs&feature=youtube_gdata

Astronomers at NASA's Goddard Space Flight Center in Greenbelt, Md., and the Pennsylvania State University in University Park, Pa., have used NASA's Swift satellite to create the most detailed surveys of the Large and Small Magellanic Clouds, the two closest major galaxies, in ultraviolet light.
Thousands of images were assembled into seamless portraits of the main body of each galaxy to produce the highest-resolution surveys of the Magellanic Clouds at ultraviolet wavelengths. The project was proposed by Stefan Immler, an astronomer at Goddard.

The Large and Small Magellanic Clouds, or LMC and SMC for short, lie about 163,000 and 200,000 light-years away, respectively, and orbit each other as well as our own Milky Way galaxy.

Compared to the Milky Way, the LMC has about one-tenth its physical size and only 1 percent of its mass. The SMC is only half the size of the LMC and contains about two-thirds of its mass.
The new images reveal about a million ultraviolet sources within the LMC and about 250,000 in the SMC.

Viewing in the ultraviolet allows astronomers to suppress the light of normal stars like the sun, which are not very bright at these higher energies, and provide a clearer picture of the hottest stars and star-formation regions.

Only Swift's Ultraviolet/Optical Telescope, or UVOT, is capable of producing such high-resolution wide-field multi-color surveys in the ultraviolet. The LMC and SMC images range from 1,600 to 3,300 angstroms, UV wavelengths largely blocked by Earth's atmosphere.

The Large and Small Magellanic Clouds are readily visible from the Southern Hemisphere as faint, glowing patches in the night sky. The galaxies are named after Ferdinand Magellan, the Portuguese explorer who in 1519 led an expedition to sail around the world. He and his crew were among the first Europeans to sight the objects. All visible light imagery provided by Axel Mellinger, Central Michigan University.

This video is public domain and can be downloaded at:http://svs.gsfc.nasa.gov/goto?11293




Panoramic Large and Small Magellanic Clouds


NASA's Hubble Space Telescope Finds Source of Magellanic Stream

Astronomers using NASA's Hubble Space Telescope have solved a 40-year mystery on the origin of the Magellanic Stream, a long ribbon of gas stretching nearly halfway around our Milky Way galaxy.
The Large and Small Magellanic Clouds, two dwarf galaxies orbiting the Milky Way, are at the head of the gaseous stream. Since the stream's discovery by radio telescopes in the early 1970s, astronomers have wondered whether the gas comes from one or both of the satellite galaxies. New Hubble observations reveal most of the gas was stripped from the Small Magellanic Cloud about 2 billion years ago, and a second region of the stream originated more recently from the Large Magellanic Cloud.


http://apod.nasa.gov/apod/ap130815.html

The Magellanic Stream 
Credit: Science - NASAESAA. Fox, P. Richter et al.
Image - D. Nidever et al.NRAO/AUI/NSFA. MellingerLAB SurveyParkesWesterbork, and Arecibo Obs.
Explanation: In an astronomical version of the search for the source of the Nile, astronomers now have strong evidence for the origin of the Magellanic Stream. This composite image shows the long ribbon of gas, discovered at radio wavelengths in the 1970s, in pinkish hues against an optical all-sky view across the plane of our Milky Way galaxy. Both Large and Small Magellanic Clouds, dwarf satellite galaxies of the the Milky Way, are seen near the head of the stream at the right. Data from Hubble's Cosmic Origins Spectrograph were used to explore abundances of elements along sightlines to quasars that intersect the stream. The results indicate that most of the stream's material comes from the Small Magellanic Cloud. The Magellanic Stream is likely the result of gravitational tidal interactions between the two dwarf galaxies some 2 billion years ago, the Small Magellanic Cloud losing more material in the encounter because of its lower mass.






https://www.facebook.com/CapturingTheNight/photos/pb.386621064729791.-2207520000.1409394819./617968308261731/?type=1&theater


"The Neighbours"

Balancing boulders and the Magellanic Clouds, 9/11/2013

The Large and Small Magellanic Clouds are small satellite galaxies of our own Milky Way Galaxy. Along with the Andromeda Galaxy they are the only objects you can easily see with only your own unaided eyes that are outside of our galaxy. Being close to the South Celestial Pole the Magellanic Clouds are best seen from the Southern Hemisphere.

Canon 5D MkII, 14mm, F/2.8, ISO 1600, Single 25 Second Exposure, 35% illuminated Moon is lighting up the landscape. Some of you may recognise this rock formation from my panorama image "The Sentinel"