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Post by clone on Feb 26, 2012 17:53:31 GMT -8
This same sense of shock came as scientists announced that the Sun, the Moon, our planet and its siblings, were not born into the familiar band of stars known as the Milky Way galaxy, but we actually belong to a strange formation with the unfamiliar name of the Sagittarius Dwarf galaxy! How can this be? Using volumes of data from the Two-Micron All Sky Survey (2MASS), a major project to survey the sky in infrared light led by the University of Massachusetts, the astronomers are answering questions that have baffled scientists for decades and proving that our own Milky Way is consuming one of its neighbors in a dramatic display of ongoing galactic cannibalism. The study published in the Astrophysical Journal, is the first to map the full extent of the Sagittarius galaxy and show in visually vivid detail how its debris wraps around and passes through our Milky Way. Sagittarius is 10,000 times smaller in mass than the Milky Way, so it is getting stretched out, torn apart and gobbled up by the bigger Milky Way. The fact that the Milky Way is seen in the sky at an angle has always puzzled astronomers. If we originated from the Milky Way, we ought to be oriented to the galaxy's ecliptic, with the planets aligned around our Sun in much the same angle as our Sun aligns with the Milky Way. Instead, as first suggested by researcher Matthew Perkins Erwin, the odd angle suggests that our Sun is influenced by some other system. Together with data from the Two-Micron All Sky Survey we now know what it is. We actually belong to the Sagittarius Dwarf galaxy. cont. viewzone2.com/milkywayx.html___________________________________ Earth from Sagittarius Dwarf, not Milky Way? Bad Astronomy blogs.discovermagazine.com/badastronomy/ spends a fair bit of time debunking the claim blogs.discovermagazine.com/badastronomy/2007/06/27/is-the-sun-from-another-galaxy/ that our solar system is from Sagittarius Dwarf: I talked to Steve Majewski, the lead author on the horribly maligned scientific paper about the Sagittarius Dwarf galaxy. He thanks me for saving him the trouble of having to debunk the claim himself. :-) He has updated his original page www.astro.virginia.edu/~mfs4n/sgr/ about all this with a disclaimer saying the Viewzone article is wrong, too. www.disobey.com/node/1805This image, and its associated movie, shows the distribution of stars in the shredded Sagittarius dwarf galaxy as revealed by the observations reported here. The image is based on the best model match to the map of 2MASS M-giant stars. The thin flat blue spiral represents the disk of our Milky Way galaxy (the shape and size of this disk is not derived as part of this work). The yellow dot represents the position of the Sun. Sagittarius debris can be seen extending from the dense 'core' of the Sagittarius dwarf, wrapping around the galaxy, and descending through the Sun's position. Click on the image to obtain an MPEG movie showing a 3-D 'flyaround' view of Sagittarius' current predicament. Credit David Law/University of Virginia This image, and its associated movie, is illustrative of work by other astronomers, Kathryn Johnston of Wesleyan University in this case, to simulate the evolution of the interactions of dwarf galaxies like Sagittarius with the Milky Way through time. The animation, obtained by clicking on the image, begins when a Sagittarius-like dwarf galaxy was a compact, largely undisturbed system, and follows the Milky Way's disruptive influence over time as the dwarf orbits the Milky Way. If this were the Sagittarius system, this simulation would span approximately 2 billion years in the past through 500 million years into the future. Credit Kathryn Johnston/Wesleyan University.
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Post by carina on Feb 26, 2012 18:15:15 GMT -8
Light echoes reveal an unexpectedly cool η Carinae during its nineteenth-century Great Eruption η Carinae is one of the most massive binary stars in the Milky Way1, 2. It became the second-brightest star in our sky during its mid-nineteenth-century ‘Great Eruption’, but then faded from view (with only naked-eye estimates of brightness3, 4). www.nature.com/nature/journal/v482/n7385/full/nature10775.htmlCarina Nebula revealed in all its glory - Wednesday 8 February 2012 16.23 GMT The European Southern Observatory has released the most detailed infrared image of the Carina Nebula ever created www.guardian.co.uk/science/2012/feb/08/carina-nebula-revealed-gloryWiki: Eta Carinae (η Carinae or η Car) is a stellar system in the constellation Carina, about 7,500 to 8,000 light-years from the Sun. The system contains at least two stars, one of which is a Luminous Blue Variable (LBV), which during the early stages of its life had a mass of around 150 solar masses, of which it has lost at least 30 since. It is thought that a Wolf-Rayet star of approximately 30 solar masses exists in orbit around its larger companion star, although an enormous thick red nebula surrounding Eta Carinae makes it impossible to see optically. Its combined luminosity is about four million times that of the Sun and has an estimated system mass in excess of 100 solar masses.[7] It is not visible north of latitude 30°N and is circumpolar south of latitude 30°S. Because of its mass and the stage of life, it is expected to explode in a supernova or even hypernova in the astronomically near future. In traditional Chinese astronomy, Eta Carinae has the names Tseen She (from the Chinese 天社 [Mandarin: tiānshè] "Heaven's altar") and Foramen.[8] It is also known as 海山二 (Hǎi Shān èr, English: the Second Star of Sea and Mountain).[9], referring to Sea and Mountain, an asterism that Eta Carinae forms with s Carinae, λ Centauri and λ Muscae.[10] This stellar system is currently one of the most massive that can be studied in great detail. Until recently, Eta Carinae was thought to be the most massive single star, but in 2005 it was realised to be a binary system.[11] The most massive star in the Eta Carinae multiple star system probably has more than 100 times the mass of the Sun.[12] Other known massive stars are more luminous and more massive. Stars in the mass class of Eta Carinae produce more than a million times as much light as the Sun. They are quite rare — only a few dozen in a galaxy as big as the Milky Way. They are assumed to approach (or potentially exceed) the Eddington limit, i.e., the outward pressure of their radiation is almost strong enough to counteract gravity. Stars that are more than 120 solar masses exceed the theoretical Eddington limit, and their gravity is barely strong enough to hold in their radiation and gas. Eta Carinae's chief significance for astrophysics is based on its giant eruption or supernova impostor event, which was observed around 1843. In a few years, Eta Carinae produced almost as much visible light as a supernova explosion, but it survived. Other supernova impostors have been seen in other galaxies, for example the possible false supernovae SN 1961v in NGC 1058[13] and SN 2006jc in UGC 4904,[14] which produced a false supernova, noted in October 2004. Significantly, SN 2006jc was destroyed in a supernova explosion two years later, observed on October 9, 2006.[15] The supernova impostor phenomenon may represent a surface instability[16] or a failed supernova. Eta Carinae's giant eruption was the prototype for this phenomenon, and after nearly 170 years the star's internal structure has not fully recovered.[citation needed] Because of their disproportionately high luminosities, very large stars such as Eta Carinae use up their fuel very quickly. Eta Carinae is expected to explode as a supernova or hypernova some time within the next million years or so. As its current age and evolutionary path are uncertain, however, it could explode within the next several millennia or even in the next few years. LBVs such as Eta Carinae may be a stage in the evolution of the most massive stars; the prevailing theory now holds that they will exhibit extreme mass loss and become Wolf-Rayet stars before they go supernova, if they are unable to hold their mass to explode as a hypernova.[27] One theory of Eta Carinae's ultimate fate. Drawing of a massive star collapsing to form a black hole. Energy released as jets along the axis of rotation forms the gamma ray bursts.
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Post by leo on Mar 23, 2012 15:43:57 GMT -8
Astronomers find distant galaxy cluster to shed light on early universe - March 6, 2012 A decade ago, Houston businessman and philanthropist George P. Mitchell was so certain there were big discoveries to be made in physics and astronomy and that they should come out of Texas A&M University, he put money on it, endowing the George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy to bring the world's most eminent minds in physics and astronomy to Aggieland. www.physorg.com/news/2012-03-astronomers-distant-galaxy-cluster-early.html
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Post by clone on Aug 1, 2012 21:04:36 GMT -8
Brightest Stars Don't Live Alone: Most Stellar Heavyweights Come in Interacting Pairs, VLT Finds ScienceDaily (July 26, 2012) — A new study using the European Southern Observatory's Very Large Telescope (VLT) has shown that most very bright high-mass stars, which drive the evolution of galaxies, do not live alone. Almost three quarters of these stars are found to have a close companion star, far more than previously thought. Surprisingly most of these pairs are also experiencing disruptive interactions, such as mass transfer from one star to the other, and about one third are even expected to ultimately merge to form a single star. www.sciencedaily.com/releases/2012/07/120726142156.htm
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Post by clone on Aug 17, 2012 8:53:51 GMT -8
Canadian heads up major galactic discovery Thursday, August 16, 2012 06:20 AM EDT The team calls the new cluster they identified the “Phoenix Cluster” based on its unique properties. It contains hundreds of thousands of galaxies, and is about 2,500 trillion times the mass of the sun. The largest galaxy in the cluster, the central galaxy, has been found to form 740 new stars a year. In comparison, the Milky Way forms only one new star in the same period of time. www.torontosun.com/2012/08/15/canadian-heads-up-major-galactic-discovery
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Post by Data Release 9 on Aug 18, 2012 9:26:01 GMT -8
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Post by clone on Feb 4, 2013 5:50:46 GMT -8
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Post by clone on Mar 4, 2013 18:43:44 GMT -8
Black Hole's Mystery 'Wave' Surprises Scientists by Nola Taylor Redd, SPACE.com Contributor Date: 28 February 2013 Time: 02:02 PM ET Astronomers studying an unusual black hole system have spotted a never-before-seen structure in the disk of matter encircling the system. The black hole contained in Swift J1357.2 is one of the millions of stellar black holes that dot the Milky Way galaxy. www.space.com/20008-black-hole-mystery-wave-structure.html_____________________________________________________ Edit: image size reduced and posted it here too: s903.photobucket.com/user/pyrelog/library/Astronomy?page=1 interesting, thanks
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Post by EGS-zs8-1 on May 9, 2015 17:07:00 GMT -8
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Post by guest on May 20, 2015 21:33:15 GMT -8
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Post by guest on May 20, 2015 21:41:21 GMT -8
The Milky Way May Already Be Colliding With Another Galaxy | Posted: 18/05/2015 08:37 BST Updated: 18/05/2015 08:59 BST www.huffingtonpost.co.uk/2015/05/18/nasa-discovers-the-milky-way-is-already-colliding-with-another-galaxy_n_7303558.htmlA team of scientists have used Hubble to discover that our galaxy the Milky Way could already be in the process of colliding with another galaxy. Nicolas Lehner of the University of Notre Dame, Indiana and his team discovered a giant invisible halo of gas around our nearest neighbour the Andromeda galaxy. While they knew about the halo before, what they didn't realise was just how large it was. It's enormous, 1000 times more enormous in fact than previously thought. By using this data, the team were able to predict that our own galaxy probably has this same halo effect. If true, that means the Milky Way and Andromeda galaxies could already be touching, pre-empting a collision that wasn't due to start for around 4 billion years.
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