The "Field of Streams"

[telfrow]

<b>Our galaxy's halo is round not squashed</b><br /><br /><i>Streams of stars that are being ripped to shreds as they spiral into the Milky Way have been imaged in unprecedented detail using data from the Sloan Digital Sky Survey. The so-called Field of Streams suggests the halo of dark matter that cocoons our galaxy is spherical - not squashed like an American football as previously thought.<br /><br />Galaxies are thought to have massive dark matter halos that extend many times farther than the galaxies themselves. Theories predict that the halos are flattened – ellipsoid - in shape, but different observations of gas and stars in the Milky Way have suggested different shapes for its halo.<br /><br />Then in 1997 astronomers discovered a powerful new tool to probe the structure of the halo - a stream of stars extending from a small galaxy called Sagittarius that lies about 82,000 light years from Earth. The dwarf galaxy is being stretched into a stream by the gravitational tug of the Milky Way, which will one day consume it entirely. <br /><br />"It's spiralling in and losing its stars all the way," says Vasily Belokurov at the University of Cambridge, UK.<br /><br />Several smaller streams have since been observed trailing from clusters of stars, and potentially another dwarf galaxy, as they fall prey to the Milky Way's pull. Now, Belokurov and colleagues have used the Sloan Digital Sky Survey - which is mapping a quarter of the sky - to study this "Field of Streams"</i><br /> <div class="Discussion_UserSignature"> <strong><font color="#3366ff">Made weak by time and fate, but strong in will to strive, to seek, to find and not to yeild.</font> - <font color="#3366ff"><em>Tennyson</em></font></strong> </div>

 

[michaelmozina]

Darn, you beat me to it. I was just about to post that link in the thread related to the drawf galaxies that were discovered. <br /><br />I think the observation that these forks only work with a spherical cocoon is quite interesting. It seems like every observation we come across continues to defy our earlier predictions. I wonder if they every tried running these simulations with large scale Birkeland currents running through the galaxy? <img src="/images/icons/smile.gif" /> <div class="Discussion_UserSignature"> It seems to be a natural consequence of our points of view to assume that the whole of space is filled with electrons and flying electric ions of all kinds. - Kristian Birkeland </div>