Magnetic Fields in Spiral Galaxies ? Explained at Last?
id="attachment_61682" class="wp-caption alignnone" style="width: 494px">href="http://www.universetoday.com/wp-content/uploads/2010/04/350px-M51.jpg">src="http://www.universetoday.com/wp-content/uploads/2010/04/350px-M51-e1270325211164.jpg" alt="" title="M51 (Hubble) overlaid by 6cm radio intensity contours and polarization vectors (Effelsberg and VLA) Credit: MPIfR Bonn" width="484" height="350" class="size-full wp-image-61682" />class="wp-caption-text">M51 (Hubble) overlaid by 6cm radio intensity contours and polarization vectors (Effelsberg and VLA) Credit: MPIfR Bonn
/> That
href="http://www.universetoday.com/guide-to-space/galaxies/spiral-galaxy/" class="alinks_links" title="" rel="external">spiral galaxies have magnetic fields has been known for well over half a century (and predictions that they should exist
href="http://articles.adsabs.harvard.edu/full/1990IAUS..140...29T">preceded discovery by several years), and some
href="http://www.universetoday.com/guide-to-space/galaxies/" class="alinks_links" title="" rel="external">galaxies' magnetic fields
href="http://www.scholarpedia.org/article/Galactic_magnetic_fields">have been mapped in great detail.
But how did these magnetic fields come to have the characteristics we observe them to have? And how do they persist?
A recent paper by UK astronomers Stas Shabala, James Mead, and Paul Alexander may contain answers to these questions, with four physical processes playing a key role: infall of cool gas onto the disk, href="http://www.universetoday.com/guide-to-space/stars/supernova/" class="alinks_links" title="" rel="external">supernova feedback (these two increase the magnetohydrodynamical turbulence), href="http://www.universetoday.com/guide-to-space/stars/how-does-a-star-form/" class="alinks_links" title="" rel="external">star formation (this removes gas and hence turbulent energy from the cold gas), and differential href="http://www.universetoday.com/guide-to-space/galaxies/" class="alinks_links" title="" rel="external">galactic rotation (this continuously transfers field energy from the incoherent random field into an ordered field). However, at least one other key process is needed, because the astronomers' models are inconsistent with the observed fields of massive spiral galaxies./> (...)
Read the rest of href="http://www.universetoday.com/2010/04/03/magnetic-fields-in-spiral-galaxies-%e2%80%93-explained-at-last/">Magnetic Fields in Spiral Galaxies – Explained at Last? (672 words)
/>
© Jean Tate for href="http://www.universetoday.com">Universe Today, 2010. | href="http://www.universetoday.com/2010/04/03/magnetic-fields-in-spiral-galaxies-%e2%80%93-explained-at-last/">Permalink | href="http://www.universetoday.com/2010/04/03/magnetic-fields-in-spiral-galaxies-%e2%80%93-explained-at-last/#comments">6 comments |
Add to href="http://del.icio.us/post?url=http://www.universetoday.com/2010/04/03/magnetic-fields-in-spiral-galaxies-%e2%80%93-explained-at-last/&title=Magnetic Fields in Spiral Galaxies – Explained at Last?">del.icio.us
Post tags: href="http://www.universetoday.com/tag/magnetic-field/" rel="tag">magnetic field, href="http://www.universetoday.com/tag/spiral-galaxies/" rel="tag">spiral galaxies
Feed enhanced by href='http://planetozh.com/blog/my-projects/wordpress-plugin-better-feed-rss/'>Better Feed from href='http://planetozh.com/blog/'>Ozh
Full story at http://www.universetoday.com/2010/04/03/magnetic-fields-in-spiral-galaxies-%e2%80%93-explained-at-last/
Posts
No comments:
Post a Comment