XPost: sci.electronics.design, sci.astro   
   From: PointedEars@web.de   
      
   Jeremiah Jones wrote:   
   > Bill Sloman wrote:   
   >> Earth has a magnetic field, and nobody uses magnets to drag boats or   
   >> aircraft around.   
   >   
   > Earth *is* a magnet.   
      
   You could say that, *because* it has a (non-zero) magnetic field (not   
   vice-versa). An object is not a magnet /per se/.   
      
   > It is pushed by the magnetic fields of the sun and galaxies.   
      
   Not enough.   
      
   > That's what makes the earth go round the sun.   
      
   No, that's nonsense. The best explanation that we have for that is   
   _gravitation_. Gravitation is NOT the same as magnetism.   
      
   Terra (Earth) orbits the barycenter of the Sol System because it formed from   
   a rotating planetary disk. That disk was rotating because it formed from   
   the rotating part of a molecular cloud at the same time as Sol (the Sun)   
   formed; it was what was left over from the star's formation (the star formed   
   because that part of the cloud had cooled enough by emitting radiation, and   
   was dense enough so that gravitation caused it to collapse on itself; the   
   collapse caused its density to increase further, and its temperature to   
   increase again, eventually that much that nuclear fusion became possible and   
   likely). That piece was rotating, because small imbalances in mass (perhaps   
   supported by a nearby supernova) cause particles of a molecular cloud to   
   move in different directions, and when they become too close, they begin to   
   orbit each other (or rather their common barycenter) due to gravitation.   
      
   This is not just a story or a model anymore because we can observe it in the   
   formation of other stars and their planetary systems.   
      
   F'up2 sci.astro   
      
   --   
   PointedEars   
      
   Twitter: @PointedEars2   
   Please do not cc me. / Bitte keine Kopien per E-Mail.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   
|