XPost: sci.astro.research   
   From: alfps@start.no   
      
   * vince@offshore.ai (Vincent Cate) schriebt:   
   >   
   > How can heat generate gravity?   
      
   Consider that heat can be turned into radiation, which in turn can be turned   
   into ordinary mass, which has gravity.  Essentially your question therefore   
   shows the pure Newtonian picture to be incomplete, and leads to General   
   Relativity or something like it.  Which I think is on-topic in at least one   
   of the groups posted to, or at least not completely off-topic, but that's one   
   darned complicated theory that probably nobody understands in full, so don't   
   expect full, clear & illuminating answers...   
      
   A short short answer to one aspect is that even in Special Relativity when   
   you expand the formula for energy for an object as a series the first two   
   terms turn out as E = m*C^2 + 0.5*m*v^2 + ..., where the first is the   
   energy/mass-equivalence for the object at rest relative to the chosen   
   coordinate system, and the second is the ordinary kinetic energy, relative.   
   So assuming the two or three basic premises of the theory to hold wrt. to   
   reality the math, as just a logical consequence of those premises, spits out   
   that motion is energy and energy is mass.  So far there is every reason,   
   including a large number of very fine measurements, to assume that is so,   
   but even with all that confidence there are still very expensive experiments   
   being undertaken to further verify it or disprove it (one such, a space-based   
   gravitational probe, is scheduled for the 17.th of April this year, IIRC).   
      
   A short short answer to another aspect is that I have not the foggiest idea   
   how radiation is converted to and from velocity (which heat is all about).   
   That is, the physical mechanism  --  and I suspect nobody understands that   
   in full, either.  This little conversion at least _seems_ to lie squarely in   
   the extremely poorly understood gray zone between GR and quantum mechanics,   
   e.g. consider a 5 meter wide photon from Andromeda as an electromagnetic   
   wave that suddenly, at some point in the middle, interacts with an electron.   
      
   Perhaps some of the experts can help out.   
      
   I'm just a newbie relying on common sense & old high-school-level knowledge.   
      
   - --   
   A: Because it messes up the order in which people normally read text.   
   Q: Why is top-posting such a bad thing?   
   A: Top-posting.   
   Q: What is the most annoying thing on usenet and in e-mail?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)