Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Energy density in Stress Energy Tensor

  1. Oct 18, 2012 #1

    I am new to this, if somebody could help me:

    The energy density in stress-energy-tensor is the amount of energy stored in a given system per unit mass. The T00=energy density.

    In a 4x4 matrix, we generally start with 1,1. Why it is 0,0?

    Secondly, what does energy density mean mathematically? I am unable to get over the concept.


    -- Shounak
  2. jcsd
  3. Oct 18, 2012 #2
    It's common (but not universal) to number the time dimension as 0 instead of 4 (x, y, and z or other spatial directions would be 1-3). It doesn't make a big difference either way.

    Energy density = energy per unit volume.
  4. Oct 18, 2012 #3
    Ok, thanks a lot.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook