Dark Matter

After watching the season finale for 'Cosmos: A Space time Odyssey', I was contemplating that strange stuff called 'Dark Matter'.
A little background is in order, I believe.  The whole issue stems from the fact that scientists observing the heavens see the affect of there being much more matter in the universe than they can account for.  This sounds very mysterious, until we remember how we can see anything in space.
Astronomers can only detect matter in three ways: something emits energy (light or radio waves), something blocks or bends energy (think 'black holes'), or something causes one of the first two to 'wobble' causing a shift in the energy.
Right there, you can see the crux of the issue, and why it is called 'dark'.  It isn't because it is evil, or sinister, or even ask that mysterious.  It simply isn't putting out any energy.
So really, we have a bunch of 'Dark Matter' right here, under our feet.  The Earth only produces energy from three sources: man-made, radioactivity, and weather.  If we were over on Andromeda, listening to the energy coming from the  solar System, it would be difficult to pick out the energy coming from the Earth from all of the energy being blasted out from all of the active stars in the Milky Way, much as it is hard to distinguish what one guy is shouting in a stadium full of people.
  We can even include dark matter in our stadium example, where it would be everything not shouting- the building itself, the seats, the clothing, etc.  Black holes would simply be people walking in front of the fans, not shouting themselves, but blocking some of the noise with their bodies.
    The intent here is not to detract from the mysteries that astronomers are attempting to solve.  There are very real and observable effects of dark matter, and as they said in 'Cosmos', many are very surprising.  'Dark Matter' is just a shorthand way of saying 'All of the stuff that doesn't produce energy but still has mass'.