<When you say 13 billion years does that mean the
estimated distance to the farthest visible object in light years?

Sort of...

13 - 14 billion years ago was the Big Bang.

A lot of folks ask where the Big Bang occurred, and we can give a general direction, but reality states that the Big bang actually occurred right here where we are -- since it involved the entire Universe. The Universe was not cast out into the nothingness that was before the Universe, because even this implies something beyond the Universe -- even if that something is nothing. The Universe includes everything -- including 'nothing'.

We assume the Big Bang was universal in direction, which would imply there are galaxies 13 - 14 billion light-years on the other side of the point where the Big Bang is assumed to have occurred. At the moment, I don't think we can see that far. Looking to the core of the Big Bang for an object 13 - 14 billion light-years away would likely turn out to be impossible. The heat and reaction during the initial expansion was incredible, forcing all matter away, possibly at greater-than-light speed. We would be looking into a near vacuum.

Objects seen to be 13 - 14 billion light-years away are not at the expansion core, but are objects that were accelerated just as the matter of the Milky Way was, but in a different direction.

And if the object is 13 billion lys away are'nt we viewing its position 13 billion years ago? Wouldn't that put it about (just a guess) 22 billion lys away from us at the present time?

No.

Expansion means that we would be seeing the Universe/the object as it was 13 - 14 billion years ago. We would be looking back through time. There is no distance to add. 13-14 billion years ago, the object being viewed would have been in the same location, relatively speaking, as the milky Way galaxy was.

Interesting stuff:

* A Monster in the Middle
* The Galactic Habitable Zone (.PDF file)
* Galaxies behind the Milky Way
* From the Big Bang to the End of the Universe: The Mysteries of Deep Space Timeline
* How the Universe Will End
* An Atlas of the Universe

An attempt, anyway,
Dan