Is there anyone named geoffg poldi raymond if there is please step up

can you tell me whats the diffence between a gas giant and a brown dwarf? and all other answers are welcome:)

This question can be answered by a lot of people. In fact, the information is already available in wikipedia (where it is reasonably correct on this topic) and in many books.

Here is a summary:

For an object to be called a "star" (in the modern sense), there has to be some fusion (or at least the possibility of fusion) in its core. And, as in most rules, there are exceptions.

Since we are talking about "small" objects, we will use two sets of units, one is called a Jupiter-mass (Jupiter has a mass of exactly 1 MJ) and the other is called a solar mass (with our Sun having a mass of exactly 1 MS)
1 MS = 1047.55 MJ
1 MJ = 0.0009546 MS

Calculations show that for object with less than 13 MJ (0.0124 MS), fusion of any kind is simply impossible (not enough pressure).

For objects between 13 MJ and 75 MJ, fusion is possible if it involves Deuterium (atoms of hydrogen that consist of one proton and one neutron) and Lithium (above 65 MJ).

Above 80 MJ (0.07637), the pressure is sufficient (in a young star) to trigger fusion of hydrogen. This would make the object a real "star", which would be plotted on the "Main Sequence" in the Hertzsprung–Russell diagram.
http://en.wikipedia.org/wiki/Hertzsprung…

This leaves a gap between 75 and 80 MJ where it depends on the conditions (for example, is the star made of primordial gas - mostly H and He - or does it contain "metals"). This gap is the wide borderline between a brown dwarf and a "real" star.

However, between planet and brown dwarf, the borderline of 13 MJ appears to be relatively precise; is it really 12.9 or 13.4? who knows, we'd need to observe a large number of objects with exactly these masses to determine if the gap is narrow or large.