In article ,
Chris L Peterson wrote:

On Sat, 24 Mar 2007 20:04:10 -0800 (PST), (Brian Tung)
wrote:

I *think*, but don't know for sure, that it's basically too inert to
get absorbed, too massive to leak into outer space.

It's not _that_ inert. N2 is always being removed from the atmosphere by
various nitrogen fixation processes. Other processes are converting
nitrates to free N2. Nitrogen, oxygen, and CO2 are at their present
concentrations because they are maintained there by active processes,
both biological and geological.

When first discovered it was given the name _azote_, "lifeless", because
the gas would not support respiration; somewhat ironically, considering
its important functions in all living organisms, this term (or
variations thereof) remains the usual name for the element in several
European languages, including the original French. Some other languages
use terms derived from their words for suffocation or choking.

--
Odysseus