Who are our Keepers of Time and Space ?

Two questions befo
When was the exact vernal equinox 2000 aD., that is:
does You know the Greenwich Mean Time of the moment, where the
axis of earth were at right angle with
the line center of earth - sun, more exact than just
20 th of March 2000, 7 o'clock 35 minutes a.m.?
Was this measured and observed, or -if it was calculated - on which
observation is it based?
Keeping the pass of time and fixing the "maal"(danish for point of
reference) is one important source of social power.
I know, that for example in Germany in Braunschweig there are people
who count regular cycles, and they coordinate their number (it must be
by now the greatest (biggest) number counted) with a few other centers
in the world. This number has to be converted into a "civilian time",
a time reflecting the movement of earth in the light of sun and i
guess, that this can only be done by observation, observation carried
out by astronomers. These - i think - are the real powerful people,
or may be their bosses. Who are they and are they working in a
democratic spirit or are they like GPS-coordinates-deliverers ?
The same for fixing the origin of a space-coordinate-system. I know,
that astronomers observe a number of distant objects and calculate
from this the changes of our coordinate-system. So, who is applying
this to our earth-centered direction-of-vernal-equinox reference ?
I surfed the web quite a time for this and i saw wonderful formulas,
with more than ten digits behind the decimal point ( i'm not expert
enough to calculate these), so i'm optimistic for an answer and i'm
optimistic about the astronomer-people too, because i also read the
following from Sol Gravitas, posted on 22.3.2000:
"..In the observatory there is a clock running with the UT rate and
I could have looked at it but at the moment of transit the house cat
Airy was sleeping in front of it and no one dared wake him up.
(If you do, he gets nasty and one finds claw marks on the lens the
next day.) So, now I am stuck with an observation with unknown UT.
I need to convert this observation to UT. .."
Sincerely Yours
Hero

May be You had some trouble with a hurricane,
or may be You're back from holiday now,
so i question again.
Sincerely Yours
Hero

Now, some more postings here. So, may be You read it
this time.
Or - is it an unreasonable question here, to ask for vernal
equinox? You could tell me.
Hero

Back from Athens? May be i'm lucky this time.
or-
what's wrong with my question?
Thanks anyhow
Yours
Hero