My name is Lucia McCallum. I'm a
geodesist. My job is to measure
the Earth and I do this at
the University of Tasmania.
We are here in Cambridge, close
to Hobart in Tasmania at one of
the three AuScope VLBI radio
telescope sites in Australia.
We also have a permanent GPS
station here in Hobart.
GPS relies on the satellites 
flying in space and at some point
due to the fact that the Earth is
constantly moving and wobbling around,
you cannot determine
anymore whether the Earth is
a little bit faster rotating, or
the satellite orbit is slowing
down or speeding up. So one of
our main products is the Earth
orientation parameters, so to
determine how fast the Earth is
rotating and how the axis
spins with relation to the
background stars or black holes.
We are using radio telescopes to
look at the furthest distance
object we know, and these are
black holes.
So what we are receiving here with 
our large radio telescopes is a tiny
signal from a black hole, and we
give it a timestamp when it arrives in Hobart.
A fraction of a second later it 
arrives in Hawaii
and there it also gets a
timestamp. And then we can
measure by the speed of light we
can really precisely measure the
distance between the two
telescopes. And by doing this not
with only two telescopes but with
thirty telescopes globally, we can
really, really precisely measure
a network of radio telescopes on
the Earth. So we have to collect
really a lot of data to be able
to find this little noise of the
black hole in our recorded data.
So that's why one 24 hour
experiment is a few
terabytes a day. We are the busiest 
consumer of the Bass Strait link
We are sending out the most data 
[from] Tasmania to the mainland
and to the global Internet.
We have a few exciting research 
projects going on
and anybody else who is
interested in this work
is very welcome to use our telescope.
