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Blown Away By The Very Large Array

From: UFO UpDates - Toronto <ufoupdates.nul>
Date: Wed, 01 Aug 2007 22:22:17 -0400
Archived: Wed, 01 Aug 2007 22:22:17 -0400
Subject: Blown Away By The Very Large Array

Source: CNET News.Com


August 1, 2007

[Images & links at site]

Blown Away By The Very Large Array
By Daniel Terdiman
Staff Writer CNET News.com

Datil, N.M. - I'm standing in the middle of "the center of the
known universe", as this room is sometimes called. And in a way,
it feels like that's actually where I am.

That's because I'm in the control center of the Very Large
Array, a collection of 27 dish antennas, each of which weighs
230 tons and has a diameter of 25 meters. Together, the antennas
form the world's largest radio telescope.

The VLA, as it's known, is a true sight to behold. It is located
at 6,970 feet in the Plains of San Agustin, about 50 miles west
of Socorro, N.M., and I've come here as part of Road Trip 2007,
my journey around the Southwest in search of some of the most
interesting science- and technology-related destinations. This
definitely counts.

This is awesome country, with gorgeous brown and tan mountains,
a huge sky and, it turns out, some of the most advanced and
prodigious scientific equipment the world has ever known.

You try looking at more than two dozen giant dish antenna spread
over a giant plain on a beautiful day and not be impressed.
Almost impossible.

Together, the 27 antennas combine to create the resolution of a
single antenna 22 miles across, with the sensitivity of a dish
130 meters in diameter, according to the VLA's Web site. What
that means is that "you can make images of almost anything you
can look at in the universe", Dave Finley, the public
information officer for the National Radio Astronomy Observatory
(NRAO), which operates the VLA, told me.

The VLA is a radio telescope, a message that Finley and the NRAO
are eager to have people understand. But it doesn't collect
sound. It collects radio waves, which, Finley tells me, are
exactly the same as light waves. Only different.

Finley explains that optical telescopes like Hubble and Palomar
are designed to collect light waves, while the VLA collects
radio waves. The end result is the same: To understand what's
going on in the universe. And it seems that the VLA is doing a
good job of that.

"The VLA is the most scientifically productive ground-based
telescope in the history of astronomy", Finley said. "There are
between 180 and 200 scientific papers a year that announce
discoveries" based on research done at VLA.

The VLA is a project of the National Science Foundation, and as
such, is available to any scientist who wants to use it, and who
submits a successful proposal.

Finley explained that the NRAO receives about two hours of
proposals for every hour of available time on the VLA, so it's a
competitive process. But those who are accepted get access to
incredible machinery.

The VLA was designed and built in the 1960s and '70s, and it was
dedicated in 1980. Today, it is undergoing a multiyear process
to upgrade all of the antennas from analog systems to all
digital. This project, known as the Expanded Very Large Array,
is expected to be completed by 2011 or 2012 at a cost of about
$75 million.

Finley explained that the upgraded VLA will be 10 times more
capable as a scientific instrument than it was originally.

Today, the project is well under way, with 11 of the antennas
having already been upgraded, and one literally being worked on
while I'm here.

It's quite a sight, actually: a giant building, known as the
"barn", with one of these mammoth antennas inside it. It's kind
of the astronomy version of an auto mechanic, with the antenna
seemingly up on blocks and technicians banging away at it, to
make the necessary changes.

One major piece of the upgrade involves switching out the old
analog microwave waveguide systems - essentially pipes that
signal waves traveled through - with modern fiber optics.

Another major piece is installing a new "correlator", the
complex system that takes the signals from all 27 antennas and
combines them into one cohesive signal.

The current correlator is an all-analog system that's going to
be replaced by a new one to be donated by Canadian scientists as
their contribution to the Expanded Very Large Array.

The net effect of the upgrade, Finley says, is to get the
equivalent of 10 VLAs for the cost of about one-third of the
original (taking the original costs and factoring in inflation).

The idea, he explained, is to keep the VLA at the forefront of
astronomy for the foreseeable future.

"We've already marked our 25th anniversary", Finley said. "I'm
pretty sure we'll have people here to mark the 50th."

One major challenge associated with the upgrade is not reducing
the amount of research that gets done while the antennas are
being worked on. Finley said that for the most part, the VLA has
been able to meet that goal, though there have been times when
not all 27 antennas are available at the same time. But while
that means slightly less data is available, it's not a critical
problem, he said.

One question I had was why the VLA is here on the Plains of San
Agustin, of all places. Clearly, it's good to have a place large
enough to spread out three arms many miles long, but there are
plenty of those in the West.

Finley said the Plains of San Agustin - which, he added, are
about as big as Connecticut - were the perfect location because
of the NRAO's criteria: a large, flat and dry site at high
elevation that's away from large population centers so there is
no problem with radio interference, but a site that is also
close to good highways so it's easy to get equipment and people

Thus, here we are.

Today, the VLA is in its 'A' configuration, which means all
three arms are spread out over the many miles. But the antennas
at the VLA can actually be moved into seven different
configurations depending on the time of year and the specific
scientific need.

The 'D' configuration is the one most tourists - including
myself - want to see because that's when all the antenna are
clustered closely, all within .4 miles to the center. But alas,
it wasn't to be. There's actually an online schedule for the
different configurations, with "A" running until September 10.

And moving them is quite a production. The VLA has two giant
transporters that lift the antennas and move them, on railroad-
style tracks, from "pier" to "pier", the anchors where the
antennas are locked down.

The whole idea behind the VLA, meanwhile, is to create as many
different pairings of antennas - and the signals they can
receive - as possible, and then combine them.

With 27 antennas, Finley explained, there are 351 different
possible pairings. So the concept is to receive a signal with
all these pairings, then turn the antennas a little and start
over. That means another 351 sets of signals to add to the mix.

"So when you rotate the antennas, you get 351 new pieces of
information", Finley said. "And Earth's rotation gives you 351
(more). You do it enough that if you have good enough software
and computing power, you can get a good enough image."

Ultimately, that's what the VLA is about: imaging the universe.
Even though it's a radio telescope, it produces images, not
sounds. It's a common misconception that Finley said he is
constantly trying to overcome.

To me, unfortunately, it's all a little bit of Greek. I can,
however, understand the impact of so many of these incredible
antennas, and how they can produce the data that is moving the
science of astronomy forward.

And as I look out over the many, many miles of the plains,
admiring the antennas far off in the distance, as well as the
ones up close, I can't help but be captivated by the feeling
that I'm at the center of the universe. Even if only for a
little while.

[Thanks to Bob Shell for the lead]

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