Episode 4 (050329)
Gone With the Wind
** Draft Transcript **
Written by Aaron Price
Hosted by Travis w/clips from Aaron and Pamela.

  Welcome to episode #2 of Slacker Astronomy. Every week or so we will bring
you a recent news event in the world of astronomy. And if nothing is happening,
we'll point our telescopes in our neighbors windows and give a play-by-play. 

  As many of you have probably seen from our site, Pamela was away last week
with Aaron at a workshop in Las Cruces, New Mexico. On Thursday they went on a
day trip to a local radio telescope facility called the Very Large Array, or
VLA for short. If you have seen the movies Contact or 2,010 then you have seen
the VLA. The radio dishes are big and white and in the middle of a vast field
surrounded by mountains. 

  They had intended to make a sound seeing tour of the visit. So they brought
our trusty ipods and italks and proceeded to look goofy talking loudly into our
hands like Captain Kirk on an away mission. While people are used to
astronomers being goofy, they turned it into an art form worthy of the Turner
Prize. But of course the best laid plans get stomped on by mother nature. It
was very windy out there and our mics were quite unhappy. But there were able
to save a few segments of various quality, which they will intersperse in this
show. So when you hear poor quality audio, that's us in the studio. When you
hear poor quality audio and some wind, that's us at the VLA sound seeing tour. 

   The VLA has 27 telescopes spread out in a Y shape over 36 kilometers (22
miles for us stubborn americans) near Socorro, New Mexico. Instead of looking
for visual light from the sky these radio telescopes listen for radio waves.
Note that radio waves are not sound waves, they are electromagnetic waves just
like visible light. Radio waves *can* be used to transmit information that can
be turned into sound, which is how a car radio works, but by themselves, they
don't make any noise at all. 
   Let's listen to the first segment of the tour. 
    == CLIP 1 ==

   Now why would we be listening to radio waves from space? Do we expect to hear
rock in roll coming from alpha centauri? Not yet, but everything in the Universe
emits light. The temperature of the object determines the color of that light.
Most of the light coming from objects that are very cool is in the form of radio
waves. So when we want to look at a cool object, we prefer to use radio waves
since the object will be brighter. 

   Examples of cool objects are clouds of gas, regions of low density dust,
pulsars, old galaxies and ZZ Top. But radio telescopes can look at anything, those
are just the coolest and therefore brightest. Radio scopes also look at planets,
asteroids, blazars, neutron stars and more. 
  At one point in the tour the dishes moved from one target to another. Aaron and 
Pamela described it into the iPod:
   == CLIP 5 ==

   Light is a weird thing. It can be a wave or a particle. When described
as a wave it naturally has a wave*length*. The length of optical light is
a few nanometers. The length of radio waves is very long, sometimes miles
long.  One benefit of long wavelength is that the radio waves can
penetrate many objects so astronomers can use the VLA radio telescopes
during bad weather conditions that usually tick off other astronomers.
Let's hear about that from one of the VLA tour guides talking from the
outdoor observation deck: 
  == CLIP 3 ==

   The real advantage of long wavelength is something really cool called
interferometry. Interferometry is a method to combine many small radio telescopes
so that they act as one super big one. The VLA was the first large scale system 
to use interferometry.

  Each of the 27 scopes points to the same object in the sky at the same time. 
The light is recorded by each scope and then combined using very precise
computers and timing equipment. When combined, all 27 telescopes spread out
over 36 kilometers act as one single telescope of 36 kilometers in size! That
is one big scope. Instead of building a 36 kilometer sized telescope, which
would be almost impossible, we only have to build 27 much smaller ones. 

    So what is the benefit of a scope of this size? It's in the details. We can 
really zoom in on a tiny portion of the sky allowing us to see details in objects 
that were previously hidden. Aaron once talked to a VLA expert about possibly 
using the VLA to look at a star. The expert responded "Sounds like a good idea, which 
part of the star do you want to look at?" Aaron meekly got the point, the VLA is all 
about detail.

    So the detail is nice, but what is the catch? The catch is that the sensitivity of
the instrument is still only as good as the size of one of those dishes. So we can't
see really faint objects, but what we can see, we see very very well. It's like 
using a microscope while wearing sunglasses.

    Each of the 27 dishes sits atop three pylons while observing the sky. The
pylons are connected by railroad tracks. Every few months the dishes are moved
from one pylon to another as the array is extended or contracted in that
y-shape. Scientists do this in order to change the detail seen on an object.
Sometimes you don't want alot of detail. For example, if you want to look at an
entire star you don't want to be zoomed in on a specific feature, as aaron
found out. 

   Let's listen to Aaron and Pamela describe the VLA from the observation deck.
 == CLIP 4 ==

    The VLA was built in the 1970's and 80's and funded by the National
Science Foundation. They are in the process of updating the receivers and
computer equipment from 1970's to cutting edge technology. It is one of
the most visible astronomical observatories to the public and is one of
the most popular among astronomers. It is very difficult for astronomers
to get time on the VLA. If you aren't wicked smart then you better have
some blackmail goods on a member of the VLA scheduling committee. 

    And now for something completely different. On the way to the VLA 
there is a rock formation that looks exactly like jabba the hut. Fellow 
astronomy Matthew Templeton, who got his PhD at New Mexico State 
University, alerted us to it and took a picture from the tour bus. It's 
available in the show notes on our site. Our question now is, how long 
will it take for george lucus to sue the owner of the land for 
loyalties? Take our poll at the site.

    Thanks for bearing with us through episode #2 and our first sad attempt at
a sound seeing tour. Next week we all will be back together for a regular show.
In the meantime visit slackerastronomy.org for show notes, pictures from the
visit and to leave feedback. We will soon create a second feed for our non-news
shows such as sound seeing tours, chit chat shows, monolithic monologues and
more. Stay tuned to the site for info. Thanks for listening and no you don't
get your 8 minutes back. 

    This has been travis searle for pamela and aaron. You have been listening
to slacker astronomy, a podcast for us, for you, for the voices in our heads.