Green Bank - Part 2
For a second time this school year, our Glenville
State College class took a trip to the National Radio Astronomy
Observatory. This week I will tell you about the type of work I did on
the 40-ft. telescope. We were given two celestial objects, one known and
one unknown. The job of my group was to figure out what the unknown
object was and how the known object compared to the unknown.
The known object was Cassiopeia A, a supernova
remnant located in the constellation Cassiopeia. A supernova is a
stellar (star) explosion, which throws a shock wave of most of the
star’s material out into space. The shock wave sweeps up an expanding
shell of gas and dust called a supernova remnant. Even though it is the
brightest radio source in the sky, Cas A cannot easily be seen
optically. At around 11 a.m., the group collected data, using the 40-ft.
radio telescope, to compare to our unknown.
The unknown object was visible around 6:15 a.m. To
get to the 40-ft telescope about a mile away, we are required to drive a
diesel engine. Spark plugs of gas-powered vehicles can be picked up by
the largest telescope and skew data astronomers are trying to collect.
So at 6 a.m., the group went outside to find the diesel Expedition and
drive to the telescope. When we got outside, we did not see the
Expedition. If you do not “look” at your object at the specified time,
there is no way to see it again until the same time the next day.
Since we had limited days on our trip, we decided
to hike the two-mile round trip to the telescope. We made it on time and
collected the necessary data. After walking back to the bunk house, we
find that there was a diesel vehicle waiting for us the whole time. We
did not know that there were two vehicles. I had a good laugh at myself
and thought “at least I got some exercise in today.”
We compared our data from the known and unknown
object for an extended time. After several failed solutions, we found a
star atlas and tracked the objects we “looked” at across it. We found
that our unknown object had the highest intensity when it crossed the
galactic equator, and Cas A had just crossed the galactic equator when
we viewed it. This seemed like very important information. The galactic
equator is similar to the equator on Earth. It’s an imaginary line that
divides the Milky Way Galaxy in half. The equator is aligned to the
galactic plane, which is the plane in which the majority of a
disk-shaped galaxy’s mass is found.
After comparing our data, we decided the unknown
object was the galactic plane, and our known object related to it by
crossing over it. The intensity of our objects changed relative to the
position of the galactic plane. This was an excellent trip that took a
lot of time and brain power to figure out our unknown.
If you enjoy science or just want to see something
interesting, plan a trip to Green Bank to take advantage of all they
have to offer. Hands-on experiences and tours can make science come
alive. The center is open Thursday-Monday, 10 a.m. to 5 p.m., until
Memorial Day, and 8:30 a.m. to 7 p.m., Memorial Day to Labor Day.