Eavesdropping on Distant Galaxies – The Green Bank Radio Telescope

The National Radio Astronomy Observatory (NRAO) at Green Bank

Despite forecasts of possible showers, Sunday morning in East Fork Campground began with low fog over the mountains and patches of blue sky above. Morning coffee was accompanied by a totally expected question, “What do you want to do today?” I still had a trip to Cass in mind. Even if we did not ride the train, it would be an interesting place to explore and shop. I could tell that idea did not “stick!” We had pretty much explored the town of Durbin. So my next suggestion was, “We could go out to the National Radio Astronomy Observatory. Green Bank is about 13 miles—not far. And we can get the real story about why our cell phones won’t work here.” That got a positive nod, and our plans were set.

The entrance to NRAO Green Bank is right on Route 92 in Green Bank, West Virginia.

The entrance to NRAO Green Bank is right on Route 92 in Green Bank, West Virginia.

The entrance to NRAO is off of Us Route 92 in the town of Green Bank. About five miles north of Green Bank, traveling south on Rt 92, we could see what is more precisely called the Green Bank Telescope or GBT. This huge structure, nearly as tall as the Washington Monument, and much larger overall, is easily visible—many locals refer to the GBT as that “Great Big Thing.” A brochure obtained from our host at the campground indicated there is a guided tour of the facility.

For visitors, everything begins in the Green Bank Science Center. Here there is the ticket counter, a theater where all tours begin, a gallery of radio telescope images and science demonstrations, and the obligatory gift shop. Tours begin every hour and cost $6.00, less for children and seniors. We arrived ten minutes before the next tour and purchased our tickets just in time to hear the announcement for the tour.

All tours begin at the Green Bank Science Center.

All tours begin at the Green Bank Science Center.

The Science Center offers activities and  displays of images, a food court, a gift shop, and views of the surrounding area, including the GBT.

The Science Center offers activities and displays of images, a food court, a gift shop, and views of the surrounding area, including the GBT.

The tour begins with a 15-minute briefing that describes the mission and facilities of the NRAO. Green Bank is only one of five major radio astronomy facilities managed by the NRAO. NRAO is federally funded through the National Science Foundation. Other sources of funding include universities, industries, and even other countries using NRAO facilities. For example, Russia is renting one of the smaller Green Bank radio telescopes for a fee of $3 million annually. (They did not say “what for.”)

The top of the horn of the Green Bank Telescope stands 485 above ground.

The top of the horn of the Green Bank Telescope stands 485 above ground.

Green Bank is in the Monogahela National Forest and protected under the United States National Radio Quiet Zone. The zone consists of a 13,000-square-mile area where fixed transmitters (e.g., radio stations, cell towers, etc.) are prohibited or restricted. No fixed radio transmitters are allowed within the area closest to the telescope. This prohibits cell towers and is why cell phones do not operate in the Quiet Zone.

To aid in limiting outside interference, the area surrounding the Green Bank observatory was at one time planted with pines with needles of a certain length to block electromagnetic interference at the wavelengths used by the observatory. Electric fences, electric blankets, faulty automobile electronics, and other radio wave emitters can be sources of interference for astronomers in Green Bank. Even flying squirrels tagged with US Fish & Wildlife Service telemetry transmitters have interfered with the operation of the GBT.

After the briefing, we boarded a tour bus for an up-close look at the radio antennas.
We were also cautioned not to use digital cameras once inside the fenced area around the radio telescopes. There is an observation deck just outside the fenced area that provides a good view of the GBT from where it is permissible to take photos. Simple film cameras are permitted inside the area and are available in the gift shop.

A scale model of the GBT on display in the Science Center.

A scale model of the GBT on display in the Science Center.

On our 30-minute bus tour, our guide pointed out a number of different antenna structures in addition to the GBT, all of which were engaged in specific radio astronomy tasks. We stopped near the GBT and to get a closer look. It looks like your typical television dish antenna, only much larger. The dish is more than a football field in diameter or 2.3 acres in area, and the top of the antenna stands some 485 feet above the ground. The total structure weighs 16 million pounds (8,000 tons).

Radio astronomy has allowed researchers to detect and characterize astronomical features—black holes, galaxies, etc., far beyond the range of the most sensitive visible light telescopes.

This is a false-color image of the Smith Cloud based on data collected from the Green Bank Telescope early in 2014 (Source: Newswise).

This is a false-color image of the Smith Cloud based on data collected from the Green Bank Telescope early in 2014 (Source: Newswise).

An example of a recent image is the Smith Cloud, a one-of-a-kind, high-velocity stellar cloud that may have all of the right stuff to form a galaxy.

A key mission of NRAO and the GBT is to promote education. Recently, a group of high school students—the Radio Astronomy Team (RATs) from Pontiac, Michigan celebrated 25 years of association with Green Bank. The team formed in 1989 when a group of students visited the observatory and decided to build a radio telescope on the roof of their school. Since its inception, more than 200 students have been part of the club. RATs continues the tradition of visiting the observatory at least once each year, driving from southeast Michigan, to learn about radio astronomy and use the NRAO’s 40 Foot Telescope – a radio telescope dedicated to educational purposes. These students often continue their involvement in astronomy far beyond graduation and many have gone on to careers in engineering and science. (Source: NRAO Website)

Back at the Science Center, we enjoyed a meal from their food service window and ate outside on a deck that offered a broad view of the facilities, including the GBT and broad meadows where we saw deer.

My Takeaway

I was somewhat puzzled by the incongruous display of a blue 1970s (?) Checker Marathon taxi cab in front of the Science Center. Still, it was cool and I took photos!

Not sure of the connection with the NRAO, but this older Checker Marathon taxicab was on display in front of the Green Bank Science Center.

Not sure of the connection with the NRAO, but this older Checker Marathon taxicab was on display in front of the Green Bank Science Center.

The science and capabilities of the radio astronomy center are really fascinating (at least to me). The tour was interesting and informative, and the size of the GBT is indeed impressive. It was well worth the price of the tour and the couple of hours it took for the tour and to explore the science center and grounds.

For more information on the National Radio Astronomy Observatory and the Green Bank Telescope, and for tour schedules, go to: https://science.nrao.edu/facilities/gbt/
For more information on the Smith Cloud see: http://newswise.com/articles/failed-dwarf-galaxy-survives-galactic-collision-thanks-to-full-dark-matter-jacket?ret=/articles/list&category=science&page=1&search%5Bstatus%5D=3&search%5Bsort%5D=date+desc&search%5Bsection%5D=20&search%5Bhas_multimedia%5D=

Story and photographs (except where noted): © Jeff Richmond

Contents

Eavesdropping on Distant Galaxies – The Green Bank Radio Telescope Several people in the campground and in town asked if we had seen the “Great Big Thing” and learned why we could not use our cell phones. So Sunday, we decided to visit the National Radio Astronomy Observatory, only 13 miles from Durbin, West Virginia,

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3 Responses to Eavesdropping on Distant Galaxies – The Green Bank Radio Telescope

  1. Pingback: Renaissance Musings Table of Contents | Renaissance Musings

  2. Keith Johnson says:

    The taxicab may have been obtained simply because it was a diesel. When I was a summer student at Green Bank years ago, the cars were all diesels, because gasoline cars’ ignition systems tended to produce too much radio noise. They are strict about their “no radio interference” policy!

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