From GBO via Science Friday: “Searching For E.T. In An Electronic Dead Zone”


Green Bank Radio Telescope, West Virginia, USA
Green Bank Radio Telescope, West Virginia, USA


Green Bank Observatory


Science Friday on NPR

There are no filters added to this photo of the Green Bank Telescope in West Virginia. It was taken on a real-film disposable camera. Credit: Charles Bergquist

The hills of Green Bank, West Virginia are tranquil and serene. But peeking out of a shallow valley is something quite unnatural—the huge ivory dish of the Green Bank Telescope (also referred to as GBT, or the “Great Big Thing” by locals). It is the largest fully steerable radio telescope in the world, with a huge ear that can listen to 85 percent of the sky.

The massive dish is like a basin, but instead of water it collects radio signals from space. Astronomical signals can be incredibly weak (the telescope often measures signals on the order of 10-29 Watts/m2/Hertz, or milli-Janskies). In order to be able to pick those distant transmissions out of Earthly electronic noise, the observatory must sit in radio silence.

[Frank Drake is still searching for E.T.]

In this view of GBT, you can see the elaborate lattice structure on the back of the scope which distributes forces across the entire dish. Credit: Charles Bergquist

Green Bank Observatory lies within the national radio quiet zone—a 13,000 square mile region of Virginia and West Virginia that is protected from radio frequency interference. “Within that region anyone that puts a fixed license antenna has to talk to us,” Karen O’Neill, Green Bank site director, explained in a video. The observatory helps locals within the zone design special cell towers and antenna that don’t disrupt the observatory’s research.

“The energy given off by a single snowflake hitting the ground is much more powerful than the radio signal an astronomer is trying to receive,” says Michael Holstine, an engineer and business manager at Green Bank. “Any manmade transmitter, electronic device, unintentional transmitter basically overwhelms the usable signal for the observer.”

Past a certain point on the Green Bank Observatory campus, you must abandon all of your precious electronics. There can be no radio signals emitted from your cell phone, microwave heating up dinner, or digital camera—so when SciFri visited the sanctuary in February, photos had to be snapped on a low-tech, real-film disposable camera. The result were these blue-tinted, looming views of GBT. Sleet and cobalt clouds cast a gloomy grey over the usually gleaming white reflector surface of the telescope.

What happens if we detect extraterrestrial intelligence?

It’s easy to feel minuscule beneath the towering latticed structure. The GBT stands taller than the Statue of Liberty at 485 feet and can fit an entire football field in its 2.3-acre reflector. Its tremendous size is needed to collect those faint signals in space.

Peering up at GBT from the grounds of the observatory. Credit: Charles Bergquist

The telescope is used to monitor pulsars, find gravitational waves, view comets, and map diffuse clouds of gas. GBT has been involved in the search for extraterrestrial intelligence (SETI) since the 1960s, and now is currently working on the Breakthrough Listen project, an intensive search for extraterrestrial intelligence, spending hundreds of hours per year searching for potential signs of intelligent life.

See the full article here .

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Mission Statement

Green Bank Observatory enables leading edge research at radio wavelengths by offering telescope, facility and advanced instrumentation access to the astronomy community as well as to other basic and applied research communities. With radio astronomy as its foundation, the Green Bank Observatory is a world leader in advancing research, innovation, and education.


60 years ago, the trailblazers of American radio astronomy declared this facility their home, establishing the first ever National Radio Astronomy Observatory within the United States and the first ever national laboratory dedicated to open access science. Today their legacy is alive and well.