This Two-Acre Telescope Powers Science's Search for Dark Energy

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For lack of a better word, the Robert C. Byrd Green Bank Telescope (GBT) is ginorgantic. (That's the evolved form of ginormous). At 17 million pounds, it is both the world's largest, most technologically-advanced single-dish radio telescope—and the single biggest land-based movable structure on the planet.

The telescope was dedicated in 2000 to honor the late Senator Robert C. Byrd (D - WV). It's located at the National Radio Astronomy Observatory (NRAO) site in Green Bank, West Virginia, within the National Radio Quiet Zone, which protects it from signal interference.

The GBT's dish measures 100 by 110 meters—equal surface area as an English football pitch—and is composed of more than 2,000 aluminum surface panels. These ride over 2,200 actuators designed to help correct for gravity distortions. The reflector is offset, like a DirectTV dish, which gives the aperture a clearer view of the sky while minimizing diffraction. The GBT is fully steerable and can focus anywhere within 85 percent of the visible sky.


The Green Bank Telescope operates an average of 6,500 hours every year, roughly 2,500 of which are dedicated to high frequency science. Its sensitive dish probes the nature of pulsars, sniffs out atoms and molecules in deep space, and studies the effects of magnetic fields. It searches for Dark Energy, and even looks around for extraterrestrial life. Astronomers from around the world vie to spend some time with the machine. [NRAO - Wikipedia - 100 Hours of Astronomy - Image: NRAO/AUI]