Qualla: Green Bank Telescope

Green Bank Telescope: Introduction

Sun, 31 May 2026 00:00:00 GMT

Photo credit Cyberbaud, CC BY-SA 3.0. On the night of November 15, 1988, a single steel gusset plate inside the framework of the world's largest moving telescope failed, and the 300-foot dish at Green Bank, West Virginia collapsed in the middle of the night. Nobody was hurt. The next morning, astronomers stood looking at a twisted heap of metal where, the day before, the most sensitive radio antenna on Earth had been listening to the cosmos. Senator Robert C. Byrd, who represented West Virginia in Washington, pushed funding through Congress for a replacement. The result, completed in 2001, is bigger - 100 meters by 110 meters, 16 million pounds, 485 feet tall, sixty percent taller than the Statue of Liberty. The locals call it the Great Big Thing.

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Image: Cyberbaud | CC BY-SA 3.0

Green Bank Telescope: What the Telescope Sees

Sun, 31 May 2026 00:00:00 GMT

Photo credit Z22, CC BY-SA 4.0. The Robert C. Byrd Green Bank Telescope listens at radio wavelengths - frequencies between 290 megahertz and 115 gigahertz, from VHF up into the millimeter-wave band. Its 100-meter-diameter dish has a collecting area of 2.3 acres - more than two football fields. The dish can be s...

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Image: Z22 | CC BY-SA 4.0

Green Bank Telescope: The Active Surface

Sun, 31 May 2026 00:00:00 GMT

Photo credit Geremia at en.wikipedia, Public domain. The dish is not a single rigid piece. It is made of 2,004 individual aluminum panels, each polished to a surface accuracy better than 50 micrometers RMS - about half the thickness of a human hair. Underneath each panel, 2,209 actuators - small computer-controlled motors - constan...

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Image: Geremia at en.wikipedia | Public domain

Green Bank Telescope: What the GBT Has Found

Sun, 31 May 2026 00:00:00 GMT

Photo credit Geremia at English Wikipedia, Public domain. The GBT began regular science operations in 2001 and has accumulated a remarkable discovery list. In 2002, astronomers detected three new millisecond pulsars in the globular cluster Messier 62. In 2006, the telescope mapped a coil-shaped magnetic field in the Orion molecular clou...

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Image: Geremia at English Wikipedia | Public domain

Green Bank Telescope: Listening for Civilizations

Sun, 31 May 2026 00:00:00 GMT

Photo credit Geremia at en.wikipedia, Public domain. The GBT is one of the principal facilities of the Breakthrough Listen project, a 10-year, $100 million SETI effort funded by Russian billionaire Yuri Milner since 2015. Breakthrough Listen uses the GBT to scan nearby stars, galaxies, and other targets for any radio signals that m...

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Image: Geremia at en.wikipedia | Public domain

Green Bank Telescope: Saved from Defunding

Sun, 31 May 2026 00:00:00 GMT

Photo credit Jarek Tuszyński, CC BY-SA 3.0. The GBT nearly closed. In August 2012, an NSF portfolio review committee chaired by Daniel Eisenstein of Harvard recommended defunding the Green Bank Telescope over a five-year period as part of a broader reallocation of astronomy budgets. The recommendation set off a years-long ...

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Image: Jarek Tuszyński | CC BY-SA 3.0