NANOGrav using GBT to study Einstein’s prediction

Suzanne Stewart
Staff Writer
Theoretical physicist Albert Einstein passed away near the time that the Green Bank Observatory was coming in to being, yet, today, his theories and predictions are connected in many ways to the Green Bank Telescope – the world’s largest, fully steerable radio telescope.

The North American Nanohertz Observatory for Gravitational Waves, or NANOGrav, is using the GBT, as well as the Arecibo Telescope in Puerto Rico, to search for gravitational waves.

“NANOGrav is searching for gravitational waves – tiny ripples in space predicted by Einstein – using pulsars,” Green Bank Observatory assistant scientist Ryan Lynch said. “Pulsars can be thought of as interstellar clocks and gravitational waves will cause a very specific change in the way these clocks ‘tick.’ We hope to detect these changes using the GBT and the Arecibo Telescope.”

The change in the clocks is very small, Lynch added – only about 0.00000001 seconds. With such a small change, sensitive equipment is imperative in detecting the waves.

“The reason this is all interesting is because for almost all of human history, we have only been able to learn about the distant universe using light,” Lynch said. “But studying the universe using gravitational waves is like suddenly having a whole new sense. We’ll be able to learn about things, like black holes and cosmic strings, that we could not otherwise detect. Not only that, but we hope to learn more about gravity itself, which is still a mysterious fundamental force of nature in many ways.” 

While the Arecibo Telescope is much larger than the GBT, it is stationary and cannot observe as many pulsars as the GBT. Using both instruments in the search will provide a wider range of pulsars to observe.

“About half of NANO-Grav’s sensitivity comes from the GBT and about half from the Arecibo Telescope,” Lynch said. “This is true even though Arecibo is much larger because the GBT can see more pulsars, thanks to its fully steerable design. NANOGrav currently pays for five hundred hours per year of dedicated time on the GBT.”

NANOGrav is a scientific collaboration between astronomers, physicists and engineers at two dozen institutions throughout the United States and Canada, Lynch said. Of the group, there are 40 on the professor/senior researcher level, 22 postdoctoral scholars and several graduate and undergraduate students. A large number of students and faculty from West Virginia University are participating in the search, as well.

To learn more about the NANOGrav search, visit

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