Dr. Li Di, who once worked at Cornell-NAIC, the operator of Arecibo, and is now the chief scientist of FAST, wrote a tribute to the Arecibo telescope in memory of its glorious days and its world-view-altering discoveries.

“She is gone.”

Jonathan Friedman, a long time Arecibo staffer, wrote these words on his social media page on the morning of December 1 (Puerto Rico time). For radio astronomers who have spent a substantial part of their careers — often the best part — on the project, not many more words could have been uttered. Now two weeks have passed, I am still getting a steady stream of emails from my colleagues about Arecibo’s demise, its future, and mostly just sharing the shock they feel. Apparently, we are all still in the first stage of grief.

Dr. Li Di

The Arecibo telescope project began following a presentation by Dr. William Gordon of Cornell University at the URSI meeting in 1958. The project was granted funding the same year and was finished in November of 1963. It was the top radio antenna in the world in terms of collecting area for an astonishing 53 years, until the first light of the Five-hundred-meter Aperture Spherical radio Telescope (FAST) on September 19, 2016. Rarely, if not ever in the modern era, has a scientific instrument stayed at the cutting edge for more than half a century. The audacious vision of Dr. Gordon and continuous innovation of the staff and users of the observatory made those years full of glorious finds: the first measurements of Mercury’s spin, the discovery of the first double neutron star (Nobel prize in 1993) and the first millisecond pulsar, the largest sample by far of gaseous galaxies, the first repeating fast radio bursts, and many more.

I started my graduate years in the middle of the 1990s in Cornell University, particularly in the National Astronomy and Ionosphere Center, which operated Arecibo. Although most of my time spent at the observatory involved struggling with data reduction, the science-engineering wonder that is the Arecibo telescope never failed to leave me in awe. I owe to her my early career and, later on, an opportunity to work on FAST. As one of many hardcore radio astronomers, I present these few words as a tribute as well as a sincere promise:

“We will carry on.”

By Dr. Li Di, Chief Scientist at the FAST Operation and Development Center