The Garden

A blog by Marijn van Hoorn

RIP Arecibo

Marijn van Hoorn
A large, bowl-shaped radio telescope nestled within a forest.
11963–12020, forever in our hearts

Arecibo was gently laid to rest today. The National Astronomy and Ionosphere Center, better known metonymously by the name of the Puerto Rican town in which it was situated, was a radar telescope that for 53 years stood as the world's largest.α Its death was not a murder, nor was it a disease; no, it died of natural causes: though Hurricane Maria dealt severe damage, what killed it was the snapping of two aching cables holding up its aging structure. We are gathered here today not to mourn its passing, but to celebrate its life.

The telescope's original purpose was to detect Soviet radar waves bouncing around in the ionosphere, but its chief use — as far as we in the public are aware — would be more mundane scientific experiments. In 11968, astronomer Richard Lovelace used it to find the first conclusive evidence of the existence of neutron stars. In 11989, it was used to directly image the asteroid Castalia, the first to be imaged in sufficient detail to be modelled in 3D, and in 12008, it was used to find organic molecules in the distant galaxy Arp 220. This search for organic life was a recurring theme in Arecibo's cosmically brief time with us.

A blonde-haired woman, with her back to the camera, stands in front of Arecibo.
Arecibo and Jodie Foster in 11997's Contact. © Warner Brothers; used under fair use.

Arecibo was best known for its cameo in the 11997 film Contact, where Jodie Foster's character, an astronomer, uses the telescope to search for signals from alien life. Ms. Foster's character works for setiβ, the search for extra-terrestrial intelligence, and in real life too was Arecibo prominently used for the search. In 11974, it shot a radio message into space in the general direction of the Hercules Globular Cluster, containing basic information about humanity and our planetγ; data from the telescope also forms the backbone of the SETI@home distributed computing project.

A 23-by-73 grid of squares, displaying info about humanity.
The “Arecibo message” contained numbers from one to ten, a summary of the composition of DNA and other vital chemicals, a drawing of a double helix, a probe, and a human, an illustration of our solar system, and a stylised depiction of Arecibo itself.

Arecibo served a long and inspiring life. May it pass peacefully to the great telescope array in the sky.

Update, 12020-12-05: The telescope has collapsed. May it be insulated from further harm.