The death of the Arecibo Telescope
Normally I don't comment on current events, but I thought I'd make a somewhat sad comment here. The Arecibo telescope, a 380m reflector dish located on the island of Puerto Rico in the Caribbean sea, has been destroyed.
The dish of the telescope was built in a natural depression between hills. This not only made the construction a little easier, it also protected it from hurricanes (which were, of course, the eventual downfall - literally - of the facility).
The dish itself was a spherical shape, rather than a parabola. This meant that the telescope could be aimed in a range of directions rather than being pointed at a fixed altitude and azimuth. To allow the telescope to be pointed, the array of receivers had to be above the dish and also had to be movable.
After a few proposals for towers emerging from the centre of the dish, the designers settled on a receiver which hung over the dish on cables.
The receiver itself moved under an inverted arch. This arch was suspended from a circular track that was in turn hung from a triangular frame that was suspended from the cables that went to three towers on surrounding hills. It was complex, and the whole gondola weighed about 900 tonnes.
Over its life, the telescope provided critical observations related to the solar system (in particular related to Mercury as well as providing radar images of asteroids). In addition, the telescope gathered data on comets, exoplanets and pulsars, neutron stars and galaxies.
Notably, the dish not only played a part in the search of extraterrestrial intelligence, it was also the source of the Arecibo Message, which was transmitted outwards.
I won't bother you with details of the telescope's destruction, suffice to say a cable failed following a hurricane and the whole gondola collapsed onto the dish a few days later.
The telescope had been recently surpassed in size by the Chinese Tianyan facility. Scientific study by humans will continue.
Image: Mariordo via Wikipedia