When was construction on the Arecibo Observatory completed? 1921 1963 1980 2001 None Which celestial object did the Arecibo Observatory discover in 1967, providing the first direct evidence of a neutron star? Pulsar Quasar Black hole Exoplanet None What significant scientific concept did the Arecibo Observatory's discovery of exoplanets in the 1990s contribute to? Plate tectonics Quantum mechanics Big Bang theory Planetary habitability None In what year did the Arecibo Observatory receive a UNESCO World Heritage Site designation? 1974 1983 2004 2020 None Which famous scientist used the Arecibo Observatory in 1974 to broadcast a message aimed at potential extraterrestrial civilizations? Carl Sagan Stephen Hawking Albert Einstein Isaac Newton None Time's up
