When the 60-year-old Arecibo Observatory collapsed in 2020, the crash didn’t just take down one of the world's preeminent radio telescopes, it also dealt a massive blow to the future of radio astronomy. Arecibo may have been old, but it also had unique capabilities that made it ideal for studying things like gravitational waves, as well as mapping the surfaces of asteroids as they slip by Earth.
Now, radio astronomers around the world are debating what comes next. Should Arecibo be rebuilt anew? If so, where would the money come from?
Those questions don’t have easy answers, but the discussions are happening. Preliminary plans for another revolutionary radio telescope continue to inch forward every day. And interestingly, these talks have led NASA to reconsider a bold idea that was first dreamed up a half-century ago: building a behemoth radio telescope on the farside of the Moon.
Arecibo’s design benefited from being built in a natural sinkhole in Puerto Rico. Similarly, astronomers could use existing lunar craters to build a radio telescope on the Moon for (relatively) cheap; impacting space rocks have already done the digging for them. And unlike Earth, the Moon has no weather or wind to accelerate erosion. Even the pull of gravity itself is weaker on the lunar surface.
