“Arecibo 2.0” For nearly 60 years, the world’s most iconic radio telescope consisted of a 305-meter dish embedded in a natural sinkhole in Puerto Rico with a 900-ton receiver suspended from above. But on December 1, 2020, the receiver fell to the ground after its support cables snapped, destroying the antenna.
The US National Science Foundation, which runs the facility, has long been aware of the aging observatory’s shortcomings. In fact, she had closed the observatory and announced plans to demolish it. But it is also said that the huge cost of replacing it is too much for an already overstretched budget. There would be no new telescope in Arecibo.
It looked like the end of an international icon – the observatory has appeared in numerous films, such as Species, Contact and most famously the James Bond film Goldeneye.
Dash for plate
But now an ordinary team of staff in Arecibo, along with telescope users, have other ideas. They say the collapse left a significant scientific void for the researchers who used it. To solve this, they collaborated on a new design that would be more capable and more cost-effective than anything previously conceived. “We show that it outperforms all other radar and single antennas,” said Anish Roshi of the University of Central Florida and colleagues, who published their design.
One possibility for a future Arecibo observatory is a dish to replace the old 305-meter design.
But Roshi and company say a more cost-effective approach is to create a steerable structure supporting 102 smaller dishes, each 13 meters in diameter.
Together, these dishes will have a collection area equivalent to a dish with a diameter of 130 meters. The team calls their device the Next Generation Arecibo Telescope-130, or NGAT-130, and has already begun collaborating on its design.
One of the key challenges is to understand how the structure will deform as it moves. Large radio dishes are known to change shape as they spin due to the force of gravity. This is relatively easy to fix, provided it doesn’t happen during monitoring.
So an important goal is to find out how fast the new structure will deform, and whether this is slow enough to allow the kind of observations astronomers want to make. To that end, Roshi and colleagues suggest creating a detailed computer model of the machine to see how it behaves. Next, they must design electronics that will compensate for any aiming or focusing deviations caused by the deformation.
Another question is how the multitude of small dishes will interact electromagnetically with each other. This will also require detailed simulation. “We plan to take on these tasks in the coming years and encourage collaboration for these goals from those who are interested,” the team said.
Although this device will have a diameter of up to 175 meters, it will be scientifically competitive with a single 300-meter antenna. And it will be highly customizable.
One application will be to map radio emissions from hydrogen atoms and molecules such as carbon monoxide and ammonia throughout the galaxy and beyond. Another is to study the Sun by observing radio emissions from coronal mass ejections. It will also be able to study Earth’s ionosphere and even spot Earth-threatening asteroids.
All this makes it crucial for radio astronomers, but also for planetary scientists and atmospheric scientists. In fact, the previous Arecibo Observatory served all three groups, which is why it was so unique and useful.
But the key question is whether the National Science Foundation or someone else will pay for the new observatory. “Our preliminary study shows that a ~146 m NGAT with one hundred and two 13 m diameter dishes can be developed economically,” say Roshi and company.
There will have to be considerable lobbying. And if all else fails, there’s always Hollywood. Maybe it’s time for Tinseltown to repay its debt to the astronomy community while contributing an amazing new set for future movies.
Ref: The Next Generation Arecibo Telescope: Preliminary Survey: arxiv.org/abs/2305.07780