3200 Phaethon: How the Still-Recovering Arecibo Telescope Saw This Asteroid Coming

On December 16, a unique telescope in Puerto Rico caught stunning images of the asteroid 3200 Phaethon as it swung by Earth. Those images suggest that the asteroid, which is classified as "potentially hazardous" because of its size and orbital trajectory, is actually a half mile larger than scientists had previously realized.

The machine behind those observations is the Arecibo Observatory Planetary Radar, which is the most powerful device of its kind. But the facility sustained minor damage in September, when Hurricane Maria ravaged Puerto Rico. The radar system only came back online earlier in December because of its high demand for power, which is still in short supply on the island.

12_29_arecibo_radar_telescope Arecibo Telescope in Puerto Rico. pedrik/Flickr

And in fact, the radar observatory took its Phaethon images with reduced power, making it less sensitive than the instrument usually would be. "It would be like if your flashlight batteries are operating at half capacity," Alessondra Springmann, a graduate research associate studying asteroids at the University of Arizona who has worked on the radar observatory at Arecibo in the past, told Newsweek.

Radar observations are unusual in astronomy because they aren't just about picking up signals from the universe around us. Just like radar systems here on Earth, scientists instead actively produce a radio signal directed at an object like the asteroid Phaethon, then wait for that signal to bounce back and be detected like any other signal.

Read more: How You Can Help Scientists Find Alien Life After Hurricane Maria

It's not just the radar's power that sets Arecibo apart. "Not many people know that it can do three different sciences," said Abel Mendez, an astrobiologist at the University of Puerto Rico Arecibo who has observed with the nearby telescope. Those three sciences are planetary science with its radar, astrophysics by passively gathering radio emissions from galaxies and stars, and atmospheric science.

Despite the damage Hurricane Maria did to the site and the ways it has slowed both Arecibo's and Puerto Rico's scientific activities, the storm brought one positive to the facility, thanks to some furry friends. Springmann is the founder of the Twitter handle @ObservatoryCats, inspired by her previous stay at Arecibo, when she found herself taking care of cats lingering around the observatory. There had always been a handful of cats around the facility, since there's a large stray cat population in Puerto Rico, and some staff members have a reputation for feeding or adopting the felines.

But when two new mother cats and six kittens were spotted in the neighborhood in the aftermath of Hurricane Maria, Springmann was inspired to coordinate a supply drive, for humans and animals alike, and was heartened by the response the campaign garnered. (Maria and her kittens have found a temporary home with one of Arecibo's astronomers, she said.)

Even beyond the hurricane recovery process, the science being done by the Arecibo telescope would be facing a period of some upheaval after the National Science Foundation, which owns and operates the facility, decided to dramatically decrease its funding of the site.

After considering a few potential paths, the NSF in November decided to focus on building partnerships with other groups to fund the site's work, and an announcement about who will be managing the facility beginning next spring is due imminently. "This has been a long wait," Mendez said, but November's decision not to shutter the facility was welcomed by the Arecibo community.

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