by David Kindy/Smithsonianmag.com
Amateur astronomer Kai Ly is on a roll. They rediscovered four “lost” Jupiter moons last year. Now, Ly has located a previously unknown moon orbiting the biggest planet in our solar system.
“I’m proud to say that this is the first planetary moon discovered by an amateur astronomer!” they posted June 30 in a message at the Minor Planet Mailing List (MPML), an online community of the world’s leading amateur astronomers.
Using old telescope images, Ly was able spot the unnamed satellite orbiting Jupiter, which is nearly 385 million miles from Earth. The distant planet has at least 79 moons—now 80—some so small and indistinct they can only be detected by a large telescope one month of the year.
To locate this satellite, Ly scoured images taken by the Canada-France-Hawaii Telescope in 2003, reports Jeff Hecht of Sky & Telescope. This dataset was the same one they used to find the four “lost” moons last year. The barely discernable satellites disappeared from view until Ly was able replot their trajectories and identify them on the images.